PEERLESS RCT Compares Large-Bore Mechanical Thrombectomy to CDT for Intermediate-Risk PE

October 29, 2024—Findings were presented from the international PEERLESS randomized controlled trial comparing patient outcomes after treatment with large-bore mechanical thrombectomy (LBMT) versus catheter-directed thrombolysis (CDT) for intermediate-risk pulmonary embolism (PE).

The study found that LBMT is superior with respect to the hierarchically tested aggregated outcome of (1) all-cause mortality, (2) intracranial hemorrhage, (3) major bleeding, (4) clinical deterioration and/or escalation to bailout therapy, and (5) postprocedural intensive care unit (ICU) admission and length of stay.

PEERLESS results were presented at TCT 2024, the 36th annual Transcatheter Cardiovascular Therapeutics annual scientific symposium of the Cardiovascular Research Foundation held October 27-30 in Washington, DC, and simultaneously published by Wissam A. Jaber, MD, et al in Circulation. The study was funded by Inari Medical.

According to the TCT press release, the study enrolled a total of 550 patients from February 2022 to February 2024. The patients were hemodynamically stable adults with acute PE, right ventricular dysfunction, and at least one additional clinical risk factor for adverse outcomes; patients did not have absolute contraindications to thrombolytics. They 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 30 days.

As summarized by TCT, the study’s primary endpoint was a hierarchal win ratio of the five outcomes listed above, which were assessed at discharge or at 7 days postprocedure, whichever came sooner. The primary endpoint favored LBMT versus CDT with a corresponding win ratio of 5.01 (95% CI, 3.68-6.97; P < .001).

Among the individual components of the aggregate outcome, 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 after the procedure compared with approximately all CDT patients (41.6% vs 98.6%; P < .001). Although infrequent, there was also a lower rate of clinical deterioration and/or escalation to bailout therapy with LBMT compared with CDT (1.8% vs 5.4%; P = .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 vs 5.3 ± 3.9 overnights; P = .002), and fewer LBMT patients were readmitted to the hospital within 30 days (3.2% vs 7.9%; P = .03). All-cause mortality within 30 days was similar between both groups (0.4% vs 0.8%; P = .62).

“The PEERLESS results represent the most robust evidence comparing two methods of intervention for PE to date,” commented Dr. Jaber in the TCT press release. “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.” Dr. Jaber is Professor of Medicine and Director of the Cardiac Cath Lab at Emory University Hospital in Atlanta, Georgia.