Clinical and Applied Thrombosis/Hemostasis recent issues

Anticoagulant Therapy for Acute Venous Thromboembolism: What We Think We Know and What the Data Show for the Timing of Recurrent Events

Stein, P. D., Hull, R. D., Matta, F., Yaekoub, A. Y. — Wed, 18 Nov 2009 21:33:27 PST

Although heparin is administered to prevent early recurrences of venous thromboembolism (VTE) by preventing new thrombi, allowing old thrombi to attach to venous walls, and covering warfarin until it is therapeutic, heparin largely prevents late recurrences of VTE (after 5 days). The dreaded early occurrence of pulmonary embolism (PE) (on or before day 5) while waiting for the vitamin K antagonist to become antithrombotic did not occur among patients with deep venous thrombosis (DVT), who received acencoumarol alone. Fewer total recurrences resulted if a therapeutic level of heparin was reached within the first 24 hours of treatment of DVT. Fewer total recurrences also resulted if heparin was consistently maintained at therapeutic levels. A recurrent VTE within 5 days, however, occurred infrequently in those in whom heparin was not given, or therapeutic levels were delayed or not maintained. The incidence of early recurrent VTE was not lower in those who received adequate heparin than in those who did not, although the data are sparse. The true incidence of early recurrent VTE is uncertain due to the broad confidence intervals for the observed frequency of early recurrent events. Later recurrences are the norm and may be reduced by early treatment with adequate heparin.

Rivaroxaban in Orthopedic Surgery -- A Change of Paradigm?

Schulman, S. — Wed, 18 Nov 2009 21:33:27 PST

Two selective, orally available anticoagulant agents, although with different targets in the coagulation cascade, have recently been approved in many countries on the indication of prophylaxis against venous thromboembolism (VTE) after major joint arthroplasty. This review discusses mainly the antifactor Xa drug, rivaroxaban, with a focus on the orthopedic trials. Pharmacokinetic characteristics and other clinical development programs with rivaroxaban are briefly reviewed. Although the aim of this article is not to review the direct thrombin inhibitor, dabigatran etexilate, some comparisons are made. For clinical results, these are obviously indirect and conclusions must be drawn with caution until head-to-head comparisons are performed. Whether the introduction of rivaroxaban is a change of paradigm will ultimately be decided in the eyes and mind of the beholder.

Unexplained Discrepancies in the Activity--Antigen Ratio in Congenital FX Deficiencies With Defects in the Catalytic Domain

Wed, 18 Nov 2009 21:33:27 PST

Studies on molecular biology have considerably enhanced our understanding of congenital coagulation disorders but have failed so far to supply tools for an adequate classification of defects. In fact, mutations in the same domain may give rise to different phenotypes. Conversely, mutations in different domains, controlled by different exons, may cause similar patterns. The 37 kindreds with congenital factor X (FX) deficiency, known to have a defect in the catalytic domain, have been evaluated in an attempt to investigate the genotype—phenotype relation. Discrepant results were obtained because about half kindreds showed a type I pattern, namely a concomitant decrease in FX activity and antigen. The other half showed a type II pattern, namely a decrease in FX activity with a normal or near normal FX antigen. In a few instances, the allocation of the kindred either to type I or to type II defect could not be reached, due to the lack of information about the antigen.

The comparison of the kindreds in which the same mutation has been discovered by different investigations is not always possible also for lack of information.

The study analyzes the need to have a multipronged approach to the study of congenital FX deficiency. The indication of a mutation in a given domain does not provide clear information about the phenotype.

Effect of Recombinant Activated Factor VII in Critical Bleeding: Clinical Experience of a Single Center

Wed, 18 Nov 2009 21:33:27 PST

Recombinant activated factor VII (rFVIIa) has been successfully used ‘‘off-label’’ in patients with refractory life-threatening hemorrhage. Intravenous rFVIIa was given to 31 patients unresponsive to standard therapy with blood products and surgical reexploration, who were bleeding due to trauma, surgery, organ transplantation, liver cirrhosis, ruptured uterus. We recorded their coagulation and hematologic profiles, acid-base balance, blood loss, number of red blood cells (RBC), plasma and platelet transfusions, complications, and survival. rFVIIa (mean dose 132.2 ± 56.3 µg/kg) effectively contained the hemorrhage in 28/31 (90.3%) cases, with a mean reduction in blood loss from 12.4 ± 10.2 to 2.7 ± 2.2 L (P < .0001). The need for RBC, platelet, and plasma transfusion decreased significantly after rFVIIa, with a consequent significant improvement in clotting of test hematocrit, pH, and bicarbonates. Four patients had adverse events potentially related to rFVIIa. The survival rates after 1 and 30 days were 48.4% and 29.1%, respectively.

Use of Heparin in Women With Early and Late Miscarriages With and Without Thrombophilia

Monien, S., Kadecki, O., Baumgarten, S., Salama, A., Dorner, T., Kiesewetter, H. — Wed, 18 Nov 2009 21:33:27 PST

Objective: In women with a history of recurrent miscarriage, the risk of miscarriage in a subsequent pregnancy is about 30% to 40%. In patients with thrombophilia, the risk is even higher. Placental thrombosis has been found in women with unexplained recurrent miscarriage independent of thrombophilia. In addition, proinflammatory changes, for example, altered Th1 to Th2 cytokine ratio and complement activation, have been repeatedly demonstrated in these women. Because of the fact that heparin has both anticoagulative and anti-inflammatory effects, the current study evaluated the efficacy of low-molecular-weight heparin (LMWH) in unexplained abortions. Study Design: A total of 164 women with unexplained early and late miscarriages presented in our hemostaseological clinic for thrombophilia screening. For these 164 women, 82 subsequent pregnancies in 79 patients were treated with subcutaneous LMWH independently of thrombophilia. In 54/82 unselected pregnancies, 100 mg aspirin was administered in addition to LMWH. Two patients were excluded due to termination of pregnancy. Results: Overall, 83.8% (67/80) of pregnancies resulted in live births. In 22/79 women (27.8%), thrombophilia markers were positive. Most noteworthy, patients with thrombophilia markers had live births at a similar frequency as patients without those parameters. No severe side effects of LMWH were seen. Conclusions: Our data support the notion that LMWH is efficacious in patients with recurrent abortions and thrombophilia. We demonstrated the same effect of LMWH in women with unexplained abortions without thrombophilia. The potential mechanism of action of LMWH in early and late abortions warrants further study.

European Community and US-FDA Approval of Recombinant Human Antithrombin Produced in Genetically Altered Goats

Adiguzel, C., Iqbal, O., Demir, M., Fareed, J. — Wed, 18 Nov 2009 21:33:27 PST

Thrombin and factor Xa play a central role in thrombogenesis in both medical and surgical patients. Antithrombin (AT) is the key inhibitor, which controls the action of these enzymes in hypercoagulable states. The AT concentrates prepared from human blood have been used to treat patients with thrombotic disorders and heparin resistance. The AT concentrates are prepared from pooled human plasma and beside limited supply, suffer from viral and other biological contaminants. The availability of recombinant human AT (rhAT) obtained from genetically engineered goats provide a biologically equivalent product that can be used in practically all indications where human AT is indicated including heparin resistance. Moreover, because of its high affinity to heparin and related drugs, recombinant AT can also be developed in further indications. On review of the preclinical and clinical data on the safety and efficacy, the European Union and U.S. Food and Drug Administration (US-FDA) have recently approved the use of rhAT in specified clinical indications.

Utility of the PFA-100 Instrument and the Novel Multiplate Analyzer for the Assessment of Aspirin and Clopidogrel Effects on Platelet Function in Patients With Cardiovascular Disease

Mueller, T., Dieplinger, B., Poelz, W., Haltmayer, M. — Wed, 18 Nov 2009 21:33:27 PST

This study evaluated the utility of the PFA-100 and the Multiplate analyzer for the assessment of aspirin and clopidogrel effects on platelet function in patients with cardiovascular disease. Platelet function was determined with the PFA-100 using collagen+epinephrine (CEPI) and collagen+adenosine-5’-diphosphate (CADP) cartridges, and with whole blood impedance aggregometry using the Multiplate ASPI and ADP+PG tests (aggregation triggered with arachidonic acid and ADP+ prostaglandin E1, respectively). Four study groups were identified from the 154 patients enrolled: patients without antiplatelet therapy, patients with 100 mg aspirin daily but without clopidogrel treatment, patients with 75 mg clopidogrel daily but without aspirin treatment, and patients with both 100 mg aspirin daily plus 75 mg clopidogrel daily. It was found that the PFA-100 instrument is useful for detection of aspirin but not for detection of a clopidogrel effect, while the Multiplate analyzer is useful for specific detection of both aspirin and clopidogrel effects on platelet function.

The Impact of Prothrombotic Mutations on Factor Consumption in Adult Patients with Severe Hemophilia

Ar, M. C., Baykara, O., Buyru, A. N., Baslar, Z. — Wed, 18 Nov 2009 21:33:27 PST

About 10% of patients with severe hemophilia exhibit a milder clinical phenotype with less frequent bleeds. Among many other factors, coinheritance of prothrombotic mutations have been proposed to act as modulators of clinical severity in severe hemophilia. We conducted a study to evaluate the impact of 3 prothrombotic mutations (factor V Leiden, factor II, and methylenetetrahydrofolate reductase mutations) on clinical phenotype of patients with severe hemophilia in our institution. For this purpose we compared the average annual factor concentrate consumption between carriers and noncarriers of prothrombotic mutations. A total of 38 hemophilia A and B patients with factor levels less than 1 were recruited between October 2006 and October 2007. Prothrombotic mutations were detected in venous blood using polymerase chain reaction amplification technique. Eighteen patients (47%) carried no prothrombotic mutations. The remaining 20 patients (53%) were found to be carriers of either 1 or 2 mutations. Median age in both carrier and the non-carrier groups was 27 years. None of the patients in either group gave a history of thromboembolic event. Median annual factor concentrate consumptions in carriers and noncarriers were 610 ± 530 units/kg and 770 ± 670 units/kg, respectively (P = .203). Our results demonstrated no significant difference in annual factor concentrate consumption between carriers and noncarriers of prothrombotic mutations. Considering that average annual factor consumption is a surrogate indicator of clinical phenotype, we concluded that coinheritance of prothrombotic mutations was not associated with occurrence of different clinical phenotypes in severe hemophilia.

D-Dimers, Thrombin--Antithrombin Complexes, and Risk Factors for Thromboembolism in Hospitalized Patient

Pottier, P., Fouassier, M., Hardouin, J.-B., Volteau, C., Planchon, B. — Wed, 18 Nov 2009 21:33:27 PST

Introduction There is lack of data about the correlation between hemostatic markers and the clinical and biological risk factors (RFs) for venous thromboembolism (VTE) in medical inpatients without suspicion of acute VTE. Material and methods To evaluate the coagulation activation status in patients with current known RFs for VTE, the authors measured 2 markers of hypercoagulability, thrombin antithrombin (TAT) complexes and D-dimers, at day 1 in 165 patients hospitalized in internal medicine wards without suspected acute VTE. All known RFs for VTE were systematically assessed at admission and classified in a chronological way as permanent or transient. Results Surprisingly, TAT values followed a multimodal distribution. D-dimers showed a normal distribution after a logarithmic transformation (P = .34, Shapiro—Wilk test). Interestingly, a significant progression in D-dimer levels was found according to the chronological classification of RFs. D-dimer variations on multivariate analysis (not applicable for TAT because of the multimodal distribution) correlated independently with a recent inability to walk and an increase in C reactive protein level more than 10 mg/L. Conclusions (a) this study is the first to describe the variations of hypercoagulability markers according to a systematic screening of RFs for VTE in inpatients without suspicion of acute VTE, (b) TAT appeared as a less relevant marker of hypercoagulability than D-dimers in internal medicine inpatients, (d) the chronological classification of RFs identified clearly groups at risk for the prethrombotic state, and (d) an increased hypercoagulability state was demonstrated in patients with an association between a recent immobility and increased inflammatory markers.

Venous Thromboembolism in Patients Hospitalized With Thyroid Dysfunction

Wed, 18 Nov 2009 21:33:27 PST

The objective of this investigation is to explore a possible role of thyroid dysfunction in venous thromboembolism (VTE). The number of patients discharged from short-stay nonfederal hospitals in the United States, from 1979 to 2005, with a diagnostic code for hypothyroidism or hyperthyroidism, pulmonary embolism (PE), and deep venous thrombosis (DVT) was obtained from the National Hospital Discharge Survey (NHDS). Among 19 519 000 hospitalized patients discharged with a diagnosis of hypothyroidism from 1979 to 2005, 119 000 (0.61%) had PE. Among patients with no thyroid dysfunction, PE was diagnosed in 3 372 000 of 908 805 000 patients (0.37%; relative risk = 1.64, 95% CI 1.63-1.65). Deep venous thrombosis was diagnosed in 1.36% of hypothyroid patients and in 0.84% of patients with no thyroid dysfunction (relative risk = 1.62, 95% CI 1.61-1.62). The relative risk of PE in patients with hypothyroidism was highest in patients <40 years of age (relative risk = 3.99) and the relative risk of DVT was also highest in patients <40 years (relative risk = 2.25). Hyperthyroidism was not associated with an increased risk of VTE (relative risk = 0.98, 95% CI = 0.96-1.01). In conclusion, an increased risk of PE, DVT, and VTE was shown in patients with hypothyroidism but not hyperthyroidism. Antithrombotic prophylaxis in patients with severe hypothyroidism, however, should be viewed with caution because of a possible hyperfibrinolytic state in such patients.

Relative Purity of Different Bovine Thrombin Preparations

Zhu, H., Hoppensteadt, D., Iqbal, O., Litinas, E., Adiguzel, C., Fareed, J. — Wed, 18 Nov 2009 21:33:27 PST

The aim of this study was to compare the relative purity of bovine crude thrombin and its purified forms, namely, thrombin 4A and thrombin 4B (the products of King Pharma, Middleton, Wisconsin) by virtue of the detection of bovine prothrombin-related antigens in these preparations. Bovine prothrombin was administered intravenously to 3 individual rabbits on days 0, 21, 42, 91, 123, and 151 using standard immunologic method. Blood was drawn from each rabbit on days 30, 50, 105, 137, and 165, and the pooled antisera from 3 rabbits were purified to isolate immunoglobulin G (IgG) using protein G affinity columns. Using Western blotting method, serially diluted bovine crude thrombin, thrombin 4A, and 4B preparations were probed using the prothrombin IgGs obtained from each time point to explore prothrombin-related antigens in these preparations. The results revealed that compared with the prothrombin IgG collected on day 30, the IgGs collected on days 50 to 165 showed a time-dependent increase in their ability to detect the prothrombin-related antigens in 3 bovine thrombin preparations studied. The lowest amount of crude thrombin, thrombin 4A, and 4B preparations that prothrombin IgG could detect was 0.125, 10, and 20 U, respectively. The rank order of the number of immunoreactive bands detectable in 3 bovine thrombin preparations probed by the prothrombin IgGs collected from any given time point was always the same: crude thrombin > thrombin 4A > thrombin 4B. The results indicate that thrombin 4B preparation contains the least amount of antigens detectable by prothrombin IgG, suggesting that relatively thrombin 4B represents the most purified thrombin preparation among the 3 thrombin preparations studied.

Effects of rhG-CSF Plus Dexamethasone on Hemostatic Parameters in Healthy Granulocyte Donors: Role of u-PA and Nitric Oxide

Wed, 18 Nov 2009 21:33:27 PST

Granulocyte colony-stimulating factor (G-CSF) is widely used to reduce the risk of infection resulting from neutropenias and to mobilize and collect CD34+ hematopoetic progenitor cells (HPCs) for autologous and allogenic transplantation. The safety of recombinant human G-CSF (rhG-CSF) administration in healthy donors has been investigated in several studies. However, there are limited cumulative data about the effects of rhG-CSF on hemostasis. Hemostatic parameters, including urokinase-type plasminogen activator antigen (u-PA:Ag) and nitric oxide in 17 healthy granulocyte apheresis donors who donated for neutropenic patients were evaluated. rhG-CSF (single dose, 10 µg/kg subcutaneously) and dexamethasone (8 mg, single dose oral) were given to donors 12 hours before granulocyte apheresis. Two blood samples were drawn at time 0 (T₀) before rhG-CSF and dexamethasone administration and at time 1 (T1), immediately before the apheresis. A statistically significant rise in coagulant factor VIII (FVIII) and von Willebrand factor (vWF), and slightly rise in u-PA:Ag were observed after G-CSF plus dexamethasone administration. In addition, there were positive correlations between vWF-D-dimer and FVIII-D-dimer. A significant decrease in mean total nitric oxide (NOx), nitrite, and nitrate levels was also found after G-CSF plus dexamethasone administration. Moreover, there was a strong negative correlation between nitrite and D-dimer levels (r = –0.611; P = .009). Even if partially compensated with u-PA and protein C, increased FVIII and vWF activity, and decreased nitric oxide levels may still partially contribute to progress of thrombosis risk in rhG-CSF plus dexamethasone administered healthy granulocyte donors. Large numbers of healthy donors exposed to G-CSF plus dexamethasone will be needed to evaluate the risk of thrombosis in this population.

Oxidative Stress and Total Antioxidant Capacity in Diabetic and Nondiabetic Acute Ischemic Stroke Patients

Guldiken, B., Demir, M., Guldiken, S., Turgut, N., Turgut, B., Tugrul, A. — Wed, 18 Nov 2009 21:33:27 PST

Free radical formation is the pivotal mechanism of neuronal injury of ischemic and reperfused brain tissue. In healthy individuals, antioxidant activity counterbalances free radical production, but in the case of ischemia, the balance between reactive oxygen species and antioxidant activity is shifted toward free radicals, causing oxidative stress. The aim of this study is to assess total antioxidant capacity (TAC) and oxidative stress in diabetic and nondiabetic acute stroke patients with 2 different stroke subtypes: large and small vessel disease stroke. Sixty-five acute ischemic stroke patients (29 diabetic and 36 nondiabetic) and 20 age-matched healthy control subjects were recruited in the study. Plasma TAC and nitric oxide (NO) metabolite levels (nitrite and nitrate) were measured by enzyme-linked immunosorbent assay. The subtypes of stroke were defined according to Trial of Org 10172 in Acute Stroke Treatment criteria. The main findings of this study are that the TAC and NO levels were significantly higher in diabetic acute stroke patients than in nondiabetic patients and control cases (P < .001 and P < .001, respectively). The TAC and NO levels were higher also in nondiabetic stroke patients than in controls, but the difference did not reach any significance. No difference was found between NO and TAC levels in large and small vessel stroke subtypes of diabetic and nondiabetic patients. The authors conclude that oxidative stress and counterbalancing antioxidant capacity are more pronounced in diabetic acute stroke patients than in nondiabetic acute stroke patients.

Single Nucleotide Polymorphisms That Affect Homocysteine Levels in Turkish Population

Koc, Y. L., Akar, N. — Wed, 18 Nov 2009 21:33:27 PST

In this study, single nucleotide polymorphisms (SNPs) involved in homocysteine metabolism such as CT replacement in the 677th nucleotide in 5,10-methylenetetrahydrofolate reductase (MTHFR) enzyme; 68-bp insertion in the 844th nucleotide of cystathionine β-synthase (CBS) enzyme; 6-bp insertion/deletion in the region of 3'UTR in thymidylate synthase (TYMS) enzyme and 19-bp deletion in dihydrofolate reductase (DHFR) enzyme were investigated. The effects of these mutations on homocysteine levels were studied. As a result; we found that TT genotype of MTHFR 677 CT is an influencing factor on homocysteine levels in Turkish population. Furthermore, there seems to be another MTHFR 677 TT haplotype, which does not have an effect on homocysteine levels .Our data revealed that other SNPs did not have any influence on homocysteine levels.

Diffuse Cerebral Infarct Associated With Factor V Leiden and Prothrombin 20210A Mutations in a Patient With Tetralogy of Fallot

Sipahi, T., Karademir, S., Kuybulu, A., Akar, N. — Wed, 18 Nov 2009 21:33:27 PST

A 2-year-old girl with tetralogy of Fallot presented with diffuse cranial infarct after cardiac angiography. Heterozygosity for factor V Leiden and prothrombin 20210A mutations were detected. The authors suggest that if thrombosis develops in patients with congenital heart disease, genetic risk factors should be evaluated.

Acute Massive Pulmonary Embolism With Hemodynamic Compromise Treated Successfully With Thrombolytic Therapy Selcuk

Pala, S., Kahveci, G., Bozok, S. — Wed, 18 Nov 2009 21:33:27 PST

A 78 year-old woman presented with a history of 15 days of dyspnea and tachypnea at rest. A distended right ventricle with free-wall hypokinesis and displacement of the interventricular septum toward the left ventricle were shown on echocardiography. The patient suddenly arrested. She underwent cardiac catheterization and selective pulmonary angiography for suspected pulmonary embolism while undergoing cardiopulmonary resuscitation. With the diagnosis of pulmonary embolism confirmed, recombinant tissue plasminogen activator was given immediately in the catheterization room. This case shows how pulmonary embolism can be diagnosed with pulmonary angiography during cardiopulmonary resuscitation and the life-saving result from rapid thrombolysis with recombinant tissue plasminogen activator.

A Woman With Rectal Sinus and Left Transversal Sinus Thrombosis After Ovarian Stimulation: Case Report

Santoro, R. — Wed, 18 Nov 2009 21:33:27 PST

Thromboembolic events are an infrequent complication of hormonal treatment for infertility and are generally related to the ovarian hyperstimulation syndrome. The presence of factor V Leiden and a mutation of G20210A prothrombin mutation are further risk factors for thromboembolic events. We describe a case of dual cerebral vein thrombosis in a woman with prothrombin mutation homozygosity and ovarian hyperstimulation syndrome.

Book Review: Coagulation in Cancer. David Green and Hau C. Kwaan, Editors. New York, NY: Springer Science + Business Media LCC, 2009. 339 pp. Price $129.00

Messmore, H. L., Wehrmacher, W. H. — Wed, 18 Nov 2009 21:33:27 PST

Book Review: New Therapeutic Agents in Thrombosis and Thrombolysis. Jane E. Freedman and Joseph Loscalzo, Editors. 3rd ed. New York, London: Informa Healthcare, 2009. 690 pp. $299.95. USBM 13 1420069235. Illustrated

Messmore, H. L., Wehrmacher, W. H. — Wed, 18 Nov 2009 21:33:27 PST

A Platelet Defect Modulates Bleeding in Mild Hemophilia: The Tale of 2 Brothers

Wed, 18 Nov 2009 21:33:27 PST

Clinical and Applied Thrombosis/Hemostasis: Instructions for Authors

Wed, 18 Nov 2009 21:33:27 PST

Economic and Practical Aspects of Thromboprophylaxis With Unfractionated and Low-Molecular-Weight Heparins in Hospitalized Medical Patients

Pineo, G. F., Hull, R. D. — Wed, 11 Nov 2009 21:30:02 PST

Acutely ill medical patients are at significant risk of developing venous thromboembolic (VTE) complications during or after their hospitalization. Venous thromboembolic events, such as proximal deep vein thrombosis (DVT) or pulmonary embolism (PE), place a high and unacceptable burden on health care resources, up to US$1.5 billion annually in the United States. However, the burden of VTE can be reduced by use of appropriate thromboprophylaxis. Prophylaxis of VTE with either a low-dose unfractionated heparin (UFH) or a low-molecular-weight heparin (LMWH) in medical inpatients is effective, well tolerated and cost-effective, compared with no prophylaxis. Low-molecular-weight heparins have a number of practical benefits over UFH, including once-daily subcutaneous injection and the potential to be used in the outpatient setting. These clinical advantages could translate to improved patient adherence to therapy and provide economic benefits, where LMWHs are more cost-effective compared with UFH.

Comparative Anticoagulant and Platelet Modulatory Effects of Enoxaparin and Sulodexide

Wed, 11 Nov 2009 21:30:03 PST

Sulodexide represents a novel antithrombotic agent with multiple sites of action on blood coagulation and vascular processes. The purpose of this study was to compare sulodexide and enoxaparin on anticoagulant effects, tissue factor (TF)-induced activation of platelets, inhibition of microparticle generation and to investigate their effect on heparin-induced platelet aggregation (HIPA). Sulodexide was compared with enoxaparin at equigravimetric concentrations. When compared to enoxaparin, sulodexide produced a stronger anticoagulant effect in the prothrombin time (PT), activated partial thromboplastin time (APTT), Heptest, and thrombin time (TT) assays. In addition, sulodexide had a stronger inhibitory effect on TF-mediated microparticle generation (IC₅₀ = 2.8 µg/ mL), P-selectin expression (IC₅₀ = 4.8 µg/ml), and platelet aggregate formation (IC₅₀ = 8.5 µg/mL) compared to higher IC₅₀ values with enoxaparin. Sulodexide and enoxaparin exhibited a similar effect on heparin-induced thrombocytopenia (HIT) antibody-mediated platelet activation HIPA assays. These results suggest that sulodexide is a relatively stronger anticoagulant agent than enoxaparin. Sulodexide is subcutaneously absorbed. Its ability to inhibit TF-mediated platelet activation may contribute to the observed therapeutic effects of sulodexide in microvascular vasculopathy such as diabetic nephropathy. These results also suggest that inhibition of TF activation of platelets by sulodexide may be independent of its anticoagulant effects. These results warrant further investigation of sulodexide in additional preclinical and clinical studies.

Deep Vein Thrombosis in Orthopedic Surgery

Calfon, M., Seddighzadeh, A., Piazza, G., Goldhaber, S. Z. — Wed, 11 Nov 2009 21:30:03 PST

We compared 315 patients with deep vein thrombosis who underwent major orthopedic surgery with 618 who underwent general surgery in a prospective registry of consecutive ultrasound-confirmed deep vein thrombosis patients. Orthopedic patients had fewer indwelling central venous catheters (14.0% vs. 46.4%, P < .0001) as well as lower rates of congestive heart failure (7.0% vs. 13.4%, P = .002), cancer (5.1% vs. 28.6%, P < .0001), and diabetes (7.0% vs. 12.6%, P = .004). Extremity discomfort (43.5% vs. 30.3%, P < .0001) and erythema (10.1% vs. 4.8%, P = .001) were more common in orthopedic patients, but dyspnea was less common (11.4% vs. 18.0%, P = .005). There was an increased use of graduated compression stockings (19.4% vs. 15.0%, P = .04), low-molecular-weight heparin (18.7% vs. 12.1%, P = .003), and warfarin (31.7% vs. 11.0%, P < .0001) for deep vein thrombosis prophylaxis in the orthopedic surgery group. Orthopedic surgical patients had a higher frequency of calf deep vein thrombosis than patients who underwent general surgery (38.4% vs. 2.1%, P < .0001). In both groups, 28% did not receive prophylaxis. In conclusion, despite having fewer comorbid conditions, orthopedic patients with deep vein thrombosis remain particularly vulnerable to calf deep vein thrombosis. Rates of venous thromboembolism prophylaxis were inadequate.

Should Plasma Homocysteine Be Used as a Biomarker of Venous Thromboembolism? A Case--Control Study

Wed, 11 Nov 2009 21:30:03 PST

Mild or moderate hyperhomocysteinemia as a risk factor for venous thrombosis is still a matter of debate. The strength of this study is to bring a body of elements to evaluate whether hyperhomocysteinemia should be used as a biomarker for venous thromboembolism (VTE). These elements consist of a biological evaluation of several hematological risk factors, and an original control group made of patients with a negative Doppler ultrasonography. A total of 151 cases and 155 controls were included. Total plasma homocysteine level, MTHFR C677T polymorphism, inherited abnormalities of the natural anticoagulant system as well as plasma folate and cobalamin levels were determined. A total of 41 (27.2 %) of cases and only 9 (5.8%) of controls had at least one of the coagulation defects studied. No significant difference was observed for total homocysteine levels between the 2 groups: median (interquartile range) = 8.3 (7.2-10.8) µmol/L for cases and 8.4 (7-10.9) µmol/L for controls. We found significantly more plasma folates and/or cobalamin deficiencies in controls (18.3%) than in cases (8.6%). After adjustment for several variables significantly related to risk factors of VTE, hyperhomocysteinemia (>" xbd="2200" xhg="2176" ybd="1302" yhg="1257"/>13.2 µmol/L) was not found statistically associated with VTE: odds ratio 1.36 (95% confidence interval, 0.52-3.54). The prevalence of the homozygous 677TT polymorphism in the MTHFR gene was not increased in cases compared with controls. Mild or moderate hyperhomocysteinemia does not seem to be a strong determinant in VTE not only when the control group does not exclusively include healthy persons but also in investigated disease-free (thromboembolic disease) controls.

Prothrombotic and Hemorrhagic Effects of Aspirin

Aguejouf, O., Eizayaga, F., Desplat, V., Belon, P., Doutremepuich, C. — Wed, 11 Nov 2009 21:30:03 PST

Aspirin remains the most widely used drug for prevention of vascular events. Recent observational epidemiological evidence has raised the concern that aspirin withdrawal for treatment noncompliance, surgery, or side effects can carry an increased thrombotic risk. The delay to the thrombotic event was between 7 to 30 days in most reports and most frequently 7 to 10 days. The mechanism underlying this effect remains poorly understood. Using an in vivo model of laser-induced thrombosis, aspirin injected in 1 single dose of 100 mg/kg body weight has also shown a prothrombotic activity in the rat 8 to 10 days after injection in the normal rat. The hypothesis was made that minimal concentrations of aspirin or ultra-low dose aspirin (ULDA) could induce this effect. ULDA showed prothrombotic properties in the same model of induced thrombosis that were very similar to those described after aspirin withdrawal, but the effect was observed only 1 hour after aspirin administration. This prothrombotic effect of ULDA is very similar to the effect observed after COX 2 selective inhibition with NS 398. The administration of both the selective COX 2 inhibitor and ULDA did not produce further changes. In conclusion, the prothrombotic effects described in recent observational studies are likely produced by a direct effect of aspirin, whose putative mechanism involving COX 2 inhibition remains poorly understood.

The Prevalence of Methylenetetrahydrofolate Reductase 677 C-T, Factor V 1691 G-A, and Prothrombin 20210 G-A Mutations in Healthy Populations in Setif, Algeria

Bourouba, R., Houcher, B., Djabi, F., Egin, Y., Akar, N. — Wed, 11 Nov 2009 21:30:03 PST

The polymorphic mutation 677 C-T in the methylenetetrahydrofolate reductase (MTHFR) gene presents a heterogeneous worldwide distribution and is associated with different disorders such as cardiovascular disease. Its frequency shows great ethnic and geographic variations. The aim of this work is to determine the frequency of MTHFR 677 C-T and coexistence of MTHFR 677 C-T with 2 other common, hereditary thrombophilia causes—namely, factor V 1691 G-A and prothrombin (PT) 20210 G-A mutation—in the Sétif region of Algeria. The study involved 147 apparently healthy participants (82 men and 65 women). Genotyping was carried out by a real-time polymerase chain reaction. The MTHFR 677T carrier frequency was found to be 54.4% (80/147); 59 individuals were heterozygous (40.1%), and 21 were homozygous (14.3%). The frequency of MTHFR 677T was found to be 34.3%. Among the 147 individuals, 3 (2.0%) had factor V Leiden, and 5 (3.4%) had PT 20210 A mutation. Of the 80 participants with MTHFR 677T mutation, 2 had heterozygote factor V 1691 G-A gene mutation, and 4 had heterozygote PT 20210 G-A gene mutation. The results showed that MTHFR 677T prevalence is quite high: an allelic frequency of 34.3% with a genotype frequency of 14.3%. Factor V 1691 G-A and PT 20210 G-A gene mutations are rare in the healthy population of the Sétif region of Algeria.

The Risk of Cancer Progression in Women With Gynecological Malignancies and Thrombophilic Polymorphisms: A Pilot Case-Control Study

Wed, 11 Nov 2009 21:30:03 PST

Cancer produces a hypercoagulable state, which might lead to thrombosis, and on contrary, unprovoked venous thromboembolism might be the manifestation of an occult cancer. In this pilot case-control study, we assessed the risk of gynecological malignant diseases related to the presence of the factor V Leiden and prothrombin G20210A polymorphisms. Fifty-two women underwent an operation for gynecological malignancy and were enrolled in the study. Women who underwent an operation for gynecological nonmalignant disease in the same days of cases were considered as controls. The presence of factor V Leiden and prothrombin G20210A was assessed in case and control groups. In all, 7 out of 52 cases were carriers of the 2 polymorphisms compared with 20 out of 198 controls (odds ratio = 1.3; 95% confidence interval, 0.6-3.0). The results were also similar when the risk was considered separately for the site of cancer. As for advanced and metastatic malignancies, the odds ratios were 2.3 (95% confidence interval, 0.9-6.0) and 3.3 (95% confidence interval, 1.0-11), respectively, compared to noncancer patients. When these 2 groups were compared to nonadvanced cancer group, the odds ratios for carriers of polymorphisms were 2.7 (95%confidence interval, 0.7-11.0) and 3.9 (95%confidence interval, 0.8-18.6) for advanced cancer and metastatic malignancies, respectively. Women with factor V Leiden or prothrombin G20210A polymorphisms who developed gynecological malignancy might present with a higher stage of cancer at the time of surgery. Larger case-control studies in similar cohort of patients are needed to confirm these findings.

Use of Aspirin Versus Clopidogrel Plus Aspirin After Coronary Artery Bypass Graft Surgery

Sanon, S., Lee, V.-V., Elayda, M., Wilson, J. M. — Wed, 11 Nov 2009 21:30:03 PST

Aspirin and clopidogrel together reduce the risk of recurrent thrombosis-related events in patients with acute coronary syndromes or stent revascularization and may reduce thrombosis-induced saphenous vein graft failure. In this retrospective, observational study, 4297 patients were assigned to 2 groups after coronary artery bypass graft surgery, based on medications prescribed at hospital discharge: aspirin only (n = 3318) or aspirin plus clopidogrel (n = 979). At 4-year follow-up, unadjusted survival was similar between the 2 groups (aspirin—clopidogrel, 87.9% vs aspirin-only, 88.8%, P = .43). After statistical adjustment using Cox regression analysis, dual anti-platelet therapy at hospital discharge was not associated with improved survival (odds ratio 1.055, 95% confidence interval 0.7-1.4, P = .72). In propensity score-based, case-matched populations (962 patients each), similar results were obtained (odds ratio 0.996, 95% confidence interval 0.7-1.4, P = .98). In our study population, aspirin plus clopidogrel did not provide survival benefit over treatment with aspirin alone in 4 years after coronary artery bypass graft surgery.

The Relation Between Cytokines, Soluble Endothelial Protein C Receptor, and Factor VIII Levels in Turkish Pediatric Stroke Patients

Yururer, D., Teber, S., Deda, G., Egin, Y., Akar, N. — Wed, 11 Nov 2009 21:30:03 PST

The aim of the authors is to examine the relationship between the cytokine levels that are thought to be involved in stroke etiopathogenesis (tumor necrosis factor [TNF]-, interleukin [IL]-2, IL-6, IL-8, IL-11), soluble protein C receptor (sEPCR), and factor VIII (FVIII) levels. The study included 27 patients with stroke and 30 healthy controls, aged 0 to 18. In the comparison of the sEPCR, cytokine, and FVIII levels between patient and control groups, median levels of TNF-, IL-2, IL-6, and IL-8 are found to be high in the patient group when compared with controls, whereas there is no difference in sEPCR, IL-11, and FVIII levels. In the patient group, a positive correlation is seen between TNF- levels and IL-2 and IL-6 levels, between IL-2 and IL-6 levels, and between IL-6 and IL-8 levels, whereas a negative relationship is seen between sEPCR and FVIII. In the control group apart from the patient group, a negative relationship is seen between TNF- and FVIII, whereas there is a positive relationship between IL-11 and sEPCR levels. Median sEPCR levels in patients who have normal or low FVIII levels are significantly high when compared with those with high FVIII levels. In conclusion, in the pediatric population, an increase in TNF-, IL-2, IL-6, and IL-8 levels is seen. Also, an inverse relationship of sEPCR and FVIII levels is shown for the first time. This study provides a basis for ongoing studies that aim to clarify stroke etiopathogenesis. Studies with larger series of patients are warranted to confirm this hypothesis.

Stem Cell Therapy: A Promising and Prospective Approach in the Treatment of Patients With Severe Buerger's Disease

Wed, 11 Nov 2009 21:30:03 PST

No effective blood-flow enhancement therapies are available for patients with severe peripheral arterial disease (SPAD), thus amputation remains the only option for relief of rest pain or gangrene. Autologous bone marrow—derived stem cell therapy (ABMSCT) is an emerging modality to induce angiogenesis from endothelial progenitors. A total of 5 patients with SPAD were treated by ABMSCT using isolated CD34+ cells with characterized phenotype administered by intramuscular injections. The follow-up before and 1, 3, 6, 9, and 12 months after ABMSCT was based on clinical (rest pain, walking distance without pain, nonhealing ulcers, ankle-brachial index [ABI]) and laboratory (angiography, duplex and laser ultrasonography, TcPO₂) parameters. Significant improvement of pain and walking distance was observed in all patients. Nonhealing ulcers disappeared in 3 patients and became smaller and thinner in 1 patient. The average of ABI improved significantly on the treated limb but did not change on the contralateral limb. New collaterals were detected by angiography in 3 patients, but duplex ultrasonography detected improvement in one patient only. Laser ultrasonography showed a mild significant change, TcPO₂ values improved mainly on the foot. Severe adverse events were not observed. We conclude that ABMSCT with isolated CD34+ cells is safe, effective, and results in sustained clinical benefit for patients with SPAD.

Effects of Antithrombin III in Patients With Disseminated Intravascular Coagulation Diagnosed by Newly Developed Diagnostic Criteria for Critical Illness

Sawamura, A., Gando, S., Hayakawa, M., Hoshino, H., Kubota, N., Sugano, M. — Wed, 11 Nov 2009 21:30:03 PST

A study was conducted to test the hypotheses that antithrombin III (antithrombin) improves disseminated intravascular coagulation (DIC) when applied to DIC patients diagnosed by sensitive criteria and that the administration of high-dose antithrombin is a beneficial treatment for DIC. Twenty-three DIC patients diagnosed based on the Japanese Association for Acute Medicine (JAAM) DIC diagnostic criteria were treated with either high-dose (60 IU/kg/day) or low-dose (30 IU/kg/day) antithrombin concentrates for 3 days. The clinical conditions that cause DIC were restricted to systemic inflammatory response syndrome (SIRS) and sepsis. Data of antithrombin activity, platelet counts, coagulation and fibrinolytic markers, and DIC scores before antithrombin administration (day 0), on days 1 to 3, and on day 7 were retrospectively collected from computer-based records. Patients who met the JAAM DIC criteria were administered either high-dose (12 patients) or low-dose (11 patients) antithrombin. The patients’ backgrounds and antithrombin activity (high dose, 51.5 ± 14.5%; low dose, 62.6 ± 19.3%; P = .153) on day 0 were identical in the 2 groups. The JAAM DIC score and prothrombin time ratio on day 7 significantly improved when compared with those on day 0. However, mortality at 28 days as well as interaction within the antithrombin doses administered showed no difference. There were also no differences in the time course of the platelet counts, coagulation and fibrinolytic markers, and DIC scores in the 2 groups. The authors conclude that the effects of antithrombin on prognosis and coagulation and fibrinolytic parameters are independent of the doses administered in patients with SIRS/sepsis-associated DIC.

Venous Thromboembolism in Young Female While on Oral Contraceptives: High Frequency of Inherited Thrombophilia and Analysis of Thrombotic Events in 400 Czech Women

Dulicek, P., Maly, J., Pecka, M., Beranek, M., Cermakova, E., Maly, R. — Wed, 11 Nov 2009 21:30:03 PST

Oral contraceptive use is a common risk factor for venous thromboembolism in women of reproductive age. The presence of inherited thrombophilia further increases this risk. Methods: We analyzed a large group of 400 Czech women with venous thromboembolism in association with oral contraceptive with regard to duration of use at the time of manifestation of venous thromboembolism, the frequency of inherited and acquired thrombophilia, the frequency of eliciting risk factor for thrombosis including immobilization, surgery, administration of plaster cast, long travel, and so on, and the type of thrombosis. The mean age of the women was 26 years, and the average duration of use was 45 months at the onset of thrombosis. Results: Venous thrombosis solely due to the pill occurred in 57% of the women, and in the other 43%, an additional transient eliciting factor was recognized. Among the clinical manifestation, distal thrombosis prevailed (N = 231, 58%) followed by proximal deep vein thrombosis (N = 65, 16%), pulmonary embolism (N = 21, 5%), and thrombosis in unusual sites (N = 20, 5%). Inherited or acquired thrombophilia was diagnosed in 195 (49%) women: factor V Leiden mutation in 35%, congenital deficiency of antithrombin in 1.8%, protein C in 0.8%, protein S in 1%, F IIG20210A in 5%, and antiphospholipid syndrome (APS) in 5.3%. Among the most common risk factors were immobilization of lower limb, minor and major surgery, and trauma. Conclusion: The results confirm that venous thromboembolism is a multifactorial disease in which thrombophilia screening is needed in young symptomatic women on the pill with thrombosis. The results also emphasize the value of proper thromboprophylaxis in women while on oral contraceptive in situations of increased risk for venous thromboembolism.

Haplotype Analysis of the CYP8A1 Gene Associated With Myocardial Infarction

Wed, 11 Nov 2009 21:30:03 PST

Objective: The aim of this study was to assess the association between the human CYP8A1 gene and myocardial infarction (MI) in Chinese people. Methods: 210 MI patients and 206 age-matched controls were genotyped and constructed haplotypes for 3 SNPs [3982C>T (rs5602), C1117A (rs5629), C251T (rs454-98106)] of the human CYP8A1 gene. Results: The CC genotype of rs5629 was more frequently in MI patients than in control subjects (P = .030). The frequency of the A-C-T haplotype was significantly higher in MI patients than in control subjects (P =.001). The frequency of the C-T-T haplotype was significantly lower in MI patients than in control subjects (P= .011). Conclusions: The present results indicate that MI is associated with the CC genotype of rs5629 in the human CYP8A1 gene. The A-C-T haplotype appears to be a useful genetic marker and the C-T-T haplotype might be a protective factor of MI in Chinese people.

Congenital Thrombotic Risk Factors in {beta}-Thalassemia

Sipahi, T., Kara, A., Kuybulu, A., Egin, Y., Akar, N. — Wed, 11 Nov 2009 21:30:03 PST

Thalassemia major patients have increased risk for thromboembolic complications because of the chronic hypercoagulable state. The question arising from this is whether thromboembolic complications are the result of genetic polymorphisms of prothrombotic factors. Here, we studied factor V 1691 G-A (FVL), factor II polymorphism (G20210A), methyltetrahydrofolate reductase mutation (MTHFR, C677T), and endothelial cell protein C receptor (EPCR) deletion polymorphism and their relationship with thromboembolic complications. We found significant decrements of protein C and protein S and a slight increased prevalence of congenital thrombophilic mutations when compared with controls. Although 5 of the patients had high soluble EPCR (sEPCR) levels, no significant change was found in sEPCR values between patients and controls.

Limitations of ADAMTS-13 Activity Level in Diagnosing Thrombotic Thrombocytopenic Purpura in Pregnancy

Ehsanipoor, R. M., Rajan, P., Holcombe, R. F., Wing, D. A. — Wed, 11 Nov 2009 21:30:03 PST

In pregnancy, it may be difficult to differentiate the syndrome of hemolysis, elevated liver enzymes, and low platelets from thrombotic thrombocytopenia purpura. Severely depressed (<5%) or absence of a disintegrin and metalloproteinase with thrombospondin motifs-13 activity levels are associated with thrombotic thrombocytopenia purpura and mildly decreased levels are associated with other disease processes, including pre-eclampsia and hemolysis, elevated liver enzymes, and low platelets syndrome. We present a case of a patient that presented at 20 weeks gestation with elevated liver enzymes and thrombocytopenia. The diagnosis was unclear at the time of presentation. She underwent induction of labor, and during the postpartum course, she was eventually diagnosed with thrombotic thrombocytopenia purpura; however, her activity level of a disintegrin and metalloproteinase with thrombospondin motifs-13 was only moderately depressed at 15% (normal pregnancy value 41%-105%).

Idiopathic Factor VIII Inhibitor Autoantibody in a Man Presented After Accident

Mansouritorghabeh, H., Lak, M., van Heerde, W. L. — Wed, 11 Nov 2009 21:30:03 PST

Acquired hemophilia A is a rare but severe autoimmune bleeding disorder caused by autoantibodies against factor VIII activity and is a potentially life-threatening hemorrhagic disorder. The incidence of acquired hemophilia A has been estimated as 1.48 cases per million per year. The overall rate of death from all causes of acquired hemophilia reaches up to 22%. In this article, the authors describe the case of a 55-year-old man who presented with unusual bleeding after an accident and the fluctuation of his hemostatic parameters during 13 months of follow-up. Initially he had 43 Bethesda unit (BU) inhibitor to factor VIII and <1% of factor VIII activity. The patient was given prednisone and azathioprine therapy (30 and 100 mg/day, respectively) for 4 months, but his hemostatic parameters did not improved during this phase. Then, 2 g cyclophosphamide was injected every 2 days, but no remarkable improvement was observed. Nine months later his inhibitor titers were high. The inhibitor and factor VIII concentrations were assessed 11 times during these 13 months, and the mean level of factor VIII inhibitor was 44 BU (with a minimum of 2 BU and a maximum of 103 BU); the minimum and maximum factor VIII concentrations were <1% and 20%, respectively. The patient experienced hemarthroses, severe epistaxis, hematoma, and gastrointestinal bleeding episodes during this phase. His factor VIII concentration spontaneously and gradually improved and increased to 51.5% 8 months after stopping the treatment with undetectable factor VIII inhibitor.

Deep Venous Thrombosis Caused by Congenital Malformation of the Inferior Vena Cava and Heterozygous Factor V Leiden Presenting as Venous Claudication

Fass, G., Nasroolah, D., Cavenaile, J.-C. — Wed, 11 Nov 2009 21:30:03 PST

A case of an 18-year-old man with deep venous thrombosis of the lower limbs caused by hypoplasia of the inferior vena cava in combination with heterozygous factor V Leiden is presented. Both anomalies were found when the patient complained of venous claudication in both thighs. Inferior vena cava malformation is a rare condition and may predispose to the development of deep venous thrombosis. This patient was at an even higher risk for deep venous thrombosis as the inferior vena cava malformation was combined with a hypercoagulable state.

Intravenous and Oral Sulodexide Versus Coagulation Activation Markers in Humans

Borawski, J., Dubowski, M., Rydzewska-Rosolowska, A., Mysliwiec, M. — Wed, 11 Nov 2009 21:30:03 PST

State-of-the-Art Review: Assessing the Safety Profiles of New Anticoagulants for Major Orthopedic Surgery Thromboprophylaxis

Hull, R. D., Yusen, R. D., Bergqvist, D. — Tue, 01 Sep 2009 21:30:42 PDT

Background: The safety and efficacy of new anticoagulants are often initially tested for venous thromboembolism (VTE) prevention in patients undergoing major orthopedic surgery. Concern among surgeons about the risks for bleeding may result in suboptimal use of thrombophylaxis. Objective: To evaluate the definitions used to define bleeding outcomes in studies of new anticoagulants and to examine the influence the definition has on the perceived bleeding risk of thromboprophylaxis. Methods: The MedLine database was searched for phase III studies of new anticoagulants versus the standard comparator, enoxaparin, in patients undergoing major orthopedic surgery. Results: The definitions for major bleeding outcomes varied widely both across and within clinical trial programs of new anticoagulants. Studies which did not include surgical site bleeding in their definition for major bleeding showed lower major bleeding rates in comparison to those that did include this outcome. Other factors that influenced the rate of major bleeding included the timing of prophylaxis initiation in relation to surgery and the dose of anticoagulant therapy. The wide range of definitions used for major bleeding made it difficult to compare bleeding risk among studies of new anticoagulants. Conclusions: The definitions of bleeding events that clinical trials of thromboprophylaxis use in their assessment of new anticoagulants strongly influences each drug’s perceived safety profile and may underestimate bleeding risks. Clinical studies of new anticoagulants urgently need standardization of bleeding definitions to allow intertrial comparability and to ensure consistent reporting of clinically relevant outcomes.

Interpretation of Benefit-Risk of Enoxaparin as Comparator in the RECORD Program: Rivaroxaban Oral Tablets (10 milligrams) for Use in Prophylaxis in Deep Vein Thrombosis and Pulmonary Embolism in Patients Undergoing Hip or Knee Replacement Surgery

Van Thiel, D., Kalodiki, E., Wahi, R., Litinas, E., Haque, W., Rao, G. — Tue, 01 Sep 2009 21:30:42 PDT

The Regulation of Coagulation in Major Orthopedic surgery reducing the Risk of DVT and PE (RECORD) clinical program of rivaroxaban consists of 4 phase III clinical trials comparing rivaroxaban with enoxaparin for the prevention of venous thromboembolism (VTE) in patients undergoing either total hip or total knee replacement surgery. Despite the comprehensive and extensive nature of this program, it had some logistic issues that included the dosing of the enoxaparin which was not only inconsistent with the recommendations but the dosages used were not optimal. The duration of treatment while consistent with rivaroxaban did vary with enoxaparin and was somewhat short. The bleeding definitions and safety evaluations were not consistent in accordance with the current recommendations. Moreover, the RECORD program has no power to show differences in major bleeding. The cardiovascular rebound phenomenon should have been adequately addressed and may require additional clinical validation to establish the safety of rivaroxaban. Although the US Food and Drug Administration (FDA) advisory committee has recommended approval of rivaroxaban, the reported analysis strongly suggests additional clinical validation on the claimed benefit/risk ratio of this monotherapeutic anticoagulant.

Isolation and Characterization of Contaminants in Recalled Unfractionated Heparin and Low-Molecular-Weight Heparin

Tue, 01 Sep 2009 21:30:42 PDT

Recently, a contaminant was found in some clinically used unfractionated heparin (UFH) preparations. Administration of this UFH was associated with an increased risk of developing a wide range of adverse effects including death. To further investigate the chemical profile of the contaminant, contaminated batches of UFH were treated by exhaustive nitrous acid depolymerization followed by methanol precipitation to remove heparin oligosaccharides. Because contaminated heparins may have been used as starting material in the production of low-molecular-weight heparins (LMWHs), a similar procedure was carried out using an experimental batch of enoxaparin prepared from contaminated heparin. While high-pressure liquid chromatography (HPLC) analysis of contaminated heparin did not distinguish the presence of the contaminant, it could readily be observed as a high-molecular weight shoulder in the elution profile of contaminated enoxaparin. Digesting contaminated heparin with heparinase-I prior to HPLC analysis showed the presence of a nondigestible component (15%-30% of the mixture). This contaminant was also resistant to degradation by chondroitinases A, B, and C. Proton nuclear magnetic resonance (NMR) indicated that the contaminant was oversulfated chondroitin sulfate (OSCS). Size-exclusion chromatography indicated that the mean molecular weight of the OSCS was 16.8 kD, comparable to that of a synthetic porcine cartilage OSCS preparation that was used as a reference material (17.2 kD). While varying degrees of high-molecular weight dermatan sulfate and other minor impurities were detected, OSCS appeared to be the major contaminant in these preparations. The process involved in the production of enoxaparin does not significantly degrade OSCS.

Are Prothrombotic Variants of Platelet Glycoprotein Receptor Polymorphisms Involved in the Pathogenesis of Thrombotic Microangiopathies?

Tue, 01 Sep 2009 21:30:42 PDT

Thrombotic microangiopathies are life-threatening disorders characterized by vascular microthromboses, schistocytic hemolytic anemia, and thrombocytopenia. Although recent research has partially explained the pathogenesis of these rare entities, the determinants contributing to the onset and modulating the severity of thrombotic microangiopathies are largely unknown. The present study assessed the putative role of prothrombotic platelet receptor polymorphisms in thrombotic microangiopathies that have been found to be associated with premature onset of myocardial infarction in predisposed individuals. Thirty-four consecutive patients admitted with the diagnosis of thrombotic microangiopathy and 759 healthy subjects were enrolled. Genotyping of the human platelet antigen (HPA) 2 an the Kozak sequence polymorphism of GP Ib of the platelets’ von Willebrand factor receptor glycoprotein (GP) Ib-V-IX, the HPA-1 and the HPA-3 polymorphism of the fibrinogen receptor GP IIb-IIIa (integrin _IIbβ₃) and the HPA-5 and GP Ia 807 C/T polymorphism of the collagen receptor GP Ia-IIa (integrin ₂β₁) were determined according to standard procedures. As a result, no significant differences in the prevalence of prothrombotic variants of platelet-receptor polymorphisms between patients and healthy control subjects were observed. However, although not significant, the prothrombotic bb genotype of the HPA-1 polymorphism was more prevalent in the patients. The findings do not provide evidence that platelet receptor polymorphisms are determinants for the onset of thrombotic microangiopathies or predispose to a more severe course. Along with this observation, screening for respective platelet-receptor polymorphisms does not appear to contribute to risk stratification of affected patients.

Assessing the Coagulation Factor Levels, Inherited Thrombophilia, and ABO Blood Group on the Risk for Venous Thrombosis Among Brazilians

Tue, 01 Sep 2009 21:30:42 PDT

Increased coagulation factor levels have been demonstrated to be a risk factor for venous thromboembolism in patients of Caucasian origin. Coagulation factors, hereditary thrombophilia, and ABO blood group were evaluated for venous thrombosis risk in a heterogeneous Brazilian population consisting of 122 women and 53 men, with a median age of 36 years (range 13-63), matched to a control group by age, sex, and ethnicity. Increased levels of factor VIII (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.6-6.0), von Willebrand factor (OR, 2.8; 95% CI, 1.4-5.4), non-O blood group (OR, 2.1; 95% CI, 1.3-3.4), and thrombophilia (OR, 3.4; 95% CI, 1.6-7.1) emerged as independent risk factors for venous thromboembolism. The interaction of high levels of factor IX and factor XI with other independent variables increased the potential for thrombosis synergistically. Therefore, the ability of identifying underlying thrombophilia risk factors in our population was enhanced by the inclusion of these factors in the prothrombotic laboratory workup.

Prevalence of Thrombophilic Mutations and ACE I/D Polymorphism in Turkish Ischemic Stroke Patients

Celiker, G., Can, U., Verdi, H., Yazici, A. C., Ozbek, N., Atac, F. B. — Tue, 01 Sep 2009 21:30:42 PDT

The aim of this study was to evaluate the prevalence of factor V Leiden (FVL), prothrombin G20210A, methylenetetrahydrofolate reductase (MTHFR) C677T gene mutations, and angiotensin-converting enzyme (ACE) I/D polymorphism in ischemic stroke (IS) patients. A total of 162 Turkish IS patients were included and analyzed according to stroke subtype by the TOAST classification. Their genotype data were compared with those of the control group, representing the healthy population, using the ² test. The frequency of FVL heterozygocity was 12.3% in this series—higher than that in the normal population (9.8%; statistically insignificant, P = .478). The frequency of the ACE D/D genotype in all stroke patients and those with stroke of undetermined etiology was higher than that in our population (52.5% and 59.2%, respectively, vs 39.3%; statistically significant, P = .034, P = .020). Our results may suggest that ACE D/D genotype is a risk factor for IS, particularly in those with stroke of undetermined etiology in the Turkish population.

Prevalence of Platelet Dysfunction and Abnormal Coagulation: Results of a Population-Based Study

Marxsen, J. H., Forchheim, S., Zuske-Matthaus, A., Wagner, T. — Tue, 01 Sep 2009 21:30:42 PDT

The prevalence of impairments in the hemostatic process is unknown in acutely ill people. Data on hemostasis (PFA 100^®) and the coagulation cascade of 1015 people are presented here, establishing a cohort of unselected emergency patients in a population-based approach. A high prevalence of reduced platelet function (38%) was found, which was more frequent than expected. In contrast, there was a lower prevalence (20%) of abnormal plasmatic coagulation, which was almost always explained by medication, whereas medication could not predict abnormal platelet function. Moreover, a history of disproportionate bleeding did not correlate well with abnormal platelet or coagulation factor function and could not substitute for a screening in this setting. The effect of acetylsalicylic acid (ASA) on PFA-closure time was frequently missing (34%), indicating a considerable prevalence of ASA nonresponse among the study population. These data should be applicable in similar settings. The high prevalence of unexpectedly abnormal platelet function in acute illness as well as the high prevalence of possible ASA nonresponders suggests a functional platelet assay to be effective in screening certain subpopulations of emergency patients.

Heparin-Induced Thrombocytopenia: An Estimate of the Average Cost in the Hospital Setting in France

Tue, 01 Sep 2009 21:30:42 PDT

Heparin-induced thrombocytopenia is a severe drug adverse effect with possible dramatic consequences. The risk is 0.1% to 5%. The costs of heparin-induced thrombocytopenia in France were estimated using the Programme Médicalisé des Systèmes d’Information (PMSI) national discharge database. Hospitalizations with heparin-induced thrombocytopenia were identified using diagnostic codes. Costs were assessed from the perspective of the French Sickness Fund or hospitals. Heparin-induced thrombocytopenia could be the reason of admission or could occur during the stay and lead to a different tariff or to additional costs associated with extra length of stay. Direct costs were also estimated from experts’ opinions. A sensitivity analysis was performed from data collected in 1 center. During 2005, 445 hospitalizations with heparin-induced thrombocytopenia codes were identified. For 45 patients, the main diagnosis was heparin-induced thrombocytopenia; for the remaining 400 patients, heparin-induced thrombocytopenia occurred during the hospital stay. Tariffs and extra costs were used to estimate an overall average cost of 3230 for heparin-induced thrombocytopenia. For patients with heparin-induced thrombocytopenia as main diagnosis, the average cost was 3400; for the patients with heparin-induced thrombocytopenia that occurred during the stay, 1910 was due to an increased of the tariff and 3348 to an increased length of stay. Estimated direct costs of an episode were 3350 to 3700. Different methods were used to arrive at an estimated cost of 3500 for a heparin-induced thrombocytopenia episode for inpatients. One limitation of the study is that heparin-induced thrombocytopenia tends to be underreported by physicians during hospitalization.

Association of Angiotensin-Converting Enzyme Gene 2350G>A Polymorphism With Myocardial Infarction in a Chinese Population

Tue, 01 Sep 2009 21:30:42 PDT

Angiotensin-converting enzyme (ACE) gene 2350G>A polymorphism has the most significant effect on plasma ACE concentrations. But the association between this polymorphism and myocardial infarction (MI) is presently unknown. We carried out a case-control study in the Chinese Han population. ACE2350G>A genotypes of 231 patients with MI and 288 healthy controls were detected by PCR-RFLP. Differences in frequencies of ACE genotypes and alleles and their associations with clinical features were assessed. The distribution of the ACE2350G>A genotypes (GG, GA, and AA) was 20.78%, 51.08%, and 28.14% in the MI group and 31.60%, 46.53%, and 21.87% in controls, respectively (P = .0167).The frequency of the A allele in the MI group was significantly higher than that in controls (53.68% vs 45.14%, P = .0062). The A allele carriers (GA + AA genotypes) had approximately 2-fold increased risk of MI when compared with the GG genotype (odds ratio = 1.76; 95% confidence interval = 1.24-3.52). There were no significant differences among the 3 genotypes in plasma levels of lipids, apolipoproteins, high-sensitivity C-reactive protein, and soluble CD40 ligand in either the MI group or the control group (P > .05). No statistical difference was observed between ACE2350G>A polymorphism and severity of the coronary lesions (P > .05). These results suggest that ACE2350G>A polymorphism is associated with acute MI, and A allele carrier is an independent risk factor for acute MI in the Chinese Han population.

The Effect of Plasminogen Activator Inhibitor-1 -675 4G/5G Polymorphism on Familial Mediterranean Fever (FMF) Disease

Ozel Demiralp, D., Ekim, M., Akar, N. — Tue, 01 Sep 2009 21:30:42 PDT

Familial Mediterranean fever (FMF) is an autosomal recessive disease that is the most common of a rare group of disorders collectively termed familial hereditary periodic fever syndromes, also known as autoinflammatory syndromes. FMF is predominantly affecting people of Mediterranean descent and clinically characterized by intermittent attacks of fever with peritonitis and abdominal pain, pleuritis, arthritis, or erysipelas-like rashes. Amyloidosis due to chronic inflammation progressing to renal failure is one of the most serious potential complications of this disease.

Patients with inflammatory diseases, such as systemic lupus erythematosus and rheumatoid arthritis, and conditions with chronic subclinical inflammation, like obesity and diabetes mellitus, are now considered to have an increased risk of atherosclerotic cardiovascular complications. FMF is also an inflammatory disease, and it is accepted that even during attack-free periods significant inflammatory reaction continues. However, whether this inflammatory process causes premature atherosclerosis is not known due to a lack of data.

Different studies have investigated the association between the fibrinolytic and inflammatory process parameters. PAI-1 is paracrine secretion of pro- and antiinflammatory cytokines, thereby playing a possible role in the adiposity-related inflammation and atherosclerosis. The patients with IRS have higher values of fibrinogen, factor VII, VIII, Von Willebrand factor and Plasminogen Activator Inhibitor (PAI) compared to control subjects. So that we aimed in this study to investigate whether FMF patients with/without amyloidosis and with M694V homozygote mutation, have increased risk for atherosclerotic cardiovascular complications and to determine the strength of association between MEFV gene-mutation types. To our knowledge, this is the first case control and cross-sectional study in the pediatric age groups.

Patterns of Acquired Bleeding Disorders in a Tertiary Care Hospital

Tue, 01 Sep 2009 21:30:42 PDT

Bleeding disorders constitute a large proportion of referrals to hematology departments. Worldwide, acquired causes of bleeding are commoner than inherited ones. To identify the spectrum of these disorders, we evaluated all referrals for bleeding encountered in this tertiary care centre over a one-year period. Of the total 1342 cases, 1040 (77.5%) had underlying exclusively acquired causes, whereas inherited causes constituted 302 cases (22.5%). Amongst acquired causes, disseminated intravascular coagulation was seen in 297 (28.6%), hepatic coagulopathy in 218 (20.9%), neurosurgical causes (intracranial bleeds) in 154 (14.8%), malignancy in 89 (8.6%), and miscellaneous multiple acquired causes including those due to anticoagulant drug overdose in 282 patients (27.1%). Referrals for isolated prolonged prothrombin time or thrombocytopenia were common, but were excluded from this study because not all presented with bleeding. Prompt laboratory work-up and precise identification of acquired causes of bleeding is the key to planning appropriate patient management including transfusion support.

Is There Any Effect of Tumor Burden on Hemostatic Parameters in Cancer Patients? A Case--Control Study of Hemostatic Abnormalities and Anticardiolipin Antibodies in Solid Tumors

Turna, H., Ozguroglu, M., Bolayirli, M., Orhanoglu, T., Balci, H. — Tue, 01 Sep 2009 21:30:42 PDT

Hemostatic complications are one of the leading causes of mortality in cancer patients. In the present study, we assessed the hemostatic parameters and anticardiolipin antibodies in patients with solid tumors (n = 104) and healthy controls (n = 25) and also find out whether the abnormalities in these hemostatic parameters vary related to tumor burden. Prothrombin time, activated partial thromboplastine time, D-dimer, and fibrinogen as hemostatic parameters were determined by photo-optometric clot detection system, and serum anticardiolipin levels were measured by enzyme-linked immunosorbent assay. The plasma levels of fibrinogen, D-dimer, and serum anticardiolipin IgM levels in cancer patients were significantly higher compared with those in controls (P < .001, P = .001, and P = .01, respectively). Only fibrinogen levels were significantly higher in metastatic group than nonmetastatic group (P < .001 ). Hemostatic abnormalities that are detected in asymptomatic cancer patients may not give any clue about tumor burden or stage of the cancer patients.

PIA1/A2 Polymorphism of the Platelet Glycoprotein Receptor IIb/IIIIa and Its Correlation to Cerebrovascular Diseases: An Appraisal

Wiwanitkit, V. — Tue, 01 Sep 2009 21:30:42 PDT

Platelet glycoprotein (GP) IIb/IIIa is a membrane receptor for fibrinogen and von Willebrand factor. There is considerable controversy regarding the clinical role of the GP IIb/IIIa PIA1/A2 as a risk factor of cerebrovascular diseases. Here, the author performs a summative analysis on the recent previous reports on the GP IIb/IIIa PIA1/A2 and its correlation to cerebrovascular diseases. The metanalysis was performed to assess the correlation between the pattern of GP IIb/IIIa PIA1/A2 polymorphism and cerebrovascular diseases. From available 4 case-control studies, 553 patients and 1059 controls are evaluated. From overall risk estimation, the subjects with PIA2 alleles have 1.18 times higher risk to develop cerebrovascular diseases. According to this analysis, the author proposes that the pattern of GP IIb/IIIa PIA1/A2 polymorphism does not represent a useful marker of increased risk for cerebrovascular diseases. The lack of association between pattern of GP IIb/IIIa PIA1/A2 polymorphism and ethnicity can also be showed in this study.

Successful Use of Danaparoid in Two Pregnant Women With Heart Valve Prosthesis and Heparin-Induced Thrombocytopenia Type II (HIT)

Gerhardt, A., Scharf, R. E., Zotz, R. B. — Tue, 01 Sep 2009 21:30:42 PDT

Anticoagulant therapy with heparin for the prevention of thromboembolism in pregnant women with prosthetic heart valves is associated with an increased risk to the mother and/or the fetus. A life-threatening complication of the therapy with heparin is heparin-induced thrombocytopenia type II (HIT). danaparoid has not yet been reported to be safe and effective for this indication. This study reports on a 26-year-old woman with tricuspidal valve prosthesis and a 37-year-old woman with a St. Jude Medical mitral valve prosthesis who were anticoagulated with danaparoid during pregnancy because of HIT. Anti-Xa levels were between 0.6 and 1.2 IU/mL during pregnancy with target levels of 1.0 IU/mL. Cesarean section was performed at anti-Xa levels of 0.3 and 0.7 IU/mL. One woman developed a placental hematoma at the 32nd week of gestation, which did not increase over the following week. Both patients delivered healthy boys. Heparin-induced thrombocytopenia in pregnant women with prosthetic heart valve can be successfully managed with danaparoid.

Pericardial Hemorrhage Due to Acetylsalicylic Acid in a Patient With Essential Thrombocythemia

Kayrak, M., Acar, K., Yazici, M., Kaya, C., Selim Ayhan, S., Gok, H. — Tue, 01 Sep 2009 21:30:42 PDT

Essential thrombocythemia is a clonal myeloproliferative disorder that causes thrombocytosis. Essential thrombocythemia is characterized by increased incidence of thrombosis with arterial event more than venous events and hemorrhagic complications. Acetylsalicylic acid enhances both minor and major bleedings. The authors describe pericardial hemorrhage, which is related to the use of low-dose acetylsalicylic acid in a patient with essential thrombocythemia. The patient was successfully managed with clopidogrel therapy during the 16 months follow-up without recurrent thrombotic or hemorrhagic events.

Myocardial Infarction in a 28-Year-Old Thalassemia Intermedia Patient

El Rassi, F. A., Ismaeel, H. A., Koussa, S. C., Taher, A. T. — Tue, 01 Sep 2009 21:30:42 PDT

A 28-year-old Lebanese thalassemia intermedia (TI) patient with homozygous IVS1-110 mutation sustained atypical chest pain of 1 day’s duration. The EKG reading revealed ST segment elevation in the chest leads V₁ to V₅. Coronary angiography showed 2 plaques in the left anterior descending coronary artery. He underwent subsequent angioplasty with stenting of the left anterior descending coronary artery. An extensive thrombophilia profile was negative. He was started on medication, and his medical condition improved and chest pain ceased. This is the first case report of myocardial infarction in a TI patient among thalassemics. We propose that such cases will emerge more frequently as our population ages, keeping in mind a possible thrombotic mechanism.

Potential Role of Thrombelastography in the Monitoring of Acquired Factor VIII Inhibitor Hemophilia A: Report on a 78-year-old Woman With Life-threatening Bleedings

Tue, 01 Sep 2009 21:30:42 PDT

A 78-year-old woman was admitted to our hospital because of syncope associated with hematomas in both legs. Acquired hemophilia A (AHA) with a low antifactor VIII antibodies activity was diagnosed. Whole blood (WB) thrombelastographic profile depicted a hypocoagulable state. During hospitalization, the patient experienced life-threatening bleedings in the neck and in the right thigh. FVIII concentrates and rFVIIa was safe and effective in controlling acute hemorrhagic symptoms. Immunosuppressive therapy was used successfully to eradicate the inhibitor. At discharge, FVIII inhibitor was absent and thrombelastogram showed a normal profile. Our report confirms that AHA is a heterogeneous condition in terms of risk of bleeding. Even though the criteria for the diagnosis of AHA is quite well defined, a laboratory test useful to predict the bleeding risk and monitor the response to treatment is lacking. ROTEM profile appears to be correlated with the response to treatment and with the eradication of the inhibitor.

Factor V Leiden in Mexican Pediatric Patients With Thrombosis

Parra-Ortega, I., Sanchez-Huerta, J. L., Lopez-Martinez, B. — Tue, 01 Sep 2009 21:30:42 PDT

Response to Factor V Leiden in Mexico

Majluf-Cruz, A. — Tue, 01 Sep 2009 21:30:42 PDT

Book Review: TRALI: Mechanisms, Management, and Prevention. Stephen Kleinman and Mark A. Popovsky, Editors. AABB Press, Bethesda, MD. 2008. pp 196. ISBN 978-1-56395-267-8 soft cover, price $196.50

Wehrmacher, W. H., Messmore, H. L. — Tue, 01 Sep 2009 21:30:42 PDT

Book Review

Wehrmacher, W. H — Tue, 01 Sep 2009 21:30:42 PDT

Clinical and Applied Thrombosis/Hemostasis: Instructions for Authors

Tue, 01 Sep 2009 21:30:42 PDT

The Effectiveness of Measuring for Fragmented Red Cells Using an Automated Hematology Analyzer in Patients With Thrombotic Microangiopathy

Fri, 15 May 2009 13:51:30 PDT

Thrombotic microangiopathy (TMA) or thrombotic thrombocytopenic purpura (TTP) is a life-threatening syndrome characterized by increased number of fragmented red cells (FRCs) and thrombocytopenia. FRCs can be measured using the recently developed automated hematology analyzer XE-2100. The normal range for FRCs is 0% to 0.205%, as determined by the automated hematology analyzer XE-2100. The FRC count is significantly elevated in patients with TMA associated with liver transplantation, bone marrow transplantation, or TTP. In patients with TMA after liver transplantation, the FRC count is significantly higher than in those without TMA. In receiver operating characteristic analysis for the diagnosis of TMA, the area under the curve is 0.986, suggesting that FRC is a useful marker for the diagnosis of TMA. When the cutoff value of FRC for TMA is 1.2%, the sensitivity is 90% and the specificity is 96%, indicating that FRC is the most useful screening test for the diagnosis of TMA.

Need for Inferior Vena Cava Filters in Cancer Patients: A Surrogate Marker for Poor Outcome

Fri, 15 May 2009 13:51:30 PDT

Background. Cancer patients have an increased incidence of venous thromboembolism (VTE). Inferior vena cava (IVC) filters are used extensively in the US, and more than 40 000 are inserted annually. The impact on survival of cancer patients receiving IVC filters has not been studied. Methods. A retrospective study examined 206 consecutive cancer patients with VTE to compare the effects of IVC filter placement with anticoagulation (AC) therapy on overall survival (OS), as measured from the time of VTE. Patients were classified into 3 treatment groups: AC (n = 62), IVC filter (77), or combination IVC filter + AC (67). Results. Treatment groups did not differ with respect to age, sex, or albumin levels. Median OS was significantly greater in patients treated with AC (13 months) compared with those treated with IVC filters (2 months) or IVC + AC (3.25 months; P < .0002). IVC patients were 1.9 times more at risk of death than AC only (hazard ratio = .528; 95% confidence interval = .374 to .745). Multivariate analysis revealed that performance status and type of thrombus were not confounders and had no effect on OS. Conclusion. The need for the insertion of an IVC filter projected markedly reduced survival. Patients requiring an IVC filter rather than AC as initial therapy face a 2-fold increase in risk of death. Whether or not this therapeutic procedure has a positive impact on outcome in cancer patients is uncertain. Complications resulting from thrombosis were also analyzed in this cohort. A prospective randomized trial at our institution is addressing this issue.

In Vivo Hemostatic Effect of the Medicinal Plant Extract Ankaferd Blood Stopper in Rats Pretreated With Warfarin

Thu, 21 May 2009 14:31:26 PDT

Aim: Ankaferd comprises a mixture of Thymus vulgaris, Glycyrrhiza glabra, Vitis vinifera, Alpinia officinarum and Urtica dioica. Ankaferd Blood Stopper (ABS) has been approved in the management of bleedings. This study aimed to evaluate in vivo hemostatic effect of ABS in rats pretreated with warfarin. Materials and methods: Wistar rats (210-270 g) were treated either with warfarin (2 mg/kg) or vehicle (0.9% NaCl) orally before bilateral hind leg amputation. ABS was administered topically to one of the amputed legs. The duration of bleeding and the amount of bleeding were measured to evaluate the hemostatic effect of ABS. Results: Topical ABS administration to amputed leg shortened the duration of bleeding markedly in both untreated and warfarin-treated rats by 31.9% [1.42 min (95% CI: 0.35-2.49)] and 43.5% [5.12 min (95% CI: 2.16-8.07)] respectively. The amount of bleeding in ABS-administered amputed leg showed a decrease by 53.8% in warfarin-treated group. Conclusions: ABS has in vivo hemostatic actions that may provide a therapeutic potential for the management of patients with deficient primary hemostasis in clinical medicine.

Evolution of Prenatal Diagnostic Techniques From Phenotypic Diagnosis to Gene Arrays: Its Likely Impact on Prenatal Diagnosis of Hemophilia

Ghosh, K., Shetty, S., Tulsiani, M. — Fri, 15 May 2009 13:51:30 PDT

Prenatal diagnostic techniques in hemophilia have evolved through the early sex-determination techniques of offering a nonspecific diagnosis in case of a male fetus through the various mutation screening techniques to the more recent gene array techniques. Each of these techniques has specific advantages and disadvantages. The sampling techniques have evolved simultaneously to suit the requirements of each technique and also the different gestation periods. The DNA-based testing methods provide a range of aberrations detected with different levels of genomic resolution. The more recent gene array analysis is poised to have substantial impact on prenatal diagnosis of hemophilia not only in studying the highly heterogeneous mutations but may also be useful in studying the effect of various ameliorating or epistatic genetic mutations/ polymorphisms simultaneously, providing a wide range of options to the prenatal diagnosis experts, the genetic counselors, and the couples opting for prenatal diagnosis.

The TT Genotype of the C677T Polymorphism in the Methylentetrahydrofolate Reductase as a Risk Factor in Thrombotic Microangiopathies: Results From a Pilot Study

Fri, 15 May 2009 13:51:30 PDT

In this study, we assessed the potential role of the TT genotype of the gene of the methylenetetrahydrofolate reductase for the manifestation of thrombotic microangiopathies, enrolling 40 affected patients (mean age [± standard deviation] 35 ± 11 years). As a result, the methylenetetrahydrofolate reductase 677TT genotype was more prevalent in patients with thrombotic microangiopathies compared with controls (adjusted odds ratio = 2.58, 95% confidence interval = 1.2-5.7, P = .018), particularly in those suffering from the hemolytic uremic syndrome. A hemolytic more severe clinical course of thrombotic microangiopathies in carriers of the methylenetetrahydrofolate reductase 677TT genotype was not observed. In summary, our findings suggest a significant influence of the methylenetetrahydrofolate reductase genotype on the manifestation of thrombotic microangiopathies. The 677 TT genotype of this polymorphism appears to be a risk factor for manifestation of these rare thrombotic disorders, possibly explained by endothelial activation and increased oxidative stress.

Global Risk Profile Verification in Patients with Venous Thromboembolism (GRIP VTE) in 5 Gulf Countries

Fri, 15 May 2009 13:51:30 PDT

Background: The Global Risk Profile Verification in Patients with Venous Thromboembolism was the first prospective multicenter registry conducted in Arabian Gulf countries to explore the epidemiology of venous thromboembolic (VTE) disorders and to provide data on diagnosis and disease management. Methods: Data on 242 patients with confirmed VTE were submitted between September 2003 and November 2003 from 28 contributing hospitals in the Arabian Gulf region. Differences between groups were assessed by the ² test or Fisher exact test for categorical variables. The Student's t test was used for testing proportions. Results: The frequency of VTE cases is deep vein thrombosis (DVT), 187 (77.27%); pulmonary embolism (PE), 35 (14.46%); and DVT with PE, 20 (8.26%). The most common symptoms of DVT and DVT/PE patients were calf pain (72%), calf swelling (63.8%), and localized tenderness (52.2%). The most common symptoms in patients with PE alone and DVT/PE were dyspnea (83.6%), thoracic pain (69.1%), and cough (40%). Risk factors for VTE were immobilization (41.3%), age >65 years (28.9%), a history of VTE (20.7%), and trauma (19%). Among surgical interventions, orthopedic procedures induced the greatest number of VTE cases, followed by general surgery and gynecological procedures. Low-molecular-weight heparins were chosen to treat 33.7% of DVT cases, whereas unfractionated heparin was used in 21.9% of cases. Conclusion: VTE remains a common problem in medical and surgical patients in the Arabian Gulf states. Recognition of the common risk factors is of extreme importance to implement the appropriate prophylactic strategy according to the published guidelines.

Monitoring of Functional Plasminogen in the Blood of Patients on Fibrinolytics

Stief, T. W., Richter, A., Maisch, B., Renz, H. — Fri, 15 May 2009 13:51:30 PDT

There are no reliable data on functional plasminogen in the blood of patients receiving fibrinolytic treatment. Here, artifactual in vitro changes of functional plasminogen were prevented by arginine stabilization blood samples of myocardial infarction patients: 12 received 36.4 mg reteplase in bolus, and 1 patient received 100 mg tissue plasminogen activator in continuous infusion. Arginine (1.5 M, 1.3 mL, pH 8.7) was used to stabilize 2.6 mL ethylenediaminetetraacetic acid-blood. The arginine-stabilized plasma was analyzed with a functional oxidative assay for plasminogen. Functional plasminogen decreased within 2 minutes of reteplase treatment by about 40% and by about 80% after 60 minutes. Lowest plasminogen concentrations were found in plasmas with highest plasmin activities. Chloramine oxidation of purified Glu-plasminogen increased its activation by urokinase up to 3-fold. Arginine stabilization allows reliable determinations of functional plasminogen in the blood of patients receiving fibrinolytics, enabling the rapid diagnosis of prothrombotic plasminogen consumption. The present findings support the profibrinolytic action of chloramines.

Seasonal Variation in the Occurrence of Venous Thromboembolism: Data From the MASTER Registry

Fri, 15 May 2009 13:51:30 PDT

Many studies showed that the occurrence of cardiovascular and cerebrovascular events exhibits a seasonal variation. As for venous thromboembolism (VTE), not univocal results are available, and studies are mainly retrospective. We aimed to confirm the existence of a seasonal pattern in the occurrence of VTE on a large prospective population. The analysis considered consecutive cases of VTE enrolled into the MASTER Registry in 25 Italian hospitals, between January 2002 and November 2004. The total population consisted of 2119 subjects (1056 men, mean age 59 ± 18 years). The total sample was divided into subgroups by gender, age (<40, 41—60, 61—80, ≥80 years), type of event (first episode; proximal or distal; upper or lower limb; idiopathic or secondary deep vein thrombosis or pulmonary embolism, or both), and underlying risk factors, eg, cancer, previous VTE, estroprogestinic therapy, lack of prophylaxis, immobilization, surgery, pregnancy or puerperium, and medical diseases. Cases were grouped according to season and month of occurrence, and the data were analyzed by either the ² test for goodness of fit and chronobiological analysis. VTE was most frequent in Autumn and less frequent in Spring (32.9% vs 19%, respectively, ² = 90.62; P < .001). This pattern was shown for most subgroups. Chronobiological analysis identified a significant rhythmic annual pattern, with a main September—October peak for several subgroups (men, age 41—60 and 61—80 years, secondary event, previous VTE, immobilization), and a trend for most of the others. It is possible that subjects at increased risk could perhaps deserve appropriate or potentiated VTE prophylaxis in certain periods of the year.

Lessons From Ximelagatran: Issues for Future Studies Evaluating New Oral Direct Thrombin Inhibitors for Venous Thromboembolism Prophylaxis in Orthopedic Surgery

Lazo-Langner, A., Rodger, M. A., Wells, P. S. — Thu, 21 May 2009 14:31:26 PDT

Venous thromboembolism is a frequent complication of total hip and knee replacement requiring prophylaxis with anticoagulants. A direct thrombin inhibitor— ximelagatran—did not show advantages over other anticoagulants and it was withdrawn from the market; however, new drugs are being developed. We conducted a systematic review and meta-analysis to identify conditions under which ximelagatran might potentially be superior to current standards. Medline, EMBASE, the Cochrane Library, and grey literature were screened for randomized trials comparing ximelagatran with warfarin or low-molecular-weight heparin for thromboprophylaxis in total hip or knee replacement. Two reviewers independently assessed and extracted data. A meta-analysis with especial attention to statistical heterogeneity was conducted. This study suggested that the risk-benefit profile of ximelagatran—and probably other similar agents— depends on the type of surgery, the initial timing of administration, and probably the dose. These issues should be explicitly explored in future trials evaluating new direct thrombin inhibitors.

Methodological Issues in Genetic Association Studies of Inherited Thrombophilia: Original Report of Recent Practice

Simundic, A.-M., Nikolac, N., Topic, E. — Fri, 15 May 2009 13:51:30 PDT

The aims of this article are to evaluate the methodological quality of genetic association studies on the inherited thrombophilia published during 2003 to 2005, to identify the most common mistakes made by authors of those studies, and to examine if overall quality of the article correlates with the quality of the journal. Articles were evaluated by 2 independent reviewers using the checklist of 16 items. A total of 58 eligible studies were identified. Average total score was 7.59 ± 1.96. Total article score did not correlate with the journal impact factor (r = 0.3971; 95% confidence interval [CI], 0.1547-0.5944, P = .002). Total score did not differ across years (P = .624). Finally, it is concluded that methodological quality of genetic association studies is not optimal, and it does not depend on the quality of the journal. Journals should adopt methodological criteria for reporting the genetic association studies, and editors should encourage authors to strictly adhere to those criteria.

Factor VIII Gene Haplotypes and Linkage Disequilibrium for the Indirect Genetic Analysis of Hemophilia A in India

Singh, M., Singh, P. — Fri, 15 May 2009 13:51:30 PDT

Genomic consequences of factor VIII gene haplotypes for the indirect genetic analysis of haemophilia A has not been done in India hitherto. Consequently, BclI/intron18, HindIII/intron 19, and XbaI/intron 22 restriction sites were investigated in 159 individuals from 42 families with hemophilia A. The frequencies of haplotype II, IV, VI, that is, BclI (+)-HindIII (–)- XbaI (+), BclI (+)HindIII (+)-XbaI (–), and BclI (–)-HindIII (–)-XbaI (+) were 0.312, 0.198, and 0.164 respectively. The high heterogeneity of haplotype II highlighted its potential for indirect genetic diagnosis of factor VIII. Analysis revealed strong but incomplete linkage disequilibrium (D' = 0.76, 0.68, and 0.51) between BclI/HindIII, HindIII/XbaI, and BclI/XbaI, respectively. The overall cumulative polymorphism information content (PIC) of these three markers increased from 0.36 to 0.80. Escalation of PIC up to 80% in the present study suggests that haplotyping of factor VIII gene determines better prognosis in the direction of indirect genetic analysis of hemophilia A.

Thrombophilia in Human Immunodeficiency Virus--Infected Patients with Osteonecrosis: Is There a Real Connection? The First Case-Control Study

Fri, 15 May 2009 13:51:30 PDT

Several reports have described an increased incidence of osteonecrosis in human immunodeficiency virus—infected patients (HIV+), but the cause has not been established. The association between thrombophilia and osteonecrosis in HIV+ was studied. A case-control study in HIV+, 19 cases and 38 controls, was designed. Magnetic resonance imaging was made in both groups to confirm or exclude hip osteonecrosis. The extensive tests of thrombophilia were measured, and the clinical data were recorded, nadir of CD4⁺ cell count and well-known risk factors for osteonecrosis. Thrombophilia has been frequently found both in patients with and without osteonecrosis (thrombophilia, 68.4% vs 60.5%), but no specific thrombophilia tests were significantly associated with osteonecrosis. A low nadir of CD4⁺ (<60 cells/µL) and corticoid use were significantly (P < .05) associated with osteonecrosis. In multivariate analysis, only nadir of CD4⁺ <60 cells/µL remained a predictor of osteonecrosis (odds ratio = 7.33; 95% confidence interval, 1.80-29.82, P = .005). Thrombophilia might have a limited role in the development of osteonecrosis in HIV+. Nadir of CD4⁺ <60 cells/µL and corticoid use were main factors.

Coagulation and Fibrinolysis are in Balance After Moderate Exercise in Middle-aged Participants

Menzel, K., Hilberg, T. — Thu, 21 May 2009 14:31:26 PDT

Increased age is associated with a higher risk of thrombotic events. The aim of this study was to investigate the age-related changes in hemostasis before and after moderate exercise controlled by individual anaerobic threshold as recommended for rehabilitation training. In this study, 24 young (25 + 1 years) and 24 middle-aged healthy nonsmokers (48 + 1 years) underwent an individualized exercise test with 80% of individual anaerobic threshold (young individuals: 127 + 6 W; middle-aged individuals: 128 + 5 W; values are expressed as mean + standard error of mean) for 60 minutes. The blood samples were collected before and after the exercise. The age-related higher (P ≤ .05) levels could be detected in factors II, VII, VIII, IX, XI, XII, prothrombin fragment 1+2, in tissue plasminogen activator antigen and activity, as well as in plasminogen. The relative exercise-induced increases in these parameters were similar in both groups, although beginning at a higher level for those in the middle-aged group. A statistically enhanced increase after exercise in the middle-aged group could be shown in prothrombin fragment 1+2 (young individuals: 98 + 6 to 102 + 6 pmol/L; middle-aged individuals: 138 + 7 to 156 + 8 pmol/L) and in thrombin—antithrombin complex (young individuals: 2.2 + 0.1 to 3.1 + 0.2 µg/L; middle-aged individuals: 2.4 + 0.3 to 3.9 + 0.6 µg/L); the latter only showing a tendency. The data show the age-related changes with a rise in blood coagulation and fibrinolysis in a healthy middle-aged group compared with younger participants. Moderate exercise leads to comparably relative increases in hemostatic parameters but starting at higher levels. However, the exercise-induced thrombin generation (prothrombin fragment 1+2) is enhanced in the middle-aged participants in comparison with younger participants, but may be compensated by a sufficient fibrinolysis, and therefore the hemostatic system remains in balance.

High Incidence of Factor V Leiden and Prothrombin G20210A in Healthy Southern Italians

Fri, 15 May 2009 13:51:30 PDT

Factor V Leiden (FVL) and G20210 prothrombin (FII G20210A) mutations are risk factors for thromboembolism. In Europe, FVL is more prevalent in the north (7%) than in the south (3%), whereas FII G20210A is more common in the south (3% to 7%) than in the north (2% to 5%). In Italy, the prevalence is 2% to 3% for both. The aim of this study was to assess if these polymorphisms could be more frequent in the south than in the rest of Italy. In 105 blood donors in southern Italy, the prevalence of FVL and FIIG20210A was 9.5% and 5.7%, respectively. These prevalence data are higher when compared with published data. The results of this study are as high as those observed in Greece and the Middle East. The diffusion of FVL and FII G20210A in the Mediterranean, consequent to Phoenician and Greek colonization, could be a reason for the high prevalence observed.

The G1691A Mutation of the Factor V Gene (Factor V Leiden) and the G20210A Mutation of the Prothrombin Gene as Risk Factors in Thrombotic Microangiopathies

Fri, 15 May 2009 13:51:30 PDT

Factor V Leiden (FVL) mutation and prothrombin G20210A mutation are common hereditary risk factors for venous thrombosis. In the current study, 40 patients (mean age ± standard deviation, 35 ± 11 years) and 764 healthy control subjects (mean age ± standard deviation, 37 ± 14 years) were enrolled to assess the potential role of these mutations in the manifestation of thrombotic microangiopathies. Compared with controls, neither the heterozygous FVL mutation (7.5% vs 8.5%; P = 1) nor the heterozygous prothrombin mutation (2.5% vs 2.8%; P = 1) was more prevalent in the patients. The findings do not support a significant role of FVL and prothrombin mutations as risk factors for the manifestation of thrombotic microangiopathies. Thus, screening for these mutations does not allow the identification of individuals at increased risk for these rare thrombotic disorders.