Resistance to activated protein C in unselected patients with arterial and venous thrombosis

✍ Scribed by Faioni, Elena M.; Razzari, Cristina; Martinelli, Ida; Panzeri, Daniela; Franchi, Franca; Mannucci, Pier Mannuccio

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 44 KB
• Volume: 55
• Category: Article
• ISSN: 0361-8609
• DOI: 10.1002/(sici)1096-8652(199706)55:2<59::aid-ajh2>3.0.co;2-1

✦ Synopsis

Four hundred and ninety-three consecutive patients referred for arterial or venous thrombosis were screened for congenital and acquired abnormalities of blood coagulation predisposing to thrombosis, and were compared to 341 age-and sex-matched controls. The aim of the study was to determine the prevalence and clinical characteristics of resistance to activated protein C (APC), a defect shown to have different prevalences in different ethnic groups and to be associated with an increased risk of thrombosis. Seventy-three (15%) patients had both APC resistance and the 1691 G to A factor V gene mutation, compared to 6/341 (2%) controls. Seven patients had antithrombin deficiency (1.4%), 11 had protein C deficiency (2.2%), and 4 had protein S deficiency (0.8%). The relative risk of thrombosis in APC-resistant patients was 9.4. Resistance to APC was associated mainly with venous thrombosis, the most frequent being deep-vein thrombosis of the lower limbs. Fifty-eight percent of APC-resistant patients had an associated risk factor at the first thrombotic event: pregnancy and oral contraceptive intake were associated with the first thrombotic episode in 35% and 30% of women, respectively. APC resistance is the most frequent defect of blood coagulation in the general population and in the unselected thrombotic population studied by us. Am.