Outflow graft stenosis after left ventricular assist device implantation: the rotterdam experience

Abstract Introduction Outflow graft stenosis (OGS) has been reported in patients with the HeartMate 3 left ventricular assist device (LVAD) as a result of biodebris accumulation outside the graft. As a result, patients may experience unexpected low-flow alarms, relapse of heart failure symptoms, cardiogenic shock, or even death. Different cutoff values are used to define OGS, and the literature also lacks clarity regarding how the severity of OGS relates to potential clinical outcomes. Purpose The purpose of this study is to describe the prevalence, clinical presentation, outcomes, and treatments associated with different degrees of HeartMate 3 LVAD OGS. Methods In this single-centre retrospective cohort study, we reviewed all HeartMate 3 patients between March 2016 and December 2023 with an available computed tomographic angiogram (CTA) sufficient to assess the outflow graft lumen. Before 2022, CTAs were conducted only at baseline after LVAD implantation and on specific indications, such as low-flow alarms. However, since 2022, routine biennial CTAs have been performed for all patients, starting 2 years post-LVAD implantation, reflecting increased awareness of LVAD OGS. We determined the percentage of lumen narrowing by measuring perpendicular to the outflow graft in different axes, categorizing as: no stenosis (0-25%), mild stenosis (25-50%), moderate stenosis (50-75%), and severe stenosis (>75%). Results We included 135 patients (median age: 53 years, 63% male), with a total of 330 available CTA scans. Throughout the study period (median FU of 31.8 months, IQR:11-43), evidence of OGS was observed in 16 (11.8%) patients: 8 (5.9%) with mild stenosis, 6 (4.4%) with moderate stenosis, and 2 (1.5%) with severe stenosis. The median time to mild stenosis, moderate stenosis, and severe stenosis was 2.5, 3.9, and 4.9 years respectively. Figure illustrates the prevalence, clinical presentation and treatment of various degrees of OGS. Among patients with mild stenosis, 75% (6/8) were detected incidentally during routine CTA scans, while 50% (3/6) of those with moderate stenosis presented with low-flow alarms. Only 7.6% (9/119) of patients with no stenosis experienced low-flow alarms. Mild and moderate stenosis were not associated with mortality compared to no stenosis (p>0.05), but severe stenosis was (p<0.05). Five patients underwent stenting, and one patient underwent surgery for outflow graft stenosis. Conclusions LVAD OGS is a significant late complication affecting approximately one in eight patients, with potentially severe consequences. Severe stenosis is associated with higher mortality compared to no stenosis. The true prevalence may be underestimated due to delayed radiological surveillance initiation. CTA plays a pivotal role as a non-invasive diagnostic step to identify OGS and systematic screening may be warranted. Endovascular stenting or surgery can effectively treat patients with OGS.