Factor V Leiden: a disorder of factor V anticoagulant function

PURPOSE OF REVIEW: Activated protein C (APC) resistance, which is often associated with the factor V R506Q (FV Leiden) mutation, is a common risk factor for venous thrombosis. Study of the mechanism of APC resistance has revealed that coagulation FV stimulates the APC-catalysed inactivation of FVIIIa, and that this anticoagulant function of FV is impaired in FV Leiden. The present review covers the discovery, the physiological significance and the structural requirements of the APC-cofactor activity of FV. RECENT FINDINGS: Recent in vitro and in vivo experiments indicate that the anticoagulant activity of FV is physiologically relevant and that FV plays a major role in the maintenance of the haemostatic balance. Quantitative and functional defects of the APC-cofactor activity of FV lead to increased thrombin generation and are associated with a prothrombotic state. Although the structural requirements for the expression of the APC-cofactor activity of FV are now beginning to be unravelled, the underlying molecular mechanism remains elusive. SUMMARY: The APC-cofactor activity of FV and its impairment in FV Leiden can explain the different thrombosis risks associated with heterozygosity, homozygosity and pseudo-homozygosity for FV Leiden. Elucidation of the molecular mechanism of the anticoagulant function of factor V may provide novel targets for the design of antithrombotic drugs.     

Lupus anticoagulant,Factor V Leiden,and methylenetetrahydrofolate reductase gene mutation in a lupus patient with cerebral venous thrombosis

We describe the case of a young Lebanese woman with systemic lupus erythematosus (SLE) and a positive lupus anticoagulant (LAC) who developed right internal jugular vein and sigmoid sinus thrombosis. Coagulation studies showed that in addition to the LAC the patient was heterozygous for the factor V (FV) Leiden mutation, and C677T mutation of the methylenetetrahydrofolate reductase gene. The high prevalence of FV Leiden in the eastern Mediterranean region suggests that we should probably screen our SLE patients in this area, especially those with anticardiolipin antibodies and/or LAC who have no history of thrombosis, for this and other thrombophilia markers. The detection of such abnormalities may have major practical consequences for the long-term management of these patients to prevent further thrombotic episodes.Abbreviations APS Antiphospholipid syndrome - CVT Cerebral venous thrombosis - LAC Lupus anticoagulant - DVT Deep vein thrombosis - SLE Systemic lupus erythematosus - SVC Superior vena cava     

Bioprosthetic aortic valve thrombosis under effective direct oral anticoagulant therapy

With the increase in transcatheter procedures, the use of bioprosthetic valves has become more frequent in clinical practice. However, the optimal antithrombotic management of patients with bioprosthetic valves remains controversial. In this case report, we describe a patient with a bioprosthetic aortic valve who developed a thrombus while receiving effective dose direct oral anticoagulant (DOAC) therapy. A 73-year-old male patient with a bioprosthetic aortic valve replacement 2 years prior presented with a mobile thrombus and early degeneration of the valve, detected during routine follow-up while being treated with apixaban. Although the valve thrombus regressed after switching to a different anticoagulant drug, we observed that the decreased but still high gradient persisted due to the early degeneration. Anticoagulant management of bioprosthetic valve patients demands careful attention. Although evidence supporting the use of DOACs is growing, close patient follow-up and further evaluation in case of doubt remain critical. The development of a thrombus in a bioprosthetic valve patient who is receiving anticoagulation therapy, as in this case, highlights the need for optimal management to prevent thromboembolic complications and valve degeneration.     

Incidence of Factor V Leiden in Patients with Acute Myocardial Infarction

The genetic defect of coagulation factor V known as factor V Leiden produces a resistance to degradation by activated protein C (APC) and increases the risk of venous thromboembolism. The data on arterial thrombosis associated with APC resistance are still not clearly defined. We conducted a study in patients presenting with acute myocardial infarction (MI) to assess whether factor V Leiden increases the risk of arterial thrombosis. We studied 109 patients who had a diagnosis of acute MI (69 males and 40 females, aged 25–91 years), and 112 controls. The study population was identified by characteristic ECG changes and elevation of serum CK-MB, whereas the control subjects were anonymous healthy blood donors with no known history of coronary artery disease. Blood samples from the patients and controls were analyzed for the factor V Leiden mutation by DNA analysis, using the polymerase chain reaction. Heterozygous factor V Leiden mutation was found in 9 of 109 (8%) MI patients and 5 of 112 (4%) control subjects (P = .42). In conclusion, this study shows no evidence of an association between factor V Leiden and acute MI.     

Spontaneous venous thrombosis in a young patient with combined factor V Leiden and lupus anticoagulant.

We describe a case of a 28-year-old man who developed an extensive spontaneous deep venous thrombosis. Testing revealed heterozygotic factor V Leiden mutation, and the presence of both lupus anticoagulant (LA) and elevated IgM anticardiolipin antibody (ACA). Several family members were found to be heterozygous for factor V Leiden. A paternal aunt had the factor V Leiden mutation, an elevated plasma homocysteine and a borderline increased IgG ACA level. No other family member had a history of a venous thrombotic event. This case illustrates that evaluation of young patients who present with venous thrombosis should be performed for both hereditary and acquired thrombophilic defects. The family studies suggest that the presence of a lupus anticoagulant may be more clinically significant than elevated ACA in risk assessment. Although screening family members when the proband carries factor V Leiden is controversial, psychological reassurance of those who test negative and simple advice on occupations or social habits (e.g., smoking) for those who test positive may be important benefits.     

Factor V HR2 haplotype: a risk factor for venous thromboembolism in individuals with absence of Factor V Leiden

Venous thromboembolism (VTE), including deep venous thrombosis (DVT) and pulmonary embolism (PE), occurs secondary to a number of hereditary and acquired disorders of hemostasis. A recently recognized polymorphism in Factor V (FV) gene H1299R (also named HR2) has been reported to be a possible risk factor for the development of VTE. The aim of this study is to evaluate the role of HR2 polymorphism in VTE in a group of Lebanese patients. Seventy-three VTE patients and 125 healthy subjects were examined for HR2. The average ages for the patients and controls were 45.0 ± 19.1 years and 35.4 ± 18.6 years, respectively. Sixty patients (82.2%) had DVT, eight patients (11%) had PE, and five patients (6.8%) had both. There was significant association between FV Leiden and VTE (p < 0.001). HR2 haplotype had a prevalence of 16.4% in patients. VTE patients with normal FV were 2.7 times more likely to have the HR2 haplotype as compared to controls with normal FV (p = 0.036, 95% CI = 1.04–7.06). We conclude that the FV HR2 haplotype significantly affects the risk of VTE in subjects with normal FV. This finding entails that screening for the HR2 haplotype should be done in VTE patients with normal FV Leiden results. No conflicts of interest. No source of funding.     

Stuttering priapism complicating warfarin therapy in a patient with protein C deficiency

Priapism is a rare disorder defined as a persistent penile erection that continues hours beyond, or is unrelated to, sexual stimulation. There are two types of priapism; ischemic low-flow type or non-ischemic high flow, with differing etiologies. Priapism associated with thrombophilia is a well-recognized entity. However, the pathogenesis of this association is not fully understood. We report a rare case of recurrent (stuttering) priapism in a patient with protein C deficiency while maintained on Warfarin therapy. This therapy was also complicated by Warfarin-induced skin necrosis.     

Bronchiectasis following colectomy in a patient with ulcerative colitis and factor V Leiden mutation

For some years it has been known that lung disease may be present in patients with inflammatory bowel disease (IBD). Diseases of the central airway, bronchi, and lung parenchyma are among the most common forms of lung involvement in IBD patients. Bronchiectasis is frequent and almost always appears after the onset of disease and in close association with inflammatory activity. However, reports of the appearance of bronchiectasis following colectomy for an exacerbation of IBD have been rare. We present the case of a 36-year-old man with severe ulcerative colitis who, following a total colectomy, developed bilateral bronchiectasis 12 months after surgery and for whom both preoperative and postoperative computed tomography scans were available.     

Budd-Chiari Syndrome Associated with Visceral Leishmaniasis and Factor V Leiden Mutation

We here report a case of subacute Budd-Chiari syndrome (BCS) related to Factor V Leiden (FVL) mutation in the presence of visceral leishmaniasis. A 17-year-old man was admitted to hospital because of abdominal pain, pretibial edema and fever. The clinical picture of BCS had been developed within several months. BCS was diagnosed by radiographic examination. On DNA analysis, a heterozygote Arg506Gln mutation in the factor V gene was found. Histological examination of the bone marrow showed intracellular leishmania amastigotes. Despite appropriate treatment patients clinical condition deteriorated rapidly and died with multiorgan failure. FVL mutation is the most common procoagulant disorder and account for many cases of BCS. This case report demonstrates that in addition to duration and severity of the disease accompanying conditions including infections are prognostically significant for the outcome of this potentially lethal disease.This revised version was published online in May 2005 with a corrected cover date.     

Factor V Leiden mutation in Turkish patients with homozygous cystathionine beta-synthase deficiency

Venous and arterial thromboembolism can occur in patients with homocystinuria. Resistance to activated protein C, which is caused by a single point mutation in the gene for factor V, renders an individual at risk for thrombosis. It has been suggested that coexistence of hereditary homocystinuria and factor V Leiden mutation might jointly play a role in the development of thrombosis. We analysed six patients with homocystinuria due to cystathionine -synthase deficiency for factor V Leiden and prothrombin G20210A mutations. Only one patient was found to have the factor V Leiden mutation in homozygous form and this patient had suffered from severe thrombosis. One patient was found to be heterozygous with no documented thrombosis. None of the patients had prothrombin G20210A mutation. We stress the necessity for screening for known thrombophilic risk factors in patients with cystathonine -synthase deficiency. The coexistence of the factor V Leiden mutation can cause severe thrombotic events in patients with homocystinuria.     

Fabry disease and Factor V Leiden: a potent vascular risk combination

A 45-year-old man with heterozygous Factor V Leiden presented with his third cerebrovascular accident despite being on warfarin at a therapeutic international normalized ratio. Subsequent investigation revealed a second genetic diagnosis of Fabry disease. He then had an acute myocardial infarction whilst on aspirin and warfarin.     

Postoperative Pulmonary Embolism in a Young Female Accompanying with Factor V Leiden Mutation and Hereditary Sypherocytosis

A 20 year-old female, heterozygous for Factor V Leiden mutation (FVLM) is presented. Her personal history was prominent for severe anaemia during her gestation. Aetiology of anaemia was found to be hereditary spherocytosis (HS). Intrauterine foetal death had occurred at 20 weeks of gestational age. Two days after curettage, she developed pulmonary embolism (PE). This is an unusual case of pulmonary embolism and intrauterine foetal death coexisting with FVLM and/or HS. We present the case so that a general practitioner or haematologist can hardly see such cases in daily practice. Hence, a young female with PE should be screened for hypercoagulable states including FVLM or HS.     

Factor V Leiden,hormone replacement therapy,and risk of venous thromboembolic events in women with coronary disease

Oral contraceptive use in women with factor V Leiden is associated with increased rates of venous thromboembolic events (VTEs). However, the effects of hormone replacement therapy (HRT) in postmenopausal women with factor V Leiden are not known. A nested case-control study was conducted among women with established coronary disease enrolled in 2 randomized clinical trials of HRT, the Heart and Estrogen/Progestin Replacement Study (HERS) and the Estrogen Replacement and Atherosclerosis (ERA) trial. The Leiden mutation was present in 8 (16.7%) of 48 cases with VTE compared with only 7 (6.3%) of 112 controls (odds ratio [OR](Leiden) 3.3, 95% CI 1.1 to 9.8; P=0.03). In women without the factor V Leiden mutation, risk associated with HRT use was significantly increased (OR(HRT) 3.7, 95% CI 1.4 to 9.4; P<0.01). On the other hand, in women with the factor V Leiden mutation, the estimated risk associated with HRT was increased nearly 6-fold, although the CIs were wide and included unity (OR(HRT) 5.7, 95% CI 0.6 to 53.9; P=0.13). The OR for women with the Leiden mutation who were also assigned to HRT compared with wild-type women assigned to placebo was 14.1 (95% CI 2.7 to 72.4, P=0.0015). In women with the factor V Leiden mutation who were treated with HRT, the estimated absolute incidence of VTE was 15.4 of 1000 per year compared with 2.0 of 1000 per year in women without the mutation who were taking a placebo (P=0.0015). On the basis of these data, in women with coronary disease, the estimated number needed to screen for factor V Leiden to avoid an HRT-associated VTE during 5 years of treatment is 376. If factor V Leiden genotyping becomes less expensive, it could be cost effective to screen for the presence of the mutation before instituting HRT in women with coronary disease.     

Minimum effective intensity of oral anticoagulant therapy in primary prevention of coronary heart disease

BACKGROUND: There is mounting evidence that low-intensity oral anticoagulation is effective, particularly in primary prevention of thrombosis, with important implications for safety and the practicalities of using warfarin. Because it is desirable to know possible benefits for different indications so that optimal therapy can be administered in as wide a range of conditions as possible, we analyzed data from the Thrombosis Prevention Trial, a factorial trial that compared treatment with low-intensity, dose-adjusted warfarin and low-dose aspirin separately and together, to determine the minimum effective intensity of oral anticoagulation in the primary prevention of coronary heart disease. METHODS: The international normalized ratio (INR) most recent to an event and overall time at each INR were used to calculate the INR-related event rate for coronary events, strokes, and major and minor bleeding episodes in 2545 men receiving warfarin with or without aspirin (75 mg/d) and followed up for a total of 9952 person-years. RESULTS: Compared with placebo, warfarin alone at a dose that maintained the INR at 1.4 or more significantly reduced the risk of a coronary event by 47% (95% confidence interval, 4%-70%; P =.03), whereas the risk of a coronary event was not reduced at INRs below 1. 4. Coronary events, strokes, and major bleeding episodes combined were significantly reduced by 45% (95% confidence interval, 9%-67%; P =.02) in the warfarin group compared with the placebo group when the INR was 1.4 or more. Minor bleeding episodes increased as the INR rose above about 2.0. No significant association of INR with coronary events was observed with combined warfarin and aspirin, possibly reflecting the small number of such events that occurred in this group, therefore limiting the power to detect an association with INR. CONCLUSIONS: Warfarin alone is effective in the primary prevention of coronary heart disease when the dose is adjusted to maintain an INR of 1.4 or more. The results add to the evidence that low-intensity, dose-adjusted oral anticoagulation is effective for a range of conditions.     

False-negative factor V Leiden genetic testing in a patient with recurrent deep venous thrombosis

False-negative genetic testing of the factor V Leiden (fVL) mutation is unusual. We report a case of a young woman with a history of deep venous thrombosis tested for the fVL at four separate laboratories on four separate dates. Two laboratories reported the patient to be heterozygous for the fVL, while the other two reported no evidence of a mutation. Testing methods of the various laboratories were reviewed, and additional testing was performed on stored and newly drawn DNA samples, including sequencing of the fVL gene segment. The preponderance of evidence indicates the patient to be heterozygous for the fVL mutation. Dissection of data suggests that either sample misidentification or faulty allele specific amplification methods could have led to false-negative results in two laboratories. In one of the two laboratories, misinterpretation of results and clerical error could not be excluded. There is a need for standardization of optimized fVL genetic testing methods. Further education of ordering physicians on the limitations of genetic testing is necessary.