Effects of aortic valve calcification on transcatheter aortic valve replacement for low-flow, low-gradient aortic stenosis.

Abstract

Background: Patients with low-flow, low-gradient (LFLG) aortic stenosis (AS) have precarious hemodynamics and are a fragile population for intervention. Quantification of aortic valve calcification (AVC) severity is a critical component of the evaluation for transcatheter aortic valve replacement (TAVR); this study aims to further clarify its utility for risk stratification in LFLG AS.

Methods: This retrospective study evaluated 467 patients with LFLG AS undergoing TAVR at a large quaternary-care hospital from January 2019 to December 2021. AVC was quantified with Agatston scores using pre-operative computed tomography angiograms. Primary endpoint was a composite of all-cause mortality and heart failure rehospitalization rates.

Results: 51 patients (10.9 %) had mild calcification, 137 (29.3 %) had moderate, and 279 (59.7 %) had severe. Increased AVC severity correlated with increased AS severity by aortic valve area (0.69cm² for mild AVC vs. 0.63cm² for severe; p ≤0.001), peak velocity (3.1 m/s vs. 3.9 m/s; p ≤0.001), and mean gradient (21 mmHg vs. 36 mmHg; p ≤0.001). Kaplan-Meier analysis showed increased reductions in the primary composite endpoint (p = 0.023) and heart failure rehospitalization rates (p = 0.005) for patients with greater AVC severity undergoing TAVR. Multivariate adjustments confirmed a significant reduction in heart failure rehospitalizations when comparing TAVR outcomes between mild and severe AVC (HR 0.40, 95 % CI 0.18-0.91; p = 0.028). Between the 3 groups, there were no significant differences in adjusted rates of paravalvular leak or other periprocedural complications.

Conclusions: Increased AVC in LFLG AS does not correlate clinically with more severe AS by echocardiography. Patients with more severe AVC have less heart failure rehospitalizations and derive greater benefit from TAVR.