Coronary artery bypass surgery without extracorporeal circulation

Abstract

Introduction: Coronary artery bypass surgery with extracorporeal circulation is associated with a systemic inflammatory response syndrome that contributes to morbidity and mortality. Aortic cross clamping and cardioplegic arrest induces an ischemic insult to the heart and is a risk factor for neurological injury. Neurological deficits are important complications after coronary artery bypass grafting (CABG) with severe effects on health and quality of life. As the population of patients referred to CABG gets older, neurological complications will increase. Coronary artery bypass surgery without extracorporeal circulation has attracted new interest during the past 10 years and is believed to reduce the risk of some of these complications.

Methods: In a series of randomized studies, we evaluated the effects of extracorporeal circulation. Low risk patients between 50 and 80 years of age, admitted for elective coronary surgery, were included. Cardiovascular function was evaluated with hemodynamic monitoring (cardiac index, systemic vascular resistance index) and by measurement of markers of myocardial damage. Pulmonary hemodynamics and gas exchange were analyzed. We also investigated the activity of inflammatory and hemostatic systems by taking cell counts and measuring adhesion molecules, plasma cascade factors, interleukins, complement factors and coagulation potential. Finally, we undertook neuropsychological examination of the patients before and up to six months postoperatively.

Results: Higher cardiac index, lower systemic vascular resistance index and less release of markers of myocardial damage were seen in the off pump group the first few hours after surgery. We could not detect any differences in pulmonary hemodynamics or gas exchange at any time. Less activation of the complement, coagulation and fibrinolysis systems was found in off pump patients in the immediate postoperative period. The differences noted all became negligible 24 hours after surgery. We found no difference in cognitive function between on pump and off pump patients.

Conclusion: Coronary artery bypass surgery without extracorporeal circulation performed in low risk patients shows but minor advantages compared to surgery with extracorporeal circulation in terms of hemodynamics, inflammation, and coagulation the first 24 hours postoperatively. No differences in cognitive function could be seen up to six months after surgery.