Abstract 11701: Ultrasound Acceleration Does Not Provide Detectable Benefit During Catheter-Directed Thrombolysis for Massive or Submassive Pulmonary Embolism: A Meta-Analysis of the Available Evidence

Abstract

Introduction: Compared with systemic thrombolysis, catheter-directed thrombolysis (CDT) for acute pulmonary embolism (PE) reduces the risk of mortality and major bleeding due to lower thrombolytic doses. The only FDA-approved device for CDT is a more expensive ultrasound-accelerated CDT (USAT) device, which uses high frequency ultrasound waves to disrupt the fibrin mesh of the thrombus. No trials comparing CDT vs USAT exist. We conducted a meta-analysis of all published studies that employed CDT and/or USAT for acute PE, stratified by PE severity. Hypothesis: Ultrasound acceleration will improve mortality, bleeding risk, and right heart strain in acute PE over standard CDT. Methods: We performed a retrospective non-time-limited literature search of PubMed for all studies of either catheter-directed thrombolysis technique. Outcome measures (30-day mortality, major bleeding, RV/LV ratio, pulmonary artery systolic pressure) were extracted. Meta-analyses were performed using RevMan Review Manager 5.3 (Cochrane Collaboration). Random Effects Model was used to calculate proportion, mean difference, and Chi-square with 95% confidence intervals. Results: Of 1260 patients in the 34 identified studies, 311 had massive PE, and 928 underwent USAT. There was no difference between CDT and USAT in 30-day mortality in massive PE (27% [7, 48] vs 30% [-2, 62], Chi2=0.02, p=0.90, I2=40%) or submassive PE (5% [-5, 15] vs 3% [0, 7], Chi2=0.16, p=0.69, I2=0%), in major bleeding in massive PE (21% [0, 43] vs 16% [2, 31], Chi2=0.15, p=0.70, I2=58%), in pulmonary artery systolic pressure in massive PE (md 25.73 [16.06, 35.40] vs 19.75 [5.38, 34.12], Chi2=0.46, p=0.50, I2=89%) or submassive PE (15.71 [10.31, 21.89] vs 15.62 [9.77, 21.47] Chi2=0.01, p=0.91, I2=85%). Conclusions: Both techniques are efficacious in improving mortality, bleeding, and right heart strain. However, few studies report outcomes for standard CDT, and between-study heterogeneity is high. Differences in 30-day mortality, major bleeding events, and markers of right heart strain were not detected between techniques in our met-analysis. Practitioners are left without evidence of benefit for ultrasound acceleration, pending the results of the ongoing randomized-controlled trial .