Retrospective Cohort of Unprovoked Venous Thromboembolism Patients: What Proportion Have Potent Thrombophilias Necessitating Indefinite Anticoagulants?

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2318-2318
Author(s):  
Junghyun Park ◽  
Marc Rodger
Keyword(s):  
Protein C ◽  
Factor V Leiden ◽  
Protein S ◽  
Factor V ◽  
Gene Variant ◽  
Anticoagulation Management ◽  
Antithrombin Deficiency ◽  
S Deficiency ◽  
Prothrombin Gene ◽  
Thrombophilia Testing

Introduction Thrombophilia testing in unprovoked venous thromboembolism patients (VTE) is controversial. Common thrombophilias such as Factor V Leiden or prothrombin gene variant appear to not importantly increase the risk of VTE recurrence, and thus are not considered in anticoagulation management decisions. However, patients with potent thrombophilias such as antiphospholipid antibodies (APLA), antithrombin deficiency, protein C and S deficiency, and homozygous genetic thrombophilias or combined defects are at higher risk of recurrence and it is recommended that they receive long-term anticoagulation. If the proportion of patients with "potent" thrombophilia is high then thrombophilia testing should be conducted. We sought to determine the proportion of unprovoked VTE patients with "potent" thrombophilia. Methods All patients with managed in our oral anticoagulation management system in the period from 1998 to 2015 were potentially eligible for the study. Inclusion criteria were: 1) symptomatic, objectively confirmed VTE unprovoked proximal deep vein thrombosis or pulmonary embolism. Exclusion criteria were: 1) cancer or myeloproliferative disease at the time of VTE diagnosis; 2) no cast, surgery, trauma or immobilization (>3 days in bed 90% of waking hours) in the 90 days prior to diagnosis. We selected unprovoked VTE patients diagnosed between 2002 and 2010, as thrombophilia testing was relatively universal and available in our electronic system in that time frame (N=1344). We then selected a convenience sample of N=1165. The primary outcome measure was the proportion of patients with "potent" thrombophilia (potent= homozygous Factor V Leiden, homozygous Prothrombin gene variant, APLA, protein C, protein S or anti-thrombin deficiency or combined deficiencies). Results In 1165 patients with unprovoked VTE, complete screening was done in 470 patients (40.34%) and 976 (83.78%) had at least one thrombophilia test. Complete thrombophilia testing was defined as a screen including testing for factor V Leiden, prothrombin gene defect, APLA, anti-thrombin deficiency, protein C, and protein S. Potent thrombophilias were demonstrated in 103/1165 patients (8.84%; 95% CI, 7.34 to 10.61) (Table 2) in the total study population, and 103/976 (10.55%; 95% CI, 9.62-14.47) in patients with at least one thrombophilia test. Conclusion The proportion of unprovoked VTE patients with "potent" thrombophilia is high. Given a high proportion of "potent' thrombophilia patients who likely benefit from indefinite anticoagulation, complete thrombophilia testing appears warranted in patients with unprovoked VTE in whom anticoagulants maybe discontinued. Thrombophilia testing is warranted for a selected group of patients to detect high-risk thrombophilias that could impact anticoagulation management. Table 1. Thrombophilia screening Complete screening 470 (40.3%) No screening 189 (16.2%) At least one thrombophilia test 976 (83.8%) Table 2. Thrombophilia All patients (n=1165) Tested for individual thrombophilia % 95% CI % 95% CI FVL Heterozygous 162/1165 (13.9%) 12.0-16.0% 162/883 (18.4%) 15.9-21.0% FVL Homozygous 4/1165 (0.3%) 0.1-0.9% 4/883 (0.5%) 0.2-1.2% Prothrombin Heterozygous 63/1165 (5.4%) 4.3-6.9% 63/831 (7.6%) 6.0-9.6% Prothrombin Homozygous 1/1165 (0.0%) 0.0-0.5% 1/831 (0.1%) 0.0-0.7% Antithrombin deficiency 10/1165 (0.9%) 0.5-1.6% 10/815 (1.2%) 0.7-2.2% Protein C deficiency 18/1165 (1.6%) 1.0-2.4% 18/639 (2.8%) 1.8-4.4% Protein S deficiency 13/1165 (1.1%) 0.7-1.9% 13/635 (2.1%) 1.2-3.5% Lupus anticoagulant 24/1165 (2.1%) 1.4-3.1% 24/849 (2.8%) 1.9-4.2% Anticardiolipin IgM 16/1165 (1.4%) 0.9-2.2% 16/886 (1.8%) 1.1-2.9% Anticardiolipin IgG 20/1165 (1.7%) 1.1-2.6% 20/885 (2.2%) 1.5-3.5% β-2 microglobulin IgM 10/1165 (0.9%) 0.5-1.6% 10/333 (3.0%) 1.6-5.4% β-2 microglobulin IgG 8/1165 (0.7%) 0.4-1.4% 8/333 (2.4%) 1.2-4.7% Homocysteine 50/1165 (5.7%) 4.3-7.4% 50/668 (7.5%) 5.7-9.7% Factor VIII elevated 11/1165 (0.9%) 0.5-1.7% 11/646 (1.7%) 1.0-3.0% At least one or more of the above 331/1165 (28.4%) 25.9-31.1% 331/976 (33.9%) 31.0-36.9% Potent thrombophilia 103/1165 (8.8%) 7.34-10.6% 103/976 (10.6%) 9.6-14.5% Figure 1. Figure 1. Disclosures No relevant conflicts of interest to declare.

Hereditary Thrombophilia as a Model for Multigenic Disease

1999 ◽  
Vol 82 (08) ◽  
pp. 662-666 ◽  
Author(s):  
Sandra J. Hasstedt ◽  
Mark F. Leppert ◽  
George L. Long ◽  
Edwin G. Bovill
Keyword(s):  
Risk Factors ◽  
Protein C ◽  
Antithrombin Iii ◽  
Factor V Leiden ◽  
Protein S ◽  
Factor V ◽  
Antithrombin Deficiency ◽  
Factor V Leiden Mutation ◽  
The Past ◽  
S Deficiency

IntroductionNearly 150 years ago, Virchow postulated that thrombosis was caused by changes in the flow of blood, the vessel wall, or the composition of blood. This concept created the foundation for subsequent investigation of hereditary and acquired hypercoagulable states. This review will focus on an example of the use of modern genetic epidemiologic analysis to evaluate the multigenic pathogenesis of the syndrome of juvenile thrombophilia.Juvenile thrombophilia has been observed clinically since the time of Virchow and is characterized by venous thrombosis onset at a young age, recurrent thrombosis, and a positive family history for thrombosis. The pathogenesis of juvenile thrombophilia remained obscure until the Egeberg observation, in 1965, of a four generation family with juvenile thrombophilia associated with a heterozygous antithrombin deficiency subsequently identified as antithrombin Oslo (G to A in the triplet coding for Ala 404).1,2 The association of a hereditary deficiency of antithrombin III with thrombosis appeared to support the hypothesis, first put forward by Astrup in 1958, of a thrombohemorrhagic balance.3 He postulated that there is a carefully controlled balance between clot formation and dissolution and that changes in conditions, such as Virchow’s widely encompassing triad, could tip the balance toward thrombus formation.The importance of the thrombohemorrhagic balance in hypercoagulable states has been born out of two lines of investigation: evidence supporting the tonic activation of the hemostatic mechanism and the subsequent description of additional families with antithrombin deficiency and other genetically abnormal hemostatic proteins associated with inherited thrombophilia. Assessing the activation of the hemostatic mechanism in vivo is achieved by a variety of measures, including assays for activation peptides generated by coagulation enzyme activity. Activation peptides, such as prothrombin fragment1+2, are measurable in normal individuals, due to tonic hemostatic activity and appear elevated in certain families with juvenile thrombophilia.4 In the past 25 years since Egeberg’s description of antithrombin deficiency, a number of seemingly monogenic, autosomal dominant, variably penetrant hereditary disorders have been well established as risk factors for venous thromboembolic disease. These disorders include protein C deficiency, protein S deficiency, antithrombin III deficiency, the presence of the factor V Leiden mutation, and the recently reported G20210A prothrombin polymorphism.5,6 These hereditary thrombophilic syndromes exhibit considerable variability in the severity of their clinical manifestations. A severe, life-threatening risk for thrombosis is conferred by homozygous protein C or protein S deficiency, which if left untreated, leads to death.7,8 Homozygous antithrombin III deficiency has not been reported but is also likely to be a lethal condition. Only a moderate risk for thrombosis is conferred by the homozygous state for factor V Leiden or the G20210A polymorphism.9,10 In contrast to homozygotes, the assessment of risk in heterozygotes, with these single gene disorders, has been complicated by variable clinical expression in family members with identical genotypes.11 Consideration of environmental interactions has not elucidated the variability of clinical expression. Consequently, it has been postulated that more than one genetic risk factor may co-segregate with a consequent cumulative or synergistic effect on thrombotic risk.12 A number of co-segregating risk factors have been described in the past few years. Probably the best characterized interactions are between the common factor V Leiden mutation, present in 3% to 6% of the Caucasian population,13,14 and the less common deficiencies of protein C, protein S, and antithrombin III. The factor V Leiden mutation does not, by itself, confer increased risk of thrombosis. The high prevalence of the mutation, however, creates ample opportunity for interaction with other risk factors when present.The G20210A prothrombin polymorphism has a prevalence of 1% to 2% in the Caucasian population and, thus, may play a similar role to factor V Leiden. A number of small studies have documented an interaction of G20210A with other risk factors.15-17 A limited evaluation of individuals with antithrombin III, protein C, or protein S deficiency revealed a frequency of 7.9% for the G20210A polymorphism, as compared to a frequency of 0.7% for controls.18 The G20210A polymorphism was observed in only 1 of the 6 protein C-deficient patients.18 In the present state, the elucidation of risk factors for venous thromboembolic disease attests to the effectiveness of the analytical framework constructed from the molecular components of Virchow’s triad, analyzed in the context of the thrombohemorrhagic balance hypothesis. Two investigative strategies have been used to study thromobophilia: clinical case-control studies and genetic epidemiologic studies. The latter strategy has gained considerable utility, based on the remarkable advances in molecular biology over the past two decades. Modern techniques of genetic analysis of families offer important opportunities to identify cosegregation of risk factors with disease.19 The essence of the genetic epidemiologic strategy is the association of clinical disease with alleles of specific genes. It is achieved either by the direct sequencing of candidate genes or by demonstration of linkage to genetic markers.

scholarly journals Different Risks of Thrombosis in Four Coagulation Defects Associated With Inherited Thrombophilia: A Study of 150 Families

Blood ◽  
1998 ◽  
Vol 92 (7) ◽  
pp. 2353-2358 ◽  
Author(s):  
Ida Martinelli ◽  
Pier Mannuccio Mannucci ◽  
Valerio De Stefano ◽  
Emanuela Taioli ◽  
Valentina Rossi ◽  
...  
Keyword(s):  
Protein C ◽  
Factor V Leiden ◽  
Protein S ◽  
Factor V ◽  
Superficial Vein ◽  
Protein S Deficiency ◽  
Vein Thrombosis ◽  
S Deficiency ◽  
Superficial Vein Thrombosis ◽  
Coagulation Defects

AbstractDeficiency of the naturally occurring anticoagulant proteins, such as antithrombin, protein C and protein S, and activated protein C resistance due to the factor V Leiden gene mutation is associated with inherited thrombophilia. So far, no direct comparison of the thrombotic risk associated with these genetic defects is available. In this study, we wish to compare the lifetime probability of developing thrombosis, the type of thrombotic symptoms, and the role of circumstantial triggering factors in 723 first- and second-degree relatives of 150 index patients with different thrombophilic defects. We found higher risks for thrombosis for subjects with antithrombin (risk ratio 8.1, 95% confidence interval [CI], 3.4 to 19.6), protein C (7.3, 95% CI, 2.9 to 18.4) or protein S deficiency (8.5, 95% CI, 3.5 to 20.8), and factor V Leiden (2.2, 95% CI, 1.1 to 4.7) than for individuals with normal coagulation. The risk of thrombosis for subjects with factor V Leiden was lower than that for those with all three other coagulation defects (0.3, 95% CI, 0.1 to 1.6), even when arterial and superficial vein thromboses were excluded and the analysis was restricted to deep vein thrombosis (0.3, 95% CI, 0.2 to 0.5). No association between coagulation defects and arterial thrombosis was found. The most frequent venous thrombotic manifestation was deep vein thrombosis with or without pulmonary embolism (90% in antithrombin, 88% in protein C, 100% in protein S deficiency, and 57% in factor V Leiden), but a relatively mild manifestation such as superficial vein thrombosis was common in factor V Leiden (43%). There was a predisposing factor at the time of venous thromboembolism in approximately 50% of cases for each of the four defects. In conclusion, factor V Leiden is associated with a relatively small risk of thrombosis, lower than that for antithrombin, protein C, or protein S deficiency. In addition, individuals with factor V Leiden develop less severe thrombotic manifestations, such as superficial vein thrombosis.

scholarly journals Different Risks of Thrombosis in Four Coagulation Defects Associated With Inherited Thrombophilia: A Study of 150 Families

Blood ◽  
1998 ◽  
Vol 92 (7) ◽  
pp. 2353-2358 ◽  
Author(s):  
Ida Martinelli ◽  
Pier Mannuccio Mannucci ◽  
Valerio De Stefano ◽  
Emanuela Taioli ◽  
Valentina Rossi ◽  
...  
Keyword(s):  
Protein C ◽  
Factor V Leiden ◽  
Protein S ◽  
Factor V ◽  
Superficial Vein ◽  
Protein S Deficiency ◽  
Vein Thrombosis ◽  
S Deficiency ◽  
Superficial Vein Thrombosis ◽  
Coagulation Defects

Deficiency of the naturally occurring anticoagulant proteins, such as antithrombin, protein C and protein S, and activated protein C resistance due to the factor V Leiden gene mutation is associated with inherited thrombophilia. So far, no direct comparison of the thrombotic risk associated with these genetic defects is available. In this study, we wish to compare the lifetime probability of developing thrombosis, the type of thrombotic symptoms, and the role of circumstantial triggering factors in 723 first- and second-degree relatives of 150 index patients with different thrombophilic defects. We found higher risks for thrombosis for subjects with antithrombin (risk ratio 8.1, 95% confidence interval [CI], 3.4 to 19.6), protein C (7.3, 95% CI, 2.9 to 18.4) or protein S deficiency (8.5, 95% CI, 3.5 to 20.8), and factor V Leiden (2.2, 95% CI, 1.1 to 4.7) than for individuals with normal coagulation. The risk of thrombosis for subjects with factor V Leiden was lower than that for those with all three other coagulation defects (0.3, 95% CI, 0.1 to 1.6), even when arterial and superficial vein thromboses were excluded and the analysis was restricted to deep vein thrombosis (0.3, 95% CI, 0.2 to 0.5). No association between coagulation defects and arterial thrombosis was found. The most frequent venous thrombotic manifestation was deep vein thrombosis with or without pulmonary embolism (90% in antithrombin, 88% in protein C, 100% in protein S deficiency, and 57% in factor V Leiden), but a relatively mild manifestation such as superficial vein thrombosis was common in factor V Leiden (43%). There was a predisposing factor at the time of venous thromboembolism in approximately 50% of cases for each of the four defects. In conclusion, factor V Leiden is associated with a relatively small risk of thrombosis, lower than that for antithrombin, protein C, or protein S deficiency. In addition, individuals with factor V Leiden develop less severe thrombotic manifestations, such as superficial vein thrombosis.

Co-inheritance of the 20210A Allele of the Prothrombin Gene Increases the Risk of Thrombosis in Subjects with Familial Thrombophilia

1997 ◽  
Vol 78 (06) ◽  
pp. 1426-1429 ◽  
Author(s):  
M Makris ◽  
F E Preston ◽  
N J Beauchamp ◽  
P C Cooper ◽  
M E Daly ◽  
...  
Keyword(s):  
Venous Thromboembolism ◽  
Protein C ◽  
Factor V Leiden ◽  
Protein S ◽  
Factor V ◽  
Protein C Deficiency ◽  
Antithrombin Deficiency ◽  
Control Subjects ◽  
Increased Risk ◽  
Venous Thromboembolic

SummaryThe presence of the 20210A allele of the prothrombin (PT) gene has recently been shown to be a risk factor for venous thromboembolism. This is probably mediated through increased plasma prothrombin levels. The aim of this study was to compare the prevalence of the prothrombin 20210A allele in control subjects and in subjects with recognised thrombophilia and to establish whether the additional inheritance of the PT 20210A allele is associated with an increased risk of venous thromboembolism. 101 subjects with a history of venous thromboembolism and diagnosed as having either factor V Leiden (R506Q) or heritable deficiencies of protein C, protein S or antithrombin were studied. The prevalence of the PT 20210A allele in this group was compared with the results obtained for 150 control subjects. In addition, the relationships were examined between genetic status and the number of documented thromboembolic episodes, and between plasma prothrombin levels and possession of the PT 20210A allele. 8 (7.9%) of the 101 patients were also heterozygous for the PT 20210A allele. This compares with 0.7% in the control subjects (p = 0.005). After exclusion of patients on warfarin, the mean plasma prothrombin of 113 subjects without 20210A was 1.09 U/ml, as compared with 1.32 U/ml in 8 with the allele (p = 0.0002). Among the 101 patients with either factor V Leiden, protein S deficiency, protein C deficiency or antithrombin deficiency, the age adjusted mean (SD) number of venous thromboembolic episodes at diagnosis was 3.7 (1.5) in those with the PT 20210A allele, as compared with 1.9 (1.1) in those without (p = 0.0001). We have demonstrated that the prevalence of the PT 20210A allele is significantly greater in subjects with venous thrombosis and characterised heritable thrombophilia than in normal control subjects and that the additional inheritance of PT 20210A is associated with an increased risk of venous thromboembolism. We have also confirmed that plasma prothrombin levels are significantly greater in subjects possessing the PT 20210A compared with those who do not.

A multi-laboratory assessment of congenital thrombophilia assays performed on the ACL Top 50 family for harmonisation of thrombophilia testing in a large laboratory network

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Emmanuel J. Favaloro ◽  
Soma Mohammed ◽  
Ronny Vong ◽  
Kent Chapman ◽  
Priscilla Swanepoel ◽  
...  
Keyword(s):  
Protein C ◽  
Factor V Leiden ◽  
Poor Performance ◽  
Protein S ◽  
Third Party ◽  
Factor V ◽  
Reference Ranges ◽  
Laboratory Assessment ◽  
Study Objective ◽  
Thrombophilia Testing

Abstract Objectives Thrombophilia testing is commonly performed within hemostasis laboratories, and the ACL TOP 50 family of instruments represent a new ‘single platform’ of hemostasis instrumentation. The study objective was to evaluate these instruments and manufacturer reagents for utility of congenital thrombophilia assays. Methods Comparative evaluations of various congenital thrombophilia assays (protein C [PC], protein S [PS], antithrombin [AT], activated protein C resistance [APCR]) using newly installed ACL TOPs 550 and 750 as well as comparative assessments with existing, predominantly STAGO, instrumentation and reagents. Verification of manufacturer assay normal reference ranges (NRRs). Results HemosIL PC and free PS assays showed good comparability with existing Stago methods (R>0.9) and could be considered as verified as fit for purpose. HemosIL AT showed high relative bias with samples from patients on direct anti-Xa agents, compromising utility. Manufacturer NRRs for PC, PS and AT were verified with minor variance. Given the interference with direct anti-Xa agents, an alternate assay (Hyphen) was evaluated for AT, and the NRR also verified. The HemosIL Factor V Leiden (APC Resistance V) evidenced relatively poor performance compared to existing assays, and could not be adopted for use in our network. Conclusions This evaluation of HemosIL reagents on ACL TOP 50 Family instruments identified overall acceptable performance of only two (PC, free PS) of four thrombophilia assays, requiring use of third-party reagents on ACL instruments for the other two assays (AT, APCR).

Retrospective Review of Hypercoagulability in Minority Populations at an Inner City Hospital’s General Hematology Clinic.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3973-3973
Author(s):  
Pritesh R. Patel ◽  
Manila Gaddh ◽  
Sunita Nathan ◽  
Griza Decebal ◽  
Rosalind Catchatourian ◽  
...  
Keyword(s):  
African American ◽  
Inner City ◽  
Protein C ◽  
Factor V Leiden ◽  
Protein S ◽  
Minority Populations ◽  
Factor V ◽  
History Of ◽  
Prothrombin Gene Mutation ◽  
Prothrombin Gene

Abstract Background: Although much is known about the incidence of hypercoagulable disorders in the Caucasian population, data is lacking in many other racial groups. We therefore retrospectively analyzed charts of all patients referred to our inner city hospital’s general hematology clinic from January 2003 to December 2006 for evaluation of possible hypercoagulable state. Methods: We reviewed charts for all patients referred for investigation of thrombophilia or hypercoagulable state seen in our clinic. Data regarding history of thrombosis was recorded. In the case of venous thromboembolic disease possible precipitants were noted. Demographic data and family history were noted. A clinical diagnosis of hypercoagulability was made based on whether the patient had any of the following: age <40; strong family history of thrombosis; unusual location of thrombosis; 2 or more thrombotic events; lack of precipitant to thrombotic episode. Laboratory data was gathered on the following: factor V leiden mutation; prothrombin gene mutation; MTHFR mutation; antithrombin III levels; protein C and protein S function; antiphospholipid antibodies. Results: 59 patients were referred. Of these 12 patients were excluded from further analysis as the reason for referral was investigation of ischemic stroke or myocardial infarction. Using the above clinical criteria 33 patients were identified as having hypercoagulability. Diagnoses and demographics are noted in tables 1 and 2. Conclusions: Our study illustrates several important practical points about the investigation of hypercoagulable patients. A larger number of protein C or S deficiencies would likely have been diagnosed had these studies been performed prior to starting anticoagulation. Similarly it is likely that the proportion of patients diagnosed with antiphospholipid antibody syndrome is high as it is possible to test for this condition whilst patients are anticoagulated. It is therefore appropriate that the best time for testing be disseminated more widely to general internal medicine providers. Importantly it appears that certain diagnostic tests would have a much higher yield in minority populations. It is likely that resources would be better allocated if African American patients in particular were tested initially for the antiphospholipid antibodies and activated protein C resistance rather than prothrombin gene mutations or factor V Leiden. Further prospective studies are planned to confirm these findings. Baseline demographics Race Gender Age Male Female <40 years >40 years All patients 12 21 22 11 African American 6 12 11 7 White 3 5 5 3 Hispanic 1 3 4 0 Asian 2 1 2 1 Diagnosis by ethnic group Race Diagnosis Antiphospholipid Protein S def. ATIII def. V Leiden MTHFR Multiple Disorders Unknown No cases of Protein C deficiency or Prothrombin Gene Mutation identified All patients 12 3 3 1 (heterozygous) 1 2 15 African American 5 2 2 0 1 1 9 White 3 0 0 1 (heterozygous) 0 0 4 Hispanic 2 1 1 0 0 1 1 Asian 2 0 0 0 0 0 1

scholarly journals Apixaban Does Not Interfere With Protein S or Activated Protein C Resistance (Factor V Leiden) Testing Using aPTT-Based Methods

2020 ◽  
Vol 144 (11) ◽  
pp. 1401-1407 ◽  
Author(s):  
Elena Maryamchik ◽  
Elizabeth M. Van Cott
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Protein S ◽  
Factor V ◽  
Dna Testing ◽  
Activated Protein C Resistance ◽  
S Deficiency ◽  
Free Antigen ◽  
Protein S Activity

Context.— Apixaban causes a false increase in activated protein C resistance (APCR) ratios and possibly protein S activity. Objective.— To investigate whether this increase can mask a diagnosis of factor V Leiden (FVL) or protein S deficiency in an actual population of patients undergoing apixaban treatment and hypercoagulation testing. Design.— During a 4.5-year period involving 58 patients, we compared the following 4 groups: heterozygous for FVL (FVL-HET)/taking apixaban, wild-type/taking apixaban, heterozygous for FVL/no apixaban, and normal APCR/no apixaban. Patients taking apixaban were also tested for protein S functional activity and free antigen (n = 40). Results.— FVL-HET patients taking apixaban had lower APCR ratios than wild-type patients (P &lt; .001). Activated protein C resistance in FVL-HET patients taking apixaban fell more than 3 SD below the cutoff of 2.2 at which the laboratory reflexes FVL DNA testing. No cases of FVL were missed despite apixaban. In contrast to rivaroxaban, apixaban did not interfere with the assessment of protein S activity (mean activity 93.9 IU/dL, free antigen 93.1 IU/dL, P = .39). A total of 3 of 40 patients (8%) had low free protein S antigen (30, 55, and 57 IU/dL), with correspondingly similar activity results (27, 59, and 52 IU/dL, respectively). Apixaban did not cause a missed diagnosis of protein S deficiency. Conclusions.— Despite apixaban treatment, APCR testing can distinguish FVL-HET from healthy patients, rendering indiscriminate FVL DNA testing of all patients on apixaban unnecessary. Apixaban did not affect protein S activity.

scholarly journals Inherited Hypercoagulable States

1997 ◽  
Vol 2 (4) ◽  
pp. 313-320 ◽  
Author(s):  
A Koneti Rao ◽  
Sunita Sheth ◽  
Robert Kaplan
Keyword(s):  
Arterial Thrombosis ◽  
Protein C ◽  
Factor V Leiden ◽  
Protein S ◽  
Factor V ◽  
Thromboembolic Events ◽  
Heparin Cofactor Ii ◽  
Predisposing Factor ◽  
Inherited Thrombophilia ◽  
Prothrombin Gene

Hypercoagulable states are a group of conditions associated with increased predisposition to thromboembolic events. Most of the inherited abnormalities recognized to date are associated with venous thromboembolism (VTE) rather than arterial thrombosis. The well-recognized inherited hypercoagulable states are the deficiencies of antithrombin, protein C and protein S, and the resistance to APC (factor V Leiden). These entities represent aberrations in the natural anticoagulant systems that exist in plasma. Other causes of inherited thrombophilia include abnormalities in the proteins of the fibrinolytic system, dysfibrinogenemias, deficiency of heparin cofactor II, abnormal thrombomodulin, elevated levels of histidine-rich glycoprotein, and the recently described variation in the prothrombin gene. One entity that has become firmly established as a predisposing factor for recurrent VTE is hyperhomocysteinemia. About half of VTE episodes in patients with inherited thrombophilias occur in relation to events that are generally recognized as predisposing states, such as surgery, pregnancy (particularly puerperium) and immobilization. In this review, the risks of VTE associated with inherited risk factors are discussed, and guidelines for the diagnosis and management are presented.

Sign in / Sign up

Export Citation Format

Share Document