176 Myocardial extracellular volume pre and post aortic valve replacement in severe aortic stenosis

Introduction Histological studies show that myocardial fibrosis accompanies cellular hypertrophy in severe aortic stenosis (AS). Following valve replacement (AVR), left ventricular regresses by 20%-30% one year (1) and both may regress as early 6 months post AVR (2, 3). With T1 mapping, CMR can measure diffuse quantifying extracellular volume fraction (ECV) which reflects the of myocardium occupied matrix is an independent predictor mortality outcome patients with AS (4). Previous methods measuring ECV have used Modified Look-Locker Inversion recovery (MOLLI) sequences shown a significant reduction cell 12 AVR(5). We aimed to investigate changes seen pre AVR, using multiparametric SAturation-recovery single-SHot Acquisition (mSASHA) has higher accuracy precision due its reduced sensitivity T2 (6). This particularly important blood markedly after contrast administration (7). Methods 16 referred for were recruited consent. Mean age was 66 ± years 56% male. Patients scanned before (visit 1) 2). measurements made on 3 T Siemens system mSASHA at 10 minutes gadobutrol injection (0.15 mmol/kg) per recommendations SCMR calculation (8) . Derived indexed derived calculated from product mass index ´ [1-ECV] ECV, respectively previously described.(5) Results Visit 2 data acquired 167 44 days AVR. There hypertrophy, end-diastolic (table 1, figure 1). Post there and, while increase no change 2, Conclusion For first time mSASHA, we AS, less than (derived decreases) remains stable). Further will need be undertaken determine if decreases mSASHA. Conflict Interest No