Anatomical characteristics of aortic valve diseases: Implications for transcatheter aortic valve replacement.

Background: The etiology of aortic stenosis (AS) significantly impacts transcatheter heart valve (THV) implantation, with rheumatic etiology posing challenges. The concept of valve anchoring during transcatheter aortic valve replacement (TAVR) for patients with aortic regurgitation (AR) remains unclear. Objective: This study aims to investigate the clinical and CT anatomical characteristics of various aortic valve diseases. Methods: A retrospective analysis was conducted on consecutive patients who underwent CT for severe aortic diseases between April 2019 and February 2023. CT analysis was performed in eight anatomical landmarks: left ventricular outflow tract (LVOT), aortic annulus, sinus of Valsalva (SOV), sinotubular junction (STJ), ascending aorta (AAO), coronary height, aortic angle, and aortic valve calcification volume. Results: 121 patients with severe aortic valve disease were included, divided into AS (71 cases, 59%) and AR (50 cases, 41%) groups. In patients with AR, the absolute diameters of the annulus, LVOT, SOV, STJ, and AAO, as well as the heights of SOV and STJ and the cardiac angle, are larger than those in patients with AS (all P < 0.05). In normalized aortic root dimensions, the AR group had a higher SOV and STJ diameter-to-annulus ratio than the AS group (STJ-SOV-annulus: 1.51-1.44-1.00 vs 1.33-1.28-1.00). The bicuspid and rheumatic AS groups had smaller sinuses (STJ-SOV-annulus:1.27-1.35-1.00, 1.17-1.30-1.00, respectively), necessitating the downsizing of the THV. For 74% of AR patients, the sinotubular junction could not be used as a second anchoring zone, and anchoring relied primarily on the annulus. Conclusions: Patients with rheumatic etiology require smaller valves, and anchoring in AR patients depends on the valve annulus. These structural characteristics will influence TAVR selection.