Zhou W, Sun YP, Divakaran S, et al. - In this single-center prospective observational study, the association of myocardial flow reserve (MFR) and stress myocardial blood flow (MBF) with adverse myocardial characteristics, including markers of myocardial injury and wall stress, was evident in aortic stenosis (AS). This indicates that MFR may represent an early sensitive marker for myocardial decompensation.

• This study involved 34 patients with AS (1 mild, 9 moderate, and 24 severe) and 34 matched control individuals.

• Ammonia N13 positron emission tomography myocardial perfusion imaging was used to quantify MBF and MFR.

• There was an independent association of MFR with left ventricular ejection fraction and global longitudinal strain on echocardiography.

• Stress MBF was found to be related to circulating high-sensitivity troponin T and N-terminal pro–B-type natriuretic peptide.

• Improvement in mean (SD) MFR from 1.73 (0.57) to 2.11 (0.50) was seen in 9 patients at 6 months post-aortic valve replacement.