Impact of renal dysfunction on early outcomes of coronary artery bypass grafting surgery

INTRODUCTION: Impaired renal function as seen in chronic kidney disease (CKD) is a known risk factor for coronary artery diseases and has been linked to inferior outcome after myocardial revascularization. Studies on the outcome of coronary bypass grafting (CABG) in CKD-patients are scarce. We aimed to study this subgroup of patients following CABG in a well defined whole-nation cohort, focusing on short term complications and 30 day mortality. MATERIALS AND METHODS: A retrospective study on 2300 consecutive patients that underwent CABG at Landspitali University Hospital 2001-2020. Patients were divided into four groups according to preoperative estimated glomerular filtration rate (GFR). and the groups compared. GFR 45-59 mL/min/1.73m(2). GFR 30-44 mL/min/1.73m(2). GFR <30 mL/min/1.73m(2) and controls with normal GFR (>= 60 mL/min/1.73m(2)). Clinical information was gathered from medical records and logistic regression used to estimate risk factors of 30-day mortality. RESULTS: Altogether 429118.7%) patients had impaired kidney function: these patients being more than six years older. having more cardiac symptoms and a higher mean EuroSCORE II (5.0 vs. 1.9. p<0.001) compared to controls. Furthermore, their left ventricular ejection fraction was also lower. their median hospital stay extended by two days and major short-term complications more common, as was 30 day mortality (24.4% vs. 1.4%, p<0.001). In multivariate analysis advanced age, ejection fraction <30% and GFR <30 mL/min/1.73m(2) were independent predictors of higher 30-day mortality (OR=10.4: 95% CI: 3.98-25.46). CONCLUSIONS: Patients with impaired renal function are older and more often have severe coronary artery disease. Early complications and 30-day mortality were much higher in these patients compared to controls and advanced renal failure and the strongest predictor of 30-day mortality.