Cardiac MRI-derived extracellular volume fraction is associated with failed left ventricular reverse remodeling after aortic valve replacement in severe aortic regurgitation With a giant left ventricle

Severe chronic aortic regurgitation (AR) with a markedly dilated left ventricle (LV) (‘giant left ventricle’; LV end-diastolic diameter, LVEDD ≥65 mm) carries a high risk of incomplete LV reverse remodeling after aortic valve replacement (AVR), yet reliable preoperative stratification tools remain limited. This retrospective cohort study aimed to evaluate whether preoperative cardiac magnetic resonance (CMR)-derived extracellular volume fraction (ECV) is associated with 6-month LV reverse remodeling in this high-risk population. We enrolled 46 consecutive patients with severe AR and LVEDD ≥65 mm receiving contrast-enhanced CMR and elective AVR. The primary analysis assessed the association between preoperative ECV and the continuous relative change in LVEDD at 6 months; a binary definition (≥20% LVEDD reduction) was used as a secondary, clinically oriented outcome. Absence of significant LV reverse remodeling (<20% reduction) was observed in 47.8% (22/46) of patients. In linear regression analysis, higher preoperative ECV was significantly associated with a smaller LVEDD reduction ( β = −0.924 per 1% absolute increase in ECV, 95% CI −1.528 to −0.320, P = 0.004). In multivariable logistic regression restricted to the preoperative variables significant on univariable analysis (ECV and LVEDD), ECV remained associated with failed reverse remodeling (adjusted OR = 1.281 per 1% absolute increase in ECV, 95% CI 1.001–1.640, P = 0.049), although the association attenuated after further adjustment for age (OR 1.227, 95% CI 0.950–1.585, P = 0.117); with an exploratory cutoff of 34.1% (AUC=0.74, 95%CI 0.59–0.89). Patients with ECV >34.1% exhibited impaired postoperative LV systolic function and prolonged hospital stay. These exploratory findings suggest that preoperative CMR-ECV may help identify severe AR patients at risk of incomplete LV reverse remodeling after AVR, and warrant prospective validation.