Ultrasound-accelerated thrombolysis (USAT) versus standard catheter-directed thrombolysis (CDT) for treatment of pulmonary embolism: A retrospective analysis

Ultrasound-accelerated thrombolysis (USAT) is advocated in pulmonary embolism (PE) based on the hypothesis that adjunctive ultrasound provides superior clinical efficacy compared to standard catheter-directed thrombolysis (CDT). This retrospective study was designed to compare outcomes between the two modalities. We analyzed patients with computed tomography-diagnosed PE at our institution treated with either USAT or standard CDT. Efficacy parameters assessed included invasive pulmonary artery systolic pressure (PASP; pre- and 24 hours post-treatment), non-invasive right-to-left ventricle (RV/LV) ratio (pre- and post-treatment), and general clinical outcomes (length-of-stay, significant bleeding, and mortality). We analyzed 98 cases (62 USAT and 36 CDT), in whom massive PE was diagnosed in 7%, intermediate/high risk in 81%, and intermediate/low risk in 12%. Overall, 92% had bilateral clot and 40% saddle embolus. At 24 hours, PASP decreased similarly in both groups (CDT Δ14.7 mmHg, USAT Δ10.8 mmHg; p = 0.14). Post-treatment, CDT showed similar improvement in the RV/LV ratio (CDT Δ0.58 vs USAT Δ0.45; p = 0.07), despite the baseline ratio being greater in the CDT group, indicating more severe RV strain (1.56 ± 0.36 vs 1.40 ± 0.29; p = 0.01). Intensive care unit and hospital length-of-stays were similar in both groups. A trend toward lesser significant bleeding rates in the CDT group (8.3% vs 12.9%, p = 0.74) as well as improved survival-to-discharge (97.2% vs 91.9%, p = 0.66) was observed. Compared to USAT, standard CDT achieves similar beneficial effects on hemodynamics, RV/LV ratios, and clinical outcomes. These observations suggest that salutary clinical results may be achieved without the need for very expensive devices.