Coronary Microvascular Dysfunction and Diastolic Load Correlate With Cardiac Troponin T Release Measured by a Highly Sensitive Assay in Patients With Nonischemic Heart Failure

Objectives This study investigated factors associated with cardiac troponin T (cTnT) release from failing myocardium. Background Persistent and modest elevation of serum cTnT is frequently observed in heart failure (HF) patients free of coronary artery disease, although the mechanisms underlying this finding remain unclear. Methods We evaluated serum cTnT levels in the aortic root (Ao) and coronary sinus (CS) using a highly sensitive assay in 90 nonischemic HF patients and 47 non-HF patients. Transcardiac cTnT and plasma B-type natriuretic peptide (BNP) release were described as the differences between CS and Ao cTnT levels [Delta cTnT (CS-Ao)] and BNP levels [Delta BNP (CS-Ao)], respectively. Coronary flow reserve (CFR) was measured in 68 HF patients using an intracoronary Doppler guidewire. Results Delta cTnT (CS-Ao) levels were available in 76 HF patients and 28 non-HF patients (84% vs. 60%; p = 0.001), and higher in HF patients than non-HF patients (p < 0.001). Among HF patients, log[Delta cTnT (CS-Ao)] correlated with log[Delta BNP (CS-Ao)] (r = 0.368, p = 0.001), pulmonary capillary wedge pressure (r = 0.253, p = 0.03) and left ventricular end-diastolic pressure (LVEDP) (r = 0.321, p = 0.005). Multivariate regression analysis identified LVEDP as an independent parameter that correlated with Delta cTnT (CS-Ao). Delta cTnT (CS-Ao) levels were available in 58 HF patients who were evaluated for CFR. Coronary microvascular dysfunction, diagnosed by CFR <2.0, was observed in 18 HF patients. Delta cTnT (CS-Ao) was higher in patients with coronary microvascular dysfunction (4.8 [2.0 to 8.1] ng/l) than those without (2.0 [1.2 to 4.6] ng/l; p = 0.04). Conclusions cTnT release from failing myocardium correlated with diastolic load and coronary microvascular dysfunction in nonischemic HF patients. (C) 2013 by the American College of Cardiology Foundation