CNP and intermediate coronary syndrome: C-type natriuretic peptide (CNP) is a regulator of cardiovascular homeostasis with protective effects in hypertension and endothelial dysfunction as well as vasodilatory capabilities within the microcirculation.8, 9, 10, 11, 12 Clinical studies have shown that high plasma concentrations of amino-terminal proCNP (NT-proCNP) and bioactive CNP in circulation are independent predictors of outcome in patients with unstable angina pectoris and chronic heart failure, respectively.