Pulmonary Embolism Begets Pulmonary Embolism?: A Meta-Analysis Depicting the Type of Recurrence Following an Index Pulmonary Embolism

INTRODUCTION: Conflicting evidence suggests a person who suffers an index pulmonary embolism (PE) is more likely to develop a recurrent PE than a deep vein thrombosis (DVT). We performed a meta-analysis of randomized controlled trials (RCTs) to determine the proportion of recurrent events that will be PE in such people.

METHODS: A literature search of MEDLINE, EMBASE and CENTRAL (through 7/2014) was performed to identify RCTs of acute treatment and prevention of recurrent VTE in persons suffering an index PE, enrolling ≥50 subjects, requiring anticoagulation for ≥3 months and reporting the proportion of recurrent events that were DVT or PE (±DVT). RCTs not in English, enrolling only cancer, surgical or thrombophilia patients, primary prevention and extended treatment trials were excluded. We extracted recurrent VTE event data; and used a random-effects approach to pool the proportion [along with 95% confidence intervals (CIs)] of recurrent events that were PE and fatal PE, as well as, the proportion of recurrent PEs that were fatal.

RESULTS: Nine RCTs (n=13,606 subjects; 413 recurrent events) were included. In persons presenting with an index PE, 67%; 95%CI, 62-71% of their recurrent events were PE and 27%; 95%CI, 22-33%) were fatal PE. Of all recurrent PEs observed, 41%; 95%CI, 33-48% resulted in death. No statistical heterogeneity was observed in any analysis (I²<32% for all).

CONCLUSION: Our meta-analysis suggests a majority of recurrent events in those experiencing an index PE will be PEs. Moreover, recurrent PEs are associated with a high mortality rate.