Association of Pre-Operative Albuminuria with Post-Operative Outcomes after Coronary Artery Bypass Grafting

Abstract

The effect on post-operative outcomes after coronary artery bypass graft(CABG) surgery is not clear. Among 17,812 patients who underwent CABG during October 1,2006-September 28,2012 in any Department of US Veterans Affairs(VA) hospital, we identified 5,968 with available preoperative urine albumin-creatinine ratio(UACR) measurements. We examined the association of UACR<30, 30-299 and >=300 mg/g with 30/90/180/365-day and overall all-cause mortality, and hospitalization length >10 days, and with acute kidney injury(AKI). Mean ± SD baseline age and eGFR were 66 ± 8 years and 77 ± 19 ml/min/1.73 m2, respectively. 788 patients(13.2%) died during a median follow-up of 3.2 years, and 26.8% patients developed AKI(23.1%-Stage 1; 2.9%-Stage 2; 0.8%-Stage 3) within 30 days of CABG. The median lengths of stay were 8 days(IQR: 6-13 days), 10 days(IQR: 7-14 days) and 12 days(IQR: 8-19 days) for groups with UACR < 30 mg/g, 30-299 mg/g and ≥300 mg/g, respectively. Higher UACR conferred 72 to 85% higher 90-, 180-, and 365-day mortality compared to UACR <30 mg/g (odds ratio and 95% confidence interval for UACR ≥ 300 vs. <30 mg/g: 1.72(1.01-2.95); 1.85(1.14-3.01); 1.74(1.15-2.61), respectively). Higher UACR was also associated with significantly longer hospitalizations and higher incidence of all stages of AKI. Higher UACR is associated with significantly higher odds of mortality, longer post-CABG hospitalization, and higher AKI incidence.