Myocardial fibrosis in severe asymptomatic versus symptomatic aortic stenosis: A cardiac magnetic resonance cross-sectional study.

Purpose The degree of myocardial fibrosis may guide the timing of aortic valve replacement in patients with severe asymptomatic aortic valve stenosis (AS). We aimed to examine the prevalence and degree of myocardial fibrosis in severe asymptomatic AS compared with severe symptomatic AS. Methods We prospectively included 42 patients with severe asymptomatic AS and 80 patients with severe symptomatic AS, all with a left ventricular ejection fraction ≥ 50% and no ischemic heart disease. All patients underwent a standard cardiac magnetic resonance examination, including native T1 mapping. Gadolinium contrast was administered to evaluate extracellular volume fraction (ECV%) and late gadolinium enhancement (LGE). Results There were no differences in myocardial fibrosis markers when comparing symptomatic with asymptomatic patients and adjusting for sex, age, and aortic peak velocity, including native T1 (mean difference [MD] -1 ms; 95% confidence interval [CI] -11 to 10; p = 0.90), ECV% (MD 0.2%; 95% CI -1 to 1; p = 0.65), LGE prevalence (odd ratio [OR] 1.2; 95% CI 0.4 to 3.3; p = 0.72), and a combined binary high- or low-grade fibrosis parameter (OR 1.1; 95% CI 0.3 to 4.0; p = 0.94). Conclusion Patients with severe asymptomatic AS exhibited similar severity of myocardial fibrosis markers as those with severe symptomatic AS, suggesting that substantial myocardial damage precedes symptom development.