Abstract 13551: Non-Invasive Assessment of Systemic Microvascular Function in Patients With Severe Aortic Stenosis Pre- and Post- Transcatheter Aortic Valve Intervention

Abstract

Background: Aortic stenosis (AS) is associated with pathophysiological changes in both left ventricular and coronary microvascular structure and function. The treatment of AS with transcatheter aortic valve replacement (TAVR) has been associated with improvements in invasive indices of coronary microvascular function. This study sought to address whether systemic microvascular dysfunction was present in patients with AS and if microvascular function was altered by treatment of aortic stenosis with TAVR. The conjunctival microcirculation was used as the site for the non-invasive assessment of systemic microvascular function. Methods: Patients undergoing TAVR for the treatment of severe AS were compared to a cohort of age- and sex-matched controls without valvular heart disease. Conjunctival vascular imaging was performed in all subjects using a previously validated combination of a smartphone and slit-lamp biomicroscope. This technique allowed measurement of vessel diameter and other indices of microvascular function by tracking erythrocyte motion. Conjunctival hemodynamics were compared pre- and post-TAVR, in addition to between the severe AS and control cohorts. Results: A total of 165 patients were included (90 severe AS and 75 controls). Baseline characteristics were well matched between groups. In comparison to the control cohort, arteriole axial (Va) and cross-sectional velocity (Vcs) were significantly lower in females with AS (Va severe AS 0.53 ± 0.11mm/s vs control 0.59 ± 0.12mm/s, p=0.047; Vcs severe AS 0.38 ± 0.07mm/s vs control 0.41 ± 0.08mm/s, p=0.043), but not in males (Va severe AS 0.61 ± 0.11mm/s vs control 0.58 ± 0.10mm/s, p=0.19; Vcs severe AS 0.43 ± 0.08mm/s vs control 0.41 ± 0.07mm/s, p=0.20). Arteriole Va and Vcs significantly increased following TAVR in females (Va Pre-TAVR 0.52 ± 0.16mm/s vs post-TAVR 0.59 ± 0.15mm/s, p<0.001; Vcs Pre-TAVR 0.37 ± 0.11mm/s vs post-TAVR 0.42 ± 0.11mm/s, p<0.001). Conclusion: This study highlights sex-specific differences in conjunctival microvascular function in patients with severe AS. In this study TAVR resulted in significant improvements in conjunctival arteriolar V a and V cs . These findings are consistent with severe AS being a reversible cause of systemic microvascular dysfunction.