Cardiovascular MRI–derived Right Atrial Strain for Improved Risk Stratification in Patients with Severe Aortic Stenosis

Purpose To assess the prognostic implications of cardiac MRI-derived imaging markers in individuals with severe aortic stenosis (AS). Materials and Methods This prospective study (German Clinical Trials Register, DRKS00024479) enrolled individuals with severe AS who underwent cardiac MRI before transcatheter aortic valve replacement (TAVR) from January 2017 to March 2022. Image analyses included myocardial volumes, cardiac MRI feature tracking-derived left atrial (LA) and right atrial (RA) as well as left ventricular (LV) and right ventricular (RV) strain, myocardial T1 mapping, and late gadolinium enhancement analyses. Cardiovascular (CV) mortality was defined as primary clinical end point. Cox proportional hazards models were used to determine the association between cardiac MRI-derived parameters and CV mortality. Results The final analysis included 145 participants (median age, 80 years [IQR, 75-83 years]; 91 male). Participants who experienced CV death during follow-up had significantly enlarged RV end-diastolic volumes (median, 82.9 [IQR, 70.8-96.0] mL/m² vs 62.8 [54.7-76.0] mL/m²; <i>P</i> < .001) and impaired strain values of all cardiac chambers compared with those who survived (LV global longitudinal strain [GLS], -18.1% [-13.1% to -20.4%] vs -22.5% [-16.1% to -27.3%], <i>P</i> = .02; RV GLS, -22.9% [-18.6% to -25.4%] vs -27.9% [-22.9% to -32.0%], <i>P</i> = .002; LA atrial reservoir strain [Es], 9.5% [7.2%-15.4%] vs 14.3% [9.0%-18.1%], <i>P</i> = .04; RA Es, 12.4% [6.8%-14.4%] vs 16.2% [11.2%-22.1%], <i>P</i> < .001). RA reservoir strain independently helped predict CV mortality after adjustment for other cardiac MRI markers and clinical parameters of heart failure (hazard ratio, 0.82 [95% CI: 0.71, 0.95]; <i>P</i> = .008). Within the subgroup of participants with high extracellular volume values, RA strain further identified participants with AS at high risk for CV mortality (<i>P</i> = .001 on log-rank testing). Conclusion In individuals with AS undergoing TAVR, several cardiac MRI parameters were significantly associated with CV mortality. RA strain was an independent predictor of CV mortality and may provide more optimized patient management. <b>Keywords:</b> Cardiac MRI, Aortic Stenosis, TAVR, Risk Assessment, Strain Analyses German Clinical Trials Register no. DRKS00024479 <i>Supplemental material is available for this article.</i> © RSNA, 2025.