Exploratory proof-of-concept study and failure mode analysis of a dual-lumen stent graft for transapical off-pump...

Transapical off-pump implantation of left ventricular assist devices (LVADs) requires a separate inflow cannula and outflow graft. This study represents the first exploratory proof-of-concept evaluation of a dual-lumen stent graft designed to redirect blood from the left ventricle across the aortic valve into the ascending aorta while enabling LVAD support. The stent graft was tested in a mock circulatory loop, during wet-lab experiments on explanted porcine hearts, and in an exploratory acute large-animal study. In vitro testing showed no relevant impairment of pump performance. Wet-lab experiments confirmed that transapical positioning is feasible while revealing incomplete device expansion and myocardial tearing during balloon-assisted apical displacement. In vivo, a reinforced prototype could be positioned across the aortic valve, but myocardial compression impaired inflow expansion and LV unloading, while insufficient apical sealing resulted in bleeding and air embolism. Postmortem analysis confirmed correct device positioning without macroscopic valvular injury but identified myocardial tearing. These failure modes highlight the need for alternative design strategies for transapical off-pump LVAD implantation.