Oral Contraceptive-Associated Thromboembolism. A Retrospective Analysis of Thrombophilic Work-out and Long Term Follow up in 57 Cases

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5348-5348
Author(s):  
Emmanouil Papadakis ◽  
Smaragda Efremidou ◽  
Haris Kartsios ◽  
Margarita Mpraimi ◽  
Kiriaki Kokoviadou ◽  
...  
Keyword(s):  
Family History ◽  
Protein C ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Factor V ◽  
Factor V Leiden Mutation ◽  
Apc Resistance ◽  
Increased Risk ◽  
Fv Leiden

Abstract Introduction: The increased risk of venous thrombosis in women taking oral contraceptives (OCs) has been recognized since the early 1960s. Coexistence of hereditary risk factors appears to have an additive effect. Women under OCs that carry the factor V Leiden mutation have a 35-fold increased risk of thromboembolic events compared to women without the mutation who are not on OCs. Evaluation of family and personal history is the mainstay of prophylaxis prior to OC administration, but often family thrombophilia or thromboembolic (TE) events are not reported prior to OCs prescription. Patients-Methods: Fifty-seven women with a median age of 28 (21–48) years, which suffered OC-associated TE, were studied. The median period of OC therapy prior to TE event was 2 months (0.5–60). Fifty-five of them experienced VTE while 2 suffered stroke. Leg thrombosis was the most common clinical finding [37/55 (67,2%) patients] Apart from personal and family history, Thrombophilia investigation included measurement of : serum Homocysteine, Antithrombin, Protein C and S, Lipoprotein (a), Activated Protein C (APC) resistance, antiphospholipid antibodies and lupus anticoagulant. In addition the presence of FV Leiden, FII 20210 GA mutations and MTHFR 677 CT polymorphism were determined. Results: A high prevalence of the factor V Leiden mutation was detected in the study group; 50% had APC-resistance test positive, 26 (45%) patients were found to be heterozygous and 3 (5,2%) homozygous for the FV Leiden mutation. Lp(a) elevation was observed in 19,3% and Homocysteine elevation in 15,8% of patients. In 9 women (15,8%) both family history and thrombophilic profile were negative. Serious VTE events (2 abdominal and 6 CNS thromboses) were observed only in the Leiden subgroup. During the follow up period ranging from months to 18 years, 3 women (6,25%) experienced a miscarriage and 14 suffered additional VTE events (25%) and they are currently on permanent anticoagulation. Conclusions : Universal thrombophilia screening of women prior to prescription of OCs is not advisable as it does not appear to be cost effective. However, screening certain subgroups, such as women with a known personal or family history, may be of great value. If a full thrombophilic profile can’t be performed, a mere activated protein C resistance test, that reflects the presence of the factor V Leiden mutation, may provide an easy and cheap way of identifying and consulting properly women at higher risk for VTE prior to OC use. Women with OC-associated VTE and thrombophilia carry a substantial recurrence risk that persists for years.

A Reduced Sensitivity for Activated Protein C in the Absence of Factor V Leiden Increases the Risk of Venous Thrombosis

Blood ◽  
1999 ◽  
Vol 93 (4) ◽  
pp. 1271-1276 ◽  
Author(s):  
Marieke C.H. de Visser ◽  
Frits R. Rosendaal ◽  
Rogier M. Bertina
Keyword(s):  
Risk Factor ◽  
Confidence Interval ◽  
Venous Thrombosis ◽  
Protein C ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Factor V ◽  
Factor V Leiden Mutation ◽  
Apc Resistance ◽  
Increased Risk

Abstract Activated protein C (APC) resistance caused by the factor V Leiden mutation is associated with an increased risk of venous thrombosis. We investigated whether a reduced response to APC, not due to the factor V point mutation, is also a risk factor for venous thrombosis. For this analysis, we used the Leiden Thrombophilia Study (LETS), a case-control study for venous thrombosis including 474 patients with a first deep-vein thrombosis and 474 age- and sex-matched controls. All carriers of the factor V Leiden mutation were excluded. A dose-response relationship was observed between the sensitivity for APC and the risk of thrombosis: the lower the normalized APC sensitivity ratio, the higher the associated risk. The risk for the lowest quartile of normalized APC-SR (<0.92), which included 16.5% of the healthy controls, compared with the highest quartile (normalized APC-SR > 1.05) was greater than fourfold increased (OR = 4.4; 95% confidence interval, 2.9 to 6.6). We adjusted for VIII:C levels, which appeared to affect our APC resistance test. The adjusted (age, sex, FVIII:C) odds ratio for the lowest quartile was 2.5 (95% confidence interval, 1.5 to 4.2). So, after adjustment for factor VIII levels, a reduced response to APC remained a risk factor. Our results show that a reduced sensitivity for APC, not caused by the factor V Leiden mutation, is a risk factor for venous thrombosis.

A Reduced Sensitivity for Activated Protein C in the Absence of Factor V Leiden Increases the Risk of Venous Thrombosis

Blood ◽  
1999 ◽  
Vol 93 (4) ◽  
pp. 1271-1276 ◽  
Author(s):  
Marieke C.H. de Visser ◽  
Frits R. Rosendaal ◽  
Rogier M. Bertina
Keyword(s):  
Risk Factor ◽  
Confidence Interval ◽  
Venous Thrombosis ◽  
Protein C ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Factor V ◽  
Factor V Leiden Mutation ◽  
Apc Resistance ◽  
Increased Risk

Activated protein C (APC) resistance caused by the factor V Leiden mutation is associated with an increased risk of venous thrombosis. We investigated whether a reduced response to APC, not due to the factor V point mutation, is also a risk factor for venous thrombosis. For this analysis, we used the Leiden Thrombophilia Study (LETS), a case-control study for venous thrombosis including 474 patients with a first deep-vein thrombosis and 474 age- and sex-matched controls. All carriers of the factor V Leiden mutation were excluded. A dose-response relationship was observed between the sensitivity for APC and the risk of thrombosis: the lower the normalized APC sensitivity ratio, the higher the associated risk. The risk for the lowest quartile of normalized APC-SR (<0.92), which included 16.5% of the healthy controls, compared with the highest quartile (normalized APC-SR > 1.05) was greater than fourfold increased (OR = 4.4; 95% confidence interval, 2.9 to 6.6). We adjusted for VIII:C levels, which appeared to affect our APC resistance test. The adjusted (age, sex, FVIII:C) odds ratio for the lowest quartile was 2.5 (95% confidence interval, 1.5 to 4.2). So, after adjustment for factor VIII levels, a reduced response to APC remained a risk factor. Our results show that a reduced sensitivity for APC, not caused by the factor V Leiden mutation, is a risk factor for venous thrombosis.

“Pseudo Homozygous” Activated Protein C Resistance due to Double Heterozygous Factor V Defects (Factor V Leiden Mutation and Type I Quantitative Factor V Defect) Associated with Thrombosis: Report of Two Cases Belonging to Two Unrelated Kindreds

1996 ◽  
Vol 75 (03) ◽  
pp. 422-426 ◽  
Author(s):  
Paolo Simioni ◽  
Alberta Scudeller ◽  
Paolo Radossi ◽  
Sabrina Gavasso ◽  
Bruno Girolami ◽  
...  
Keyword(s):  
Protein C ◽  
Dna Analysis ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Type I ◽  
Factor V ◽  
Factor V Leiden Mutation ◽  
Thrombotic Risk ◽  
Apc Resistance ◽  
Quantitative Factor

SummaryTwo unrelated patients belonging to two Italian kindreds with a history of thrombotic manifestations were found to have a double heterozygous defect of factor V (F. V), namely type I quantitative F. V defect and F. V Leiden mutation. Although DNA analysis confirmed the presence of a heterozygous F. V Leiden mutation, the measurement of the responsiveness of patients plasma to addition of activated protein C (APC) gave results similar to those found in homozygous defects. It has been recently reported in a preliminary form that the coinheritance of heterozygous F. V Leiden mutation and type I quantitative F. V deficiency in three individuals belonging to the same family resulted in the so-called pseudo homozygous APC resistance with APC sensitivity ratio (APC-SR) typical of homozygous F. V Leiden mutation. In this study we report two new cases of pseudo homozygous APC resistance. Both patients experienced thrombotic manifestations. It is likely that the absence of normal F. V, instead of protecting from thrombotic risk due to heterozygous F. V Leiden mutation, increased the predisposition to thrombosis since the patients became, in fact, pseudo-homozygotes for APC resistance. DNA-analysis is the only way to genotype a patient and is strongly recommended to confirm a diagnosis of homozygous F. V Leiden mutation also in patients with the lowest values of APC-SR. It is to be hoped that no patient gets a diagnosis of homozygous F. V Leiden mutation based on the APC-resi-stance test, especially when the basal clotting tests, i.e., PT and aPTT; are borderline or slightly prolonged.

Prevalence of Activated Protein C Resistance Due To Factor V Leiden Mutation among South Asians (India and Pakistan) with Venous Thromboembolism.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4043-4043
Author(s):  
Sirisha Perumandla ◽  
Yelena Patsiornik ◽  
Neetha Mahajan ◽  
Anju Ohri
Keyword(s):  
Protein C ◽  
Chart Review ◽  
South Asians ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Factor V ◽  
Inherited Thrombophilia ◽  
Apc Resistance ◽  
Fv Leiden ◽  
Work Up

Abstract Objective: To study the prevalence of Activated Protein C (APC) resistance due to Factor V Leiden (FV Leiden) mutation among the first generation immigrants from India and Pakistan with venous thromboembolism (VTE). Introduction: APC resistance due to the substitution of Arginine 506 by Glutamine in coagulation Factor V is caused by G1691A mutation in exon 10 of Factor V gene. This is the commonest cause of inherited thrombophilia in Caucasians, but the frequency of this mutation is low in non-Caucasians. Among subjects in the Physician Health Study, the frequency of FV Leiden was found to be 5.27% in Caucasian Americans vs. 0.45% in Asian Americans. Another study found no mutation in 191 Asian Americans tested. In non-Caucasians with VTE, it is generally considered not cost effective to screen for this mutation. However Asians are a heterogeneous group and the Leiden gene frequency varies among different ethnic populations. While the frequency of FV Leiden gene has been documented to be low in China, Korea, Japan, Thailand, Indonesia etc, the frequency in India and Pakistan is not well studied. Two studies found a carrier frequency of 2% (Rees et al) and 4.2 % (Gou et al) among the general population from India and Pakistan. This is similar to the frequency found in Middle Eastern and European population. We did not come across any study of FV Leiden gene frequency in patients with VTE from India and Pakistan. Patients and Methods: A retrospective chart review of patients of Indian or Pakistani origin seen at Coney Island Hospital, from July 1996 to June 2003, who had a work up for inherited thrombophilia after an episode of VTE. During the chart review age, sex, first or recurrent episode and any predisposing factors such as immobilization, malignancy, hormonal therapy, surgery, pregnancy, and the presence of SLE or MPD were noted. Thrombophilia work up included functional assays for Protein C, S and Antithrombin III, Lupus anticoagulant, ACA and Homocysteine levels. APC resistance was measured by a clotting assay using Factor V depleted plasma and all patients who were borderline or resistant were tested for the presence of FV Leiden mutation by PCR. Results: A total of 18 patients were studied. All had an episode of VTE documented by a Doppler ultrasonography or a Ventilation Perfusion lung scan or a CT angiogram. 3 out of 18 patients (16.6%) had APC resistance. All the three patients were confirmed to be heterozygous for FV Leiden mutation. Two were male and one was a female with a median age of 36 yrs (27, 36 and 57 yrs). The female patient had a recurrent episode, first one occurred during pregnancy, but the second episode had no precipitating events. One male patient had trauma to the leg and was immobilized at the time of the VTE, another male patient was a cab driver by occupation. None of the patients had any other concurrent inherited thrombophilic state. Conclusions: The prevalence of the FV Leiden mutation is significantly high among South Asians with VTE in our study. If the findings are confirmed by a larger study, screening for this mutation for thrombophilia would be relevant in patients of South Asian origin and screening recommendations for family members would be identical to Caucasian population. The high prevalance as in Caucasians suggests a founder effect and possible spread of the mutation by the migration of Neolithic farmers from the Middle East towards Europe and India, ten thousand years ago. This has been confirmed by haplotype analysis.

Thrombin generation and activated protein C resistance in the absence of factor V Leiden correlates with the risk of recurrent venous thromboembolism in women aged 18–65 years

2011 ◽  
Vol 106 (11) ◽  
pp. 901-907 ◽  
Author(s):  
Svetlana Tchaikovski ◽  
Margareta Holmström ◽  
Jan Rosing ◽  
Katarina Bremme ◽  
Gerd Lärfars ◽  
...  
Keyword(s):  
Risk Factor ◽  
Protein C ◽  
Thrombin Generation ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Peak Height ◽  
Factor V ◽  
Risk Of Recurrence ◽  
Apc Resistance ◽  
Increased Risk

SummaryIdentification of patients at high risk of recurrence after a first event of venous thromboembolism (VTE) remains difficult. Resistance to activated protein C (APC) is a known risk factor for VTE, but data on the risk of recurrence is controversial. We wanted to investigate whether APC resistance in the absence of factor V Leiden, determined with global coagulation test such as the thrombin generation assay, could be used as a marker for increased risk of recurrent VTE among women 18–65 years old after a first event of VTE. In a cohort of 243 women with a first event of VTE, plasma was collected after discontinuation of anticoagulant treatment and the patients were followed up for 46 months (median). Thrombin generation was measured via calibrated automated thrombography, at 1 pM and 10 pM of tissue factor (TF). In women without factor V Leiden (n=117), samples were analysed in the absence and in the presence of APC. Increase in ETP (endogenous thrombin potential) and peak height analysed in the presence of APC correlated significantly with higher risk of recurrence. At 1 pM, peak height correlated with increased risk of recurrence. In conclusion, high thrombin generation in the presence of APC, in women after a first event of VTE is indicative for an increased risk of a recurrence. We also found that thrombin generation at low TF (1 pM) is correlated with the risk of recurrence. Our data suggest that APC resistance in the absence of factor V Leiden is a risk factor for recurrent VTE.

ProC® Global Assay in the Evaluation of Women with History of Severe Preeclampsia or HELLP Syndrome

2002 ◽  
Vol 8 (4) ◽  
pp. 319-324 ◽  
Author(s):  
Lothar Heilmann ◽  
Georg-Friedrich v. Tempelhoff ◽  
Kuhnhart Pollow
Keyword(s):  
Hellp Syndrome ◽  
Protein C ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Protein S ◽  
Anticardiolipin Antibodies ◽  
Factor V ◽  
Factor V Leiden Mutation ◽  
Lupus Anticoagulants ◽  
Apc Resistance

Preeclampsia/HELLP syndrome has been associated with a high incidence of defects in the protein C pathway and increased anticardiolipin-antibodies/lupus anticoagulants. It is also apparent that thrombophilia is responsible for other pregnancy complications, such as recurrent spontaneous abortion, fetal growth restriction, intrauterine fetal death, and abruptio placentae. ProC® Global is a new global clotting assay designed to evaluate the abnormalities in the protein C anticoagulant pathway. It is based on the ability of endogenous activated protein C, generated by activation of protein C by Protac®, to prolong an activated partial thromboplastin time. A total of 61 patients with a history of severe preeclampsia or HELLP syndrome and 61 normal pregnant women (controls) were evaluated, 15 of whom had factor V Leiden mutation, 12 had protein C/S deficiency, 30 had a repeated lupus anticoagulants, and 27 increased anticardiolipin antibodies (ACA). All carriers of factor V Leiden mutation (N= 15) as well as all the patients with low activated protein C (APC) resistance ratio (N= 15) had a ProC® Global normalized ratio (NR) less than 0.80 (sensitivity 100%). Twenty-four patients positive for the lupus anticoagulants (LA) and 19 patients positive for ACA (> 5.0 IgG U/mL) had a ProC® Global NR less than 0.8, while six and eight, respectively, had a ProC® Global NR greater than 0.8 (sensitivity, 70%-80%). The detection of a reduced protein C/protein S activity (<70%) was low (sensitivity, 33%-44%). In 25 cases with pathologic ProC® Global results, a thrombophilic defect (protein S/LA/ACA without APC resistance) was diagnosed in 18 women; but in 7 cases, no known thrombophilic defect was present. ProC® Global is a new screening test to identify patients with defects of the protein C system and an activated clotting system in preeclampsia but cannot correctly cover each thrombophilic component.

Comparison of three activated protein C resistance tests in the risk assessment of venous thrombosis in non-carriers of the factor V Leiden mutation

2006 ◽  
Vol 95 (04) ◽  
pp. 728-734 ◽  
Author(s):  
Felipe Guerrero ◽  
Catherine Arnaud ◽  
Francoise Nguyen ◽  
Bernard Boneu ◽  
Pierre Sié
Keyword(s):  
Venous Thrombosis ◽  
Protein C ◽  
Activated Protein C ◽  
Significant Risk ◽  
Factor V Leiden ◽  
Factor V ◽  
Activated Protein C Resistance ◽  
Factor V Leiden Mutation ◽  
Risk Increase ◽  
Increased Risk

SummaryActivated protein C resistance (APCR), measured using the original assay described by Dahlbäck, is a risk factor for venous thrombosis independent of the factor V Leiden (FVL) mutation. This assay is based on the activated partial thromboplastin time (APTT) after plasma exposure to activated protein C (APC).As this assay was sensitive to numerous interferences, new assays have been developed for FVL screening. The objectives of the study were to investigate the association of second generation assays for APCR with venous thrombosis in FVL non-carriers. One hundred ninety-seven subjects with a history of venous thrombosis and 211 controls were explored using 3 APCR assays, the original APTT-based assay (test A), an APTT-based assay with factorV depleted plasma pre-dilution (test B) and a direct factorX activation-based assay with the same pre-dilution (test C).We found that subjects with results in the lowest quartile of the APTT-based assays are at increased risk, compared to those in the highest quartile (test A Odds Ratio = 6.39; 95%CI 3.23–12.63; test B OR=2.72; 95%CI 1.50–4.94). There was no significant risk increase associated with test C results. After adjusting for FVIII levels, the ORs of tests A and B were similar (test A OR=3.22; 95%CI 1.47–7.08; test B OR=3.10; 95%CI 1.54–6.21). In conclusion, APTT-based assays, but not direct factor X activation-based assays, effectively detect the risk for venous thrombosis independent of FVL. Pre-dilution in factor V depleted plasma is an effective way to directly assess the risk independent of FVIII levels.

Activated Protein C Resistance, the Factor V Leiden Mutation, and a Laboratory Testing Algorithm

2002 ◽  
Vol 126 (5) ◽  
pp. 577-582 ◽  
Author(s):  
Elizabeth M. Van Cott ◽  
Britt L. Soderberg ◽  
Michael Laposata
Keyword(s):  
Laboratory Testing ◽  
Protein C ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Protein S ◽  
Factor V ◽  
Activated Protein C Resistance ◽  
Factor V Leiden Mutation ◽  
Increased Risk ◽  
Testing Algorithm

Abstract Objectives.—To present the current understanding of factor V Leiden and activated protein C resistance, and to propose a laboratory testing algorithm. Data Sources.—Publications on MEDLINE with the terms factor V Leiden or activated protein C resistance through mid 2001, as well as publications in the authors' files, were screened for inclusion in this report. Study Selection.—Original studies that report a novel finding on testing or clinical features of activated protein C resistance or factor V Leiden are included. Data Extraction.—The novel or key findings from the selected studies are analyzed. Data Synthesis.—Protein C and protein S are the integral components of an anticoagulation pathway that limits fibrinogen conversion to fibrin through the degradation of factors Va and VIIIa. When factor Va is resistant to degradation by activated protein C, this anticoagulation pathway does not operate properly, and patients have an increased risk for thrombosis. This report describes the protein C/protein S pathway, the significance of activated protein C resistance and the factor V Leiden mutation, and the clinical testing used to detect activated protein C resistance and the factor V Leiden mutation. A proposed laboratory testing algorithm is also provided. Conclusions.—Factor V Leiden is a risk factor for venous thrombosis and it is particularly common in white populations. A laboratory testing algorithm is proposed.

Oral contraceptive use in women with poor anticoagulant response to activated protein C but not carrying the factor V Leiden mutation increases the risk of venous thrombosis

2004 ◽  
Vol 91 (04) ◽  
pp. 712-718 ◽  
Author(s):  
Michela Cini ◽  
Benilde Cosmi ◽  
Silvia Mattarozzi ◽  
Giuseppa Manto ◽  
Gualtiero Palareti ◽  
...  
Keyword(s):  
Protein C ◽  
Contraceptive Use ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Reproductive Age ◽  
Factor V ◽  
Lower Quartile ◽  
Factor V Leiden Mutation ◽  
Healthy Women ◽  
Apc Resistance

SummaryThe factor V Leiden mutation (FVL), associated with reduced sensitivity to activated Protein C (APC), is a risk factor for venous thromboembolism (VTE) and displays a strong interaction with oral contraceptives (OC). The aim of this study was to evaluate the risk of VTE in OC users with reduced APC sensitivity unrelated to the FVL. APC sensitivity was measured by an original aPTT-based test (without sample pre-dilution in factor V-deficient plasma) in 195 women who suffered from VTE in reproductive age and in 487 healthy women with results being expressed as normalized ratio. Subjects with currently known clinically relevant thrombophilic alterations were excluded. APC normalized ratios were stratified into quartiles. The adjusted ORs of subjects in the lower quartile (≤0.90) was 2.46 (95%CI: 1.02–5.95). Of the 195 patients, 89 had suffered VTE during OC. The 181 healthy women who had used OC for at least 6 months in the two year period before presentation but who had stopped OC at least 3 months before blood sampling were considered OC users. The risk of VTE in subjects using OC with APC normalized ratio in the lower quartile was increased 4.9-fold (95% CI: 1.92–12.6). In conclusion, our results showed that altered APC resistance in women not carrying the FVL significantly increased the VTE risk, albeit to a lesser extent than in women also carrying the FVL. Our data also showed that OC use in women with altered APC resistance further increased the risk of VTE in a way that exceeded the additive expectation.

scholarly journals Mortality and Causes of Death in Families With the Factor V Leiden Mutation (Resistance to Activated Protein C)

Blood ◽  
1997 ◽  
Vol 89 (6) ◽  
pp. 1963-1967 ◽  
Author(s):  
Elysée T.M. Hille ◽  
Rudi G.J. Westendorp ◽  
Jan P. Vandenbroucke ◽  
Frits R. Rosendaal
Keyword(s):  
Life Expectancy ◽  
Cause Of Death ◽  
Protein C ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Ischemic Heart ◽  
Malignant Neoplasms ◽  
Factor V ◽  
Factor V Leiden Mutation ◽  
Apc Resistance

AbstractTo investigate whether resistance to activated protein C (APC resistance) because of a mutation in the factor V gene (factor V Leiden) leads to a decrease in life expectancy, we analyzed overall and cause-specific mortality in 171 parents whose offspring carried this mutation. Compared with the Dutch general population, and after adjustment for age, sex, and calendar period, we found no excess deaths in the parents (standardized mortality ratio [SMR], 1.0; 95% confidence interval [CI], 0.8 to 1.2). The cause-specific SMR for malignant neoplasms (1.0; 95% CI, 0.6 to 1.4), diseases of the circulatory system (1.0; 95% CI, 0.7 to 1.4), and cerebrovascular disease (1.0; 95% CI, 0.4 to 1.9) also did not differ from unity. The SMRs for diseases of the respiratory system (1.4; 95% CI, 0.6 to 2.6) and for ischemic heart diseases (1.1; 95% CI, 0.7 to 1.7) were slightly increased. Under the age of 45 years, there was a ninefold increase of dying from ischemic heart disease. Thromboembolic complications were mentioned only once (venous embolism or thrombosis) as an underlying (“primary”) cause of death (SMR, 2.3; 95% CI, 0.1 to 13.0) and three times (pulmonary embolisms) as a contributing (“secondary”) cause of death (SMR, 1.5; 95% CI, 0.3 to 4.4). We conclude that there is no major effect of APC resistance on life expectancy. Therefore, long-term anticoagulation in carriers of factor V Leiden, on the basis of the carrier state alone, is not indicated.

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