Prospective investigations for the frequency of hypoattenuated leaflet thickening (HALT) and its clinical implications in transcatheter aortic valve implantation (TAVI) patients are limited. We initiated a prospective screening program of TAVI patients for HALT beginning in July 2015. Eligible patients were evaluated with gated, contrast-enhanced multidetector computed tomography within 30 days of TAVI, and examined for HALT and clinical outcomes. During the study period, 287 patients (81 ± 8 years; 53% men) who underwent TAVI with commercially approved devices were examined. Overall, 26 patients (9.1%) had occurrence of HALT, and only one of these patients had detectable hemodynamic changes on echocardiography at diagnosis. Notably, 9 of 26 HALT patients had been receiving warfarin, however, the HALT patients more often had subtherapeutic international normalized ratio whereas using warfarin than patients without HALT on index multidetector computed tomography imaging (p = 0.01). Patients who developed HALT had lower baseline aortic gradient, valvuloarterial impedance, and peak aortic velocity, and more commonly had been treated with balloon-expandable valves (73% of all HALT cases) with a higher incidence among those who received larger prostheses. All patients with HALT were placed on anticoagulation at diagnosis, and valvular function remained unchanged at follow-up. Two patients with HALT (7.7%) experienced ischemic stroke. A statistical trend for more major adverse clinical events was present in HALT patients. In conclusion, HALT was detected in 9% of TAVI cases in this prospective observational cohort, with a greater frequency in patients with large, balloon-expandable prostheses. Prospective screening may be considered as early HALT is reversible by timely therapeutic anticoagulation.