Evaluation of liver function tests after coronary artery bypass surgery (CABG)

BACKGROUND: Coronary artery bypass graft surgery (CABG) may have systemic effects on the body organs as liver. The purpose of present study was to evaluate changes in liver function tests(LFT) after on-pump CABG surgery and risk factors associated with LFT changes.Also, the incidence of acute liver injury after on-pump CABG is determined. METHODS: 385 patients who underwent on-pump CABG surgery were randomly selected.Preoperative and intraoperative risk factors were obtained from their medical records .Postoperative liver function tests at 24, 48 and 72 hours following surgery and discharge time were compared with the preoperative ones. A univariate linear regression analysis was used to assess the possible relationships between these changes and the preoperative and intraoperative risk factors. RESULTS: Statisitcal analysis revealed direct and significant relationship between LFT changes and pump time, aortic cross-clamp clamp time and use of intra-aortic balloon pump(IABP). Also a medical history of previous myocardia infarction was significantly related to the changes in direct bilirubin in the first 48 hours following surgery.level of preoperative left ventricle ejection fraction,smoking and using opium had significant correlation with postoperative AST changes in different days.In 12.9% of patients, the aminotransferases levels increased to more than three folds over normal upper limit but the probability for incidence of acute ischemic liver injury (transient increase in aminotransferases to over 500IU/L) was 0.77%. CONCLUSION: Using techniques to reduce clamp and pump time when possible is important during CABG. Probable liver injuries post inserting IABP should be expected for appropriate monitoring and treatment.