Long-term prognostic value of big endothelin-1 and its combination with late gadolinium enhancement in patients with idiopathic restrictive cardiomyopathy.

ABSTRACT

BACKGROUND AND AIMS: Idiopathic restrictive cardiomyopathy (RCM) has a low incidence. This study aimed to determine the prognostic value of big endothelin-1 (ET-1) in idiopathic RCM. MATERIALS AND METHODS: We prospectively enrolled patients with idiopathic RCM from 2009 to 2017 and followed them up. The primary outcome was a composite of all-cause mortality and cardiac transplantation, and the secondary outcome was a composite of cardiac death and cardiac transplantation. RESULTS: Ninety-one patients were divided into the high big ET-1 (>0.85 pmol/L, n = 56) and low big ET-1 (≤0.85 pmol/L, n = 35) groups, and 87 of them completed the follow-up. Big ET-1 concentrations (hazard ratio 1.756, 95 % confidence interval [CI] 1.117-2.760) and late gadolinium enhancement (LGE) (hazard ratio 3.851, 95 % CI 1.238-11.981) were independent risk factors for the primary outcome. Big ET-1 concentrations (C-statistic estimation 0.764, 95 % CI 0.657-0.871) and the combination of LGE and big ET-1 concentrations (C-statistic estimation 0.870, 95 % CI 0.769-0.970) could accurately predict the 5-year transplant-free survival rate, and 0.85 pmol/L was a suitable cutoff for big ET-1. CONCLUSION: Big ET-1 and its combination with LGE may be useful to predict an adverse prognosis in patients with idiopathic RCM.