Impact of Preoperative Occult Renal Dysfunction on Early and Late Outcomes After Off-Pump Coronary Artery Bypass

Background Renal dysfunction is independently associated with increased early and late mortality after coronary artery bypass graft (CABG) surgery. Off-pump CABG (OPCABG) avoids postoperative complications from the cardiopulmonary bypass, but it is unclear how it is impacted by occult renal dysfunction (ORD). This study aimed to investigate the effects of ORD on early and late outcomes after OPCABG. Methods This retrospective and observational cohort study reviewed data on 1,188 patients who underwent first isolated OPCABG with normal serum creatinine (SCr) levels. According to preoperative estimated creatinine clearance (eCrCl) by the Cockcroft-Gault formula, the patients were divided into an ORD group (n=260, eCrCl Results The ORD patients presented with older age, higher incidence of small body surface area, hypertension, low preoperative eCrCl, cerebrovascular accident, peripheral vascular disease, New York Heart Association (NYHA) Ⅲ, and high risk score. The prevalence of hospital mortality, postoperative acute kidney injury (AKI), peak postoperative SCr, and prolonged hospital stay were greater in the ORD patients than the control patients. Multivariable logistic regression analysis showed that the ORD patients were at significantly higher risk of postoperative AKI (OR, 2.702; 95% CI, 1.994–3.662) and in-hospital mortality (OR, 2.884; 95% CI, 1.293–6.432). Multivariate Cox proportional hazard models confirmed that ORD was significantly associated with high later mortality (HR, 2.847; 95% CI, 1.262–6.425). Conclusions Occult renal dysfunction is an independent risk factor for postoperative AKI in-hospital and later mortality in patients undergoing OPCABG with normal SCr levels.