Superficial venous thrombosis and venous thromboembolism: a large, prospective epidemiologic study.

BACKGROUND

Superficial venous thrombosis (SVT) is perceived to have a benign prognosis.

OBJECTIVE

To assess the prevalence of venous thromboembolism in patients with SVT and to determine the 3-month incidence of thromboembolic complications.

DESIGN

National cross-sectional and prospective epidemiologic cohort study. (ClinicalTrials.gov registration number: NCT00818688)

SETTING

French office- and hospital-based vascular medicine specialists.

PATIENTS

844 consecutive patients with symptomatic SVT of the lower limbs that was at least 5 cm on compression ultrasonography.

MEASUREMENTS

Incidence of venous thromboembolism and extension or recurrence of SVT in patients with isolated SVT at presentation.

RESULTS

Among 844 patients with SVT at inclusion (median age, 65 years; 547 women), 210 (24.9%) also had deep venous thrombosis (DVT) or symptomatic pulmonary embolism. Among 600 patients without DVT or pulmonary embolism at inclusion who were eligible for 3-month follow-up, 58 (10.2%) developed thromboembolic complications at 3 months (pulmonary embolism, 3 [0.5%]; DVT, 15 [2.8%]; extension of SVT, 18 [3.3%]; and recurrence of SVT, 10 [1.9%]), despite 540 patients (90.5%) having received anticoagulants. Risk factors for complications at 3 months were male sex, history of DVT or pulmonary embolism, previous cancer, and absence of varicose veins.

LIMITATION

The findings are from a specialist referral setting, and the study was terminated before the target patient population was reached because of slow recruitment.

CONCLUSION

A substantial number of patients with SVT exhibit venous thromboembolism at presentation, and some that do not can develop this complication in the subsequent 3 months.

PRIMARY FUNDING SOURCE

GlaxoSmithKline, sanofi-aventis, and the Ministère Francais de la Santé et des Sports (Programme Hospitalier de Recherche Clinique).