Abstract 245: Endothelin-1 And Procollagen Type-1 Carboxy-terminal Propeptide Are Associated With Functional Tolerance And Cardiac Structure And Function In Heart Failure With Preserved Ejection Fraction

Abstract

Introduction: The role of emerging biomarkers such as endothelin-1 (ET-1) and collagen peptides in functional tolerance among patients with heart failure with preserved ejection fraction (HFpEF) is not well understood. Hypothesis: We hypothesize that plasma ET-1 and procollagen type-1 carboxy-terminal propeptide (PICP) are associated with 6-minute walk distance and parameters of cardiac structure and function. Methods: In a cross-sectional cohort study, we evaluated the association of ET-1 and PICP with 6-minute walk distance and parameters of cardiac structure and function on cardiac magnetic resonance (CMR) imaging in patients with HFpEF. In a subset of patients, we used a novel diffusion tensor imaging CMR technique to determine the myocardial fiber orientation in the septum as characterized by the helix angle transmurality (slope of the helix angle versus transmural depth from endocardium to epicardium) (Fig 1C). Results: A total of 36 patients (25 with HFpEF, 11 controls), mean age 70 ± 7.7 yrs, BMI 33 ± 8.5 kg/m 2 , 94% men, 53% had diabetes, and 75% had hypertension. Mean LVEF 58.7 ± 7.7%, RVEF 49.1 ± 10.4%, mean global myocardial mid- LV T1 1285ms, mean LV mass indexed to body surface area 65 ± 12 g/m 2 . Using univariate linear regression, we found that both plasma ET-1 levels and PICP levels were moderately inversely associated with 6-minute walk distance (R 2 -0.56, p<0.001) and (R 2 -0.40, p=0.02) (Fig 1A) respectively, with a non-significant association with age (R 2 = 0.30, p=0.08) and indexed LV mass (R 2 =0.29, p=0.09). ET-1 was moderately associated with septal HAT, a marker of myocardial fiber orientation, (R 2 =0.58, p=0.02), measured in a subset of patients (Fig 1B, C). Conclusions: Plasma ET1 and PICP levels are moderately associated with lower 6-minute walk distance; ET-1 is associated with septal myocardial fiber orientation in this exploratory analysis. Future studies are needed to determine the prognostic value of these biomarkers in patients with HFpEF.