[A clinical study of diltiazem administration using cold glucose-insulin-potassium cardioplegic solution--comparison between diltiazem cardioplegia and diltiazem pretreatment].

A recent idea of myocardial injury during open heart surgery is thought to be caused by the intracellular calcium overload. So, one possibility for improving myocardial protection is expected on the blocking agents of transmembrane calcium movements. This study was designed to clarify the effect of Diltiazem, a kind of calcium blocking agents, on myocardial protection in terms of hemodynamics and plasma Diltiazem concentration. 38 patients who underwent coronary artery bypass grafting using glucose-insulin-potassium cardioplegic solution (GIK) were divided into three groups Control (CO) group: no Diltiazem administration. Diltiazem cardioplegia (DC) group: GIK containing 7.5 mg/l Diltiazem was used. Diltiazem pretreatment (DP) group: Diltiazem was administered intravenously 1.5 micrograms/kg/min before operation to after operation continuously. Plasma Diltiazem concentration was constantly kept at about 150 ng/ml during 24 hours after surgery in DP. On the contrary, in DC, the level was very high (10,000 ng/ml) during aortic cross clamp but decreased about 50 ng/ml at 3 hours after surgery, and Diltiazem was not detected in CO. DC included many cases of bradycardia required pacing, however, it diminished as plasma concentration decreased. Aid of catecholamin administration was reasonable in three groups. DP and DC included many cases of commendable cardiac function in terms of cardiac index, systemic vascular resistance and left ventricular work during acute stage of surgery, and there were no coronary spasm and perioperative infarction. It is concluded that Diltiazem is effective to keep good cardiac function after reperfusion, and combined (Diltiazem pretreatment--1.5 micrograms/kg/min drip infusion-and Diltiazem cardioplegia-total dose 150-300 micrograms/kg) administration should be advisable.

[Considerations in determining indication for valvular surgery].

Between 1970 and 1987 valvular operations with cardiopulmonary bypass were performed on 636 patients, with an overall early mortality of 7.5%. To determine the critical indication for valvular surgery, preoperative clinical characteristics were examined by comparing 35 patients, who had died of surgery because of low cardiac output syndrome or multiple organ failure, with operative survivors. The multivariable logistic analyses demonstrated that NYHA functional class IV, multiple valvular disease, large CTR more than 70%, high left ventricular end-diastolic pressure more than 15 mmHg, depressed left ventricular ejection fraction less than 40%, and renal and hepatic dysfunction were powerful independent clinical characteristics concerning operative mortality. The mortality was highly significant when a patient was associated with more than three of the above factors in addition to being NYHA class IV. It should be emphasized, however, that there are three survivors among 11 patients with all six factors. On the other hand the prognosis of such patients without surgery was very poor, fifteen of 21 patients, medically treated during the same period, died within two years after reaching NYHA class IV condition. These results show that several predictors are useful for decision making regarding the indication for valvular surgery. Surgery, however, should not be denied because of the severity of the disease.