8 Cardiac structuraal, functional remodelling, and perfusion impairements in varying degrees of aortic stenosis

Background Aortic stenosis (AS) accounts for substantial global morbidity and premature mortality even in moderate AS (Mod-AS). Whilst myocardial remodeling response is considered critical in the adverse prognosis of Mod-AS, the precise mechanisms remain poorly understood. We aimed to prospectively assess myocardial remodeling, perfusion and energetics differences in Mod-AS and severe AS (Severe-AS). Methods Fifty-two Severe-AS and 25 Mod-AS patients and 18 demographically-matched controls underwent cardiovascular magnetic resonance and phosphorus-magnetic resonance spectroscopy to define left ventricular (LV) mass and function, global longitudinal shortening (GLS), rest and adenosine-stress myocardial blood flow (MBF), myocardial perfusion reserve (MPR), layer-specific perfusion metrics (subendocardial Endo, subepicardial Epi MBF and MPR, and Endo-Epi-MBF ratio Endo/Epi), myocardial scar on late gadolinium enhancement (LGE) imaging, and myocardial energetics (phosphocreatine:ATP ratio PCr/ATP). Results Compared to controls, with increasing AS severity, there was progressive increase in LV concentricity (LV-mass/LV-end-diastolic-volume)(controls:0.580.54,0.62, Mod-AS:0.740.64,0.84, Severe-AS:0.890.83,0.95g/mL;PConclusions Moderate and severe-AS are associated with cardiac concentric hypertrophy, reductions in myocardial energetics, and subendocardial hypoperfusion. Patients with Severe-AS exhibit a more marked phenotype with worse LV hypertrophy, contractile dysfunction and myocardial scarring compared to Mod-AS patients. Conflict of Interest Nil