Cardiac Surgery-Associated Acute Kidney Injury

Abstract

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common and serious postoperative complication of cardiac surgery requiring cardiopulmonary bypass (CPB), and it is the second most common cause of AKI in the intensive care unit. Although the complication has been associated with the use of CPB, the etiology is likely multifactorial and related to intraoperative and early postoperative management including pharmacologic therapy. To date, very little evidence from randomized trials supporting specific interventions to protect from or prevent AKI in broad cardiac surgery populations has been found. The definition of AKI employed by investigators influences not only the incidence of CSA-AKI, but also the identification of risk variables. The advent of novel biomarkers of kidney injury has the potential to facilitate the subclinical diagnosis of CSA-AKI, the assessment of its severity and prognosis, and the early institution of interventions to prevent or reduce kidney damage. Further studies are needed to determine how to optimize cardiac surgical procedures, CPB parameters, and intraoperative and early postoperative blood pressure and renal blood flow to reduce the risk of CSA-AKI. No pharmacologic strategy has demonstrated clear efficacy in the prevention of CSA-AKI; however, some agents, such as the natriuretic peptide nesiritide and the dopamine agonist fenoldopam, have shown promising results in renoprotection. It remains unclear whether CSA-AKI patients can benefit from the early institution of such pharmacologic agents or the early initiation of renal replacement therapy.

Enteral Baicalin, a Flavone Glycoside, Reduces Indicators of Cardiac Surgery-Associated Acute Kidney Injury in Rats

“…Notably, in spite of the pharmacological interventions for CSA-AKI including the use of natriuretic peptides and dopamine agonists, there has been no clearly defined medicine for the treatment of this disorder [3]. In particular, a multisite trial in Japan showed that atrial natriuretic peptide did not significantly improve renal function in cardiac surgery patients with AKI [36].…”

“…CSA-AKI is caused by multiple factors, which involve different injury pathways including metabolic abnormalities, ischemia and reperfusion injury, neurohormonal activation, inflammation, and oxidative stress [2]. Due to the differences in baseline characteristics and surgery types, studies of the epidemiology of CSA-AKI in recent years showed the range of CSA-AKI incidence is between 8.9 and 39% [3]. Renal impairment during cardiac surgery is often associated with renal hypoperfusion caused by the bleeding complications [4], while exposure of blood to the cardiopulmonary bypass (CPB) pump and circuit often activate different inflammatory pathways [5].…”

Risk Factors for Acute Kidney Injury after Coronary Artery Bypass Surgery and Its Detection Using Neutrophil Gelatinase-Associated Lipocalin

“…Based on these findings, it can be stated that the preoperative and operative periods are important for AKI development, but the use of classical markers such as SCr levels to diagnose AKI can cause a delay in the diagnosis. To prevent CABG-related AKI, three predictive risk scores based on preoperative variables have been developed: the Cleveland Clinic Score, the Mehta Score and the Simplified Renal Index Score [7]. However, there has been no consensus among authors with regard to recommending the use of a specific score to predict AKI before CABG.…”

“…As a result of chronic inflammatory processes, atherosclerosis might affect both coronary and renal arteries. In this context, coronary artery disease was found to be closely associated with AKI [7]. …”

“…However, the optimal time at which to use NGAL for detecting AKI due to renal parenchyma damage is still unknown and needs further research. Also, the relationship between NGAL and those factors causing renal parenchymal damage during the preoperative and postoperative periods is very important while planning prophylactic treatment for possible acute renal failure [7]. …”