CRYSTALLOID VERSUS COLD BLOOD CARDIOPLEGIA AND CARDIAC TROPONIN-I RELEASE

Background Cardiac troponin I (CTnI) has been shown to be a marker of myocardial injury. The aim of this study was to compare antegrade crys talloid cardioplegia with antegrade cold blood cardioplegia with warm reperfusion using CTnI release as the criteria for evaluating the adeq uacy of myocardial protection. Methods and Results Seventy patients we re randomly assigned to receive crystalloid or blood cardioplegia. CTn I concentrations were measured in serial venous blood samples drawn ju st before cardiopulmonary bypass and after aortic unclamping at 6, 9, 12, and 24 hours and daily thereafter for 5 days. ANOVA with repeated measures was performed to test the effect of the type of cardioplegia on CTnI release. The total amount of CTnI released was higher in the c rystalloid carioplegia group than in the blood carioplegia group (11.2 +/-8.9 versus 7.8+/-8.6 mu g, P<.02). CTnI concentration was significa ntly higher in the crystalloid group than in the blood group in the sa mples drawn at hours 9 and 12. Three patients in each group had ECG ev idence of perioperative myocardial infarction. Eight patients in the c rystalloid group and five patients in the blood group had CTnI evidenc e of perioperative myocardial infarction. CTnI release was significant ly lower in patients requiring no electrical defibrillation after aort ic unclamping. Conclusions Cold blood carioplegia followed by warm rep erfusion is beneficial in an unselected group of patients with a prese rved left ventricular function undergoing an elective first coronary a rtery bypass grafting. CTnI allowed the diagnosis of small perioperati ve necrotic myocardial areas. The need for electrical defibrillation a fter aortic unclamping was related to a higher release of CTnI. A furt her study is necessary to determine whether this technique was benefic ial because of cold blood carioplegia, warm reperfusion, or both.