Pathophysiological and diagnostic importance of fatty acid-binding protein 1 in heart failure with preserved ejection fraction.

Elevated intracardiac pressure at rest and/or exercise is a fundamental abnormality in heart failure with preserved ejection fraction (HFpEF). Fatty acid-binding protein 1 (FABP1) is proposed to be a sensitive biomarker for liver injury. We sought to determine whether FABP1 at rest would be elevated in HFpEF and would correlate with echocardiographic markers of intracardiac pressures at rest and during exercise. In this prospective study, subjects with HFpEF (n = 22) and control subjects without HF (n = 23) underwent resting FABP1 measurements and supine bicycle exercise echocardiography. Although levels of conventional hepatic enzymes were similar between groups, FABP1 levels were elevated in HFpEF compared to controls (45 [25-68] vs. 18 [14-24] ng/mL, p = 0.0008). FABP1 levels were correlated with radiographic and blood-based markers of congestion, hemodynamic derangements during peak exercise (E/e', r = 0.50; right atrial pressure, r = 0.35; pulmonary artery systolic pressure, r = 0.46), reduced exercise cardiac output (r = - 0.49), and poor exercise workload achieved (r = - 0.40, all p < 0.05). FABP1 distinguished HFpEF from controls with an area under the curve of 0.79 (p = 0.003) and had an incremental diagnostic value over the H