Description of Condition
Acute Kidney Injury (AKI) is a common and serious complication after cardiac surgery [1]. Specifically, acute kidney injury is mostly caused by the usage of cardiopulmonary bypass during coronary artery bypass grafting (CABG) and valvular surgery. [2] The incidence of acute kidney injury might also be dependent on the clinical characteristics of patients undergoing cardiac surgery, such as reduced left ventricular function, presence of congestive heart failure or an elevated preoperative serum creatinine. Acute Kidney injury does not have a universal definition. The three most popular consensus definitions are Acute Dialysis Quality Initiative’s “RIFLE” criteria, the Acute Kidney Injury Network (AKIN) criteria and the Kidney Disease Improving Global Outcomes (KDIGO) criteria [3]. These criteria are based on percentage increase in serum creatine concentration over baseline, absolute increase in serum creatine concentration or urine volume. [4] The pathogenesis of AKI after CPB is multifactorial, and is mostly due to hypoperfusion, reperfusion injury, activation of the systematic inflammatory response, and/or low cardiac output. [5] Reperfusion will result in the formation of reactive oxygen species, resulting in injury to tissue. [6] The activation of the systematic inflammatory response is mostly due to the exposure of blood to the extracorporeal CPB circuit, resulting in the activation of the immune system, which is also mediated by the generation of reactive oxygen species. This results in increased recruitment of neutrophils, macrophages and lymphocytes into the renal parenchyma, leading to AKI. [7]