05. tbl. 108. árg. 2022
Impact of renal dysfunction on early outcomes of coronary artery bypass grafting surgery
Áhrif skertrar nýrnastarfsemi á snemmkominn árangur kransæðahjáveituaðgerða
Nanna Sveinsdóttir1
Sunna Rún Heiðarsdóttir1
Árni Steinn Steinþórsson1
Hera Jóhannesdóttir2
Alexandra Aldís Heimisdóttir2
Tómas Þór Kristjánsson2
Þórir Einarsson Long3
Ingibjörg Guðmundsdóttir1,4
Martin Ingi Sigurðsson1,5
Tómas Guðbjartsson1,2
1Faculty of Medicine, University of Iceland, 2Departments of Cardiothoracic Surgery, 3Nephrology, 4Cardiology and 5Anesthesia and Intensive Care, Landspitali University Hospital.
Correspondence: Tómas Guðbjartsson,
tomasgud@landspitali.is
Key words: Coronary artery bypass grafting (CABG), reduced kidney function, chronic kidney disease, short-term, complications, outcome
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 Landspítali 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/mín/1.73m2, GFR 30-44 mL/mín/1.73m2, GFR <30 mL/mín/1.73m2 and controls with normal GFR (≥60 mL/mín/1.73m2). Clinical information was gathered from medical records and logistic regression used to estimate risk factors of 30-day mortality.
RESULTS: Altogether 429 (18.7%) 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/1.73m2 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.
Figure I. The division of the 2300 patients into four groups based on GFR (mL/min/1,73m2).
Control group: GFR > 60 mL/min/1,73m2
Table I. Comparison of background factors between the GFR groups (ml/min/1,73m2).
Mean + standard deviation or number of cases (%) are shown.
Table II. Comparison between GFR groups (ml/min/1.73m2) of primary risks of coronary artery disease. Number of cases (%) are shown.
Table III. Comparison of operation related factors and hospital stay according to GFR. Mean + standard deviation or number of cases (%) are shown, except median + range for hospital stay.
GFR level, ml/min/1.73m2
Figure II. Incidence of early complications, minor and major, and 30-day mortality. The incidence of all the factors increased significantly as GFR decreased.
GFR level, ml/min/1.73m2
Control group: GFR > 60 mL/min/1,73m2
Table IV. Comparison of short term complications and 30-day mortality. Number of cases (%) are shown. Patients may have more than one complication at a time.
GFR level, ml/min/1.73m2
Table V. Predictive factors for 30 day postoperative mortality. Raw and adjusted odds ratio (OR) for 30 day mortality with 95% confidence interval.