Antihypertensive and anti-ischemic effects of nicardipine and nitroprusside in patients undergoing coronary artery bypass grafting

The efficacy of nicardipine vs nitroprusside in controlling hypertension after sternotomy was compared in 120 patients undergoing coronary artery bypass grafting and anesthetized with fentanyl (100 micrograms/kg). All had good left ventricular function and had been receiving long term oral beta-blocking therapy. Patients were randomly allocated to 1 of 3 groups: group C, the control (n = 40), received no vasodilator; group N (n = 40) received intravenous nicardipine at an initial rate of 3 micrograms/kg/min; and group S (n = 40) received intravenous nitroprusside at an initial rate of 1 microgram/kg/min. Vasodilator infusion was begun before surgery and infusion rates were adjusted to maintain systolic blood pressure between 80 and 120% of postintubation (baseline) values. Additional measurements were obtained before incision and after sternotomy. In groups N and S, arterial blood pressure was effectively controlled in all patients. Before the incision, pulmonary artery pressure decreased in group S and systemic vascular resistance decreased in groups N and S. After sternotomy, mean arterial pressure, heart rate, pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac index and rate-pressure product increased in group C. At this time, pulmonary artery pressure returned to baseline values in group S. In groups N and S, heart rate, cardiac index and rate-pressure product increased, but, compared with baseline values, systemic vascular resistance remained low after sternotomy. Ischemic changes were seen in the electrocardiogram in 11 patients (28%) in group C, 10 patients (25%) in group S and 4 patients (10%) in group N. The concentration of creatine phosphokinase MB was not significantly different in the first 24 postoperative hours in any group