Hypertrophic cardiomyopathy: Prognostic value of myocardial fibrosis volume as a predictor of chronic heart failure progression

Determining the clinical course of disease in patients with hypertrophic cardiomyopathy (HCM) with the presence of symptoms of chronic heart failure (CHF) progression remains a complex and unresolved problem.

Objective. The objective of the study was to analyze the variants of clinical course in patients with CHF due to progressive LV dysfunction and to evaluate the prognostic role of myocardial fibrosis volume according to late gadolinium enhancement cardiac magnetic resonance (CMR) as a predictor of CHF progression to NYHA FC III.

Material and Methods. A comprehensive examination including cardiac echocardiography, Holter ECG monitoring, and late gadolinium enhancement CMR, was performed in 124 patients (79 men and 45 women, median age of 46 years) with HCM who were observed in Republican Scientific and Practical Centre “Cardiology”. The median follow-up was 41 months (from 25 to 58 months). The clinical endpoint was progression of CHF symptoms from NYHA FC I–II to class III requiring hospitalization.

Results and Discussion. Among 124 patients with HCM, CHF progression requiring hospitalization during the follow-up period was observed in 24 patients with preserved systolic function (LV EF > 50%). The 5-year survival rate was 83% (95% CI 76.5–90.1). As a new marker aimed at identifying patients at risk of CHF progression, the volume of myocardial fibrosis was analyzed using the late gadolinium enhancement cardiac MR. The level of fibrosis, associated with the progression of heart failure, was 20%. The log-rank test and Kaplan-Meier survival curves showed statistically significant diff erences (p = 0.001) in groups with fibrosis volume less than 20% and more than 20%. Event-free survival was 95.2% (95% CI 89.9–100%) and 32.1% (95% CI 17.9–57.4%), respectively. Multivariate analysis showed that the independent factors associated with CHF progression and associated hospitalization were age over 50 years (HR 5.9; 95% CI 2.3–15.1, p < 0.001), atrial fibrillation (AF) episodes (HR 5.6; 95% CI 2.2–14.2, p < 0.001), and percentage of myocardial fibrosis volume ≥20% according to cardiac MR data (HR 23.3; 95% CI 7.3–74.8, p < 0.001).

Conclusion. Based on the results of a multi-factor analysis, we identified a group of HCM patients at risk of CHF progression requiring hospitalization. These patients were over 50 years of age, had AF episodes, and a myocardial fibrosis volume ≥20%. 

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