Aortic valve calcium score to mean gradient ratio: a new frontier in aortic stenosis prognostication

Abstract Introduction Aortic stenosis (AS) presents diagnostic challenges, especially in patients with discordant low gradient AS (LGAS), i.e., small aortic valve area (AVA) and low Doppler mean gradient (MG). LGAS is associated with worse outcomes compared to concordant AS. Aortic valve calcium score (AVCS) is a measure of AS severity independent of flow and helps diagnose severe AS. It is unknown if the degree of discordance in AVCS and MG is of any clinical significance. A high AVCS/MG ratio may indicate impaired ventricular function and response to pressure overload despite preserved LVEF, potentially contributing to worse outcomes. Purpose This study aims to elucidate the prognostic significance of the AVCS/MG ratio in patients with severe AS and preserved left ventricular ejection fraction (LVEF) undergoing TAVR. We hypothesized a higher AVCS/MG ratio correlates with increased mortality. Methods Patients who underwent transcatheter aortic valve replacement (TAVR) from 2010 to 2020 for native valve severe AS with LVEF≥50% were identified from an institutional database. AVCS were obtained within 90 days of pre-TAVR echocardiography. Patients were divided into tertiles based on their AVCS/MG ratio. Primary outcome was overall mortality. Results The analysis included 1067 patients (mean age 79±9 years, 43% female); overall AVA was 0.80±0.14 cm², LVEF 63±6%, MG 46±12 mmHg, AVCS 2630±1528 AU, and AVCS/MG ratio 58±31. Patients stratified by AVCS/MG tertiles showed no difference in overall comorbidity index across tertiles (Figure 1). However, the group in the highest tertile was the oldest (80±8 vs 79±8 vs 77±9 years), predominantly male (87% vs 61% vs 24%), with the highest prevalent atrial fibrillation (44% vs 28% vs 25%) and stroke volume index <35 mL/m² (16% vs 11% vs 5%). 9-year survival was 15% vs 25% vs 36% (p<0.001, Figure 2). In multivariate analysis adjusted for age, sex, comorbidities, LVEF and AVA, AVCS/MG ratio was independently associated with increased risk of mortality (HR 1.005; 95% CI [1.001-1.008], p=0.005). Conclusion Higher AVCS/MG discordance is associated with increased risk of mortality following TAVR. Serial AVCS measurements during progressive AS may help identify patients at higher risk who may potentially benefit from earlier aortic valve intervention.