Characterization of Aortic Valve Stenosis by CT Angiography in a Diverse US Cohort

BACKGROUND: Aortic stenosis (AS) involves calcific and fibrotic degeneration of the valve tissue. The only noninvasive method for evaluating both processes is contrast-enhanced computed tomography angiography. We aimed to explore the differences in aortic valve (AV) tissue composition across sex, race/ethnicity, and AS hemodynamic phenotype in US patients referred for transcatheter AV replacement planning. METHODS: We retrospectively analyzed symptomatic patients with AS who underwent computed tomography angiography for transcatheter AV replacement planning between 2015 and 2022. Using semi-automated software, we quantified the AV tissue composition by fibrotic, calcific, and fibro-calcific volumes, and the fibro-calcific ratio (fibrotic/calcific volume) as a measure of valve phenotype. RESULTS: The study included 651 patients (mean age 84 years; 55% women) with 38% non-Hispanic (NH)-White, 27% Hispanic, and 13% NH-Black. Women had lower fibro-calcific (230 versus 293 mm³/cm²; P <0.001) and calcific volumes (85 versus 149 mm³/cm²; P <0.001), and higher fibro-calcific ratio (1.47 versus 0.83; P <0.001). No differences were observed in the fibrotic volumes ( P =0.805). NH-White women had higher fibro-calcific (256 mm³/cm², P =0.002) and fibrotic volumes (145 mm³/cm²; P <0.001), and fibro-calcific ratio (1.57; P =0.01) compared with Hispanic and NH-Black women. No differences were found among men. High-gradient AS had higher fibro-calcific (295 versus 219 mm 3 /cm 2 ; P <0.001) and calcific volumes (148 versus 88 mm 3 /cm 2 ; P <0.001), and a lower fibro-calcific ratio (0.90 versus 1.45; P <0.001), although no difference in fibrotic volume ( P =0.099) compared with low-gradient AS. CONCLUSIONS: Phenotypic differences in computed tomography angiography valve tissue composition exist in AS patients referred for transcatheter AV replacement, with females and low-gradient AS showing a proportionally more fibrotic phenotype. NH-White women have the highest fibrotic tissue composition, and no differences are evident among men.