Adenosine for cardioplegic induction: a comparison with St Thomas solution

OBJECTIVE: To determine if quicker cardiac standstill obtained by adding adenosine to potassium crystalloid cardioplegia translated into better myocardial preservation and cardiac function in the early postoperative period compared with the same cardioplegia without adenosine. DESIGN: A prospective study. SETTING: Cardiac center of a teaching institute. PARTICIPANTS: Sixty consecutive patients with left main vessel or triple-vessel disease undergoing coronary artery bypass surgery under moderate hypothermia. INTERVENTIONS: The study comprised two groups of patients. Group N (n = 15) was the control group, given St Thomas cardioplegic solution after aortic cross-clamping, without adenosine; whereas group A (n = 45) received 250 microg/kg of adenosine into the aortic root after aortic cross-clamping, followed by the same St Thomas cardioplegia as in group N. The two groups were otherwise similar in all aspects of perfusion management. MEASUREMENTS AND MAIN RESULTS: Time taken to achieve cardiac standstill after aortic cross-clamping was significantly greater, 18.7+/-3.1 seconds, in the control group compared with the adenosine group, 3.4+/-0.9 seconds (p<0.001). The quicker arrest of the adenosine group led to better postoperative function, in the form of higher cardiac index (p<0.01), lower filling pressures (pulmonary artery wedge pressure) (p<0.05), and lower mean pulmonary artery pressure (p<0.05) at 6 hours. In the adenosine group, only 3 of 45 (6.6%) patients had elevated creatine phosphokinase (CPK) (MB) values greater than 50 U/L over preoperative CPK values compared with 3 of 15 (20%) in the control group (p<0.01). CONCLUSIONS: Injection of 250 microg/kg of adenosine into the aortic root before administration of cold crystalloid St Thomas cardioplegia solution after cross-clamping, in patients with severe coronary artery disease, produces significantly faster cardiac standstill, better myocardial preservation, and better cardiac function in the early postoperative period.