[The optional usage of blood cardioplegia through eleven-year experience of open-heart surgery]

We propose two clinical studies in this paper for the optimal usage of cold blood cardioplegia (CBC) to evaluate 1) the effects of increasing the volume of CBC, and 2) the optimal use of verapamil, on postischemic myocardial recovery. First, patients with valvular heart surgery were divided into three groups according to the initial dose of CBC: Group I, 5 ml/kg in 368 patients; Group II, 10 ml/kg in 41; and Group III, 12 ml/kg in 86. In all groups CBC was infused every 25 to 30 minutes. Although the preoperative conditions of Group III patients tended to be more serious compared to Groups I and II, there was no difference in cardiac-related hospital mortality among the three groups. Second, 45 patients who had undergone valvular or coronary heart surgery were divided into three groups according to the usage of verapamil: Group A, infusion of verapamil of 1 mg/L into CBC; Group B, infusion of verapamil of 0.2 mg/kg into a perfusate; and Group C, the same method as Group B with additional administration of verapamil of 0.1 mg/kg into a perfusate at 60 minutes after the commencement of cardiopulmonary bypass and a continuous drop of 0.5 micrograms/kg/min for the succeeding 24 hours. Each group consisted of nine patients who had valvular surgery and six patients who had aorto-coronary bypass surgery. There was no difference in the severity of the patients' conditions between the groups. The optimal concentration during and after the operation and good clinical results were obtained in Group C. We conclude that the initial optimal dose of CBC is 12 ml/kg, and that the combination of an infusion of verapamil into a perfusate and a succeeding continuous drop is the appropriate method.