Renoprotective Effects of Dexmedetomidine Versus Dopamine in High-Risk Renal Patients Undergoing Off-Pump Coronary Artery Bypass Grafting:A Prospective, Randomized, Comparative Study.

OBJECTIVES: To compare the renoprotective effects of dexmedetomidine and low-dose dopamine versus normal saline (control) in high-risk renal patients undergoing off-pump coronary artery bypass grafting (OPCAB). DESIGN: Prospective, open-label, randomized, parallel-group comparative study. SETTING: Department of Cardiac Anaesthesiology and Critical Care at a tertiary-level cardiac surgical center. PARTICIPANTS: In total, 105 adult patients aged ≥60 years with preexisting moderate renal insufficiency (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m² and/or serum creatinine ≥1.1 mg/dL) and 1 or more additional risk factors (diabetes mellitus, hypertension, or left ventricular ejection fraction <45%), scheduled for elective OPCAB. No patients were excluded after randomization. INTERVENTIONS: Patients were randomized equally into 3 groups: group A received dexmedetomidine infusion at 0.4 μg/kg/h (without a loading dose), group B received dopamine infusion at 3 μg/kg/min, and group C (control) received normal saline at 3 mL/h. Infusions were commenced after induction of anesthesia and continued for the first 24 postoperative hours. MEASUREMENTS AND MAIN RESULTS: Urine output, serum creatinine, blood urea nitrogen (BUN), and eGFR were measured at baseline and at 24 and 48 postoperative hours. Acute kidney injury (AKI) was defined per Acute Kidney Injury Network (AKIN) criteria. Hemodynamic parameters and adverse events were recorded throughout. Group A demonstrated significantly higher urine output than groups B and C at days 1 and 2 (p < 0.01). Serum creatinine and BUN were significantly lower in group A versus groups B and C at both time points (p < 0.05), although the absolute differences were not clinically significant. eGFR was markedly higher in group A compared with groups B and C at days 1 and 2 (p < 0.0001). No patient in any group developed AKI by AKIN criteria or required renal replacement therapy. Adverse events, including arrhythmias and need for intra-aortic balloon pump, were comparable across groups (p = 0.31). CONCLUSIONS: Dexmedetomidine infusion was superior to dopamine in improving urine output and eGFR in high-risk renal patients undergoing OPCAB, although differences in serum creatinine and BUN were not clinically significant. Neither drug prevented AKI beyond the control group. Dexmedetomidine may offer a favorable renal physiological profile in this patient population, warranting further investigation with more sensitive biomarkers.