Predictors of ARF after cardiac surgical procedures.
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).


CONCLUSIONS
Low preoperative serum ferritin level was not confirmed to predict ARF after cardiac surgery. Valve procedures, particularly AVR, increased the risk for ARF.
Tuttle
Katherine R
KR
Research Department, Heart Institute of Spokane, Seattle, WA 99204-2340, USA. ktuttle@this.org
Worrall
Neil K
NK
Dahlstrom
Lynn R
LR
Nandagopal
Radha
R
Kausz
Annamaria T
AT
Davis
Connie L
CL
D058186:Acute Kidney Injury / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D000368:Aged; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D005260:Female; D005293:Ferritins / Q000097:blood; D005500:Follow-Up Studies; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects*; D006801:Humans; D008297:Male; D010865:Pilot Projects; D011182:Postoperative Care / Q000379:methods; D011183:Postoperative Complications / Q000097:blood / Q000209:etiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012017:Referral and Consultation; D012307:Risk Factors; D013997:Time Factors
D005293:Ferritins