A Case of Atypical HeartWare Ventricular Assist Device Outflow Graft Obstruction.

Abstract

External outflow graft obstruction (EOGO) is a known complication in left ventricular assist devices (LVADs), particularly around limited spaces such as the bend relief in HeartMate pumps. While EOGO in HeartMate 3 commonly occurs due to accumulation of biodebris between the bend relief and outflow graft, the incidence of EOGO in the HeartWare Ventricular Assist Device (HVAD) is much lower (0.006 events per patient-year) than that in HeartMate 3 because of the unique grid-like strain relief structure. We report an atypical case of EOGO in a 59 year old man with previous coronary artery bypass grafting who developed progressive dyspnea and decreased pump flow 4 years after HVAD implantation. Surgical exploration revealed aggressive ingrowth of dense fibrinous tissue into the strain relief, causing outflow graft compression. Pump flow improved dramatically after debridement. This case demonstrates that EOGO can occur in any LVAD when the outflow graft passes through a confined space, such as with dense adhesions due to prior surgery. This case report implies that strategies to prevent EOGO in LVADs may require not only bend relief fenestration to avoid biodebris accumulation but also improvement of confined spaces around the outflow graft such as adhesions after surgery.