Renal and hemodynamic effects of diltiazem after elective major vascular surgery--a potential renoprotective agent?

A postoperative study was done of the effects of an infusion of diltiazem (DTZ), 1 microgram.kg-1.min-1 after a bolus dose of 0.28 mg.kg-1 on renal function and hemodynamics in 10 patients who were operated with insertion of an abdominal aortic graft. Urine flow, glomerular filtration rate (GFR) by inulin clearance, and renal plasma flow (RPF) by PAH clearance and fractional excretion of electrolytes and osmols were measured for three periods of 20 min during infusion of DTZ, in the morning after surgery. Systemic hemodynamic studies were conducted and serum levels of catecholamines were measured. GFR increased during the initial period of DTZ infusion. There were no significant changes during the study period in any of the other parameters, compared to baseline, except for a decrease in heart rate from 84 to 77 beats per minute. The absence of a sustained increase in GFR and a natriuretic and diuretic effect may possibly be ascribed to a preexisting nonconstricted status of the renal vasculature. The authors conclude that the dose of DTZ used in this study can be safely used for further investigations to elucidate the effects of peroperative infusion of DTZ on renal function in connection with major vascular surgery.