Abstract 12060: The Extent of Myocardial Injury as a New Criterion
Introduction: In acute coronary syndromes (ACS), infarct size is a primary criterion for gauging the pathological state of the post-ischemic heart and subsequent prognosis. However, early adverse outcomes may be noted even with small to moderate infarcts, suggesting that there are other contributing factors to the negative prognosis.
Hypothesis: We hypothesize that the extent of injured myocardium, which may be significantly larger than the infarct zone, can be noninvasively assessed using membrane phospholipid reorganization as a molecular marker.
Methods: The studies were conducted in a rat model of preconditioned myocardial ischemia and reperfusion. The area of injured myocardium was positively delineated by the uptake of 99mTc-duramycin, which detects phosphatidylethanolamine as a marker for cellular injury. Quantitative ex vivo studies (n = 8) were first conducted to determine the relationship among the area-at-risk, infarct size and myocardial injury, followed by in vivo radionuclide imaging studies (n = 6), with cross-validation using histopathology.
Results: We demonstrated 1) that the extent of myocardial injury can be detected noninvasively; 2) the size of injured myocardium can extend substantially outside the infarct zone (Figure 1); and 3) the injured-but-noninfarct tissue, which was missed by conventional infarct measurement, contained significant pathological changes, including apoptosis in vulnerable cells, inflammation and denervation.
Conclusions: “Global myocardial injury, or GMI” is a novel clinical concept which defines the full extent of myocardium that sustained injury both in and outside the infarct zone. Our data demonstrate the feasibility to conspicuously delineate this region of cardiac injury, thus providing an opportunity to better characterize its roles in cardiac impairment and prognosis following ACS.
Author Disclosures: K. Ren: None. J. Lomasney: None. R.K. Arora: None. G. Qin: None. S.E. Johnson: None. M. Albaghadai: None. C.R. Haney: None. E.A. Waters: None. X. He: None. D. Zhu: None. J.J. Goldberger: None. M. Zhao: None.
- © 2016 by American Heart Association, Inc.