Coronary revascularization in "high" versus "low-risk" patients: The role of myocardial protection

Abstract

Postoperative mortality, infarction, and need for inotropic support are reportedly increased following myocardial revascularization in "high-risk" patients. We believe these complications result from inadequate protection of the compromised myocardium and should not occur with greater frequency in "high-risk" than "Low-risk" patients if the heart is optimally protected during the entire course of the operative procedure. Results following revascularization in 50 consecutive "low-risk" and 50 consecutive "high-risk" patients were analyzed. One or more of the followin factors were present in the "high-risk" group: ventricular dysfunction--ejection fraction less than 0.4, preinfarction angina, evolving infarction, recent infarction (less than 2 weeks), and refractory ventricular tachyarrhythmia. The following principles were used in all patients to minimize ischemic injury: 1) avoidance of pre-bypass hypo- or hypertension, 2) limitation of ischemic arrest to less than 12 minutes, 3) avoidance of ventricular fibrillation, and 4) prolongation of total bypass as necessary to repay the myocardial oxygen debt. Postoperative inotropic support was required in 10% of "high" and 10% of "low-risk" patients, new postoperative infarction developed in 10% of "high" vs. 10% "low-risk" patients; death occurred in 2% of "high" vs. 4% "low-risk" patients. These results are comparable and indicate that optimum myocardial protection allows safe revascularization in the "high-risk" patient.