Factors v Leiden and II 20210A in patients with symptomatic pulmonary embolism and deep vein thrombosis

PURPOSE: Factor V Leiden and factor II 20210A are inherited disorders of th e clotting system that occur frequently in patients with deep vein thrombos is. We conducted this study to determine whether these factors are also com mon in patients with pulmonary embolism. SUBJECTS AND METHODS: We determined the prevalence of factor V Leiden and f actor II 20210A in 773 consecutive patients with objectively documented sym ptomatic deep vein thrombosis or symptomatic pulmonary embolism, or with a combination of these disorders. RESULTS: Isolated symptomatic deep vein thrombosis occurred in 345 patients ; isolated symptomatic pulmonary embolism occurred in 236; and both anomali es occurred in 192. Factor V Leiden was present in 21 (9%) of the patients with isolated symptomatic pulmonary embolism, in 30 (16%) with both manifes tations, and in 63 (18%) with isolated symptomatic deep vein thrombosis (P = 0.007). Factor V Leiden was more common among patients with deep vein thr ombosis (odds ratio [OR] = 2.1; 95% confidence interval [CI]: 1.2 to 3.7; P = 0.006) or both pulmonary embolism and deep vein thrombosis (OR = 1.8; 95 % CI: 1.0 to 3.3; P = 0.07) than among patients with isolated pulmonary emb olism. Factor V Leiden was less common in massive pulmonary embolism (5% [7 of 127]) than in submassive pulmonary embolism (13% [21 of 155], P = 0.03) . We found no significant difference in the prevalence of factor II 20210A among the three groups. CONCLUSION: Factors V Leiden and II 20210A vary in prevalence among patient s with pulmonary embolism and deep vein thrombosis, suggesting that the ris k of pulmonary embolization may vary among patients who have different caus es of venous thromboses. (C) 2001 by Excerpta Medica, Inc.