Matrix Metalloproteinase-9 for the Earliest Stage Acute Coronary Syndrome

Background: Matrix metalloproteinase-9 (MMP-9) is regarded as a biomarker of plaque rupture or vulnerability and is elevated in patients with acute coronary syndrome (ACS). The aim of the present study was to evaluate the diagnostic value of MMP-9 for early ACS (≤4h of onset) and late ACS (>4h after onset), compared with high-sensitivity troponin T (hs-TnT).

Methods And Results: MMP-9 and hs-TnT were measured in 200 patients with ST elevation ACS (STEACS; 115 early STEACS and 85 late STEACS patients), and 66 patients with non-ST elevation ACS (NSTEACS; 25 early NSTEACS and 41 late NSTEACS patients). Forty patients with stable angina pectoris (SAP) were enrolled as a control group. MMP-9 levels were significantly higher in patients with early STEACS (P<0.001), early NSTEACS (P<0.001), late STEACS (P<0.001) and late NSTEACS (P=0.025) than SAP. MMP-9 levels were significantly higher in patients with early STEACS (P=0.017) and early NSTEACS (P=0.034) than late STEACS and late NSTEACS, respectively. Levels of hs-TnT were significantly lower in patients with early STEACS (P<0.001) and early NSTEACS (P=0.007) than late STEACS and late NSTEACS, respectively. On receiver operating characteristic curve analysis, area under the curve of early STEACS, early NSTEACS, late STEACS and late NSTEACS was 0.880, 0.782, 0.790 and 0.648 for MMP-9, and 0.707, 0.725, 0.993 and 0.920 for hs-TnT, respectively.

Conclusions: MMP-9 levels were elevated earlier than hs-TnT and had a higher diagnostic value for early ACS, but not for late ACS, reflecting plaque rupture or vulnerability.