Clinical outcomes following TAVR for patients with low and very low gradient aortic stenosis

This study explores the impact of lower baseline aortic valve (AV) mean gradients on the clinical outcomes of patients with low-gradient aortic stenosis (LG AS) post-transcatheter aortic valve replacement (TAVR). Additionally, the study aims to understand the predictors of a lower baseline AV mean gradient (MG).

Reduced left ventricular ejection fraction (LVEF) and low-flow states are known to correlate with worse clinical outcomes. Lower mean gradients are also known to correlate with poorer outcomes, but the outcomes of patients with very low-gradient AS compared to low-gradient AS are not well understood.

This is a retrospective cohort of patients >18 years who underwent TAVR at Cleveland Clinic between 2016 and 2020. Only patients with AV area < 1 cm², and AV MG <40 mmHg were included. Patients who underwent valve-in-valve TAVR were excluded. Patients were classified into 3 tertiles according to their baseline AV MG. Clinical outcomes included mortality and heart failure hospitalization. Survival analysis was used to assess the clinical outcomes between the tertiles.

Around 60 % of the patients in this study were males, with a mean age of 80 years. The mean AV MG was 21.8 ± 4.0 mmHg for the first tertile, 30.9 ± 1.9 mmHg for the second tertile, and 37.1 ± 1.6 mmHg for the third tertile. The present study shows that patients with very low-gradient AS (first tertile) have higher mortality rates compared to those with low-gradient AS (third tertile) (hazard ratio: 2.07, 95 % confidence interval (1.2-3.6)), even after stratifying by flow and by LVEF. Lower stroke volume index (SVI), lower LVEF, atrial fibrillation, and moderate to severe TR were associated with lower mean gradients.

Patients with very low-gradient AS have worse outcomes than those with low-gradient AS. Multiple clinical characteristics, including a lower SVI, lower LVEF, and atrial fibrillation, correlate with having very low-gradient AS. Therefore patients with low-gradient AS should undergo earlier intervention to improve their clinical outcomes.