Risk of fatal pulmonary embolism in patients with treated venous thromboembolism

Context.-The most serious complication of deep vein thrombosis (DVT) or nonfatal pulmonary embolism (PE) is fatal PE, However, reliable estimates as to the risk of fatal PE in patients with treated DVT or PE are lacking. Objective.-To provide reliable estimates of the risk of fatal PE and the case-fatality rate of recurrent DVT or PE among patients presenting with symptomatic DVT or PE, during and following 3 months of anticoagulant therapy. Data Sources.-A MEDLINE literature search was performed to identify prospective studies in which patients with symptomatic DVT or PE were treated with 5 to 10 days of heparin and 3 months of oral anticoagulants. We searched the years 1966 to September 1997 using the search terms thrombophlebitis, diagnosis, drug therapy, and prognosis. Current Contents and bibliographies were also scanned. Data Extraction.-Of 137 retrieved studies, 25 studies satisfied predetermined methodologic criteria and were included in the analysis. Data Synthesis.-Among patients presenting with DVT, the rate of fatal PE during anticoagulant therapy was 0.4% (95% confidence interval [CI], 0.2%-0.6%); following anticoagulant therapy it was 0.3 per 100 patient-years (95% CI, 0.1-0.8). The case-fatality rate of recurrent DVT or PE during anticoagulant therapy was 8.8% (95% CI, 5.0%-14.1%); following anticoagulant therapy it was 5.1% (95% CI, 1.4%-12.5%), Among patients presenting with PE, the rate of fatal PE during anticoagulant therapy was 1.5% (95% CI, 0.9%-2.2%); following anticoagulant therapy it was 0 per 265 patient-years (95% CI, 0-3.6), The case-fatality rate of recurrent DVT or PE among patients presenting with PE was 26.4% (95% CI, 16.7%-38.1%). Conclusion.-Among patients with symptomatic PE or DVT who are treated with anticoagulants for 3 months, fatal PE is rare during and following anticoagulant therapy. Patients presenting with PE are more likely to die of recurrent PE or DVT than are patients presenting with DVT.