Diltiazem infusion for renal protection in cardiac surgical patients with preexisting renal dysfunction

To evaluate if the calcium channel blocker diltiazem protects postoperatively renal function in cardiac surgical patients with preexisting mild-to-moderate renal dysfunction.

Prospective, randomized, placebo-controlled, double-blind, clinical study.

Cardiothoracic anesthesia department at a university hospital.

Adult patients undergoing elective cardiac surgery using cardiopulmonary bypass, with a preoperatively elevated serum creatinine level (n = 24).

Randomized infusions of diltiazem (bolus 0.25 mg/kg followed by a continuous infusion of 1.7 microg/kg/min) (DTZ, n = 12) or placebo (C, n = 12) were started 30 minutes before induction of anesthesia and continued for 24 hours.

Median plasma concentrations of diltiazem (DTZ group) were 79 microg/L before cardiopulmonary bypass, 67 microg/L at the end of cardiopulmonary bypass, and 164 microg/L at 24 hours postoperatively. Serum creatinine levels; on postoperative days 1, 3, and 5; and 3 weeks postoperatively were similar between groups. Iohexol clearance did not differ between the groups on day 5 but was higher in the DTZ group than in the placebo group 3 weeks after surgery (median, 51 v 40 mL/min/1.73 m(2); p < 0.05). Urinary N-acetyl-beta-glucosamidase concentrations were similar between the groups during the study but were increased from baseline on days 2 and 4 and 3 weeks postoperatively.

Diltiazem can be safely used in patients who have mild-to-moderate renal dysfunction and undergo cardiac surgery using cardiopulmonary bypass. Within the limits of this study, the data suggest that addition of prophylactic diltiazem may prevent further glomerular damage resulting from cardiopulmonary bypass and may improve glomerular function 3 weeks after cardiac surgery.