Background: Acute massive pulmonary embolism (PE) carries an exceptionally high mortality rate. We explored how often adjunctive therapies, particularly thrombolysis and inferior vena caval (IVC) filter placement, were performed and how these therapies affected the clinical outcome of patients with massive PE.

Methods and results: Among 2392 patients with acute PE and known systolic arterial blood pressure at presentation, from the International Cooperative Pulmonary Embolism Registry (ICOPER), 108 (4.5%) had massive PE, defined as a systolic arterial pressure <90 mm Hg, and 2284 (95.5%) had non-massive PE with a systolic arterial pressure > or =90 mm Hg. PE was first diagnosed at autopsy in 16 patients (15%) with massive PE and in 29 patients (1%) with non-massive PE (P<0.001). The 90-day mortality rates were 52.4% (95% CI, 43.3% to 62.1%) and 14.7% (95% CI, 13.3% to 16.2%), respectively. In-hospital bleeding complications occurred in 17.6% versus 9.7% and recurrent PE within 90 days in 12.6% and 7.6%, respectively (P<0.001). In patients with massive PE, thrombolysis, surgical embolectomy, or catheter embolectomy were withheld in 73 (68%). Thrombolysis was performed in 33 patients, surgical embolectomy in 3, and catheter embolectomy in 1. Thrombolytic therapy did not reduce 90-day mortality (thrombolysis, 46.3%; 95% CI, 31.0% to 64.8%; no thrombolysis, 55.1%; 95% CI, 44.3% to 66.7%; hazard ratio, 0.79; 95% CI, 0.44 to 1.43). Recurrent PE rates at 90 days were similar in patients with and without thrombolytic therapy (12% for both; P=0.99). None of the 11 patients who received an IVC filter developed recurrent PE within 90 days, and 10 (90.9%) survived at least 90 days. IVC filters were associated with a reduction in 90-day mortality (hazard ratio, 0.12; 95% CI, 0.02 to 0.85).

Conclusions: In ICOPER, two thirds of the patients with massive PE did not receive thrombolysis or embolectomy. Counterintuitively, thrombolysis did not reduce mortality or recurrent PE at 90 days. The observed reduction in mortality from IVC filters requires further investigation.