Rationale: There is a lack of information on the long-term prognosis of patients with acute pulmonary embolism (PE).
Objectives: To assess the long-term risk for adverse events after PE.
Methods: Consecutive patients diagnosed with PE between January 2001 and July 2007, and patients in whom PE was ruled out from a previous study were followed until July 2008 for the occurrence of adverse clinical events: mortality, symptomatic recurrent venous thromboembolism, cancer, arterial cardiovascular events and chronic thromboembolic pulmonary hypertension. Hazard ratios (HR) for all endpoints and a combined endpoint were calculated and adjusted for potential confounders.
Measurements and main results: Three hundred eight patients with unprovoked, 558 with provoked, and 334 without PE were studied with a median follow-up period of 3.3 years. Patients with unprovoked PE had a lower overall risk for mortality than patients with provoked PE (HR, 0.59; 95% confidence interval [CI], 0.43-0.82), but a higher risk for nonmalignancy-related mortality (HR, 1.8; 95% CI, 1.3-2.5), recurrent venous thromboembolism (HR, 2.1; 95% CI, 1.3-3.1), cancer (HR, 4.4; 95% CI, 2.0-10), cardiovascular events (HR, 2.6; 95% CI, 1.5-3.8) and chronic thromboembolic pulmonary hypertension (1.5 vs. 0%). The risk for the combined endpoint did not differ between both groups (HR, 0.98; 95% CI, 0.82-1.1). Patients without PE had similar risks for malignancy and cardiovascular events than patients with provoked PE, but lower risks for the remaining outcomes. The fraction of both patients with provoked and unprovoked PE without events after 1 year was only 70% and decreased to fewer than 60% after 2 years and fewer than 50% after 4 years, whereas this latter was 84% for the control patients.
Conclusions: The clinical course of acute PE is complicated by high rates of serious adverse events, which occur in half of the patients within 4 years.