Abstract
AIMS: Transcatheter aortic valve replacement (TAVR) is an established therapy improving outcome in patients with severe aortic stenosis (AS). Cardiovascular magnetic resonance (CMR)-derived left atrioventricular coupling index (LACI) has demonstrated prognostic value, however, its prognostic utility in severe AS remains unknown. METHODS AND RESULTS: Between January 2017 and September 2023 138 consecutive patients with severe AS (80 years (70-83), 62% male) referred for TAVR were prospectively recruited for pre-procedural CMR imaging. LACI was defined as the ratio of the left atrial (LA) end-diastolic volume index (LA EDVi) and left ventricular (LV) end-diastolic volume index (LV EDVi). The primary endpoint was cardiovascular (CV)-mortality. The cohort was dichotomized at a median of 44.1% (high vs. low LACI). Patients with increased LACI (≥44.1%) had higher symptom burden (NYHA III/IV prevalence (68.1% vs. 44.9%; P = 0.047)), more frequently atrial fibrillation (50.7% vs. 14.5%; P < 0.001), and elevated NT-proBNP (2017 ng/L vs. 1012 ng/L; P = 0.007). Over a median follow-up of 2.7 years (IQR 1.7-3.6), high LACI was associated with higher CV mortality (log-rank P = 0.016). In exploratory multivariable Cox regression models, LACI remained associated with CV-mortality after adjustment for established parameters of left atrial or ventricular function (LA reservoir strain: HR 2.19, 95% CI 1.05-4.57, P = 0.036; LV GLS: HR 2.21 95% CI 1.00-4.9, P = 0.049). CONCLUSION: In patients with severe aortic stenosis, CMR-derived LACI was associated with cardiovascular mortality and may serve as a structural marker of advanced atrioventricular remodelling. Given its simplicity and routine availability in standard CMR workflows, LACI may serve as a clinically practical risk marker for baseline stratification.