ADEQUATE DISTRIBUTION OF WARM CARDIOPLEGIC SOLUTION

Seventy-five patients undergoing coronary artery bypass grafting were randomized to receive warm antegrade (N = 25), warm retrograde (N = 25 ), or a combination of warm antegrade and retrograde (N = 25) delivery of blood cardioplegic solution, Myocardial oxygen utilization, lactat e and acid metabolism, and adenine nucleotides and their degradation p roducts were measured during the operation and cardiac function was as sessed postoperatively, Warm retrograde delivery of cardioplegic solut ion increased lactate and acid release during cardioplegia and reperfu sion, decreased left ventricular adenosine triphosphate concentrations , and reduced the washout of adenine nucleotide degradation products f rom both left and right ventricles, Warm antegrade delivery of cardiop legic solution resulted in less lactate and acid release during cardio plegia but more lactate accumulated in the territory of the left anter ior descending artery during the crossclamp period, Intermittent anteg rade delivery of the cardioplegic solution during combination cardiopl egia washed out lactate and acid, which suggested inhomogeneous delive ry of the cardioplegic solution during continuous retrograde cardiople gia. Combination cardioplegia best preserved adenosine triphosphate in the left ventricle and resulted in the best postoperative left and ri ght ventricular function. A combination of intermittent antegrade and continuous retrograde delivery of cardioplegic solution provided bette r myocardial protection than either antegrade or retrograde delivery o f cardioplegic solution alone.