NPPB and acute myocardial infarction: The research results of Quan showed that the FMD level of patients who were treated by lyophilized recombinant human brain natriuretic peptide increased significantly.20 The results of this study also showed that FMD in the experimental group was significantly higher than that in the control group, indicating that there was vascular endothelial dysfunction in patients with acute myocardial infarction.