Renal Effects of α-Ketoglutarate Early After Coronary Operations

Background. α-Ketoglutarate (α-KG) is a Krebs cycle intermediate and the carbon skeleton of glutamate. α-Ketoglutarate has provoked interest in heart surgery because of its proposed critical role in myocardial metabolism. This study investigates the role of α-KG in renal function after cardiac surgical procedures. Methods. Twenty-two patients with normal preoperative renal function were included in a prospective, randomized, and controlled study. Eleven patients received intravenous infusion of 30 g α-KG/hour after the operation. Measurements were performed before operation, immediately after operation, and after 30 minutes of α-KG infusion. Results. Renal blood flow was higher during α-KG infusion, 297% ± 97% (of preoperative value), than in controls, 125% ± 20% (p < 0.05). Filtration fraction was lower (12.3% ± 0.05% versus 17.2% ± 1.1%, p < 0.01), which prevented a significant difference in glomerular filtration rate. The renal arteriovenous differences of lactate, glutamate, glutamine, and glycine changed toward a net release during α-KG infusion. Conclusions. Infusion of α-KG enhances renal blood flow early after coronary surgical procedures in patients with normal renal function. The mechanism is unclear, but could be associated with primarily metabolic effects, and may potentially convey a beneficial effect for renal function.