Prognostic implications of fibrosis in low risk aortic stenosis patients

Abstract

Introduction and objectivesAmong patients with aortic stenosis (AS), interstitial fibrosis has been associated with progression to heart failure and is a marker of poorer prognosis. We aimed to assess the impact of myocardial fibrosis on clinical events after aortic valve replacement (AVR) in low risk, severe AS. MethodsWe prospectively followed 56 severe AS patients with ejection fraction >40%, who underwent AVR with simultaneous myocardial biopsies and collagen volume fraction (CVF) determination. Baseline and follow-up echocardiographic parameters were assessed. Outcomes were all-cause death and the combined endpoint of all-cause death or non-fatal cardiovascular hospitalization. ResultsPatients were predominantly women (67.9%) and mean age was 66±12 years. At follow-up, there was a significant decrease in transaortic gradients and wall stress, as well as regression in indexed LV mass. Patients who suffered a fatal event or the combined endpoint had a higher degree of fibrosis (27.1±20.7% vs. 15.4±11.8%, p=0.035; 24.0±18.2% vs. 15.3±12.0%, p=0.038, respectively). Patients with CVF≥15.4% had higher rates of all-cause death (37.5% vs. 97.0%, p=0.001) and lower survival free of the combined endpoint of all-cause death or non-fatal cardiovascular hospitalization (0% vs. 91.2%, p<0.001). CVF was the only independent predictor of all-cause death (hazard ratio (HR) 1.88; 95% confidence interval (CI): 1.08-3.29 for each 10% increase; p=0.026) and all-cause death or cardiovascular hospitalization (HR 1.73; 95% CI: 1.03-2.911 for each 10% increase; p=0.038). ConclusionsIn low risk AS patients, higher levels of fibrosis are independent predictors of all-cause death and the composite of all-cause death or non-fatal cardiovascular hospitalization. Further advances in anti-fibrotic therapies in AS are needed.