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Coronary artery bypass without cardioplegia
Insights
Intermittent aortic clamping offers excellent myocardial protection during coronary artery bypass surgery. This safe method avoids concerns associated with cardioplegic solutions, especially in complex cases.
Area of Science:
- Cardiac Surgery
- Cardiovascular Research
- Surgical Techniques
Background:
- Cardioplegic myocardial protection is standard for coronary artery bypass (CAB).
- Concerns exist regarding cardioplegic protection efficacy with occluded coronaries or internal mammary grafts.
Purpose of the Study:
- To evaluate the efficacy of intermittent aortic clamping with hypothermia for myocardial protection during coronary artery bypass.
- To assess outcomes in a large cohort of unselected patients undergoing coronary artery bypass.
Main Methods:
- 500 consecutive coronary artery bypass operations were performed using intermittent aortic clamping, left ventricular venting, and 30°C hypothermia.
- Patients included those with urgent/emergency operations, unstable angina, preinfarction angina, and evolving myocardial infarction.
Main Results:
- Low hospital mortality (1%) with no deaths attributed to poor myocardial protection.
- Minimal need for postoperative inotropic support (0.4%) or balloon pump (0.6%).
- Low perioperative infarction rate (3.6%) in a high-risk patient population (80% with acute coronary syndromes).
Conclusions:
- Intermittent ischemia provides excellent myocardial protection during coronary artery bypass.
- This technique is a simple, safe alternative to cardioplegia, particularly when graft patency is a concern.
Abstract:
Cardioplegic myocardial protection has become the standard for coronary artery bypass. In contrast, we report 500 consecutive coronary artery bypass operations with intermittent aortic clamping for distal anastomoses, left ventricular venting, and 30 degrees C hypothermia. Average patient age was 62 years (range of 30 to 89 years). The number of patients who had urgent or emergency operations was 194 (39%); 251 patients had unstable angina, and 123 others had preinfarction angina (pain at rest in the hospital); 27 had evolving myocardial infarction. The average number of grafts was 3.3 per patient, and the average ischemic time was 7.65 minutes per graft. There were five hospital deaths (1%); none resulted from poor myocardial protection that caused low cardiac output. Only three survivors (0.6%) required a balloon pump to be weaned from cardiopulmonary bypass: two had acute infarctions preoperatively, and the other had an ejection fraction of 0.30 and intractable atrial arrhythmias. Only two other patients (0.4%) received any inotropic infusions postoperatively. Eighteen patients (3.6%) had a perioperative infarction. These results, particularly the virtual absence of postoperative inotropic support, in unselected patients of whom 80% had acute coronary syndromes, indicate that intermittent ischemia can provide excellent myocardial protection for coronary bypass. Brief periods of intermittent ischemia alleviate concern about cardioplegic protection via occluded coronaries or internal mammary grafts and provide a simple and safe option for myocardial protection during coronary artery bypass.