BACKGROUND: The HeartMate 3 (HM 3; Abbott) left ventricular assist device (LVAD) has improved hemocompatibility-related adverse outcomes. In sporadic cases, external compression of the outflow graft causing obstruction (eOGO) can result from substance accumulation between the outflow graft and its bend relief. We sought to evaluate the prevalence, course, and clinical implications of eOGO in an international study. METHODS: A multicenter retrospective analysis of HM 3 LVADs implanted between November 2014 and April 2021 (n = 2108) was conducted across 17 cardiac centers in 8 countries. We defined eOGO as obstruction >25% in the cross-sectional area in imaging (percutaneous angiography, computed tomography, or intravascular ultrasound). The prevalence and annual incidence were calculated. Serious adverse events and outcomes (death, transplantation, or device exchange) were analyzed for eOGO cases. RESULTS: Of 2108 patients, 62 were diagnosed with eOGO at a median LVAD support duration of 953 (interquartile range, 600-1267) days. The prevalence of eOGO was 3.0% and the incidence at 1, 2, 3, 4, and 5 years of support was 0.6%, 2.8%, 4.0%, 5.2%, and 9.1%, respectively. Of 62 patients, 9 were observed, 27 underwent surgical revision, 15 underwent percutaneous stent implantation, 8 received a heart transplant, and 2 died before intervention. One patient underwent surgical revision and later stent implantation. The mortality with therapeutic intervention was 9/53 (17.0%). CONCLUSIONS: Although uncommon, HM 3 LVAD-supported patients might develop eOGO with an increasing incidence after 1 year of support. Although engineering efforts to reduce this complication are under way, clinicians must maintain a focus on early detection and remain vigilant.

Department of Anesthesia and Intensive Care IRCCS San Raffaele Scientific Institute and Vita Salute San Raffaele University Milan Italy

Department of Cardiac Surgery Heart Center University of Leipzig Leipzig Germany

Department of Cardiac Surgery IRCCS Bologna S Orsola University Hospital Bologna Italy

Department of Cardiac Surgery Ludwig Maximilian University of Munich Munich Germany

Department of Cardiac Surgery Medical University of Vienna Vienna Austria

Department of Cardiac Thoracic Transplantation and Vascular Surgery Hannover Medical School Hannover Germany

Department of Cardiology Erasmus University Medical Center Rotterdam the Netherlands

Department of Cardiology Rigshospitalet University of Copenhagen Copenhagen Denmark

Department of Cardiothoracic and Vascular Surgery German Heart Center Berlin Berlin Germany

Department of Cardiothoracic and Vascular Surgery German Heart Center Berlin Berlin Germany; DZHK Partner Site Berlin Berlin Germany

Department of Cardiothoracic and Vascular Surgery German Heart Center Berlin Berlin Germany; DZHK Partner Site Berlin Berlin Germany; Department of Cardiothoracic Surgery Charité Universitätsmedizin Berlin Corporate Member of Freie Universität Berlin Humboldt Universität zu Berlin and Berlin Institute of Health Berlin Germany; Department of Health Sciences and Technology ETH Zürich Zurich Switzerland

Department of Cardiothoracic Surgery Jena University Hospital Friedrich Schiller University Jena Jena Germany

Department of Cardiovascular Surgery Heart Center University Freiburg Bad Krozingen Freiburg Germany; Faculty of Medicine University of Freiburg Freiburg Germany

Department of Cardiovascular Surgery Institute for Clinical and Experimental Medicine Prague Czech Republic

Department of Thoracic and Cardiovascular Surgery Heart and Diabetes Centre NRW Ruhr University of Bochum Bad Oeynhausen Germany

Division of Cardiology Department of Medicine Montefiore Medical Center Albert Einstein College of Medicine Bronx NY

Division of Cardiovascular Medicine Center for Advanced Heart Disease Brigham and Women's Hospital Boston Mass

Division of Cardiovascular Medicine University of Utah School of Medicine Salt Lake City Utah

King Faisal Specialist Hospital and Research Centre Riyadh Saudi Arabia

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