Large-bore mechanical thrombectomy (LBMT) shows significant benefits for clinical outcomes versus catheter-directed thrombolysis (CDT) in intermediate-risk pulmonary embolism (PE) patients in the PEERLESS study. The results — from the first international randomized controlled trial comparing interventional PE treatment strategies — were reported on Tuesday by the study's lead author Wissam A. Jaber, MD, from the Emory University Hospital, Atlanta, at the Transcatheter Cardiovascular Therapeutics (TCT) 2024 conference in Washington, DC. High-risk PE is currently managed with rapid reperfusion therapy, whereas guidelines recommend anticoagulation for intermediate-risk PE patients with objective evidence of right ventricle (RV) dysfunction, according to authors of the study, published consecutively in the American Heart Association (AHA) Circulation journal. Yet, these intermediate patients suffer an early mortality rate ranging from 3% to 15%, and clinical deterioration occurs in 5% to 18%, and so "alternate therapies are needed to improve outcomes," they said. Observational studies have separately reported positive outcomes for intermediate PE with LBMT and CDT. PEERLESS was therefore set up to compare the efficacy of the two treatment strategies in preventing clinical outcomes per a hierarchal win ratio (WR) composite of; all-cause mortality; intracranial hemorrhage; major bleeding; clinical deterioration and/or 40 escalation to bailout and postprocedural intensive care unit (ICU) admission and length of stay, assessed at either hospital discharge or 7 days post-procedure. Baseline A total of 550 hemodynamically stable adults with acute PE, right ventricular dysfunction and at least one additional clinical risk factor for adverse outcomes were randomized between February 2022 and February 2024 to receive either LBMT (n = 274) or CDT (n = 276). Patients were treated across 57 sites in the US, Germany and Switzerland. Patients included had systolic blood pressure (SBP) of >90mm Hg, a central clot and right ventricular (RV) dysfunction, their symptom onset had occurred within 14 days, and intervention was planned within 72 hours. Follow-up was carried out at 24 hours, hospital discharge and 30-days. At baseline, the groups were of similar age (63.7 years in LBMT vs. 61.2 years in CDT), had similar sex weighting (54.4% vs 51.4% male, respectively) and similar body mass index (34.5 ± 8.6 vs. 36.3 ± 9.4, respectively). Prior pulmonary embolism rates were seen in 15% of the LBMT groups versus 11.2% of those given CDT. Better outcomes for LBMT patients The primary endpoint occurred in significantly less LBMT patients (Win ratio: 5.01%; 95% confidence interval [CI]: 3.68 – 6.97; P<0.001). Among the individual components of the primary endpoint, there was no significant difference in mortality, intracranial hemorrhage or major bleeding between strategies, nor in a secondary WR endpoint including the first 4 components (WR 1.34; 95% CI: 0.78-2.35; P=0.30), the authors noted. 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), and there was a lower rate of clinical deterioration and/or escalation to bailout therapy with LBMT (1.8%) compared with CDT (1.8% vs. 5.4%, respectively, p=0.038). At the 24-hour visit, the respiratory rate was also lower for LBMT patients (18.3±3.3 vs 20.1±5.1; P<0.001) and fewer had moderate to severe modified Medical Research Council (mMRC) dyspnea scores (13.5% vs 26.4%; P<0.001) New York Heart Association (NYHA) classifications (16.3% vs 27.4%; P=0.002) and RV dysfunction (42.1% vs 57.9%; P=0.004). Shorter hospital stays were also observed for LBMT patients (4.5±2.8 vs 5.3±3.9 overnights; P=0.002) and fewer all-cause readmissions (3.2% vs 7.9%; P=0.03), while 30-day mortality was similar (0.4% vs 0.8%; P=0.62). The findings "represent the most robust evidence comparing two methods of intervention for pulmonary embolism to date," Jaber said in an accompanying press statement. It provides "important new information to inform endovascular treatment selection for intermediate-risk pulmonary embolism patients in whom the decision to intervene has been made by the patient’s care team," the authors concluded. Source: Jaber W, Gonsalves C, Stortecky S, et al. Large-bore Mechanical Thrombectomy versus Catheter-directed Thrombolysis in the Management of Intermediate-risk Pulmonary Embolism: Primary Results of the PEERLESS Randomized Controlled Trial. Circulation 2024 Oct 29 (Article in press). Image Caption: Wissam A. Jaber, MD, speaks during a news conference Tuesday at the Transcatheter Cardiovascular Therapeutics (TCT) conference in Washington, DC. Image Credit: Bailey G. Salimes/CRTonline.org