Ultrasound-Assisted Catheter-Directed Thrombolysis in High-Risk and Intermediate-High-Risk Pulmonary Embolism: A Meta-Analysis

Background: Catheter-directed Ultrasound-Assisted Thrombolysis (USAT) is a novel technology providing a high efficacy with a reduced bleeding risk in patients with pulmonary embolism (PE). Methods: We performed a meta-analysis based on presented or published PE series in which USAT was utilized. We searched the MEDLINE, EMBASE and the Cochrane Library for trials published up to December 2015. Results: The primary outcomes were mean pulmonary artery pressure (PAMP), right to left ventricle diameter ratio (RV/LV ratio) and computed tomography (CT) obstruction score. The secondary outcomes were all-cause and cardiovascular mortality, major and minor bleeding episodes and recurrent PE. The 11 trials (n=553) and 15 trials (n=655) met eligibility criteria of primary and secondary outcomes, respectively. USAT was found to significantly reduce PAMP, RV/LV ratio and CT obstruction scores. After adjusting for baseline covariates in meta-regression analysis, male sex and number of high-risk patients were found to be associated with PAMP and RV/LV ratio while only male sex was associated with CT obstruction scores. The pooled incidence of all-cause and cardiovascular mortality were 3.2% and 2.2%, and the incidence of major and minor bleeding episodes were 5.5% and 6.9%, respectively. In the pooled analysis of the remaning trials, the incidence of recurrent PE was 1.7%. USAT compared with three randomized thrombolytic trials showed a similar death rate with a lower rate of major bleeding. Conclusion: This meta-analysis confirmed that USAT significantly reduced PAMP, RV/LV ratio and CT obstruction scores with similar death rates and a lower risk of major bleeding compared with patients with PE undergoing systemic thrombolytic treatment. Keywords: EkoSonic® endovascular system, ultrasound-assisted thrombolysis, pulmonary embolism, thrombolytics, metaanalysis, catheter-directed thrombolysis.