Refer to: Olinger GN, Po J, Maloney JV Jr, et al: Myocardial revascularization in high-risk coronary patients. West J Med 124:265-271, Apr 1976
THE WESTERN Journal of Medicine
Myocardial Revascularization in High-Risk Coronary Patients GORDON N. OLINGER, MD; JONATHAN PO, MD; JAMES V. MALONEY, JR., MD; DONALD G. MULDER, MD, and GERALD D. BUCKBERG, MD, Los Angeles
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 320C) 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.
THE INCIDENCE of postoperative mortality, myocardial infarction and depressed cardiac performance requiring pharmacologic or mechanical circulatory support is reportedly increased in high-risk patients in whom coronary revasculariFrom the Division of Thoracic Surgery, Department of Surgery (Drs. Olinger, Maloney, Mulder and Buckberg) and the Department of Radiology (Dr. Po), University of California, Los Ange-
les, School of Medicine. Submitted August 1, 1975. This study was supported by grants-in-aid from the Beaumont Foundation, the Wilbur May Foundation, Frank W. Clark, Jr. Charities, and the Blalock Foundation. The experimental work on which the clinical study was based was supported by grants-inaid from the United States Public Health Service. Reprint requests to: Gerald Buckberg, MD, Division of Thoracic Surgery, UCLA School of Medicine, Los Angeles, CA 90024.
zation is carried out (Table 1). This group of patients includes those with ventricular dysfunction (ejection fraction less than 0.40), serious ventricular tachyarrhythmias, preinfarction angina, evolving myocardial infarction and recent infarction with signs of extension. We believe that the increased morbidity and mortality following coronary bypass surgical procedures in these patients is (1 ) frequently caused by ischemic myocardial damage during operation and (2) can be minimized significantly if careful attention is directed toward principles of myocardial protection. THE WESTERN JOURNAL OF MEDICINE
265
MYOCARDIAL REVASCULARIZATION TABLE 1.-Reported Mortality After Revascularization in High-Risk Patients (1972-1974) Deaths! Total Range (Percent)
Category
Ventricular dysfunction
(ejection fraction
THE WESTERN Journal of Medicine
Myocardial Revascularization in High-Risk Coronary Patients GORDON N. OLINGER, MD; JONATHAN PO, MD; JAMES V. MALONEY, JR., MD; DONALD G. MULDER, MD, and GERALD D. BUCKBERG, MD, Los Angeles
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 320C) 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.
THE INCIDENCE of postoperative mortality, myocardial infarction and depressed cardiac performance requiring pharmacologic or mechanical circulatory support is reportedly increased in high-risk patients in whom coronary revasculariFrom the Division of Thoracic Surgery, Department of Surgery (Drs. Olinger, Maloney, Mulder and Buckberg) and the Department of Radiology (Dr. Po), University of California, Los Ange-
les, School of Medicine. Submitted August 1, 1975. This study was supported by grants-in-aid from the Beaumont Foundation, the Wilbur May Foundation, Frank W. Clark, Jr. Charities, and the Blalock Foundation. The experimental work on which the clinical study was based was supported by grants-inaid from the United States Public Health Service. Reprint requests to: Gerald Buckberg, MD, Division of Thoracic Surgery, UCLA School of Medicine, Los Angeles, CA 90024.
zation is carried out (Table 1). This group of patients includes those with ventricular dysfunction (ejection fraction less than 0.40), serious ventricular tachyarrhythmias, preinfarction angina, evolving myocardial infarction and recent infarction with signs of extension. We believe that the increased morbidity and mortality following coronary bypass surgical procedures in these patients is (1 ) frequently caused by ischemic myocardial damage during operation and (2) can be minimized significantly if careful attention is directed toward principles of myocardial protection. THE WESTERN JOURNAL OF MEDICINE
265
MYOCARDIAL REVASCULARIZATION TABLE 1.-Reported Mortality After Revascularization in High-Risk Patients (1972-1974) Deaths! Total Range (Percent)
Category
Ventricular dysfunction
(ejection fraction
