The risk for fatal pulmonary embolism, recurrence, and bleeding in patients undergoing 1-year anticoagulation for PE. The clinical course of 1-year anticoagulated pulmonary embolism: results of a prospective, cohort study.

Background. Pulmonary embolism (PE) is a potentially fatal but treatable disease. Secondary prophylaxis is usually continued for three to six months, but the risk for recurrence or death lasts at least for one year. Knowing the clinical course of 1-year anticoagulated patients and identifying risk factors for adverse events may be of high clinical relevance. Objective. To investigate the incidence of recurrence, mortality and bleeding in PE patients anticoagulated for 1 year and to identify risk factors for such adverse events. Design. We evaluated prospectively for 1 year all consecutive in- and out-patients with a final diagnosis of acute PE referred to a single centre in Pisa, Italy, in the years 2001-2005. No exclusion criteria were adopted. Results. Out of the original 497 patients, 136 (27.4%) died before completing the 1-year follow-up, 36 (26.5%) because of PE. Of them, 31 (86.1%) did it within 10 days of diagnosis. Risk factors for death were presence of idiopathic PE (0.003), of persistently severe dyspnea in spite of treatment (0.002), of high perfusion defect score index ( PDI ). Risk of death increased proportionally when persistently severe dyspnea and high PDI were contemporary present. Recurrence occurred in 48 (9.6%) cases, 39 (81.2%) within 10 days of diagnosis. The 1-year fatality rate was 74%, the 10 days 79%. Risk factors for recurrence were persistently severe dyspnea (0.007), high PDI (0.003), cardiac or pulmonary comorbilities (0.005). Bleeding occurred in 17 (3.4%) cases and was major in 1 (0.2%); most cases (70.6%) occurred between 30 and 180 days, no case was observed after 180 days. No risk factor could be identified as associated to bleeding. Conclusions. In patients anticoagulated and carefully followed for one year, death occurred in more than a quarter of cases, a quarter of them because of PE; the vast majority did it in the first 10 days. Recurrence occurred in one every ten patients, again early. Persistently severe dyspnea and high PDI were risk factors for both mortality and recurrence. Bleeding was rare and minor and no case was observed after 180 and 360 days of treatment.