Osteoprotegerin in ST-elevation myocardial infarction: prognostic impact and association with markers of myocardial damage by magnetic resonance imaging.

BACKGROUND/
OBJECTIVES: For osteoprotegerin (OPG), a cytokine of the tumor necrosis factor superfamily, the prognostic impact in stable coronary artery disease and acute coronary syndromes has been shown recently. In acute ST-elevation myocardial infarction (STEMI) data on the correlation to myocardial damage by cardiac magnetic resonance imaging (CMR) or clinical outcome are lacking.
METHODS: We studied 221 consecutive patients with acute STEMI undergoing primary percutaneous coronary intervention (PCI) within 12h after symptom onset. Serum levels of OPG were determined from samples collected before PCI (OPG0), at 24 (OPG1) and 48 h (OPG2) after reperfusion. CMR studies for assessment of infarct size, reperfusion injury/microvascular obstruction and myocardial salvage were performed within one week after infarction. Long-term clinical follow-up for major adverse cardiovascular events (MACE), defined as death, myocardial infarction, or new onset of congestive heart failure, was performed 18.2 (interquartile range of 9.2-21.2) months after the index event.
RESULTS: OPG levels ≥ 75th percentile were associated with significantly larger infarcts, lower myocardial salvage index and greater extent of microvascular obstruction in CMR as compared to OPG levels <75th percentile. The MACE rate for patients with OPG levels in the highest quartile was also significantly higher. In a multivariable model adjusted for known risk factors, OPG1 as a continuous variable was independently predictive for MACE.
CONCLUSION: OPG serum levels collected 24h after infarction are independent predictors of MACE in acute STEMI patients. High OPG levels are associated with a greater extent of myocardial damage and lower myocardial salvage by CMR.