Prognostic significance of right heart thrombi (RHT) in patients with acute symptomatic pulmonary embolism: Systematic review and meta-analysis

Abstract

Background: For patients diagnosed with acute pulmonary embolism (PE), the prognostic significance of concomitant right heart thrombi (RHT) lacks clarity. Methods: We performed a meta-analysis of studies that enrolled patients with acute PE to assess the prognostic value of echocardiographically detectable RHT for the outcome of short-term all-cause, and PE-related mortality. We conducted unrestricted searches of Pubmed and Embase from 1980 through January 31, 2016 and used the terms “right heart thrombi”, “pulmonary embolism”, and “prognos*”. We used a random-effects model to pool study results and I 2 testing to assess for heterogeneity. Results: Six of 79 potentially relevant studies met inclusion criteria. Of the 5 cohorts (14,806 participants) that enrolled consecutive patients with acute PE, 455 (3.1%; 95% confidence interval [CI], 2.8% to 3.4%) had RHT. During the short-term follow-up, 99 of 593 patients who had RHT died (16.7%; 95% CI, 13.8% to 19.9%), compared to 639 of 14,627 who did not have RHT (4.4%; 95% CI, 4.0% to 4.7%). RHT had a significant association with short-term all-cause mortality in all patients (odds ratio [OR], 3.0; 95% CI, 2.2 to 4.1; I 2 = 20%), and with PE-associated death (3 cohorts, 12,955 patients; OR, 4.8; 95% CI, 2.0 to 11.3; I 2 = 76%). Results were consistent within prospective (OR, 4.8; 95% CI, 1.7 to 13.6; I 2 = 56%) and retrospective studies (OR, 2.8; 95% CI, 2.1 to 3.8; I 2 = 0%). Conclusions: In patients diagnosed with acute symptomatic PE, RHT were significantly associated with an increased risk of all-cause mortality and PE-associated death within 30 days of PE diagnosis.