FACTOR-V-LEIDEN PREVALENCE IN VENOUS THROMBOEMBOLISM PATIENTS

Background: Recent findings have demonstrated a high frequency of acti vated protein C resistance in patients suffering from deep venous thro mbosis (DVT). This abnormality has been related to a mutation in the f actor V gene (at nucleotide position 1,691, guanine to adenine [G --> A] substitution), Aim: To assess the frequency of the mutation in unse lected inpatients with a proved DVT. To study the clinical characteris tics of such patients, Methods: All consecutive patients admitted to t he hospital because of a clinical suspicion of DVT were eligible, Diag nosis of DVT with the help of venous ultrasound imaging or venography. Ventilation and perfusion lung scan was performed in all patients, an d interpreted according to the Prospective Investigation of Pulmonary Embolism Diagnosis criteria; in patients with a lower intermediate-pro bability lung scan, pulmonary angiography was requested, Polymerase ch ain reaction amplification was performed in patients with a proved DVT , A control group consisted of bone marrow volunteer donors. Results: From July 1994 to November 1995, 165 patients were included, Thrombosi s was considered as distal in 77 and proximal in 88; an associated pul monary; embolism (PE) was found in 75 patients, Of 165 patients, 24 (1 4.5%) showed the factor V gene mutation (95% confidence interval, 9.4 to 19.8); the mutation was present in 3.5% of 200 bone marrow voluntee r donors; odds ratio for having DVT in the presence of the mutation wa s 4.1. No difference in the level of DVT, or the presence of an associ ated PE was observed according to the presence of the mutation, Patien ts with the mutation have a significantly more frequent history of DVT (p = 0.04) and more previous reported episodes (1.1 vs 0.6; p = 0.04) . Conclusion: The factor V mutation is frequent in unselected DVT pati ents, No difference in the severity of the thrombosis episode was obse rved in these patients.