Impact of Renal Dysfunction And Outcomes After on Pump Coronary Revascularization Surgery

Abstract

Introduction: Algorithms of risk stratification for coronary artery bypass grafting (CABG) does not include a weighting for renal impairment after on pump CABG. Hence our first objective was to ascertain the effect of a mild-to-moderate elevation in the pre-operative serum creatinine level on post-operative outcome. Our second objective was to ascertain which patient variables contributed to an increase in the serum creatinine level in association with coronary artery bypass grafting. Materials and methods: We reviewed the prospectively collected data from the cardiac surgical database for 2015. A total o f 101 patients who had known pre-existing mild-to-moderate renal disease and who were undergoing first-time coronary artery bypass grafting with cardiopulmonary bypass were divided, into Group A: <130 μmol/L; Group B: 130 to 159 μmol/L; and Group C: creatinine level of 160 μmol/L or greater. Results: Multivariate logistic regression showed serum creatinine level to 130 μmol/L or greater increased the likelihood of hemodialysis post-operatively (P <0.001), as well as the need for post-operative ICU stay (P <0.001). In hospital mortality was also significantly elevated in Group B and Group C; P =0.045 and <0.001 respectively. Other factors contributing to a prolonged ICU and mortality stay were being 60 years of age or older, left ventricular Ejection Fraction <40% (P =0.001), and prolonged cardiopulmonary bypass time (P <0.001). Of particular note was the finding that the method of myocardial protection (cardioplegia with or without topical cooling) did not significantly influence in-hospital mortality, need for mechanical renal support, or ICU stay. Conclusion: Mild-to-moderate renal dysfunction is an important predictor of outcome in terms of in-hospital mortality, morbidity, and midterm survival in patients undergoing on pump CABG. As the preoperative serum creatinine level increases further (≥160 μmol/L), this effect is more pronounced.