Coronary artery bypass surgery and acute kidney injury--impact of the off-pump technique.
BACKGROUND
Acute kidney injury (AKI) is a serious and frequent complication after coronary artery bypass grafting (CABG). Cardiopulmonary bypass (CPB) was identified as a major AKI risk factor after CABG. Our aim was to assess the impact of the off-pump coronary artery bypass (OPCAB) compared to the on-pump coronary artery bypass (ONCAB) technique on the rate and severity of AKI, while taking other risk factors for AKI into account.


METHODS
An observational study of 201 consecutive adult patients was conducted; 100 were operated by the OPCAB and 101 by the ONCAB technique. All patients in each group were operated by a single, experienced surgeon. Fifteen pre-, intra- and postoperative variables that were repeatedly identified in previous studies as independent AKI risk factors were included in this analysis. AKI was defined as an increase of serum creatinine >/=50% or >/=0.3 mg/dL within 48 h and AKI severity was classified, according to current AKIN definitions.


RESULTS
Significantly fewer OPCAB patients developed AKI compared to ONCAB (14.0 versus 27.7%; P = 0.03). OPCAB was associated with milder stages of AKI, whereas ONCAB patients had more severe AKI. Congestive heart failure and chronic kidney disease were independent risk factors for AKI. The OPCAB technique for CABG was identified as the only independent factor associated with lower incidence of AKI.


CONCLUSIONS
Using current AKI definitions and classifications, the OPCAB technique for CABG, which avoids CPB; was associated with a significantly lower rate and less severe AKI compared to ONCAB. The OPCAB technique was identified as the only modifiable and potentially protective factor against postoperative AKI.
Massoudy
Parwis
P
Department of Nephrology, University Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany.
Wagner
Soeren
S
Thielmann
Matthias
M
Herold
Ulf
U
Kottenberg-Assenmacher
Eva
E
Marggraf
Günther
G
Kribben
Andreas
A
Philipp
Thomas
T
Jakob
Heinz
H
Herget-Rosenthal
Stefan
S
D058186:Acute Kidney Injury / Q000097:blood / Q000209:etiology* / Q000401:mortality; D000368:Aged; D002097:C-Reactive Protein / Q000032:analysis; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects; D003404:Creatinine / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000453:epidemiology; D017052:Hospital Mortality; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology; D012307:Risk Factors; D012720:Severity of Illness Index
D015850:Interleukin-6; D002097:C-Reactive Protein; D003404:Creatinine