A Safety and Feasibility Single-Arm Study of a Novel Catheter Thrombectomy Device for the Treatment of Pulmonary Embolism (ENGULF)

Abstract

Background: Despite advances in therapy options, pulmonary embolism (PE) continues to carry a high risk of mortality and morbidity. Currently, therapeutic options are limited with only 2 US Food and Drug Administration-cleared catheter-based embolectomy devices approved for the treatment of intermediate-risk PE. The novel Hēlo PE thrombectomy catheter (Endovascular Engineering, Inc) has a flexible and collapsible funnel with an internal agitator for a dual mechanism of treatment for acute PE. We sought to investigate the safety and feasibility of the novel Hēlo PE thrombectomy catheter in intermediate-risk PE.

Methods: A prospective, single-arm feasibility study evaluating the Hēlo PE catheter was performed in patients presenting with intermediate-risk PE. Patients underwent preprocedural and postprocedural computed tomography angiography. Primary efficacy was the difference in preprocedural to postprocedural right ventricle/left ventricle (RV/LV) ratio. Primary and secondary safety outcomes were all-cause mortality, major life-threatening bleeding, device-related serious adverse events, pulmonary or cardiac injury, and clinical decompensation at 48 hours postprocedure and at 30 days.

Results: A total of 25 patients from 8 centers were consented and included in the analysis. Preprocedural computed tomography angiography revealed an RV/LV ratio of 1.53 ± 0.27. All patients underwent a successful thrombectomy procedure. Postprocedure, the RV/LV ratio was reduced to 1.15 ± 0.18, translating into a 23.2 ± 12.81% decrease from baseline. No patients underwent adjunctive thrombolysis. Two patients had adjunctive catheter-directed embolectomy with an alternative device. Two patients had postprocedural anemia requiring transfusion but did not meet criteria for major life-threatening bleeding by VARC-2 criteria. There were no major adverse events including no deaths, major bleeding, pulmonary injury, or vascular complications at 48 hours or 30 days post procedure.

Conclusions: In this multicenter first-in-human study, use of the Hēlo PE thrombectomy catheter was feasible and safe for the treatment of acute PE.

Keywords: catheter-directed embolectomy; intermediate-risk; pulmonary embolism.

Central Illustration

Primary efficacy and safety end points. (A) Illustration of the Hēlo PE thrombectomy system in its “open funnel” configuration. (B) Illustration of the integrated handle of the Hēlo PE thrombectomy system Primary efficacy end point showing a 23.2% reduction in RV/LV ratio at 48 hours. Primary and secondary safety end points showing 0% all-cause mortality at 30 days. LV, left ventricle; RV, right ventricle; SAE, serious adverse events.

Figure 1

Representative examples of angiograms before and after the use of the Hēlo PE thrombectomy system. (A) Preprocedure: thrombus located in the right interlobar pulmonary artery with an area of 416.87 mm² and length of 48.6 mm; proximal RVD 20.2 mm. (A′) Postprocedure. Thrombus reduction of 100%. (B) Preprocedure: thrombus located in the saddle with an area of 499.88 mm² and length of 59.3 mm; proximal RVD 30.3 mm. (B′) Postprocedure. Thrombus reduction of 100%. (C) Preprocedure: thrombus located in the right interlobar pulmonary artery with an area of 568.56 mm² and length of 54.2 mm; proximal RVD 15.4 mm. (C′) Postprocedure. Thrombus reduction of 100%. (D) Preprocedure: thrombus located in the right interlobar pulmonary artery with an area of 387.68 mm² and length of 36.1 mm; proximal RVD 20.5 mm. (D′) Postprocedure. Thrombus reduction of 66%. Residual thrombus area 130.24 mm² and length of 19.5 mm. RVD, reference vessel diameter.