Myocardial Revascularization in High-Risk Coronary Patients

It is recognized that postoperative mortality, infarction and the need for inotropic support are increased following myocardial revascularization in highrisk patients. Operations were carried out in 57 such patients in whom one or more of the following factors were present: ventricular dysfunction—ejection fraction less than 0.4 (17), unstable (8) or preinfarction angina (29), evolving infarction (8), recent infarction (less than two weeks before) (5) and refractory ventricular tachyarrhythmia (4). Combined risk factors were present in nine patients. The following principles were utilized to minimize ischemic injury: (1) avoidance of prebypass hypertension and hypotension, (2) avoidance of extreme hemodilution, (3) avoidance of ventricular fibrillation, (4) maintenance of beating empty heart, when possible, (5) the limiting of ischemic periods to less than 12 minutes (hypothermia 32°C) and (6) repaying myocardial oxygen debt with total (vented) bypass, when necessary. The following results were obtained: inotropic support was required in five patients (9 percent), “new” postoperative infarction occurred in five patients (9 percent) and one patient died (2 percent). These results are comparable to those reported in good-risk patients, and indicate that optimal myocardial protection will allow safe revascularization in a high-risk patient.