Quantification of Commissural Alignment of Balloon-Expandable THV on Fluoroscopy: A Comparison Study With Post-TAVR CT

Background: Coronary access may be challenging following transcatheter aortic valve replacement (TAVR) in the setting of transcatheter heart valve (THV) commissural misalignment.

Objectives: The authors aimed to quantify the degree of commissural alignment following balloon-expandable THV implantation using a fluoroscopy-based trigonometric approach and assess its correlation with post-TAVR computed tomography (CT).

Methods: Twenty patients who had undergone both TAVR with the balloon-expandable SAPIEN 3 THV and post-TAVR CT were included in the analysis. Optimized, predeployment 3-cusp angiographic view and postdeployment angiographic view using identical fluoroscopic projections were required. The distance between the most central posterior commissural strut and the THV centerline was assessed. Commissural alignment was calculated by means of a trigonometrical approach using an arcsine function, assuming circular deployment of the THV. Commissural alignment was stratified using a 4-tier scale: aligned (0° to 15°); mildly misaligned (15° to 30°); moderately misaligned (30° to 45°), and severely misaligned (45° to 60°).

Results: Seven patients (35.0%) were misclassified by 1 tier, and no patient was misclassified by 2 or more tiers, with strong agreement between CT and fluoroscopy (weighted Cohen's kappa coefficient = 0.724). Correlation of the commissural offset angle determined from fluoroscopy and CT was excellent (r = 0.986; 95% CI: 0.965 to 0.995). Bland-Altman analysis demonstrated a strong agreement between both modalities with a mean difference of 0.5° (95% limits of agreement: -12.7° to 13.7°).

Conclusions: The degree of commissural alignment of the balloon-expandable THV can be reliably assessed and quantified on postdeployment fluoroscopy using a standardized 3-cusp view and trigonometry-based analysis.