Pathological analysis of the aortic valve after long-term left ventricular assist device support

Abstract

Aortic insufficiency (AI) often develops during left ventricular assist device (LVAD) support and is related to a poor prognosis. As LVAD implantation and the support duration increase, the risk of acquired aortic valve lesions may increase. We investigated the pathological changes in the aortic valve and its function after long-term LVAD support. Thirty-five hearts removed at heart transplantation were investigated. Thirty-one patients were supported by extracorporeal pulsatile devices, and 4 were supported by implantable devices. We compared the histological changes in the aortic valve with the echocardiogram results. The mean duration of LVAD support was 961 days. Before device implantation, all patients had a normal aortic valve opening, and only 5 had trivial AI. After LVAD support, trivial AI was observed in 18 patients, mild AI in 4 and mild-to-moderate AI in 2. Pathological examination revealed that the aortic valve had become thinner in all patients, ranging from 120 to 1400 µm. The aortic wall had also become thinner in most patients, ranging from 830 to 2220 µm. Left ventricular wall thickness was ranging from 4 to 13 mm, and aortic annular diameter was ranging from 17 to 27 mm. Partial aortic valve fusion was seen in 17 (48.6%) recipients, and curling with leaflet shortening was detected in 22 (62.9%) patients. Dense collagen accumulation in the spongiosa layer was also present. All aortic valves of the patients with mild and mild-to-moderate AI showed a scarce or no opening before explantation. Conversely, the AI grade of patients whose aortic valve frequently opened remained none or trivial. There was no close correlation between these pathological findings and the development of AI independently. Degenerative aortic valve changes were recognized after long-term LVAD support. There was also an increasing prevalence of mild and mild-to-moderate AI, which may have been associated with continuous aortic valve closure. An optimal strategy to prevent AI development should be determined, and careful periodic echocardiographic follow-up is essential.