Exploring myocardial fibrosis in severe aortic stenosis: echo, CMR and histology data from FIB-AS study

Abstract PurposeMyocardial fibrosis in aortic stenosis (AS) is associated with worse survival following aortic valve replacement (AVR). We assessed myocardial fibrosis in severe AS patients, integrating echocardiographic, cardiovascular magnetic resonance (CMR) and histological data. MethodsA total of 83 severe AS patients (age 66.4 ± 8.3, 42% male) who were scheduled for surgical AVR underwent CMR with late gadolinium enhancement (LGE) and T1 mapping and global longitudinal strain (GLS) analysis. Collagen volume fraction (CVF) was measured in myocardial biopsies (71) that were sampled at the time of AVR. ResultsCVF correlated with imaging and serum biomarkers of LV systolic dysfunction and left side chamber enlargement and was higher in the sub-endocardium compared with midmyocardium (p<0.001). CVF median values were higher in LGE-positive versus LGE-negative patients [28.7% (19-33) vs 20.7% (15-30), respectively, p=0.040]. GLS was associated with invasively (CVF; r=-0.303, p=0.013) and non-invasively (native T1; r=-0.321, p<0.05) measured myocardial fibrosis. GLS and native T1 correlated with parameters of adverse LV remodelling, systolic and diastolic dysfunction and serum biomarkers of heart failure and myocardial injury. ConclusionOur data highlight the role of myocardial fibrosis in adverse cardiac remodelling in AS. GLS has potential as a surrogate marker of myocardial fibrosis, and high native T1 and low GLS values differentiated patients with more advanced cardiac remodelling.