Imaging characterization of aortic stenosis etiologies using calcium score

Introduction

Aortic stenosis (AS) represents a heterogeneous disease entity with different underlying etiologies, including degenerative, bicuspid, and rheumatic valve disease. While echocardiography remains the reference standard for assessing hemodynamic severity, computed tomography–derived calcium scoring allows detailed anatomical characterization of calcific involvement and may enhance etiological differentiation.

Purpose

To characterize the distribution of valvular and peri-valvular calcification across different etiologies of aortic stenosis using CT calcium scoring in a real-world cohort.

Methods

This observational study included 200 consecutive patients with aortic stenosis who underwent non-contrast cardiac CT for calcium scoring. Etiology was classified as degenerative, bicuspid, or rheumatic by echocardiography. Calcium presence was assessed at the aortic valve leaflets, commissures, annulus, mitral annulus, mitral leaflets, and left atrial free wall. Data are presented as number of patients with detectable calcium in each anatomical location quantified in Agatston Unit (AU).

Results

Of the 200 patients, 154 (77.0%) had degenerative AS, 16 (8.0%) bicuspid AS, and 30 (15.0%) rheumatic AS. Female patients slightly predominated (102 women, 51.0%).

Aortic valve leaflet calcification was present in all of degenerative, bicuspid patients, and in 96.7% of rheumatic AS cases. Commissural calcification was detected in 100% of degenerative, 93.8% of bicuspid, and 100% of rheumatic AS patients. Aortic annular calcification was more frequent in degenerative (93.5%) and rheumatic (90.0%) AS compared with bicuspid AS (75.0%).

Extra-aortic calcification showed marked etiological differences. Mitral annular calcification was present in 68.2% of degenerative, 31.3% of bicuspid, and 70.0% of rheumatic AS patients. Mitral leaflet calcification and left atrial free wall calcification were more prevalent in rheumatic AS (46.7% and 36.7%, respectively) compared with degenerative (26.0% and 23.4%) and bicuspid AS (12.5% and 25.0%).

Conclusion

CT calcium scoring reveals distinct anatomical patterns of calcification across aortic stenosis etiologies that are not captured by echocardiographic assessment alone. Degenerative and rheumatic AS demonstrate more extensive annular and extra-valvular calcification, whereas bicuspid AS shows a more localized calcific phenotype. These findings support the role of CT calcium scoring as a powerful imaging tool for etiological characterization and phenotyping of aortic stenosisAS etiology according to sexFor image description, please refer to the figure legend and surrounding text.CT Calcium distributionFor image description, please refer to the figure legend and surrounding text.