NPPB and Myocardial fibrosis: Spironolactone treatment significantly reduces plasma procollagen type III aminoterminal peptide (PIIINP), a biochemical marker of myocardial fibrosis and/or remodeling, and BNP, a prognostic marker of HF, and improves endothelial function, which is associated with cardiovascular events in patients with HF of varying severity (22–24).