Large-bore mechanical thrombectomy yields better outcomes for intermediate-risk pulmonary embolism

Findings from the first international randomized controlled trial to compare patient outcomes following treatment with large-bore mechanical thrombectomy (LBMT) versus catheter-directed thrombolysis (CDT) for intermediate-risk pulmonary embolism (PE) show that LBMT is superior with respect to the hierarchically-tested aggregated outcome of all-cause mortality, intracranial hemorrhage, major bleeding, clinical deterioration and/or escalation to bailout therapy, and postprocedural ICU admission and length of stay.

Findings were reported today at TCT 2024, the annual scientific symposium of the Cardiovascular Research Foundation (CRF). Results are also published in Circulation.

Over the last decade, catheter-based interventions for intermediate- and high-risk PE, including catheter-directed thrombolysis (CDT) and large-bore mechanical thrombectomy (LBMT), have been adopted to avoid the bleeding risks of systemic thrombolysis. Observational studies of CDT and LBMT have separately reported positive outcomes but there are no prior randomized controlled trials directly comparing these two interventional strategies.

From February 2022 to February 2024, a total of 550 hemodynamically stable adults with acute PE, right ventricular dysfunction and at least one additional clinical risk factor for adverse outcomes who did not have absolute contraindications to thrombolytics were randomized in a 1:1 allocation to LBMT (n=274) or CDT (n=276). The trial was conducted at 57 sites in the United States, Germany and Switzerland. Follow-up was performed at 24-hours, discharge (or 7 days), and at 30 days.

The primary endpoint was a hierarchal win ratio of five outcomes including all-cause mortality, intracranial hemorrhage, major bleeding per ISTH definition, clinical deterioration and/or escalation to bailout therapy, and postprocedural ICU admission and length of stay. These five outcomes were assessed at discharge or 7 days post procedure, whichever came sooner. The primary endpoint favored LBMT over CDT with a corresponding win ratio of 5.01 (95% CI: 3.68–6.97, p<0.001).

Among the individual components of these, the rates of all-cause mortality, intracranial hemorrhage, and major bleeding were similar between groups. Less than half of LBMT patients were admitted to the ICU following the procedure compared with nearly all CDT patients (41.6% versus 98.6%; p<0.001). Although this occurred infrequently, there was also a lower rate of clinical deterioration and/or escalation to bailout therapy with LBMT (1.8%) compared with CDT (5.4%, p=0.038).

At 24 hours, LBMT patients also showed greater improvement in several symptom scores. In addition, the total hospital stay was shorter with LBMT compared to CDT (4.5±2.8 versus 5.3±3.9 overnights; p=0.002) and fewer LBMT patients were readmitted to the hospital within 30 days (3.2% versus 7.9%; p=0.03). All-cause mortality within 30 days was similar between both groups (0.4% vs. 0.8%; p=0.62).

“The PEERLESS results represent the most robust evidence comparing two methods of intervention for pulmonary embolism to date,” said Wissam A. Jaber, MD, Professor of Medicine and Director of the Cardiac Cath Lab at Emory University Hospital. “LBMT was shown to be superior to CDT driven by significantly lower rates of clinical deterioration or escalation of therapy and ICU admission. LBMT was also associated with faster clinical and hemodynamic improvement at 24 hours, significantly shorter hospital stays, and fewer readmissions through 30 days.”