PURPOSE: Serum creatinine (sCr) greater than 2.0 mg/dL has long been known as an independent risk factor for postoperative mortality and morbidity following cardiac surgery. Recently, glomerular filtration rate (GFR), rather than sCr has been shown to be a better predictor of adverse postoperative outcomes. The study aim was to investigate the relationship between sCr ≤ 2.0 mg/dL patients with decreased GFR and adverse postoperative outcomes.
METHODS: Subjects were all CABG patients (n=4,216) with sCr ≤ 2.0 mg/dL or no history of dialysis between 2001 and 2005. GFR (mL/min per 1.73 m2) was calculated by the Modification of Diet in Renal Disease Study formula: GFR= 186.3 × sCr-1.154 × age-0.203 × 1.212 (if black) × 0.742(if female) and subjects were dichotomized intro groups of GFR normal (≥ 90), GFR mild (90-60), GFR moderate (60-30) GFR severe (<30).
RESULTS: The following variables were found to be significantly associated with decreased GFR (p<0.05): increased age, high EuroSCORE, hypertension, female gender, and African-American. Decreased GFR across all categories was associated with increased mortality (OR: 1.60, 3.76, 18.10), prolonged ventilation time (OR: 1.31, 3.46, 3.96) and LOS ≥ 10 days (OR: 1.33, 3.41, 11.20). For renal failure (OR: 2.25, 9.35) and permanent stroke (OR: 2.07, 2.14) for mild and moderate groups only.
CONCLUSION: Cardiac surgical risk algorithms which include only dichotomized sCr values ≤ 2.0 may miss a critical subset population. The GFR is a much a better predictor of adverse outcomes following cardiac surgery specifically among high risk populations such as females, older patients and those patients with a higher EuroSCORE defined risk profile.
CLINICAL IMPLICATIONS: Increased use of the GFR is warranted for those patients that might otherwise be ignored due to sCr values ≤ 2.0.
DISCLOSURE: Niv Ad, None.