Prognostic value of myocardial computed tomography-derived extracellular volume in severe aortic stenosis requiring aortic valve replacement: A systematic review and meta-analysis

Computed tomography (CT)-derived extracellular volume (ECV) fraction 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. 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 vs. 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% confidence interval (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%; odds ratio (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 (OR: 3.5, 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). 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.