Do the presence and amount of dysfunctional but viable myocardium affect the perioperative outcome of coronary artery bypass graft surgery?

The aim of our study was to assess the influence of the presence and amount of dysfunctional but viable myocardium on the perioperative outcomes in patients with coronary artery disease and moderate-to-severe left ventricular systolic dysfunction, who underwent coronary artery bypass graft surgery. Viability evaluation with low-dose dobutamine echocardiography was performed in 302 consecutive patients with coronary artery disease and left ventricular ejection fraction < or =40%, who were referred for coronary angiography and potential coronary revascularization. To quantify the amount of dysfunctional but viable myocardium, wall motion was scored using a 16-segment model. The dysfunctional segments were defined as viable if they exhibited improvement in their thickening by at least one grade. One hundred and twenty-seven patients underwent coronary artery bypass graft surgery. The perioperative outcomes were evaluated in 122 of them. Five patients were excluded because of inability to revascularize all vessels supplying dysfunctional but viable myocardial segments. Twenty-five patients exhibited a large amount of dysfunctional but viable myocardium (> or =6 segments, group A), 59 patients had a small amount of such myocardium (2-5 segments, group B), and 38 patients were found to have their dysfunctional myocardium irreversibly damaged (group C). The perioperative mortality in groups A, B, and C was 4, 10, and 11% (all P = NS), respectively. The rate of perioperative Q-wave myocardial infarction was 8, 10, and 3% (all P = NS), respectively. Similarly, there were no significant differences among the groups with respect to perioperative outcome variables including ventricular arrhythmias, duration and magnitude of catecholamine support, renal failure, pulmonary edema, and need for mechanical ventricular support or artificial ventilation. In patients with coronary artery disease and moderate-to-severe left ventricular dysfunction who underwent coronary artery bypass graft surgery, the presence and amount of dysfunctional but viable myocardium did not influence the perioperative outcome.