Relation between mild renal dysfunction and outcomes after coronary artery bypass grafting.
BACKGROUND
Risk stratification algorithms for coronary artery bypass grafting (CABG) do not include a weighting for preoperative mild renal impairment defined as a serum creatinine 130 to 199 micromol/L (1.47 to 2.25 mg/dL), which may impact mortality and morbidity after CABG.


RESULTS
We reviewed prospectively collected data between 1997 and 2004 on 4403 consecutive patients undergoing first-time isolated CABG with a preoperative serum creatinine <200 micromol/L (2.26 mg/dL)] in a single institution. The in-hospital mortality was 2.5% (112 of 4403), the need for new dialysis/hemofiltration was 1.3% (57 of 4403), and the stroke rate was 2.5% (108 of 4403). There were 458 patients with a serum creatinine 130 to 199 micromol/L or 1.47 to 2.25 mg/dL (mild renal dysfunction group) and 3945 patients with a serum creatinine <130 micromol/L (<1.47 mg/dL). Operative mortality was higher in the mild renal dysfunction group (2.1% versus 6.1%; P<0.001) and increased with increasing preoperative serum creatinine level. New dialysis/hemofiltration (0.8%versus 5.2%; P<0.001) and postoperative stroke (2.2% versus 5.0%; P<0.01) were also more common in the patients with mild renal impairment. Multivariate analysis adjusting for known risk factors confirmed preoperative mild renal impairment (creatinine 130 to 199 micromol/L or 1.47 to 2.25 mg/dL; odd ratio, 1.91; 95% CI, 1.18 to 3.03; P=0.007) or glomerular filtration rate estimates <60 mL/min per 1.73 m2, derived using the Cockroft-Gault formula, (odds ratio, 1.98; 95% CI, 1.16 to 3.48; P=0.015) as independent predictors of in-hospital mortality. Preoperative mild renal dysfunction adversely affected the 3-year survival probability after CABG (93% versus 81%; P<0.001).


CONCLUSIONS
Mild renal dysfunction is an important predictor of outcome in terms of in-hospital mortality, morbidity, and midterm survival in patients undergoing CABG.
Zakeri
Rosita
R
University Hospital Birmingham, Edgbaston B15 2TH, United Kingdom.
Freemantle
Nick
N
Barnett
Vivian
V
Lipkin
Graham W
GW
Bonser
Robert S
RS
Graham
Timothy R
TR
Rooney
Stephen J
SJ
Wilson
Ian C
IC
Cramb
Robert
R
Keogh
Bruce E
BE
Pagano
Domenico
D
D000368:Aged; D015415:Biomarkers; D015331:Cohort Studies; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000150:complications / Q000601:surgery*; D003404:Creatinine / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D006440:Hemofiltration; D017052:Hospital Mortality; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D007674:Kidney Diseases / Q000097:blood / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D006435:Renal Dialysis; D012306:Risk; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology; D016019:Survival Analysis; D016896:Treatment Outcome
D015415:Biomarkers; D003404:Creatinine