MMP9 and heart failure: In the diagnostic value assessment of the four biomarkers for three types of heart failure, the AUC for the diagnosis of HFpEF and HFrEF by plasma NT-proBNP is higher than that of plasma sST2, MMP-2, and MMP-9, suggesting that the diagnostic predictive value of plasma NT-proBNP for HFpEF and HFrEF is better than that of other markers.