Selection of patients for emergency coronary revascularization
Emergency coronary revascularization is considered for (1) unstable/preinfarction angina; (2) subendocardial myocardial infarction with postinfarction angina; (3) acute coronary occlusion during or immediately after cardiac catheterization; (4) transmural myocardial infarction with left ventricular power failure; (5) coronary obstruction with mechanical sequelae of myocardial infarction; (6) ventricular tachyar-rhythmias.
The unstable/preinfarction angina group has constituted approximately 16% (138/843) of the patients undergoing coronary revascularization surgery at the Peter Bent Brigham (1970–1976). This syndrome is defined as unremitting chest pain requiring opiates for control, S-T and T wave abnormalities by electrocardiogram without evidence of a myocardial infarction (Q wave), a negative MB-CPK and myocardial scan, and demonstration of a significant lesion in one or more coronary arteries.
This syndrome was considered a surgical emergency in 1970, but it has been demonstrated that intensive coronary care medical treatment is effective in controlling the ischemic pain, normalizing the electrocardiogram, and preventing arrhythmic complications. Medical treatment includes maximal propranolol therapy, heavy sedation, including N2O, vasodilator therapy, and relief of aggravating conditions. Control of the ischemia then allows the surgeon to operate upon a stable patient in a low-risk situation. Urgent or emergency surgery is reserved for patients with the true preinfarction syndrome who, despite maximal medical therapy, still have signs and symptoms of ischemia; these patients often have left main coronary obstruction, ventricular arrhythmias, or global left ventricular dysfunction. Emergency angiography should be immediately followed by coronary bypass grafting. Precatheterization intra-aortic balloon counterpulsation may be indicated in unusually unstable patients in this group. The operative . . .