Ultrasound-Assisted Catheter-Directed Thrombolysis Versus Surgical Pulmonary Embolectomy for Intermediate-High or High-Risk Pulmonary Embolism: A Randomized Phase II Non-inferiority Trial.

OBJECTIVES:We hypothesized that ultrasound-assisted thrombolysis (USAT) is non-inferior to surgical pulmonary embolectomy (SPE) to improve right ventricular (RV) function in patients with acute pulmonary embolism (PE). METHODS:In a single-center, non-inferiority trial, we randomly assigned 27 patients with intermediate high- or high-risk acute PE to undergo either USAT or SPE stratified by PE risk. Primary and secondary outcomes were the baseline-to-72hour difference in right-to-left ventricular (RV/LV) ratio and the Qanadli pulmonary occlusion score, respectively, by contrast-enhanced chest computed tomography assessed by a blinded CoreLab. RESULTS:The trial was prematurely terminated due to slow enrollment. Mean age was 62.6 (SD 12.4) years, 26% were women, and 15% had high-risk PE. Mean change in RV/LV ratio was -0.34 (95% CI -0.50 to -0.18) in the USAT and -0.53 (95% CI -0.68 to -0.38) in the SPE group (mean difference: 0.152; 95% CI 0.032 to 0.271; p-valuenon-inferiority=0.80; p-valuesuperiority=0.013). Mean change in Qanadli pulmonary occlusion score was -7.23 (95% CI -9.58 to -4.88) in the USAT and -11.36 (95% CI -15.27 to -7.44) in the SPE group (mean difference: 5.00; 95% CI 0.44 to 9.56, p-value = 0.032). Clinical and functional outcomes were similar between the two groups up to 12 months. CONCLUSIONS:In patients with intermediate-high and high risk acute PE, USAT was not non-inferior compared to SPE in reducing RV/LV ratio within the first 72 hours. In a post-hoc superiority analysis, SPE resulted in greater improvement of RV overload and reduction of thrombus burden. CLINICAL TRIAL REGISTRATION:https://www.clinicaltrials.gov; NCT03218410.