Abstract 13980: Cardiac Magnetic Resonance Imaging Quantification of Myocardial Ischemia and Necrosis Using a Novel Risk Prediction Model Allows for Better Risk Stratification in Coronary Artery Disease
Background: Cardiac magnetic resonance imaging (CMR) provides information about inducible myocardial ischemia and necrosis in one single examination in coronary artery disease (CAD) patients. Both variables have been shown to correlate with prognosis. However, there is no consensus on how to assess and quantify these two variables.
Hypothesis: Objective of the present prospective study in consecutive patients was to provide a simple algorithm for quantification of ischemia and necrosis and to test for risk stratification models.
Methods: Patients with known or suspected CAD referred for adenosine-stress CMR were consecutively enrolled from 2003 to 2007. Examination was conducted on a 1.5-T whole-body scanner. Reversible ischemia was diagnosed by adenosine stress first pass perfusion imaging. Myocardial necrosis was assessed by late gadolinium enhancement (LGE). In a semiautomatic approach, extent of reversible ischemia and scar was quantified and reported as percentage of the left ventricle. Primary endpoint was defined as cardiac death, non-fatal myocardial infarction and stroke.
Results: The study cohort consisted of 845 patients. Median age was 64 years, 271 patients were women. During a median follow-up period of 3.8 years 61 primary endpoints occurred.
Statistical analysis yielded a ≥6% optimal threshold for reversible ischemia to predict a primary endpoint (univariate hazard ratio 4.91, p<.0001). Similarly, thresholds for extent of myocardial necrosis were defined (LGE >15% and ≤33%: univariate hazard ratio 2.75, p<.0001; LGE >33%: univariate hazard ratio 16.27, p<.0001). The risk prediction model containing both, quantified ischemia and necrosis, proved to be superior in comparison to the dichotomous model (ischemia present: yes/no; necrosis present: yes/no) on multivariate testing (increase in χ2-values: 45.004 to 61.545; increase in integrated discrimination improvement: .02269 to .03187; net reclassification index for optimal model: .25593, p=.001).
Conclusion: CMR cut-off values for quantification of myocardial ischemia (≥6%) and necrosis (>15% and >33%) have been found which allow for better risk stratification in CAD patients. The combination of both has been shown to yield the superior risk stratification model.
Author Disclosures: D. Buckert: None. N. Dyckmanns: None. V. Rasche: None. W. Rottbauer: None. P. Bernhardt: None.
- © 2015 by American Heart Association, Inc.