Risk of arterial cardiovascular events in patients after pulmonary embolism

Studies have reported inconsistent evidence for an association between venous thrombosis and arterial cardiovascular events. We further studied the association between both diseases by comparing the occurrence of cardiovascular events in patients diagnosed with acute pulmonary embolism (PE) contrasted to patients with comparable baseline risk characteristics (patients in whom PE was clinically suspected but ruled out). Included were 259 patients with provoked PE, 95 patients with unprovoked PE, and 334 control patients without PE. Patients diagnosed with PE were treated with vitamin K antagonists for 6 months. Median follow-up was 4.2 years. Sixty-three arterial cardiovascular events were registered (incidence, 5.1/100 patient-years). Adjusted hazard ratio was not different between patients with all-cause PE and control patients (1.39, 95% confidence interval [CI], 0.83-2.3) but increased for patients with unprovoked PE versus both patients with provoked PE and control patients without PE (2.18; 95% CI, 1.1-4.5; and 2.62; 95% CI, 1.4-4.9, respectively). This effect was confirmed after redefining the study start date to the moment the vitamin K antagonists were discontinued. Our study underlines the association between unprovoked venous thrombosis and arterial cardiovascular events; however, risk differences between patients with provoked PE and patients in whom PE was clinically suspected but ruled out could not be demonstrated.