NPPB and heart failure: ET1, a powerful vasoconstrictor and hormone promoting fibrosis, is released by vascular endothelial cells, with levels that correlate to sheer stress and pulmonary artery pressure [10]. The C-terminal portion of pro-Endothelin-1 (CTproET1) is the more stable form of ET1 [10]. Research indicates that CT-proET-1 is linked to cardiovascular death and heart failure (HF) regardless of clinical variables in stable patients with coronary artery disease and acute myocardial infarction and displays a prognostic value comparable to BNP or NT-proBNP [10].