Aim: Computed tomography (CT)-derived extracellular volume fraction (ECV) is a non-invasive method to quantify myocardial fibrosis. Evaluating CT-ECV during aortic valve replacement (AVR) planning CT in severe aortic stenosis (AS) may aid prognostic stratification. This meta-analysis evaluated the prognostic significance of CT-ECV in severe AS necessitating AVR. Methods and results: Electronic database searches of PubMed, OVID-MEDLINE, and Cochrane Library were performed. The primary outcome was to compare the occurrence of a composite of cardiovascular outcomes in patients with severe AS undergoing AVR with elevated myocardial CT-ECV values versus patients with normal values. Secondary outcomes included all-cause mortality and heart failure (HF) related hospitalization. A total of 1223 patients undergoing AVR for severe AS were included in 10 studies: 524 patients with high values of CT-ECV and 699 with normal values of CT-ECV. The pooled CT-ECV cut-off to define elevated values and predict prognosis was 30.7% (95% CI: 28.5-33.7%). At a mean follow-up of 17.9±2.3 months after AVR, patients with elevated CT-ECV experienced a significantly higher number of cardiovascular events (43.4% vs 14.0%; OR:4.3, 95% CI:3.192/5.764, p <0.001). Regarding secondary outcomes, all-cause mortality occurred in 29.3% of patients with elevated CT-ECV vs 11.6% with CT-ECV below the cut-off (OR3.5, 95% CI:2.276/5.311, p<0.001), whereas HF hospitalization was observed in 25.5% vs 5.9% (OR 4.9, 95% CI: 2.283/10.376, p<0.001). Graphical Abstract. Conclusion: Patients undergoing AVR for severe AS with elevated CT-ECV values experience a worse post-intervention prognosis. The implementation of CT-ECV evaluation in routine AVR planning protocols should be considered.
