Role of preoperative serum creatinine and estimated glomerular filtration rate values in asymptomatic patients undergoing carotid endarterectomy.

ABSTRACT

BACKGROUND: The aim of this study was to evaluate the effect of chronic kidney disease (CKD), assessed by preoperative estimated glomerular filtration rate (eGFR) and serum creatinine (Cr), on postoperative outcomes and long-term survival in asymptomatic patients undergoing carotid endarterectomy (CEA). METHODS: We examined data about patients that underwent CEA between January 2002 and September 2014 in our Institution. Retrospective analysis to assess preoperative comorbidities and postoperative complications was performed. Modification of Diet in Renal Disease (MDRD) formula was used to calculate eGFR. Patients were divided into four groups based on values of preoperative eGFR group A (≥90 mL/min/1.73 m2), group B (89-60 mL/min/1.73 m2), group C (59-30 mL/min/1.73 m2) and group D (≤29 mL/min/1.73 m2), and into two groups based on preoperative Cr values group 1 (<1.5 mg/dL) and group 2 (≥1.5 mg/dL). Primary outcomes were death or the development of one or more postoperative major complications within 30 days after surgery, for each group. Survival curves of Kaplan-Meier were plotted for each group of patients to assess long-term mortality. RESULTS: During the study period, 853 CEAs in 808 patients were performed, of which 682 CEA in 645 patients for asymptomatic carotid artery stenosis. Symptomatic patients (19.58%) and patients receiving hemodialysis (0.46%) were excluded. Among CEAs analyzed, 678 (99.4%) had preoperative Cr values recorded and 637 (93.4%) had preoperative eGFR values recorded. The number of patients in each group according to eGFR values was 84 (13.2%) for group A, 250 (39.3%) for group B, 271 (42.5%) for group C and 32 (5.0%) for group D; according to Cr values was 609 (89.8%) for group 1 and 69 (10.2%) for group 2. One death and 24 (3.52%) postoperative major complications, of which 20 postoperative neurological events (NE) and 4 postoperative myocardial infarctions (MI), occurred within 30 days after surgery. The median follow-up was 55 months (IQR 27-84). Regarding general population, multivariate analysis with age found no significant correlation between Cr and primary outcomes, to the contrary of eGFR (OR=1.02; CI 1.01-1.02; P<0.0001). No significant differences were observed concerning primary outcomes according to eGFR and Cr groups. Five-year survival rates for groups A, B, C and D were 98±0.02%, 90±0.02%, 80±0.03% and 56±0.12% respectively (P<0.0001) and 88±0.02% and 62±0.08% for group 1 and 2 respectively (P<0.0001). CONCLUSIONS: eGFR and Cr classes are not a dependable method in evaluating postoperative complications risk after CEA in asymptomatic patients, although preoperative eGFR values influence 30-days morbility. Both eGFR and Cr groups are reliable predictors to discriminate among asymptomatic patients candidates for CEA, based on their life expectancy.