Resistance to Activated Protein C Caused by the Factor V R506Q Mutation ls a Common Risk Factor for Venous Thrombosis

Pulmonary thromboembolism and role of factor v Leiden in its development: Review of literature

Pulmonary embolism (PE) and deep vein thrombosis (DVT) are associated with considerable morbidity and mortality, and for as much as twenty-five percent of PE patients the primary clinical appearance is unexpected death. Diagnosis of PE is based on clinical suspicious at first, but sometimes its diagnostics can be extremely difficult. Newly increased interest in an inherited thrombophilic states has been provoked by the discovery of several common inherited abnormalities, i.e. the prothrombin (PT) gene G20210A, Factor V Leiden (FVL) mutation (Arg506Gln), hyperhomocystenemia and homocysteiuria, Wein-Penzing defect, Sticky Platelet Syndrome (SPS), Quebec platelet disorder (QPD) and Sickle Cell Disease (SCD). PE incidence rates increase in recent years. The only explanation at this moment is increased awareness of PE, especially after any kind of surgery, immobile state or unexplained shorthness of breath.

Factor V Leiden, Prothrombin and MTHFR Mutation in Patients with Preeclamsia, Intrauterine Growth Restriction and Placental Abruption

BACKGROUND

Factor V Leiden, Prothrombin and MTHFR gene mutation, could have an influence in pregnancy with adverse outcome Preeclamsia, IUGR and Placental abruption.

AIM

The aim of this study is to investigate the presence of above mentioned inherited thrombophilias and its statistical significance, distribution among the complicated and normal pregnancy, and relative risk for carrier of mutation to develop preeclampsia, IUGR and placental abruption.

MATERIAL AND METHODS

Prospective cohort study is implemented at University Clinic for Obstetric and Gynecology in Skopje, Republic of Macedonia. The study included 109 delivered patients: 40 with preeclapmsia, 22 with IUGR, 17 with placental abruption and 30 as control group with normal pregnancy. The amount of 3 ml venous blood has been used for detection of these point mutations using ThromboStrip -Opegen, QIAGEN kit manufactured for thrombotic risk.

RESULTS

The highest frequency was found: in the group with preeclampsia 35% were MTHFR homozygous, IUGR -MTHFR heterozygous 45%, Placental abruption- 52.9% MTHFR heterozygous, and in the control group without thrombophilia 56.7%. There were combined thrombophilia in 3 patients. There aren`t statistical significance in presence of thrombophilia among groups (p > 0.05). Statistical significance (p < 0.05) was found between carriers of MTHFR homozygous in preeclampsia and group with placental abruption and control group. Relative risk in IUGR group for MTHFR homozygous was 5.54 (1.37

CONCLUSION

The presence of mutation MTHFR homozygous could increase the risk for development of IUGR and mutation of Factor V Leiden for placental abruption. Further investigations with more patients are warranted.

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Key Words

• IUGR
• MTHFR
• factor V Leiden
• placental abruption
• preeclampsia
• prothrombin

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MESH Headings Collapse

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Affiliation(s)

Vesna Livrinova University Clinic for Obstetrics and Gynecology, Faculty of Medicine, Ss. Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia
Marija Hadzi Lega University Clinic for Obstetrics and Gynecology, Faculty of Medicine, Ss. Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia
Anita Hristova Dimcheva Institute for Transfusion Medicine, Faculty of Medicine, Ss. Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia
Igor Samardziski University Clinic for Obstetrics and Gynecology, Faculty of Medicine, Ss. Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia
Rozalinda Isjanovska Institute for Epidemiology and Medical Biostatistics, Faculty of Medicine, Ss. Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia

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The search for allelic variants that cause monogenic disorders or predispose to common, complex polygenic phenotypes

The search for the mutant genes for monogenic disorders has been a spectacular success. This was accomplished because of the mapping and sequencing of the human genome, the determination of the sequence variability, the collection of well-characterized families with mendelian disorders, the development of statistical methods for linkage analysis, and laboratory methods for mutation search. The challenge of the genetic medicine is now to decipher the nucleotide sequence variants that predispose to common complex, polygenic phenotypes. The methodology for this challenge is in development and constant evolution, it is anticipated that, in the next 10 to 20 years, susceptibility alleles for these common disorders will be identified.

Factor v leiden and inflammation

Factor V Leiden, is a variant of human factor V (FV), also known as proaccelerin, which leads to a hypercoagulable state. Along these years, factor V Leiden (FVL) has been studied from the pathophysiologic point of view, and research has been focused on finding clinical approaches for the management of the FVL associated to a trombophilic state. Less attention has been paid about the possible role of FVL in inflammatory conditions known to be present in different disorders such as uremia, cirrhosis, liver transplantation, depression as well as sepsis, infection or, inflammatory bowel disease (IBD). Whether platelet FVL will increase the activation of coagulation and/or in which proportion is able to determine the final outcome in the previously mentioned inflammatory conditions is a subject that remains uncertain. This paper will review the association of FVL with inflammation. Specifically, it will analyze the important role of the endothelium and the contribution of other inflammatory components involved at both the immune and vascular levels. This paper will also try to emphasize the importance of being a FVL carrier in associations to diseases where a chronic inflammation occurs, and how this condition may be determinant in the progression and outcome of a specific clinic situation.

A class representative model for Pure Parsimony Haplotyping under uncertain data

The Pure Parsimony Haplotyping (PPH) problem is a NP-hard combinatorial optimization problem that consists of finding the minimum number of haplotypes necessary to explain a given set of genotypes. PPH has attracted more and more attention in recent years due to its importance in analysis of many fine-scale genetic data. Its application fields range from mapping complex disease genes to inferring population histories, passing through designing drugs, functional genomics and pharmacogenetics. In this article we investigate, for the first time, a recent version of PPH called the Pure Parsimony Haplotype problem under Uncertain Data (PPH-UD). This version mainly arises when the input genotypes are not accurate, i.e., when some single nucleotide polymorphisms are missing or affected by errors. We propose an exact approach to solution of PPH-UD based on an extended version of Catanzaro et al.[1] class representative model for PPH, currently the state-of-the-art integer programming model for PPH. The model is efficient, accurate, compact, polynomial-sized, easy to implement, solvable with any solver for mixed integer programming, and usable in all those cases for which the parsimony criterion is well suited for haplotype estimation.

Race differences in the prevalence of the factor V Leiden mutation in Kuwaiti nationals

Factor V Leiden mutation (FVL; G1691A) is an established risk factor for venous thromboembolic disorders. FVL was reported with high prevalence in Caucasians (1-15%) but was absent in non-Caucasians like Africans and Asians. Studies reported FVL in 5-27% of Arabs and non-Arabs living in the Middle Eastern countries northern to the Arabian Peninsula, but was almost absent in Arabs in the Arabian Peninsula itself. Kuwait is an Arabic country present on the northern border of the Arabian Peninsula, and Kuwaitis are originally from Saudi Arabia (Southern to Kuwait and within the Arabian Peninsula) or from Iran and Iraq (northern to Kuwait and the Arabian Peninsula). This study was conducted to study FVL in Kuwaitis in relation to their origin. Real-time PCR was performed on DNA samples of 285 apparently healthy Kuwaitis using specially designed primers and probes for FVL. There were 109 Kuwaitis of Iranian origin, 71 of Iraqi origin and 105 of Saudi origin. FVL was present in 7 and 5 Kuwaitis of Iranian and Iraqi origin, respectively. None of the Kuwaitis of Saudi origin had the mutation. Prevalence of FVL in Kuwaitis of Iranian (6.42%) and Iraqi (7.04%) origin were statistically different from prevalence in Kuwaitis of Saudi (0%) origin (P-value<0.05). No difference was found between females and males (P-value>0.6). In conclusion, FVL is present in Kuwaitis of Iranian or Iraqi origin only. Therefore, testing and providing genetic consultation for FVL may be needed in those Kuwaitis only which should save time, cost and efforts. However, this assumption should be confirmed by other studies and on larger number of cases.

Type and Location of Venous Thromboembolism in Carriers of Factor V Leiden or Prothrombin G20210A Mutation Versus Patients With No Mutation

Factor V Leiden (FVLeiden) and prothrombin G20210A are the most common genetic causes of thrombophilia and established risk factors for different clinical manifestations of venous thromboembolism (VTE). This study investigated whether the clinical manifestation of VTE, the extension of deep vein thrombosis (DVT) and the presence of transient risk factors at the time of the first VTE, differed among patients with mutations (97 with FVLeiden; 33 with prothrombin G20210A) and in 109 patients without thrombophilia. Isolated pulmonary embolism (PE) was less prevalent in patients with FVLeiden (6%) and no thrombophilia (6%) than in those with prothrombin G20210A (15%). No difference was found in the incidence of distal DVT. Regarding the extension of proximal DVT, the lowest incidence for isolated popliteal vein and the highest for iliofemoral vein were observed in patients with prothrombin G20210A. No difference was observed between groups of patients with or without thrombophilia by unprovoked VTE. The pregnancy/puerperium was the most prevalent risk factor in carriers of prothrombin G20210A. Among FVLeiden carriers, the most prevalent risk factor was surgery, and in patients without thrombophilia, it was trauma ( P < .05). Thrombosis of the upper limb was more frequent in a group without thrombophilia than in patients with mutations ( P < .01). Transverse sinus venous thrombosis was present only in patients with prothrombin G20210A. Carriers of prothrombin G20210A have an increased risk of developing isolated PE and more severe clinical manifestations than those with FVLeiden or without thrombophilia.

Population genetic tools: application to cancer

The availability of a reference human genome sequence, an increasingly dense catalog, knowledge of common genetic variation, and new developments in technology present an unprecedented opportunity to systematically explore the genetic basis of complex human diseases such as cancer. An understanding of the common mutations that can cause distinct human cancers will be critical for identifying new targets for drug discovery, patient stratification for clinical trials, and analysis of drug response data to delineate classes of patients that respond to therapy. The genome structure of cancer can be examined in several ways: (1) large-scale case-control or family studies can investigate germline mutations; and (2) state-of-the-art genomic technologies (eg, high-density oligonucleotide arrays and targeted re-sequencing), can identify somatic alterations. Combined, these approaches will lead to a better understanding of the cancer genome.

Phenotypic Heterogeneity in Patients with Homozygous Prothrombin 20210AA Genotype. A paper from the 2005 William Beaumont Hospital Symposium on Molecular Pathology

Venous thromboembolic events (VTEs) affect an estimated 1 in 1000 people annually, resulting in approximately 50,000 deaths, with prevalence increasing with age. The genetic contributors to thrombosis have been described and further explored within the last 15 years as molecular diagnostic techniques have become more widely used. The prothrombin G20210A mutation is the second most common inherited thrombotic risk factor after factor V Leiden. Generally present in less than 5% of the population, the mutation's prevalence varies greatly with ethnicity. The G20210A mutation confers a mildly increased thrombotic risk that is compounded by the presence of other risk factors. One striking characteristic of the G20210A mutation is the phenotypic heterogeneity of the rare homozygous cases. Forty percent of the reported homozygous cases are asymptomatic. Many of the symptomatic patients have additional risk factors that might compound the thrombotic risk. We present here a review of the literature for the homozygous prothrombin G20210A mutation and describe additional cases that exemplify the heterogeneous nature of this entity.

Effect of Factor V Leiden and prothrombin G20210-->A mutations on thromboembolic risk in the national surgical adjuvant breast and bowel project breast cancer prevention trial

BACKGROUND

In the National Surgical Adjuvant Breast and Bowel Project's Breast Cancer Prevention Project (BCPT), tamoxifen use was associated with an increased relative risk for venous thromboembolic events, including deep vein thrombosis and pulmonary emboli, compared with placebo. However, the involvement of hypercoagulability factors in this association is unclear.

METHODS

To examine possible associations among the risk of venous thromboembolic events, tamoxifen use, and Factor V Leiden (FVL) and prothrombin G20210-->A (PT20210) mutations, which are involved in promoting blood coagulation, we used a nested, matched, case-control (1 : 4) design and compared women in the BCPT who had experienced venous thromboembolic events (n = 76) with women who did not (n = 295). FVL and PT20210 mutations were detected in genomic DNA that was isolated from blood samples collected at trial enrollment.

RESULTS

Venous thromboembolic events occurred in 28 women (deep vein thrombosis in 22 and pulmonary emboli in six) who were taking placebo and in 53 women (deep vein thrombosis in 35 and pulmonary emboli in 18) who were taking tamoxifen (relative risk = 1.90, 95% confidence interval = 1.18 to 3.12). Excessive risk for venous thromboembolic events was observed only in the first 36 months of therapy. There were no differences in age, smoking, and race between the groups, but women with venous thromboembolic events had a higher body mass index than women without (mean +/- standard deviation, 30 kg/m(2) +/- 7.7 versus 27.1 +/- 5.6; P<.001). FVL and/or PT20210 mutations were found in nine women (four on tamoxifen and five on placebo) with venous thromboembolic events and in 20 control subjects (nine on tamoxifen and 11 on placebo). No associations were found between risk of venous thromboembolic events and mutation status in either treatment group.

CONCLUSIONS

Venous thromboembolic disease in the BCPT women is associated with tamoxifen use and body mass index, but not with FVL and PT20210 mutations. Screening women at risk for breast cancer for FVL and/or PT20210 appears to offer no benefit in determining the risk of tamoxifen-associated thromboembolic events.

[Association of tow thrombotic risk factors: factor V Leiden and hyperhomocysteinemia. A case report]

The identification of constitutional and/or acquired risk factor is of major importance in the treatment of thromboembolic disease in young people; it contributes to evaluate the risk of recurrence and to define the period of oral prophylactic anticoagulant treatment. Several congenital or acquired abnormalities of haemostasis are actually defined. In this paper, we report the case of a 34-year-old man who developed a deep venous thrombosis, five months before the diagnosis of megaloblastic anemia, probably due to pernicious anemia. The thrombosis was partially explained by the acquired hyperhomocysteinemia induced by vitamin B12 deficiency. Moreover, activated protein C resistance due to factor V Leiden, was revealed in our patient. This latter improved under anticoagulant treatment combined with vitamin B12. Combination in one individual, of different risk factors predisposing to inherited and/or acquired thrombophilia, results in increased risk for thrombo-embolic disease, suggesting synergic interaction between these factors.

A haplotype map of the human genome

Inherited genetic variation has a critical but as yet largely uncharacterized role in human disease. Here we report a public database of common variation in the human genome: more than one million single nucleotide polymorphisms (SNPs) for which accurate and complete genotypes have been obtained in 269 DNA samples from four populations, including ten 500-kilobase regions in which essentially all information about common DNA variation has been extracted. These data document the generality of recombination hotspots, a block-like structure of linkage disequilibrium and low haplotype diversity, leading to substantial correlations of SNPs with many of their neighbours. We show how the HapMap resource can guide the design and analysis of genetic association studies, shed light on structural variation and recombination, and identify loci that may have been subject to natural selection during human evolution.

Molecular aspects of thrombosis and antithrombotic drugs

There have been major advances in our understanding of thrombosis and antithrombotic drugs. This review focuses on the molecular aspects of thrombus formation and antithrombotic therapy. Molecules involved in arterial thrombosis are derived from inflammatory cells in the atherosclerotic plaque and blood platelets. These molecules work in concert to promote plaque instability and thrombogenicity. Thrombus formation on the ruptured plaque is mediated by platelet and coagulation activation. By contrast, molecules involved in venous thrombosis are derived from the activated coagulation cascade. Platelets appear to play a secondary role. The antithrombotic drugs are classified according to their targeted constituents: antiplatelet agents and anticoagulants; the latter are further divided into non-specific anticoagulants, such as vitamin K antagonists and heparin, and direct thrombin inhibitors, including hirudin and argatroban. Currently available antiplatelet agents target glycoprotein IIbIIIa (abciximab, tirofiban, eptifibatide), cyclooxygenase-1 (aspirin) or adenosine diphosphate receptor, P2Y12 (clopidogrel).

Trombophilic screening for nonarteritic anterior ischemic optic neuropathy

BACKGROUND

Nonarteritic anterior ischemic optic neuropathy (NAION) is an ischemic infarction of the optic nerve head, frequently leading to sudden, mostly irreversible loss of vision. In this study blood thrombophilic factors, as well as cardiovascular risk factors were investigated for their relevance to this pathology. Trombophilic risk factors so far not evaluated were included in the study.

PATIENTS AND METHODS

37 NAION patients (4 with sequential second eye involvement) and 81 matched control subjects were examined. From blood, protein C, protein S, antithrombin, von Willebrand antigen levels (vWFAg), and factor V (Leiden) mutation, factor VIIIC level, plasminogen activity, lipoprotein (a) and fibrinogen levels, and presence of anticardiolipin antibodies were investigated. Possibly relevant pathologies [e.g. diabetes mellitus (DM), hypertension, and ischemic heart disease] were also registered.

RESULTS

Elevated Lp(a) and vWFAg levels, DM, F V (Leiden), hypercholesterolemia, and hyperfibinogenemia proved to be significant risk factors associated with NAION. Forward stepwise logistic regression analysis revealed that high Lp(a), DM, and FV (Leiden) were the main predictive components, with odds ratios 16.88 (p=0.012), 5.78 (p=0.022) and 4.44 (p=0.033), respectively.

CONCLUSIONS

Based on our results it appears that thrombophilia is likely to contribute to the development of NAION besides vascular damage due to the presence of cardiovascular risk factors. Further data are needed, however, to justify the suggested use of secondary prophylaxis using anticoagulant/antiplatelet therapy.

Activated protein C resistance in anterior ischaemic optic neuropathy

PURPOSE

Protein C is a major component of the natural anticoagulant pathway. Resistance of coagulation factor V (FV) to activated protein C (APC), mostly due to FV Leiden mutation, is the most common cause of inherited thrombophilia. The aim of this retrospective study was to determine the prevalence of APC resistance and Leiden mutation in patients with non-arteritic anterior ischaemic optic neuropathy (NAION).

METHODS

A total of 25 patients with NAION were examined between 1997 and 2002. The patients were screened for APC resistance and FV Leiden mutation as well as for acquired risk factors of vascular disease such as diabetes mellitus, hypercholesterolaemia, hypertonia and ischaemic heart disease. A control group of subjects without ocular vascular disease and with homogenous distribution of the same risk factors was used for comparison.

RESULTS

Six of the 25 patients (24%) with NAION had APC resistance due to the heterozygous Leiden mutation of FV. The frequency of the same genetic mutation in the control group was only 5.9%. Odds ratio calculations showed that patients with the Leiden mutation were at a significantly higher risk of NAION than control patients (p < or = 0.021).

CONCLUSION

The high frequency of Leiden mutation in NAION suggests a pathogenic role of the mutation in the disease.

MTHFR C677T polymorphism and its relation to ischemic stroke in the Black Sea Turkish population

The MTHFR C677T mutation has been shown to be associated with venous thrombosis. The role of this mutation in ischemic stroke is unclear. We investigated whether the MTHFR mutation is a risk factor for patients with ischemic stroke in the Black Sea Turkish population or not. We analyzed 30 patients (19 male, 11 female) [median age: 50 years (range: 28-78)] with ischemic stroke who had no known predisposition factors for stroke and 242 (182 male, 60 female) healthy controls [median age: 42 years (range: 18-65)]. Detection of the MTHFR C677T mutation was performed by using commercially available allele-specific PCR-ELISA kits. Prevalence of the MTHFR C677T genotype was 49.1% (CT, 45.8%; TT, 3.3%) in controls and 50% (CT, 43.3%; TT, 6.6%) in patients [OR: 1.03, 95% CI (0.45-2.35]). The prevalence of homozygous gene mutation for MTHFR was higher among patients with stroke than control subjects, but this difference was not statistically significant. The MTHFR gene mutation is not a risk factor for ischemic stroke formation in patients from the Black Sea region in Turkey.

The International HapMap Project

The goal of the International HapMap Project is to determine the common patterns of DNA sequence variation in the human genome and to make this information freely available in the public domain. An international consortium is developing a map of these patterns across the genome by determining the genotypes of one million or more sequence variants, their frequencies and the degree of association between them, in DNA samples from populations with ancestry from parts of Africa, Asia and Europe. The HapMap will allow the discovery of sequence variants that affect common disease, will facilitate development of diagnostic tools, and will enhance our ability to choose targets for therapeutic intervention.

Role of factor V Leiden and prothrombin 20210A in patients with retinal artery occlusion

PURPOSE

Retinal artery occlusion is a common vision-threatening disease. Among other risk factors, coagulopathies leading to a hypercoagulable state have been associated with retinal artery occlusion. Numerous studies have shown that two genetic variants, factor V Leiden and prothrombin 20210A, cause a procoagulant state. However, their role in the pathogenesis of retinal artery occlusion is still unclear. The purpose of the present study was therefore to investigate a possible association between factor V Leiden, prothrombin 20210A, and retinal artery occlusion.

METHODS

In the present retrospective case-control study, we studied 136 patients with retinal artery occlusion and 136 age- and gender-matched control subjects. The presence of factor V Leiden and prothrombin 20210A alleles was determined by polymerase chain reaction.

RESULTS

The prevalence of heterozygosity for the prothrombin G20210A variant did not significantly differ between patients and controls (three patients vs two controls, P=0.65). Distribution of factor V Leiden genotypes revealed no significant difference among the two groups (heterozygosity: eight patients vs 11 controls, P=0.47). As for other risk factors, arterial hypertension, a history of stroke and myocardial infarction were significantly more frequent in patients than in controls.

CONCLUSION

Our data suggest that factor V Leiden and prothrombin 20210A do not play a major role in patients with retinal artery occlusion.

Factor V Leiden mutation and its relation to left atrial thrombus in chronic nonrheumatic atrial fibrillation

The genetic defect of coagulation factor V, known as factor V Leiden, produces a resistance to degradation by activated protein C and increased venous thrombosis. However, the role of factor V Leiden in the formation of left atrial thrombus with nonrheumatic atrial fibrillation has not been studied. We investigated whether factor V Leiden is a risk factor for left atrial thrombus in patients with nonrheumatic atrial fibrillation. We analyzed clinical, echocardiographic, and biochemical data in 105 consecutive patients with nonrheumatic atrial fibrillation. These patients were divided into two groups: group A (n = 37) with left atrial thrombus and group B (n = 68) without left atrial thrombus. The study also included 42 control subjects. Left atrial thrombus was investigated by using both transthoracic echocardiography and transesophageal echocardiography. Blood samples from the patients and controls were analyzed for the factor V Leiden mutation by DNA analysis, using the polymerase chain reaction. There was no significant difference in the prevalence of factor V Leiden between the patients and control subjects. The prevalence of factor V Leiden mutation was 8.1% (3/37) in patients with left atrial thrombus, and 8.8% (6/68) in patients without left atrial thrombus. The prevalence of factor V Leiden was 7.1% (3/42) in control subjects. The prevalance of factor V Leiden was 10% (2/20) in patients with spontaneous echo contrast and 8% (7/85) in patients without spontaneous echo contrast. Multivariate analyses showed that left ventricular ejection fraction was an independent predictor of left atrial thrombus. Factor V Leiden mutation is not a risk factor for left atrial thrombus formation and spontaneous echo contrast in patients with nonrheumatic atrial fibrillation.

Perioperative deep vein thrombosis in Chinese patients undergoing craniotomy

BACKGROUND

We attempted to determine the incidence of perioperative deep vein thrombosis (DVT) in Chinese patients undergoing elective craniotomy for brain tumors and to assess the efficacy of clinical and serial calf circumference assessment in detecting DVT.

METHODS

Between June 1999 and February 2001, 100 consecutive patients who underwent elective craniotomy for brain tumors at the Department of Neurosurgery, University of Hong Kong Medical Centre were examined for perioperative DVT. The demographic data, Glasgow coma score (GCS), mobility status, and the operative details were recorded. Graduated compression stockings and intermittent pneumatic compression were applied perioperatively as prophylaxis against DVT. Serial duplex scans were performed before and after operation. Clinical examination was also performed daily to look for signs of DVT. The calf circumference was measured at fixed levels for both limbs before each duplex scan surveillance.

RESULTS

The study group consisted of 44 males and 56 females, with a mean age of 54 +/- 15 years (range, 20-81 years). There was no preoperative DVT. Postoperative DVT was detected on duplex scan in four patients (4%), two of whom had bilateral involvement. The thrombosis was confined to the calf veins in two limbs. The demographic data, neurologic status and operative details of patients with and without DVT were similar. Patients with DVT had no clinically recognizable signs. The change in calf circumference measurement was also not predictive of DVT.

CONCLUSIONS

The incidence of perioperative DVT in Chinese patients undergoing elective craniotomy for brain tumors appears to be low with the present mechanical prophylactic measures. Given the low incidence of proximal DVT as detected by duplex scan, the use of heparin prophylaxis may not be justified because of the increased risk of intracranial bleeding. Clinical assessment with calf circumference measurement is unreliable in the diagnosis of DVT.

Donor safety in living related liver transplantation: underestimation of the risks for deep vein thrombosis and pulmonary embolism

Optimal safety for donors is a necessary condition for living related liver transplantation to expand. Although the risks for complications directly related to surgical intervention have been carefully evaluated, the extent and nature of other complications, such as pulmonary embolism, associated with living donation have not been clearly anticipated. We report a case of severe pulmonary embolism followed by ulcer-related upper digestive tract bleeding in an adult donor after right hepatectomy. In this donor, we found an unexpected predisposing coagulation disorder (increased von Willebrand factor activity) postoperatively. This finding led us to include systematic screening for coagulation disorders during evaluation of donors, a policy which led us thereafter to reject definitely or temporarily some candidates for donation. Although the cost-effectiveness of such investigations is not definitely established, we strongly recommend a specific approach to improve donor safety. In addition, we emphasize that the major complications observed in living donors should be systematically reported in an international database.

Prevalence of factor V Leiden and prothrombin 20210 A variant in Bulgarian patients with pulmonary thromboembolism and deep venous thrombosis

Factor V Leiden mutation and prothrombin variant 20210 A are well-known risk factors for venous thrombosis (DVT). Recent papers have reported a lower prevalence of factor V Leiden in patients with pulmonary thromboembolism (PTE) than in patients with deep venous thrombosis. The aim of the present study was to compare the prevalence of factor V Leiden and the prothrombin 20210 G <-- A mutation in patients with DVT and in patients with PTE. We studied 128 consecutive patients (45 with DVT, 40 with PTE, and 43 with DVT and PTE) for factor V Leiden and prothrombin 20210 A. One hundred healthy persons matched by age and sex were used as controls. Factor V Leiden was present in five of the patients with PTE [12.5%; 95% confidence interval (CI), 1.5-23.5%; not significant], 15 of the patients with DVT (33.3%; 95% CI, 9.6-38.7%; P < 0.001), and 12 of the patients with DVT and PTE (27.9%; 95% CI, 4.8-33%; P = 0.001). Results for the prothrombin 20210 A mutation were as follows: four of 40 patients with PTE (10%; 95% CI, 0-13.3%; P = 0.46), nine of 45 (20%) of the patients with DVT (95% CI, 0.5-25.5%; P < 0.05) and eight of 43 with DVT and PTE were heterozygous (18.6%; 95% CI, 0-23.9%; P = 0.02). In conclusion, there is a significantly higher frequency of factor V Leiden among patients with DVT than in patients with PTE. However, there is no significant difference of factor V Leiden or 20210 A prothrombin mutation in patients with DVT than in patients with combined DVT/PTE, therefore patients with DVT, carriers of the mutations, do not appear to be at lower risk for pulmonary embolism.

Genetics of arterial prothrombotic risk states

Coronary artery disease is a leading cause of death worldwide and the largest killer of men and women in the United States. The pathophysiology of myocardial infarction is multifactorial, and numerous physiologic systems converge to dictate the formation of the two fundamental lesions, thrombosis and atherosclerosis. In this review we address genetic aspects of arterial thrombosis and the key thrombotic factors that have been associated with the increased risk for its development. Specifically, we consider components of coagulation, fibrinolysis, and platelet adhesive receptors, and we review the genetic epidemiology and in vitro laboratory data regarding their risk for the acute coronary syndromes. In combination with traditional risk factor assessment, in the near future these inherited markers can be used to manage patients with vascular disease through a better utilization of invasive or expensive diagnostic testing, as well as pharmacologic intervention.

Stasis ulcers refractory to therapy--accelerated healing by treatment with clopidogrel +/- dalteparin: a preliminary report

Stasis ulcers are commonly the result of chronic venous insufficiency. We have recently assessed 15 patients with stasis ulcers that failed to heal after one year of routine wound care. All patients demonstrated a defect in hemostasis, and a biopsy revealed livido vasculitis. Eleven of fifteen patients were treated with clopidogrel and dalteparin, and 4 of 15 patients were treated with clopidogrel alone. Thirteen of fifteen patients (86.6%) completely healed within three months of starting antithrombotic therapy. Patients with stasis ulcers and chronic venous insufficiency who fail to heal with routine wound care should be subjected to biopsy, a procoagulant defect evaluation, and initiation of clopidogrel and dalteparin therapy if a defect is found.

Method-dependent influence of certain polymorphisms in the factor V B-domain on the response to activated protein C

The factor V (FV) B-domain is extremely important to the cofactor function of native FV for activated protein C (APC) in the inactivation of factor VIII (FVIII). In a previous study, we found that in the B-domain coding portion of DNA, the polymorphisms at nucleotide positions 2391, 2663, 2684, and 2863 were associated. In the major allele, all bases are A (A allele) and those in the minor allele are G (G allele). This study concerns itself with the question of whether or not there are differences in the APC response between the A allele and the G allele in plasma samples from persons without the FV Leiden. The APC ratios of homozygous carriers of the major A allele and the minor G allele do not differentiate themselves in classical activated partial thromboplastin time-based assays. In contrast, a test based on the deactivation of FVIII in the tenase complex in homozygous carriers of the minor G allele showed significantly lower APC ratios (P = 0.001) in comparison with the major A allele. The results of the investigation after modification of the test indicate that mutative changes in the B-domain apparently influence the interaction among phospholipids, APC, FV, and protein S. An increase in FVIII through the introduction of the FVIII concentrate Kogenate to the plasma samples was associated with a drop in the APC ratios of both genotypes. After defining 59 age- and sex-based matched pairs without the FV Leiden, the observed frequency of the minor G allele was higher in the non-thrombotic group (33.0%) than in the thrombotic group (22.8%). However, the difference did not reach the level of significance (odds ratio, 0.53; 95% confidence interval, 0.26-1.12). It does, nevertheless, appear possible that a homozygous condition for the minor allele in combination with a defect known to be associated with thrombophilia represents an additional thrombogenetic risk factor.

Recurrent miscarriage syndrome due to blood coagulation protein/platelet defects: prevalence, treatment and outcome results. DRW Metroplex Recurrent Miscarriage Syndrome Cooperative Group

Although first-time miscarriages are usually caused by chromosomal defects, about 55% of recurrent miscarriages are caused by procoagulant defects that induce thrombosis and infarction of placental vessels. Of recurrent miscarriages, about 7% are caused by chromosome defects, 15% to hormonal defects, and 10% to 15% to anatomical defects. Recurrent miscarriage involves more than 500,000 women in the United States each year. During the past 4 years, 179 patients, prescreened for chromosomal, hormonal, and anatomical defects, and found to harbor none, underwent hemostasis defect evaluation. A total of 160 of these have been analyzed. A hemostasis defect was found in 150 of 160 women (n = 94% of screened women). The mean age was 33 years; the mean number of miscarriages before referral was three. All women with a procoagulant defect (149) were treated with preconception ASA at 81 mg/d, and unfractionated porcine heparin at 5000 U every 12 hours was added immediately postconception; both agents were used to term delivery. Only two of 149 patients failed therapy. The defects found were as follows: antiphospholipid syndrome, 67%; sticky platelet syndrome, 21%; tissue plasminogen activator (TPA) deficiency, 9%; factor V Leiden, 7%; high PAI-1, 6%; protein S, 5%; high LP(a), 3%; AT, 2%; protein C, 1%. Thirty-eight patients had more than one defect. In the group with antiphospholipid syndrome, 24% only had a subgroup antibody (antiphosphatidyl-serine, -inositol, -ethanolamine, -choline, -glycerol) or antiphosphatidic acid antibody, in the absence of anticardiolipin antibody or lupus anticoagulant. This finding is similar to that recently reported in early age ischemic stroke patients (<50 years old). In summary, about 55% of patients with recurrent miscarriage harbor a procoagulant defect to account for placental vascular occlusion. More than 98% will have a normal term delivery with preconception aspirin (ASA) and addition of postconception heparin to term. Patients should be screened by an obstetrician or by reproductive specialists for hormonal and anatomic defects before initiating a procoagulant evaluation; if such prescreening is done, the yield of a defect is high and appropriate therapy leads to an excellent outcome.

Prothrombin G20210A, factor V Leiden, and factor XIII Val34Leu: common mutations of blood coagulation factors and deep vein thrombosis in Austria

Mutations in the gene for prothrombin (F2 20210A) and factor V (F5 1691A, factor V Leiden) are established risk factors for deep venous thrombosis (DVT). Recently, a mutation in the gene for factor XIII (F13 100T) leading to a Valine-Leucine exchange at amino acid position 34 has been reported to be protective against DVT. To analyze the role of these mutations for DVT in Austria, we analyzed their prevalence in 154 patients with documented DVT and 308 sex- and age-matched control subjects. Allele frequencies of F2 20210A, F5 1691A, and F13 100T were 0.018, 0.039, and 0.274 among controls, and 0.045, 0.120, and 0.211 among patients, respectively. Odds ratios for DVT associated with F2 20210A, F5 1691A, and F13 100T alleles were 2.5 (95% CI: 1.1-5.7), 3.4 (95% CI: 1.9-5.8), and 0.7 (95% CI: 0.5-1.0). We conclude that F2 20210A, F5 1691A, and F13 100T are common mutations in the Austrian population. F2 20210A and F5 1691 increase the risk for DVT, whereas F13 100T is associated with a decreased risk for DVT. Routinely, analysis of these mutations may help to analyze the individual risk for DVT.

Ten-year follow-up for male twins divided into high- or low-risk groups for ischemic heart disease based on risk factors measured 25 years previously

PURPOSE

To undertake medical follow-up in white males in the National Heart, Lung, and Blood Institute (NHLBI) twin study, previously divided on the basis of cardiovascular disease risk factors.

METHODS

Tree structured survival analysis (TSSA) used at a mean age of 63 years to classify twins into high and low risk subgroups for ischemic heart disease (IHD) found that subjects at a mean age of 48 years were at highest risk with high systolic blood pressures and low high density lipoprotein cholesterol levels. Low risk subjects had lower blood pressures, better pulmonary function tests, and a negative family history for IHD or low post load plasma glucose levels. Medical record review was performed ten years later at the 4th Examination of the NHLBI twin cohort conducted in 1995-1997.

RESULTS

The percentage of men in the NHLBI twin study who died nearly tripled (from 9.3% to 25.8%) in the ten-year period between the ages of 63 and 73 years. Deaths have tended to remain higher in DZ than MZ twins (27.8% versus 23.7%). At Exam 4, the relative risk of IHD (fatal or non-fatal) was 5.24 times higher for those in the high risk group than those in the low risk class (95% confidence limit 2.72-10.07, p < 0.0001 and 5.86 for any cardiovascular disease (95% confidence limit 3.03-11.33). The proportion of deaths from IHD in subjects with a high risk profile at entry was 51.7%, and 70.0% had died from all cardiovascular related disease.

CONCLUSION

The present results indicate TSSA remained effective in classifying subjects into subgroups with greater risk of morbidity and mortality related to cardiovascular disease after ten additional years.

Multiple retinal arteriolar occlusions associated with coexisting primary antiphospholipid syndrome and factor V Leiden mutation

PURPOSE

To investigate a case of a young woman with both primary antiphospholipid syndrome and factor V Leiden mutation who developed multiple retinal arteriolar occlusions.

METHOD

Case report of a 25-year-old woman with history and laboratory tests confirming the diagnosis of both primary antiphospholipid syndrome and factor V Leiden mutation who presented with blurred vision in both eyes.

RESULTS

Multiple retinal arteriolar occlusions were observed in both of her eyes. The patient was treated first with heparin and then with warfarin.

CONCLUSIONS

Primary antiphospholipid syndrome and factor V Leiden mutation, as well as other forms of thrombophilia, should be considered in the differential diagnosis of unexplained retinal vascular occlusions. The coexistence of several thrombophilic disorders may carry a particularly high risk for thrombotic manifestations.

The role of natural anticoagulant deficiencies and factor V Leiden in the development of idiopathic portal vein thrombosis

One of the causes of portal hypertension is portal vein thrombosis (PVT). The aim of this study was to determine whether natural anticoagulant deficiencies, activated protein C resistance (APCR), and factor V Leiden play a role in the development of PVT, leading to cavernous transformation of the portal vein (CTPV). Twenty-three patients with idiopathic CTPV (group 1) seen at Hacettepe University Hospital during the past 12 years were identified and prospectively studied. These 23 patients underwent a detailed hematological evaluation including measurement of protein S, protein C, antithrombin III, activated protein C resistance (APCR), and factor V Leiden gene mutation. Additionally, all patients were tested for anticardiolipin antibodies (ACA), IgG, IgM, and lupus anticoagulant (LA). Natural anticoagulants and APCR were measured using available commercial kits, and factor V Leiden mutation (R506Q) was detected by Mnl I digestion of an amplified factor V DNA fragment. All parameters were measured at least 6 months after the diagnosis of CTPV was established. No patient was on anticoagulant or antiaggregant treatment while tested. The findings in these 23 patients were compared with those in 20 healthy control subjects (group 2), in whom all tests mentioned above were also performed. In 23 patients (group 1), who had no recognizable factor for portal vein thrombosis, considerably natural anticoagulant deficiencies and factor V Leiden mutation positivity were found when we compare them to those healthy controls (group 2). The protein C levels of six patients (26%), the protein S levels of 10 patients (43.5%), and the antithrombin III levels of five patients (26%) were lower than in control subjects. Two patients were found to have combined protein S and antithrombin III deficiency, and one had combined protein S and C deficiency and APCR. APCR was detected in seven of the 23 patients, and six of these seven patients were found to have R506Q factor V Leiden mutations. In group 1, ACA IgG levels were higher in four patients (17%) and ACA IgM level was higher in one (4%) compared with the control group. LA was positive in only one patient in group 1. Natural anticoagulant deficiencies and factor V Leiden mutation are strongly associated with PVT. The natural anticoagulant deficiencies and APCR (almost totally caused by R506Q mutation) produce a favorable medium for thrombus generation. PVT seems to be related to the natural anticoagulant deficiencies and factor V Leiden R506Q mutation. A combination of these defects increases the incidence of PVT and these factors should be evaluated carefully in patients with idiopathic CTPV.

[Resistance to activated protein C and portal vein thrombosis: two new cases and review of the literature]

INTRODUCTION

Resistance to activated protein C is the most common inherited factor at the origin of deep venous thrombosis. As portal vein thrombosis is rare, causes such as cirrhosis, intra-abdominal infection, primary hepatocellular carcinoma, myeloproliferative disorders or coagulation abnormalities must be investigated.

EXEGESIS

We report two cases of portal vein thrombosis associated with resistance to activated protein C. This association is not frequent, as only 12 cases have been reported in the literature. These studies show that resistance to activated protein C was rarely the only factor, as other prothrombotic abnormalities were present in more than 70% of cases.

CONCLUSION

Resistance to activated protein C is rarely associated with portal vein thrombosis. When present, other causes should not be overlooked. The potential existence of resistance to activated protein C should be systematically investigated in case of either portal vein thrombosis in patients with personal or familial thrombosis history, association with multiple thrombosis, or when the disease etiology remains unknown.

Mutations in promoter region of thrombomodulin and venous thromboembolic disease

The present study was designed to analyze the thrombomodulin proximal promoter region spanning nucleotides -293 to -12 to search for polymorphisms that could modify thrombomodulin gene expression in patients with venous thromboembolic disease. The study population comprised 205 patients and 394 healthy subjects of similar age and sex distribution. No polymorphisms and only 1 point mutation (G-33A) were found. The G-33A mutation was present at the heterozygous state in 2 patients and in 1 control. Being more frequent in the patients (0.97%) than in the controls (0.25%), the G-33A mutation might be a risk factor for venous thrombosis. To investigate the effect of this mutation on the thrombomodulin promoter activity, the proximal promoter region of the gene (bearing or not bearing the G-33A mutation) was inserted into a promotorless expression vector, upstream of the firefly luciferase gene, and transiently transfected into EA.hy926 endothelial cells. Under the conditions of the assay, the G-33A mutation mildly decreased the promoter activity. This study confirms that abnormalities of the thrombomodulin proximal promoter are not frequent in patients with venous thromboembolism.

Two multiplex PCR-based DNA assays for the thrombosis risk factors prothrombin G20210A and coagulation factor V G1691A polymorphisms

Two coagulation factor polymorphisms, G1691A in the factor V gene and G20210A in the prothrombin gene, are currently the most common known genetic risk factors for venous thrombosis in caucasian populations. Experimental conditions that permit simultaneous determination of these two polymorphisms using PCR-based DNA assays with the restriction enzyme, Hind III, were developed. Moreover, novel PCR-based DNA assays were established using primers that introduce specific cleavage sequences which then permit the simultaneous determination of these polymorphisms using Sac I restriction digestion analysis. Multiplex PCR-based DNA assays were used to analyze a family with a history of venous thrombosis in which these polymorphisms were both present and the results confirm the interesting variability of these genetic risk factors among family members who are symptomatic.

Venous thrombosis in older people: prevalence of the factor V gene mutation Q506

OBJECTIVES

Old age is usually considered to be a risk factor for venous thromboembolism, in conjunction with other factors such as heart failure, major surgery, cancer, long-term immobilization, and antiphospholipid antibodies. Genetic risk factors, especially inherited deficiencies in coagulation inhibitors, also play a role in the pathogenesis of thrombosis, but these are usually diagnosed in thrombophilic patients before the age of 50. The factor V Q506 mutation, responsible for activated protein C resistance, was recently linked to thromboembolic disease. We therefore investigated the prevalence of biological risk factors in older hospital patients with venous thromboembolism.

DESIGN

A 2-year study period.

SETTING

Ivry sur Seine (Paris), France.

PARTICIPANTS

Seventy-nine geriatric patients (60 women and 19 men, mean age 83+/-6.8 years, range 70-102 years) who had had at least one proven episode of venous thromboembolism were enrolled over a 2-year period.

MEASUREMENTS

Lupus anticoagulant and antithrombin (AT), protein C (PC), and protein S (PS) levels were determined in plasma. The factor V Q506 mutation was detected on genomic DNA.

RESULTS

Lupus anticoagulant was detected in two women, one of whom also had a high level of anticardiolipin IgG, leading to the diagnosis of an antiphospholipid syndrome. No hereditary deficiency in AT, PC, or PS was found, but one patient had an acquired AT deficiency. Interestingly, nine of the 79 patients (11.4%, six women and three men) were heterozygous for the factor V Q506 mutation, although none were homozygous. The only major risk factor for thrombosis identified in these patients was prolonged immobilization in four cases. Four of the nine patients who were heterozygous for the factor V Q506 mutation had recurrent thromboembolism, and two of these patients had been immobilized for long periods.

CONCLUSIONS

This study confirms that hereditary deficiencies in coagulation inhibitors, and the lupus anticoagulant, are rarely involved in the pathogenesis of venous thromboembolism in older subjects. In contrast, the factor V Q506 mutation was frequently associated with thrombosis (11.4% of our patients) and should, therefore, be considered an important risk factor in the older people.