Influence of ischemic preconditioning in myocardial protection in patients undergoing myocardial revascularization with intermittent crossclamping of the aorta. Analysis of ions and blood gases

Abstract

Objective - To test the hypothesis that short periods of ischemia may increase the myocardial protection obtained with intermittent crossclamping of the aorta. Methods - In the control group (18 patients), surgery was performed with systemic hypothermia at 32°C and intermittent crossclamping of the aorta. Extracorporeal circulation was used. In the preconditioning group (17 patients), 2 crossclampings of the aorta lasting 3min each were added prior to the intermittent crossclamping of the conventional technique with an interval of 2min of reperfusion between them. Blood samples for analyses of pH, pCO2, pO2, sodium, potassium, calcium, and magnesium were obtained from the coronary sinus at the beginning of extracorporeal circulation (time 1), at the end of the first anastomosis (time 2), and at the end of extracorporeal circulation (time 3). Results - No difference was observed in the results of the 2 groups, except for a variation in the ionic values in the different times of blood withdrawal; sodium values, however, remained stable. All patients had a good clinical outcome. Conclusion - The results of intermittent crossclamping of the aorta with moderate hypothermia were not altered by the use of ischemic preconditioning.