34 Effect of Aortic Valve Replacement on Left Atrial and Ventricular Myocardial Deformation in Severe Aortic Stenosis

Introduction Aortic valve replacement (AVR) in patients with severe aortic stenosis (AS) leads to reverse remodelling, with reduction in left ventricle (LV) mass and volumes. However, the effect of AVR on LV and left atrial (LA) myocardial deformation using feature tracking cardiovascular magnetic resonance (FT-CMR) has not been extensively studied. Materials and Methods Patients with severe AS scheduled for AVR were recruited. CMR and echocardiography scans were performed pre- and post-AVR using a standard protocol. In addition to volumetric assessment using area-length method for LA and short-axis cine stack for LV, myocardial deformation was assessed using FT-CMR by a blinded single observer using QStrain v2.0 (Medis v3.1, medical imaging system). LA strain (LAS) corresponding to reservoir, conduit and booster pump function were assessed on 4- and 2-chamber long-axis standard steady-state free precession cine images, and average values calculated. For the LV, the three long-axis cines were utilised for global longitudinal strain (GLS), and global circumferential strain (GCS) was derived by averaging values from the basal, mid and apical short axis cine slices. Longitudinal and circumferential peak early diastolic strain rate (PEDSR) were also derived. Results We recruited 78 patients with severe AS, 66 of whom (mean age 67.0±9.4 years; 75.8% males) had matched pre- and post-AVR CMR scans. Median follow-up period was 6 months. There were significant reductions in LV volumes, mass and mass/volume. In addition, FT-CMR showed a significant increase in GLS, GCS and longitudinal/circumferential-PEDSR post-AVR. Looking at the LA, there were no significant changes in the LA volumes or LA ejection fraction post-AVR. However, FT-CMR demonstrated a statistically significant increase in booster pump LA strain (LAS_bp), with a relative increase 19.98%. Conclusion In patients with severe AS, CMR-FT was able to detect improvements in both LA and LV myocardial deformation parameters at 6 months post-AVR. Despite no change in LA volumetric parameters, LAS_bp increased, which is important in maintaining LV filling. FT-CMR is therefore a sensitive technique to detect early reverse remodelling caused by the reduction of LV afterload post-AVR.