Normothermic Ischaemic Arrest in One-Vessel Coronary Artery Surgery

Cardiac metabolism following normothermic ischaemic arrest was studied in 14 patients undergoing coronary bypass surgery for single vessel coronary artery disease. Simultaneous blood samples were taken from the radial artery and from the coronary sinus before and during the first 60 min after aortic crossclamping. O2-saturation and content, potassium, lactate and the isoenzyme MB of the creatine kinase (CK-MB) were assessed. In addition, CK-MB was followed in peripheral venous blood for 8 hours after operation. Analysis of the results revealed decreased oxygen extraction by the heart immediately after the release of the aortic crossclamping and marked lactate and potassium release with delayed metabolic recovery of the myocardium despite the very short aortic occlusion time. Increased postoperative CK-MB serum activity was also seen. We concluded that the use of normothermic ischaemic arrest is hazardous even in such surgical procedures requiring aortic occlusion times as short as 15 min and should be avoided at least by the less experienced surgeon.