Does the severity of low-gradient aortic stenosis classified by computed tomography-derived aortic valve calcification determine the outcome of patients after transcatheter aortic valve implantation (TAVI)?

Abstract

Aortic valve calcification (AVC) determined by computed tomography has emerged as a complementary measure of aortic stenosis (AS) severity and as a predictor of adverse events. Thus, AVC can guide further treatment decisions in patients with low-gradient AS (LG-AS). We compared the symptomatic and prognostic outcome of patients with low vs. high AVC after transcatheter aortic valve implantation (TAVI). Patients with an aortic valve area index ≤ 0.6cm2/m2 and a mean pressure gradient (MPG) < 40mmHg were classified as low-flow, low-gradient AS (LFLG-AS; stroke volume index [SVI] ≤ 35ml/m2, left ventricular ejection fraction [LVEF] < 50%, n = 173), paradoxical LFLG-AS (pLFLG-AS, SVI ≤ 35ml/m2, LVEF ≥ 50%, n = 233), or normal-flow, low-gradient AS (NFLG-AS, SVI > 35ml/m2, LVEF ≥ 50%, n = 244); patients with MPG ≥ 40mmHg (n = 1142) served as controls. Patients were further categorized according to published AVC thresholds. Demographic characteristics and cardiovascular risk were not different between patients with high vs. low AVC in any of the subgroups. Patients with low AVC had a lower MPG. Symptom improvement at 30days was observed in the majority of patients but was less pronounced in LFLG-AS patients with low vs. those with high AVC. Kaplan-Meier 1-year survival curves were identical between patients with low and high AVC in all three LG-AS groups. The severity of LG-AS based on AVC has no impact on 1-year prognosis once TAVI has been performed. • Aortic valve calcification (AVC) determined by computed tomography has emerged as a complementary measure of aortic stenosis (AS) severity and is of prognostic value in selected patients. • Patients with inconsistent echocardiographic measures can be classified as having severe or nonsevere AS by the computed tomography-derived AVC score. • The prognostic value of AVC in patients with low-gradient AS is abrogated after correction of afterload by TAVI.