E2 Hēlo Thrombectomy System Studied in ENGULF Pivotal IDE Study

November 3, 2025—Endovascular Engineering, Inc. (E2) announced positive results from the pivotal cohort of the ENGULF investigational device exemption (IDE) study evaluating the Hēlo thrombectomy system for the treatment of pulmonary embolism (PE).

The data were presented by National Coprincipal Investigator Andrew Klein, MD, of Piedmont Hospital in Atlanta, Georgia, as a late-breaking clinical trial at the VIVA25.

According to the company, the Hēlo system combines a 24-F clot engagement zone with a 15-F heart-crossing profile to enable high-power aspiration and clot remodeling through a single pass, according to the company’s press release.

The pivotal ENGULF trial enrolled 105 patients across 19 United States hospitals and included 40 participating operators across interventional cardiology, interventional radiology, and vascular surgery. Investigators reported a major adverse event rate of 0.95% at 48 hours and a 25.1% mean reduction in right ventricular–to–left ventricular ratio, meeting both primary safety and efficacy endpoints. The study also demonstrated workflow-integrated blood return and single-pass thrombectomy capabilities.

As noted in the press release, the ENGULF pivotal study builds on findings from the feasibility cohort published in JSCAI in May 2024, expanding the body of clinical evidence supporting mechanical thrombectomy in PE management. The company stated it plans to share additional study outcomes in the future.

E2 noted that the Hēlo Thrombectomy System remains an investigational device limited by federal law to investigational use.