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Predictors of ARF after cardiac surgical procedures
Katherine R Tuttle1, Neil K Worrall, Lynn R Dahlstrom
1Research Department, Heart Institute of Spokane, Seattle, WA 99204-2340, USA. ktuttle@this.org
Background:
In a pilot study, a low preoperative serum ferritin level predicted increased risk for acute renal failure (ARF) after cardiopulmonary bypass. It was hypothesized that this may reflect a decreased ability to bind free iron and defend against oxidative stress. However, the pilot study was performed in a small number of patients (n = 30) operated on by a single surgeon. The purpose of this study was to validate whether the serum ferritin level predicts ARF in a larger sample.
Methods:
The present study evaluated 120 patients who underwent procedures performed by eight surgeons at another tertiary referral center. Data were collected prospectively and included patient characteristics, laboratory studies, procedure types, and postoperative course. ARF was defined as a 25% or greater increase in creatinine level 48 hours after surgery.
Results:
The frequency of ARF was 42%, but no patient required dialysis therapy. Preoperative serum ferritin levels did not differ in the groups with and without ARF (158 +/- 119 and 163 +/- 125 ng/mL, respectively), and rates of ARF did not differ when examined by ferritin quartiles. ARF was more frequent in those who underwent valve surgery (54% versus 35% in patients who did not undergo valve procedures; P = 0.044). The odds ratio for ARF after valve surgery was 2.58 (95% confidence interval, 1.06 to 6.29; P = 0.037), adjusted for longer times of surgery and aortic cross-clamp. Most excess ARF occurred in those who underwent aortic valve replacement (AVR; 62%; P = 0.014 versus nonvalve procedures).
Conclusion:
Low preoperative serum ferritin level was not confirmed to predict ARF after cardiac surgery. Valve procedures, particularly AVR, increased the risk for ARF.
Insights
Low preoperative serum ferritin levels do not predict acute renal failure (ARF) after cardiac surgery. However, valve procedures, especially aortic valve replacement, significantly increase the risk of ARF.
Area of Science:
- Cardiovascular Surgery
- Nephrology
- Critical Care Medicine
Background:
- A pilot study suggested low preoperative serum ferritin levels predict acute renal failure (ARF) post-cardiac surgery.
- This hypothesis was based on the idea that low ferritin impairs iron binding and antioxidant defense.
- The pilot study's small sample size and single surgeon limited its generalizability.
Purpose of the Study:
- To validate whether preoperative serum ferritin levels predict ARF in a larger, more diverse patient cohort.
- To investigate the association between serum ferritin and ARF risk after cardiac surgery.
Main Methods:
- Prospective evaluation of 120 patients undergoing cardiac procedures performed by eight surgeons.
- Data collected included patient characteristics, laboratory results, procedure types, and postoperative outcomes.
- ARF was defined as a ≥25% increase in creatinine level within 48 hours post-surgery.
Main Results:
- The overall incidence of ARF was 42%, with no patients requiring dialysis.
- Preoperative serum ferritin levels were similar between patients with and without ARF.
- Valve surgery, particularly aortic valve replacement (AVR), was associated with a significantly higher risk of ARF (54% vs. 35%, P=0.044).
Conclusions:
- Preoperative serum ferritin levels were not confirmed as a predictor of ARF after cardiac surgery.
- Valve procedures, especially AVR, represent a significant risk factor for developing ARF post-cardiac surgery.