Comparison of ultrasound-assisted thrombolysis and mechanical thrombectomy in patients with intermediate-high-risk pulmonary embolism

Abstract Background Pulmonary embolism (PE) can cause right heart failure and is associated with a high mortality. Early risk stratification is critical for individualized management. In patients with intermediate-high-risk PE, guidelines recommend to consider a percutaneous catheter-directed treatment (CDT). While different techniques are available, comparisons between treatments regarding right heart function and outcome are still scarce. Purpose To compare changes in right heart function as well as outcome in patients with intermediate-high-risk PE after catheter-directed treatment with ultrasound-assisted thrombolysis as compared to mechanical thrombectomy. Methods This is a retrospective, single-center study in intermediate-high-risk PE. According to the ESC guidelines, all patients had PESI class III-V, RV dysfunction and elevated cardiac troponin levels, but were hemodynamically stable. PE was confirmed by CT angiography. All patients underwent a catheter-directed treatment. One group received an ultrasound-assisted thrombolysis (USAT), while the other had a large-bore mechanical thrombectomy (MT). Right heart function (RV-Diameter, RV-/LV-Ratio, TAPSE) assessed via transthoracic echocardiography before and after CDT as well as interventional characteristics and postinterventional hospital stay were compared. Results From June 2022 to January 2024, 27 patients (43% female; aged 62 ± 14 years) were diagnosed with pulmonary embolism with intermediate-high-risk and underwent a catheter-directed treatment. Most patients (89%) had bilateral pulmonary embolisms. 15 patients (55%) received an ultrasound-assisted thrombolysis. 12 patients (45%) had a mechanical thrombectomy via a large-bore aspiration system. The mean procedural time was 41 ± 19 minutes for USAT and 106 ± 33 minutes for MT (p < 0.001). Right ventricular / left ventricular ratio reduction was -0.48 ± 0.25 in the USAT group (p < 0.001) and -0.34 ± 0.14 in the MT group (p < 0.001) (between group difference p = 0.2). TAPSE increased by 8 mm ± 4.4 mm in the USAT group (p < 0.001) and by 8.7mm ± 3.8 mm in the MT group (p < 0.001) (between group difference p = 0.7). The median postinterventional hospital stay was 7 days for the USAT patients and 7 days for the MT patients (between group difference p = 1). Conclusions In patients with intermediate-high-risk PE both ultrasound-assisted thrombolysis and large-bore mechanical thrombectomy lead to an improved right heart function with both interventions leading to a similar length of postprocedural hospital stay. Further randomized data have to discriminate differential impact of novel tools for the treatment of intermediate risk PE.