CLINICAL OBSERVATIONS, INTERVENTIONS, AND THERAPEUTIC TRIALS The Incidence of Venous Thromboembolism in Asymptomatic Carriers of a Deficiency of Antithrombin, Protein C, or Protein S: A Prospective Cohort Study

an annual incidence of 1.5% (95% confidence interval [CI], 0.7 to 2.8) for the 3 deficiencies combined. Five of these events occurred spontaneously, resulting in an annual incidence of spontaneous venous thromboembolism of 0.8% (95% CI, 0.3 to 1.9). For antithrombin, protein C, and protein S deficiencies separately, this figure was 1.6%, 1.0%, and 0.4%, respectively. Thirty-four subjects experienced a total of 40 risk periods during which 4 venous thromboembolic events occurred (10% per risk period). We conclude that the use of continuous anticoagulant prophylaxis seems not warranted in asymptomatic individuals with a deficiency of antithrombin, protein C, or protein S. During risk periods for venous thromboembolism, adequate anticoagulant prophylaxis is necessary. r 1999 by The American Society of Hematology.

[1]  L. Qiu,et al.  [Hyperhomocysteinemia and deep-vein thrombosis]. , 2003, Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae.

[2]  M. Prins,et al.  Incidence of Venous Thromboembolism in Families with Inherited Thrombophilia , 1999, Thrombosis and Haemostasis.

[3]  P. Simioni,et al.  Prothrombin antigen levels in symptomatic and asymptomatic carriers of the 20210A prothrombin variant , 1998, British journal of haematology.

[4]  K. Hamulyák,et al.  Laboratory Diagnosis of Hereditary Thrombophilia , 1998, Seminars in thrombosis and hemostasis.

[5]  M. Prins,et al.  The Incidence of Venous Thromboembolism in Family Members of Patients with Factor V Leiden Mutation and Venous Thrombosis , 1998, Annals of Internal Medicine.

[6]  O. Linder,et al.  The duration of oral anticoagulant therapy after a second episode of venous thromboembolism. The Duration of Anticoagulation Trial Study Group. , 1997, The New England journal of medicine.

[7]  M. Prins,et al.  Frequency of Pregnancy-Related Venous Thromboembolism in Anticoagulant Factor-Deficient Women: Implications for Prophylaxis , 1996, Annals of Internal Medicine.

[8]  P. Prandoni,et al.  Hyperhomocysteinemia and deep-vein thrombosis. A case-control study. , 1996, Thrombosis and haemostasis.

[9]  P. Mannucci,et al.  Inherited Thrombophilia*: Part 2 , 1996, Thrombosis and Haemostasis.

[10]  P. Reitsma,et al.  A common genetic variation in the 3'-untranslated region of the prothrombin gene is associated with elevated plasma prothrombin levels and an increase in venous thrombosis. , 1996, Blood.

[11]  P. Mannucci,et al.  Inherited Thrombophilia: Part 1 , 1996, Thrombosis and Haemostasis.

[12]  M. Prins,et al.  Familial Thrombophilia: A Review Analysis , 1996 .

[13]  Vittorio Pengo,et al.  Bleeding complications of oral anticoagulant treatment: an inception-cohort, prospective collaborative study (ISCOAT) , 1996, The Lancet.

[14]  P. Simioni,et al.  “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, Thrombosis and Haemostasis.

[15]  A. Cogo,et al.  Prevalence of Antiphospholipid Antibodies and Lupus Anticoagulant in Juvenile Patients with Objectively Documented Deep-vein Thrombosis , 1996 .

[16]  Pieter H. Reitsma,et al.  Mutation in blood coagulation factor V associated with resistance to activated protein C , 1994, Nature.

[17]  S. Eichinger,et al.  The Risk of Thromboembolism in Asymptomatic Patients with Protein C and Protein S Deficiency: A Prospective Cohort Study , 1994, Thrombosis and Haemostasis.

[18]  A. Cohen,et al.  Clinical findings associated with acute proximal deep vein thrombosis: a basis for quantifying clinical judgment. , 1990, The American journal of medicine.

[19]  D. Rosenthal.  Recurrent venous thromboembolism in patients with a partial deficiency of protein S: Comp PC, Esmon CT. N Engl J Med 1984;311:1525–1528 , 1985 .

[20]  C. Esmon,et al.  Recurrent venous thromboembolism in patients with a partial deficiency of protein S. , 1984, The New England journal of medicine.

[21]  R. Bertina,et al.  Congenital protein C deficiency and venous thromboembolism. A study of three Dutch families. , 1983, The New England journal of medicine.

[22]  O. Egeberg.  Inherited Antithrombin Deficiency Causing Thrombophilia , 1965, Thrombosis and Haemostasis.