Renal dysfunction after cardiac surgery.
OBJECTIVE
To assess the causes and outcomes of patients with postcardiac surgery renal dysfunction.


METHODS
A large cardiovascular data- base including pre-, peri- and postoperative serum creatinine concentrations from 2214 consecutive cardiac surgery patients was analyzed.


RESULTS
Sixty-nine patients developed postoperative renal dysfunction, defined as at least a 15 mL/min decline in the creatinine clearance rate resulting in a value of less than 40 mL/min. These patients were significantly older, and had a higher incidence of previous cardiac surgery, diabetes, obesity, peripheral vascular disease, hypertension and poor ventricular function. Postoperatively, these patients had a higher occurrence of low output syndrome and myocardial infarction. Stepwise logistic regression predictors of postoperative renal dysfunction included the following: postoperative low output syndrome; repeat cardiac surgery; being older than 65 years; having diabetes; having poor left ventricular function; and having had valve surgery. Preoperative renal dysfunction (defined as a creatinine clearance of less than 40 mL/min) was not found to be one of the predictors. The mean creatinine concentrations of patients with mild postoperative renal dysfunction (defined as a creatinine concentration of less than 200 mmol/L on the fourth or fifth postoperative day) decreased significantly at the fifth postoperative day, while that of patients with severe postoperative renal dysfunction rose to a mean of 300 mmol/L six months postoperatively. The incidence of late dialysis (defined as a need for dialysis after postoperative day 10) approached 30% among patients with severe postoperative renal dysfunction and only 2% among patients with mild postoperative renal dysfunction. The early mortality rate (during the first postoperative month) was similar in both groups and approached 30%.


CONCLUSIONS
Patients who develop postoperative renal dysfunction have a high mortality rate. Postoperative low cardiac output is the most important cause of postoperative renal dysfunction and, therefore, should be avoided. Patients with creatinine concentrations of less than 200 mmol/L at postoperative day 4 or 5 will probably resume normal renal function. Patients with creatinine concentrations of more than 200 mmol/L at days 4 and 5 have a 30% chance of needing long term dialysis.
Abrahamov
D
D
Department of Cardiovascular Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada. abramov2@zahav.net.il
Tamariz
M
M
Fremes
S
S
Tobe
S
S
Christakis
G
G
Guru
V
V
Sever
J
J
Goldman
B
B
D017677:Age Distribution; D000368:Aged; D002303:Cardiac Output, Low / Q000503:physiopathology; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000097:blood / Q000209:etiology* / Q000401:mortality; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood / Q000401:mortality; D011237:Predictive Value of Tests; D016019:Survival Analysis
D003404:Creatinine