Acute kindey injury (AKI) is a common and serious complication following either cardiac catherization or coronary artery bypass grafting (CABG). Patients frequently undergo cardiac catheterization to define coronary artery disease prior to CABG. The purpose of this study is to examine the risk factors and impact of AKI on periperative outcome and intermediate-term survival in patients who haves both procedures during their hospitalization.
Study subjects were derived from a database combining elements of the Society of Thoracic Surgeon's National Adult Cardiac Surgery Database, American College of Cardiology National Cardiovascular Registry, and internal outcomes data. All consecutive patients who underwent cardiac catheterization and first-time, isolated CABG during the same index hospitalization from July 1, 2006 to April 30, 2008 were included in this study. AKI was defined using the classification system of the Acute Kidney Injury Network (AKIN).
591 patients were included in this study. 290 patients (49.1%) developed postoperative AKI: 233 patients (39.4%) had AKIN Stage 1, 50 (8.5%) had Stage 2, and 7 patients (1.2%) had Stage 3. Compared to patients without AKI, one-year survival worsened with increased severity of AKIN stage (99.3% vs. 99.1% vs. 93.9% vs. 85.7% respectively, p<0.001). There were 7 operative deaths in patients with AKI and no deaths in patients without AKI (p<0.007). 6 preoperative variables were found to be independently associated with AKI in a multivariate logistic model: age>65 years, BMI >30 kg/m2, preoperative platelets < 150,000/microliter, Hg 10–11.9 g/dL, and peripheral vascular disease. Contrast volume, N-aceytlycysteine, or interval between cardiac catherization and CABG were not significant predictors of AKI.
AKI following catheterization and CABG occurs frequently and is predictive of signficantly worse operative death and one-year survival. Large contrast volumes or short interval between cardiac catherization and CABG did not increase the risk of AKI however.
We have identified several preoperative factors which predict AKI. Therapies aimed at modifying these factors may reduce the incidence of AKI and therefore improve clinical outcomes.
Henry Tran, No Financial Disclosure Information; No Product/Research Disclosure Information