[Evaluation of hemostasis in venous thromboembolism pathology].
Thromboembolic disease results from an hypercoagulable state and multifactorial causes may lead to hypercoagulability. Thrombogenic risk factors can be acquired and/or inherited. For each thrombophilic patient, the main clinical features retained are: the patient age, the familial history, the recurrence of thromboembolic events, an unusual site of thrombosis. Anti-phospholipid antibodies, which are considered as acquired thrombogenic risk factors, can be detected with coagulation tests and/or Elisa methods. The association of antiphospholipid antibodies with thrombosis is defined as the anti-phospholipid syndrome. Last decades, genetic risk factors were identified. First of all, antithrombin, protein C and protein S deficiencies were described. These deficiencies are involved in about 10% of patients who develop thrombosis before the age of 50. In 1993, a new genetic risk factor was discovered: activated protein C resistance which is due to the Q506 mutation in factor V. This defect represents the most prevalent abnormality of inherited thrombophilia, affecting 20 to 40% of thrombophilic patients. Interestingly, hyperhomocysteinemia, known as potentially predisposing to arterial disease, was also recognized as a risk factor for venous occlusive disease. Several genes encoding homocystein metabolism enzymes, such as cystathionine beta-synthase or methylenetetrahydrofolate reductase are concerned. Establishment of a causal association between the presence of a biological abnormality and the occurrence of thrombosis may lead to an adapted prophylaxis whatever the risk situation.
Gaussem
P
P
Inserm U. 428, Faculté des sciences, pharmaceutiques et biologiques, 4, Paris.
Siguret
V
V
Aiach
M
M
D016736:Antiphospholipid Syndrome / Q000150:complications*; D020152:Antithrombin III Deficiency; D003663:Decision Trees; D006712:Homocystinuria / Q000097:blood / Q000150:complications*; D006801:Humans; D015995:Prevalence; D020151:Protein C Deficiency; D018455:Protein S Deficiency / Q000145:classification / Q000150:complications*; D012307:Risk Factors; D013923:Thromboembolism / Q000097:blood / Q000175:diagnosis* / Q000209:etiology*