Perioperative dexmedetomidine reduces the incidence and severity of acute kidney injury following valvular heart surgery

Acute kidney injury (AKI) following cardiac surgery is closely interrelated with hemodynamic instability and sympathetic activity, and adversely influences prognosis. Here, we investigated in a randomized placebo-controlled trial whether dexmedetomidine, an α2 adrenoreceptor agonist, could prevent AKI after valvular heart surgery. Two hundred patients undergoing valvular heart surgery were randomly assigned to equal placebo or treatment groups. Dexmedetomidine was infused at a rate of 0.4 μg/kg/h starting immediately after anesthetic induction and continuing for 24 h after surgery. We then assessed the incidence of AKI during the first 48 postoperative hours, hemodynamic variables, and a composite of major morbidity end points. The incidence of AKI, based on Acute Kidney Injury Network criteria, was significantly lower in the treatment group compared with the control group (14 vs. 33%). The dexmedetomidine group exhibited a significantly lower incidence of a composite of major morbidity end points (21 vs. 38%) and a significantly shorter length of intensive care unit stay (3 [2, 3] days vs. 3 [2, 4] days) compared with the control group. Thus, perioperative infusion of dexmedetomidine effectively reduced both the incidence and severity of AKI, and improved outcome in patients undergoing valvular heart surgery without untoward hemodynamic side effects.