Remodeling in Aortic Stenosis With Reduced and Preserved Ejection Fraction: Insight on Motion Abnormality Via 3D + Time Personalized LV Modeling in Cardiac MRI.

ABSTRACT

BACKGROUND: Increased afterload in aortic stenosis (AS) induces left ventricle (LV) remodeling to preserve a normal ejection fraction. This compensatory response can become maladaptive and manifest with motion abnormality. It is a clinical challenge to identify contractile and relaxation dysfunction during early subclinical stage to prevent irreversible deterioration. PURPOSE: To evaluate the changes of regional wall dynamics in 3D + time domain as remodeling progresses in AS. STUDY TYPE Retrospective. POPULATION A total of 31 AS patients with reduced and preserved ejection fraction (14 AS_rEF 7 male, 66.5 [7.8] years old; 17 AS_pEF 12 male, 67.0 [6.0] years old) and 15 healthy (6 male, 61.0 [7.0] years old). FIELD STRENGTH/SEQUENCE 1.5 T Magnetic resonance imaging/steady state free precession and late-gadolinium enhancement sequences. ASSESSMENT Individual LV models were reconstructed in 3D + time domain and motion metrics including wall thickening (TI), dyssynchrony index (DI), contraction rate (CR), and relaxation rate (RR) were automatically extracted and associated with the presence of scarring and remodeling. STATISTICAL TESTS Shapiro-Wilk data normality; Kruskal-Wallis significant difference (P < 0.05); ICC and CV variability; Mann-Whitney effect size. RESULTS: AS_rEF group shows distinct deterioration of cardiac motions compared to AS_pEF and healthy groups (TIAS_rEF 0.92 [0.85] mm, TIAS_pEF 5.13 [1.99] mm, TIhealthy 3.61 [1.09] mm, ES 0.48-0.83; DIAS_rEF 17.11 [7.89]%, DIAS_pEF 6.39 [4.04]%, DIhealthy 5.71 [1.87]%, ES 0.32-0.85; CRAS_rEF 8.69 [6.11] mm/second, CRAS_pEF 16.48 [6.70] mm/second, CRhealthy 10.82 [4.57] mm/second, ES 0.29-0.60; RRAS_rEF 8.45 [4.84] mm/second; RRAS_pEF 13.49 [8.56] mm/second, RRhealthy 9.31 [2.48] mm/second, ES 0.14-0.43). The difference in the motion metrics between healthy and AS_pEF groups were insignificant (P-value = 0.16-0.72). AS_rEF group was dominated by eccentric hypertrophy (47.1%) with concomitant scarring. Conversely, AS_pEF group was dominated by concentric remodeling and hypertrophy (71.4%), which could demonstrate hyperkinesia with slight wall dyssynchrony than healthy. Dysfunction of LV mechanics corresponded to the presence of myocardial scarring (54.9% in AS), which reverted the compensatory mechanisms initiated and performed by LV remodeling. DATA CONCLUSION: The proposed 3D + time modeling technique may distinguish regional motion abnormalities between AS_pEF, AS_rEF, and healthy cohorts, aiding clinical diagnosis and monitoring of AS progression. Subclinical myocardial dysfunction is evident in early AS despite of normal EF. LEVEL OF EVIDENCE 4 TECHNICAL EFFICACY Stage 1.