Myocardial infarct size for predicting improvements in cardiac function in patients with ischemic cardiomyopathy following coronary artery bypass grafting

Figures

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  Figure 1. Patient screening flowchart. ICM, ischemic cardiomyopathy; LGE-CMR, late gadolinium enhancement-cardiac magnetic resonance; MVP, mitral valve plasty; TVP, tricuspid valve plasty; CABG, coronary artery bypass grafting. The flowchart is adapted from Fu et al.’s article published in the Journal of Thoracic Disease (11).

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  Figure 2. LGE-CMR imaging data from patients with ICM who did not experience improved cardiac function following CABG. (A) A representative LGE image derived from a continuous short-axis section. (B) The endocardium (red) and epicardium (green) of the left ventricle as outlined by the software, with the normal myocardium (used for comparison) being denoted with a blue contour. The yellow area corresponds to the infarcted myocardium as identified based on a gray threshold level of 5 standard deviations. In this representative case, the myocardial infarct size was 33.7%. (C) A representative 16-segment diagram of the left ventricle, with the value for each segment representing the degree of myocardial infarction penetration of that segment. In this case, 3 segments exhibited an LGE value >50% consistent with the identification of 3 myocardial infarct segments. LGE, late gadolinium enhancement; CMR, cardiac magnetic resonance; ICM, ischemic cardiomyopathy; CABG, coronary artery bypass grafting.

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  Figure 3. LGE-CMR imaging data from patients with ICM who experienced improvements in cardiac function following CABG. (A) A representative LGE image derived from a continuous short-axis section. (B) The endocardium (red) and epicardium (green) of the left ventricle as outlined by the software, with the normal myocardium (used for comparison) being denoted with a blue contour. The yellow area corresponds to the infarcted myocardium as identified based on a gray threshold level of 5 standard deviations. In this representative case, the myocardial infarct size was 22.1%. (C) A representative 16-segment diagram of the left ventricle, with the value for each segment representing the degree of myocardial infarction penetration of that segment. In this figure, all values were <50%, which is indicative of viable myocardial segments. LGE, late gadolinium enhancement; CMR, cardiac magnetic resonance; ICM, ischemic cardiomyopathy; CABG, coronary artery bypass grafting.

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  Figure 4. ROC curve-based prediction of improvement in cardiac function based upon myocardial infarct segments or myocardial infarct size according to LGE-CMR imaging results. The AUC values for myocardial infarct segments and myocardial infarct size were 0.81 and 0.88, respectively. The optimal myocardial infarct size cutoff value for differentiating between patients with and without improved cardiac function was 26.4% (sensitivity 92.3%; specificity 71.2%). AUC, area under the curve; ROC, receiver operating curve; LGE-CMR, late gadolinium enhancement-cardiac magnetic resonance.

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  Figure 5. Kaplan-Meier MACCE-free survival curves for patients in the improved (blue) and nonimproved (red) groups. Log-rank test, P<0.001. CI, confidence interval; MACCE, major adverse cardiovascular and cerebrovascular event.

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  Figure 6. Kaplan-Meier all-cause mortality-free survival curves for patients in the improved (blue) and nonimproved (red) groups. Log-rank test, P<0.001. CI, confidence interval.

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  Figure 7. There was a negative correlation between myocardial scar size and the degree of improvement in LVEF (correlation coefficient =–0.487; P<0.001). LVEF, left ventricular ejection fraction.