Effect of N-Acetylcysteine in protecting against acute renal insult in patients undergoing cardiopulmonary bypass
Date Issued
2007
Date
2007
Author(s)
Li, Shao-Jung
DOI
zh-TW
Abstract
Background
Reactive oxygen species have been shown to cause contrast-induced nephrotoxicity (CIN). According to the previous studies, the N-acetylcysteine (NAC) has been proved to be advantageous in the avoidance of CIN. We developed this study to evaluate the efficacy of the antioxidant NAC in limiting the renal injury after the cardiovascular surgery with cardiopulmonary bypass (CPB).
Materials and methods
All patients who would receive a cardiac surgery with cardiopulmonary bypass were included in this study. The patients were randomly assigned to receive either NAC (600 mg orally twice daily for 4 doses) with 0.45% saline intravenously, before and after cardiopulmonary bypass, or placebo with 0.45% saline. Serum creatinine and blood urea nitrogen were measured before, 48 h and 5 days after the operation procedure. Besides, cystatin C (Cys C) and β2-microglobulin (β2m) were measured just before and after the operation procedure.
Results
A total of 55 patients were recruited in this randomized clinical trial. Among them, 29 subjects were randomly assigned to the intervention group of NAC. After excluding the cases with left ventricular ejection fraction（LVEF）less than 30%, there were 28 subjects in the experiment group with intervention and 23 in the control group (placebo). No particular difference was found in the baseline comparison results. In univariate analyses, elevated risks of acute renal insult were detected for age, CABG plus valve procedure, 3rd tertile of BUN level (12 hours before surgery), BUN and creatinine clearance levels on surgery day, β2m and Cys C levels right before surgery. Unfortunately, only a borderline significance was identified for the procedure of CABG plus valve (OR = 8.49; 95% CI: 0.82, 88.38, p value = 0.07) in multivariate analysis.
Because of small sample size and difficulty on statistical analysis, we recruited another cohort into placebo control group for further analysis. A total of 117 patients were recruited in the further analysis. No any significantly statistical difference was detected in the baseline comparisons before intervention. In univariate analysis, amazingly, NAC treatment before surgery increased the risk of acute renal insult by 2.62 folds (95% CI: 1.10, 6.27). Subjects who underwent CABG plus valve procedure had a remarkable OR of 5.42 (95% CI: 2.16, 13.58), relative to the ones with valve procedure only. Also, patients with diabetes and hypertension had significantly elevated risk of outcome incidence. Meanwhile, higher BUN level 12 hours before surgery, BUN, serum creatinine, creatinine clearance levels on the surgery day, andβ2m level right before surgery showed remarkably altered risk of acute renal insult. Although not significant, reopen after surgery might dramatically raise the risk of outcome by approximate three folds. In multivariate analysis, the relative risk (OR) of NAC, after controlling confounders, was 2.54 folds (95% CI: 0.82, 7.88; relative to placebo group) without statistical significance. Besides, only the significance of CABG plus valve procedure, (OR = 4.02; 95% CI: 1.19, 13.64, relative to the ones with mere valve procedure), and 3rd tertile of β2m level before surgery (OR = 5.63; 95% CI: 1.01, 31.20, relative to the 1st tertile) remained significant.
Conclusion
NAC cannot protect the renal damage during CPB. CABG plus valve procedure and higher β2m level before surgery (2.83~41.05, upper limit of normal is 2.4 mg/L for both, males and females) are 2 independent risk factor for risk of renal injury.
Subjects
體外循環
乙醯半胱胺酸
急性腎傷害
雙盲隨機試驗
血清肌胺酸酐
N-acetylcysteine
cardiopulmonary bypass
renal injury
randomized clinical trial
cystatin C
β2-microglobulin
SDGs
Type
text
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