A Multi-Center Evaluation of Outflow Graft Obstruction with a Fully Magnetically Levitated Left Ventricular Assist Device

Purpose The HeartMate3 (HM3) left ventricular assist device (LVAD) has markedly improved hemocompatibility related adverse outcomes. In sporadic cases, external compression of the outflow graft causing obstruction (eOGO) can result from gelatinous substance accumulation between outflow graft and its bend relief covering. We sought to evaluate the prevalence, temporal course and clinical implications of eOGO with the HM3 LVAD in a global cohort study. Methods A Multi-center retrospective analysis was conducted among 2014 HM3 LVAD patients across 16 cardiac centers in 8 countries (between 11/2014 and 4/2021). Presence of eOGO was defined as >25% of cross-sectional area identified by established imaging (percutaneous angiography, computed tomography or intravascular ultrasound). The prevalence and annual incidence were calculated. Serious adverse events and outcome (death, transplant or device exchange) at the end of the study were analyzed for those eOGO cases that required therapy versus those who were observed. Endpoints Among 2014 patients, 61 patients were diagnosed with eOGO at a median LVAD support duration of 1024 [IQR: 636-1409] days. The overall prevalence of eOGO was at 3.0 %. The incidence at 1, 2, 3, 4, and 5 years on support was 0.6, 2.8, 4.1, 4.6 and 9.8 %. Of 52 patients, who required a therapeutic intervention, 26 underwent surgical revision, 16 patients were treated by percutaneous stent implantation, 8 underwent urgent heart transplantation and 2 died before intervention. In 9 patients a watchful waiting strategy without treatment was chosen. The mortality among those requiring therapeutic intervention was 9 of 52 (17.3%). This global multicenter cohort study suggests that while rare, HM3 LVAD supported patients may develop eOGO with an increasing incidence after 1 year on support. While targeted engineering efforts to alleviate this complication are underway by addressing early detection as well as outflow graft and bend relief design, clinicians must remain vigilant to this complication, especially in long-term survivors supported with the HM3 LVAD. The HeartMate3 (HM3) left ventricular assist device (LVAD) has markedly improved hemocompatibility related adverse outcomes. In sporadic cases, external compression of the outflow graft causing obstruction (eOGO) can result from gelatinous substance accumulation between outflow graft and its bend relief covering. We sought to evaluate the prevalence, temporal course and clinical implications of eOGO with the HM3 LVAD in a global cohort study. A Multi-center retrospective analysis was conducted among 2014 HM3 LVAD patients across 16 cardiac centers in 8 countries (between 11/2014 and 4/2021). Presence of eOGO was defined as >25% of cross-sectional area identified by established imaging (percutaneous angiography, computed tomography or intravascular ultrasound). The prevalence and annual incidence were calculated. Serious adverse events and outcome (death, transplant or device exchange) at the end of the study were analyzed for those eOGO cases that required therapy versus those who were observed. Among 2014 patients, 61 patients were diagnosed with eOGO at a median LVAD support duration of 1024 [IQR: 636-1409] days. The overall prevalence of eOGO was at 3.0 %. The incidence at 1, 2, 3, 4, and 5 years on support was 0.6, 2.8, 4.1, 4.6 and 9.8 %. Of 52 patients, who required a therapeutic intervention, 26 underwent surgical revision, 16 patients were treated by percutaneous stent implantation, 8 underwent urgent heart transplantation and 2 died before intervention. In 9 patients a watchful waiting strategy without treatment was chosen. The mortality among those requiring therapeutic intervention was 9 of 52 (17.3%). This global multicenter cohort study suggests that while rare, HM3 LVAD supported patients may develop eOGO with an increasing incidence after 1 year on support. While targeted engineering efforts to alleviate this complication are underway by addressing early detection as well as outflow graft and bend relief design, clinicians must remain vigilant to this complication, especially in long-term survivors supported with the HM3 LVAD.