Aortic Valve Pathology in Patients Supported by Continuous-Flow Left Ventricular Assist Device

Background; Continuous-flow left ventricular assist devices (CF-LVAD) may induce pathological changes to the aortic wall and aortic valve. We assessed histological changes in the relevant anatomic structures exposed to continuous flow over time and compared the histological results with clinical features in patients supported with CFLVAD. Methods and Results; A retrospective histological analysis was performed of 38 explanted hearts supported with CF-LVAD from patients who received heart transplantation between July 2003 and February 2014. Sections of formalin-fixed paraffin-embedded tissue showing the continuity of aortic wall and left-sided valves were examined histologically. Thickness of aorta, aortic root and aortic valve as well as 3 layers of the aortic cusps were measured individually on Elastica van Gieson-stained slides using specific software. Clinical parameters concerning aortic valve dysfunction were evaluated and validated against the histology. The aortic valve spongiosa and fibrosa layers showed no significant differences in thickness with regard to support duration or occurrence of aortic insufficiency. Longer CF-LVAD support duration correlated with a thinner aortic valve ventricularis layer (rs=-0.496). Conclusions; Long-term CF-LVAD support appears to cause involution of the ventricularis layer of the aortic valve cusp, consistent with more pronounced degenerative change with longer LVAD exposure, which may be explained by continuous coaptation of the cusps.