Patients with unprovoked deep-vein thrombosis (DVT) of the leg or pulmonary embolism (PE) have a high recurrence risk. How often these recurrences are provoked by a temporary risk condition is unknown. In a cohort of patients with unprovoked venous thromboembolism (VTE), we evaluated the clinical circumstances of recurrence. We studied patients with DVT of the leg and/or PE. End point was recurrence of objectively verified symptomatic VTE. Provoked recurrence was defined according to guidance criteria. 1188 patients were followed for a median of 8.9 years after withdrawal of oral anticoagulants. 312 patients had recurrent VTE, which was provoked in 42 (13%). Recurrence was related to a major risk factor in 19, to a minor risk factor in 22, and to a persistent risk factor in one patient(s). 14 recurrences occurred after major surgery and 5 during hospitalization. Ten recurrences occurred after minor surgery, eight after trauma and three during female hormone intake. Four recurrences occurred during heparin prophylaxis. The incidence of provoked VTE recurrence appears to be low. VTE can recur when prevention is stopped or even during thromboprophylaxis. Surgery and trauma are frequent risk factors.
Keywords: Embolism; Recurrence; Risk factors; Thromboembolism; Thrombosis.