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Resistance to activated protein C in unselected patients with arterial and venous thrombosis
Author(s) -
Faioni Elena M.,
Razzari Cristina,
Martinelli Ida,
Panzeri Daniela,
Franchi Franca,
Mannucci Pier Mannuccio
Publication year - 1997
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/(sici)1096-8652(199706)55:2<59::aid-ajh2>3.0.co;2-1
Subject(s) - medicine , protein c , thrombosis , venous thrombosis , activated protein c resistance , gastroenterology , protein s , population , risk factor , factor v , factor v leiden , environmental health
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. J. Hematol. 55:59‐64, 1997. © 1997 Wiley‐Liss, Inc.