Some studies stated that the association of APN and heart failure vanished after adjusting for NT-proBNP [31], some revealed that high APN level was associated with increased risk of mortality, independent of plasma NT-proBNP [22], while Dai Z et al. found an improved diagnostic value of conjunction of NT-proBNP and APN for heart failure [30]. The gene discussed is NPPB; the disease is heart failure.