Prognostic value of postoperative proteinuria in cardiac surgery: a pilot study.
BACKGROUND
Proteinuria is a non-specific marker of inflammation that may reflect the glomerular component of systemic capillary leak. The objective of this pilot study was to determine if postoperative proteinuria is associated with adverse outcomes following cardiac surgery with cardiopulmonary bypass.


METHODS
Eligible patients were individuals undergoing cardiac surgery with cardiopulmonary bypass who did not have severe pre-existing renal dysfunction. Urine was collected after induction of anesthesia (baseline) and two to four hours after arrival to the intensive care unit (ICU). Proteinuria was measured as random protein creatinine ratio in g.mol(-1). Adverse events were defined a priori as prolonged ICU stay (> or = 90th percentile) and organ dysfunction. The relationship between proteinuria and adverse events was assessed by bivariate (Chi-square or Fisher's exact tests) and multivariable (multiple logistic regression) analyses.


RESULTS
The study included 197 (of 243 eligible) patients. Postoperative proteinuria (protein creatinine ratio > or = 30 g.mol(-1)) was associated with prolonged (> or = four days) ICU stay [odds ratio (OR) 7.0; 95% confidence interval (CI) 2.8-17.1] and organ dysfunction (OR 3.9; CI 1.9-8.1). After adjustment for confounders, proteinuria was associated with a 3.2-fold increase in the odds of both prolonged ICU stay (CI 1.1-9.7) and organ dysfunction (CI 1.4-7.0).


CONCLUSIONS
Proteinuria two to four hours after cardiac surgery with cardiopulmonary bypass may be a useful marker for systemic capillary leak and adverse postoperative events. Large prospective studies are needed to confirm these findings.
Karkouti
Keyvan
K
University Health Network, Toronto General Hospital, Department of Anesthesia, EN 3-402, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada. keyvan.karkouti@uhn.on.ca
Shayan
Shahriar
S
Wijeysundera
Duminda N
DN
McCluskey
Stuart A
SA
Ghannam
Mohammed
M
Beattie
W Scott
WS
D000768:Anesthesia, General; D001281:Atrial Fibrillation / Q000209:etiology; D002303:Cardiac Output, Low / Q000209:etiology; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D015331:Cohort Studies; D003404:Creatinine / Q000652:urine; D003422:Critical Care; D005500:Follow-Up Studies; D006801:Humans; D007902:Length of Stay; D017093:Liver Failure / Q000209:etiology; D009203:Myocardial Infarction / Q000209:etiology; D010865:Pilot Projects; D011183:Postoperative Complications; D011379:Prognosis; D011446:Prospective Studies; D011507:Proteinuria / Q000209:etiology*; D051437:Renal Insufficiency / Q000209:etiology; D012131:Respiratory Insufficiency / Q000209:etiology; D020521:Stroke / Q000209:etiology; D016896:Treatment Outcome
D003404:Creatinine