Perioperative Use of NAC to Prevent AKI in Patients With Pre-existing Moderate Renal Insufficiency Following Cardiac Surgery

Perioperative Use of N-acetylcysteine to Prevent Acute Kidney Injury in Patients With Pre-existing Moderate Renal Insufficiency Following Cardiac Surgery

Acute kidney injury (AKI) or renal impairment is an established complication of cardiac surgery occurring with an incidence up to 30%, To date, no agent has conferred renal protection. Considerable interest has developed in the potential for Nacetylcysteine (NAC) to exert a renoprotective effect in patients undergoing cardiac surgery. Due to the beneficial effect of NAC on contrast nephropathy and its reported anti-inflammatory effects.

Acute kidney injury (AKI), is a well-known complication of cardiac surgery, with an incidence of up to 30% depending on the definition. AKI caused by cardiac surgery is the second most common cause of AKI in the intensive care unit and is a common and serious postoperative complication of cardiac surgery requiring cardiopulmonary bypass (CPB).

The pathogenesis of AKI after CPB is multifactorial, and is mostly due to hypo perfusion, reperfusion injury, activation of the systemic inflammatory response, and/or low cardiac output. Reperfusion will result in the formation of reactive oxygen species, resulting in injury to tissues.

The activation of the systemic 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.

N-acetylcysteine (NAC) is well known for its antioxidant and free-radical scavenging properties, as well as its vasodilator properties. Its antioxidant properties enable it to prevent ischemic cell death, and as a free-radical scavenger, NAC mitigates the effect of increased reactive oxygen species caused by reperfusion. Hence, theoretically, NAC is able to counteract several mechanisms of kidney injury during cardiac surgery, namely, the systemic inflammatory response, free-radical injury, and ischemia.

In this study, we aimed to investigate if the perioperative use of acetylcysteine will prevent kidney injury after cardiac surgery.

Inclusion Criteria

• Scheduled for open heart Surgery with cardiopulmonary bypass (CPB) pump.
• Pre-existing moderate renal insufficiency serum creatinine more than 1.5 mg/dL

Exclusion Criteria:

• Patients on hemodialysis preoperatively
• History of renal transplantation
• IV contrast within 4 days prior to surgery
• Urgent/emergent surgery
• Preoperative hemodynamic instability (intra-aortic balloon pump support or vasoactive medications)
• Planned off-pump surgery;
• Planned deep-hypothermic-circulatory-arrest
• known or suspected allergy to NAC
• Patient Refusal.