Influence of nimodipine on cardiovascular parameters during coronary surgery

A total of 78 patients about to undergo open-heart surgery (ACVB) were given nimodipine, a new calcium antagonist, in different doses (0.5 or 1.0 microgram/kg body weight min or 0.03/0.06 mg/kg h) before and during extracorporeal circulation. During infusion (10 to 40 min), the hemodynamic parameters were recorded, including intrapulmonary pressures, the cardiac output and the left ventricular contractility parameters LVP and dp/dtmax. The administration of nimodipine resulted in a dose-dependent reduction of the pulmonary and peripheral vascular resistance with a subsequent decrease of the mean arterial pressure or perfusion pressure (during extracorporeal circulation). The left ventricular pressure (LVP) was reduced, whereas sometimes the cardiac output increased considerably. The contractility (dp/dtmax) was not impaired even by the high nimodipine dose. The heart rate, too, remained unaffected. The nimodipine dose of 0.5 microgram/kg min used in neurosurgery for therapy did not cause any clinically relevant decrease in blood pressure; at higher doses (greater than or equal to 1.0 microgram/kg min) an excessive fall of the diastolic pressure must be avoided in patients with severe (coronary) sclerosis, because a reduced perfusion of poorly vascularized myocardial regions can occur despite improved global perfusion.