Myocardial viability and cardiac dyssynchrony as strong predictors of perioperative mortality in high-risk patients with ischemic cardiomyopathy having coronary artery bypass surgery
Abstract
Myocardial viability and left ventricular dyssynchrony are important predictors of long-term outcomes in patients with ischemic left ventricular dysfunction. The objective of this study was to test the hypothesis that assessment of myocardial viability and left ventricular dyssynchrony will predict perioperative mortality in high-risk patients with ischemic left ventricular dysfunction having coronary artery bypass surgery.
The study consisted of 79 consecutive patients with ischemic cardiomyopathy (age 65 +- 9 years; 81% men; ejection fraction 30% +- 6%) and logistic European system for cardiac operative risk evaluation > 10% having coronary artery bypass surgery. Myocardial viability was assessed by delayed contrast-enhanced magnetic resonance imaging.
Left ventricular dyssynchrony was calculated using tissue Doppler from measurements of regional electromechanical coupling times in left ventricular basal segments before coronary artery bypass surgery. Twenty (25.3%) patients died within 30 days following coronary artery bypass surgery.
Survivors (n = 59) showed a larger extent of viable myocardium (6.9 +- 3.6 viable segments vs 3.4 +- 3.3 viable segments, P < .001) and smaller left ventricular dyssynchrony (75 +- 5 ms vs 179 +- 83 ms, P < .001) than nonsurvivors. The presence of significant dyssynchrony (GREATER-THAN OR EQUAL TO105 ms) and absence of myocardial viability (<5 viable segments) independently predicted 30-day mortality with hazard ratio 3.26, 95% confidence interval 1.61 to 8.33 (P < .01) and hazard ratio 1.72, 95% confidence interval 1.59 to 1.89 (P < .01), respectively.
All but 2 patients (94.1%) with viable myocardium and without left ventricular dyssynchrony survived coronary artery bypass surgery as compared with only 12 (52.2%) patients with nonviable myocardium and severe dyssynchrony (P < .001). In high-risk patients with ischemic left ventricular dysfunction having coronary artery bypass surgery, both myocardial viability and left ventricular dyssynchrony are important predictors of perioperative outcome.
Assessment of myocardial viability and left ventricular dyssynchrony should be a routine part of the preoperative evaluation of these patients.