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)?

Objectives: 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).

Methods: Patients with an aortic valve area index ≤ 0.6 cm²/m² and a mean pressure gradient (MPG) < 40 mmHg were classified as low-flow, low-gradient AS (LFLG-AS; stroke volume index [SVI] ≤ 35 ml/m², left ventricular ejection fraction [LVEF] < 50%, n = 173), paradoxical LFLG-AS (pLFLG-AS, SVI ≤ 35 ml/m², LVEF ≥ 50%, n = 233), or normal-flow, low-gradient AS (NFLG-AS, SVI > 35 ml/m², LVEF ≥ 50%, n = 244); patients with MPG ≥ 40 mmHg (n = 1142) served as controls. Patients were further categorized according to published AVC thresholds.

Results: 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 30 days 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.

Conclusions: The severity of LG-AS based on AVC has no impact on 1-year prognosis once TAVI has been performed.

Key points: • 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.