The effect of bend relief perforations upon extrinsic graft obstruction risk - a histological analysis

Extrinsic Outflow Graft Obstruction (EOGO) is a potential complication of durable left ventricular assist device (LVAD) therapy characterized by obstructive biodebris accumulation between the outflow graft (OG) and, in the case of HM3, the bend relief (BR). Recent reports have suggested that perforating the HM3 BR may help prevent EOGO. The study objective was to histologically compare the nature and constituency of explanted biologic material from beneath intact HM3 BRs (n = 7; with n = 3 EOGO) beneath perforated HM3 BRs (n = 5), and outside the BR (n = 2). Results indicate that material beneath intact BRs (EOGO and non-EOGO samples) is consistently acellular protein (fibrin) or biodebris while material beneath perforated BRs demonstrated collagen and cell infiltration through the perforations, resembling the material found outside the graft beyond the BR where EOGO is not observed. Despite the small sample size, this study provides a hypothetical mechanism(s) underlying potential benefits of BR perforations in preventing EOGO by attenuating biodebris accumulation through collagen and cell infiltration.