Underexpansion and Ad Hoc Post-Dilation in Selected Patients Undergoing Balloon-Expandable Transcatheter Aortic Valve Replacement

Abstract

This study sought to assess the clinical outcomes and hemodynamic performance associated with a strategy of underexpanding balloon-expandable transcatheter heart valves (THV) when excessive oversizing is a concern. Transcatheter aortic valve replacement depends on the selection of an optimally sized THV. An undersized THV may lead to paravalvular regurgitation, whereas excessive oversizing may lead to annular injury. Patients (n = 47) who underwent transcatheter aortic valve replacement with an intentionally underexpanded THV (balloon-filling volume reduced ~10%) were compared with consecutive control patients who had nominal THV balloon deployment (n = 87). Pre- and post-procedural computed tomography imaging and echocardiography were performed to assess THV stent expansion and hemodynamics. Underfilling resulted in THV underexpansion that was maximal at the THV inflow (85.0 ± 7.4% vs. 102.5 ± 6.2%, p < 0.001), in study versus control groups, respectively. The study group received larger THV, although annular injury was not observed. Post-dilation was required in 10.6% and 4.6% of patients of the study and control groups, respectively (p = 0.165). Echocardiographic THV area, gradient, paravalvular regurgitation, and in-hospital outcomes were similar. Intentionally underexpanding balloon-expandable THV by underfilling the deployment balloon did not adversely affect procedural clinical outcomes, THV gradients, or THV areas. A strategy of underexpansion, with post-dilation as necessary, might play in role in reducing the risk of annular injury and paravalvular regurgitation in selected patients.