Ultrasound-assisted catheter-directed thrombolysis versus surgical pulmonary embolectomy for intermediate-high or high-risk pulmonary embolism: a randomized phase II non-inferiority trial.

ABSTRACT

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-centre, 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-72-h 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 enrolment. 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 0.032-0.271; Pnon-inferiority = 0.80; Psuperiority = 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 0.44-9.56, P = 0.032). Clinical and functional outcomes were similar between the 2 groups up to 12 months. CONCLUSIONS: In patients with intermediate-high and high-risk acute PE, USAT was not non-inferior when compared with SPE in reducing RV/LV ratio within the first 72 h. In a post hoc superiority analysis, SPE resulted in greater improvement of RV overload and reduction of thrombus burden.