Findings from the PEERLESS study presented at TCT 2024 showed that patients at intermediate risk of pulmonary embolism (PE) who were treated with large-bore mechanical thrombectomy (LBMT) had significantly lower risk of all-cause mortality, intracranial hemorrhage, major bleeding, clinical deterioration and/or escalation to bailout therapy and intensive care unit utilization than those treated with catheter-directed thrombolysis (CDT).

The study, which was simultaneously published in Circulation, enrolled 550 intermediate-risk PE patients with right ventricular dilatation and additional clinical risk factors and randomly assigned them 1:1 to either LBMT or CDT. The primary endpoint, which was met in favor of LBMT vs. CDT, was a hierarchal win ratio composite of: 1) all-cause mortality, 2) intracranial hemorrhage, 3) major bleeding, 4) clinical deterioration and/or escalation to bailout, and 5) post procedural intensive care unit (ICU) admission and length of stay, assessed at hospital discharge or seven days post-procedure.

Broken down by event, patients assigned to LBMT had lower rates of clinical deterioration and/or bailout and post-procedural ICU utilization compared with CDT. No significant differences in mortality, intracranial hemorrhage or major bleeding were observed between the two groups. Additionally, patients in the LBMT group had shorter total hospital stays and fewer all-caused readmissions compared with those in the CDT at 24 hours. However, 30-day mortality was similar across the two groups.

"The PEERLESS study provides the first randomized data for mechanical thrombectomy and important new information to inform endovascular treatment selection for intermediate-risk PE patients in whom the decision to intervene has been made by the patient's care team," said Wissam A. Jaber, MD, FACC, et al.