NPPB and heart failure: NT-proBNP, N-terminal pro–B-type natriuretic peptide; HF, heart failure; RCT, randomized controlled trial; PRIMA, pro-brain natriuretic peptide guided therapy of chronic heart failure to improve heart failure morbidity and mortality; BNP, B-type natriuretic peptide; HR, hazard ratio; RDW, red cell distribution width; LV, left ventricular; P, P-value; mg/mL, milligrams per milliliter