Hemodynamic phenotypes of severe aortic stenosis in patients with small aortic annulus and implications for transcatheter aortic valve implantation outcomes.

Patients with severe aortic stenosis (AS) and small aortic annulus pose diagnostic and therapeutic challenges. To investigate the frequency of discordant grading of severe AS in patients with a small aortic annulus and to evaluate the outcomes after transcatheter aortic valve implantation (TAVI). Patients with severe AS, an aortic annulus diameter of < 21 mm on echocardiography, a mean annulus diameter of < 23 mm, and an area ≤ 4.3 cm2 on cardiac computed tomography, who underwent TAVI, were retrospectively analyzed. The frequency of low-gradient severe AS was assessed. Patients were followed up for the occurrence of the composite endpoint of all-cause mortality, rehospitalizations for heart failure, non-fatal myocardial infarction, and non-fatal stroke. Among 230 patients with severe AS and a small aortic annulus (age 82 ± 6 years, 85% female), 52 (23%) had low gradient, while 120 (52%) exhibited normal flow-high gradient and 58 (25%) had low flow-high gradient. During a median follow-up of 2 years, the composite endpoint occurred in 29% of the total cohort. Patients with low-gradient severe AS experienced the worse outcome (HR = 2.46; 95% CI: 1.13-5.33; p = 0.023). Almost one-fourth of patients with severe AS and small annulus have low gradient AS. These patients experienced worse outcomes, likely reflecting advanced myocardial remodeling due to delayed referral and the diagnostic challenges posed by small annular dimensions.