Retrograde Coronary Sinus Perfusion Prevents Infarct Extension during Intraoperative Global Ischemic Arrest

To determine whether continuous infusion of cardioplegia retrograde through the coronary sinus could improve the salvage of infarcting myocardium, 54 pigs were utilized in a region at risk model. All hearts underwent 30 minutes of reversible coronary artery occlusion, and were divided into six groups. Group 1 served as controls and underwent two hours of coronary reflow without global ischemic arrest. The remaining five groups were subjected to 45 minutes of cardioplegia-induced hypothermic arrest followed by two hours of normothermic reflow. Group 2 had a single infusion of crystalloid cardioplegia, and Group 3 received an oxygenated perfluorocarbon cardioplegic solution initially and again after 20 minutes of ischemia. After initial cardiac arrest with crystalloid cardioplegia, all hearts in Groups 4, 5, and 6 underwent a continuous infusion of a cardioplegic solution retrograde through the coronary sinus. Group 4 received a nonoxygenated crystalloid cardioplegic solution, Group 5 received an oxygenated crystalloid cardioplegic solution, and Group 6 received an oxygenated perfluorocarbon cardioplegic solution. With results expressed as the percent of infarcted myocardium within the region at risk, Group 2 hearts, which received only antegrade cardioplegia, had a mean infarct size of 44.8 ± 6.3%, a 2.2-fold increase over controls (p < 0.05). While antegrade delivery of oxygenated perfluorocarbon cardioplegia (Group 3) and coronary sinus perfusion with nonoxygenated crystalloid cardioplegia (Group 4) limited infarct size to 33.6 ± 4.7% and 35.3 ± 5.4%, respectively, only oxygenated cardioplegia delivered retrograde through the coronary sinus (Groups 5 and 6) completely prevented infarct extension during global ischemic arrest. Infarct sizes were 26.6 ± 4.6% in Group 5 and 24.2 ± 4.0% in Group 6 (p < 0.05 versus Group 2). These data suggest that optimal salvage of ischemic myocardium might best be achieved by the use of retrograde coronary sinus perfusion of oxygenated cardioplegia during surgical revascularization.