Link between fibrosis-specific biomarkers and interstitial fibrosis in hypertrophic cardiomyopathy.

Abstract

Cardiac fibrosis is a hallmark of hypertrophic cardiomyopathy (HCM) and has proven unfavorable clinical significance. Replacement fibrosis is better known, and has already been studied on a larger scale, whereas interstitial fibrosis is less explored. We aimed to analyze relationship between serum biomarkers and interstitial fibrosis, as assessed with cardiac magnetic resonance (CMR) in HCM. We performed 3T CMR scans in 50 HCM patients to assess interstitial fibrosis as expressed by extracellular volume (ECV). In all patients, we determined levels of serum cardiac-specific (troponin T [TnT], N-terminal prohormone of brain natriuretic peptide [NT-proBNP]) and fibrosis-specific (procollagen I C-terminal propeptide, procollagen III N-terminal propeptide, transforming growth factor β1, galectin 3) biomarkers. Patients were divided based on their median value of ECV. The final study population consisted of 49 patients. The median value of ECV in our cohort was 28.1%. Patients stratified according to median ECV differed in terms of several variables: body mass index, late gadolinium extent, NT-proBNP and galectin 3 levels (all P < 0.05). Cardiac biomarkers (TnT and NT-proBNP) and galectin 3 were significantly correlated with ECV (rS = 0.34; P = 0.02; rS = 0.39; P = 0.006; rS = 0.43; P = 0.002, respectively). Galectin 3 and body mass index were found to be independent predictors of ECV (odds ratio [OR], 2.29 [1.07-4.91]; P = 0.03; OR, 0.81 [0.68-0.97]; P = 0.02, respectively). Galectin 3 was an independent predictor of interstitial fibrosis in HCM patients expressed as elevated ECV values. The other fibrosis-specific biomarkers measured were not useful in detecting interstitial fibrosis in HCM. In addition, there was a positive correlation between classical cardiac biomarkers and interstitial fibrosis in HCM patients.