The Investigation of the Causes of Hepatic Dysfunction in the Postoperative Period During Open-heart Surgeries

In a prospective observational study during the six-month duration, coronary artery bypass graft surgery (CABG) and valve repair surgery (mitral, mitral, and aortic valve and/or tricuspid valve) patients were investigated for hepatic dysfunction. All patients were divided into two groups as with or without hyperbilirubinemia, and this was defined by the occurrence of a plasma total bilirubin concentration of more than 34 µmol/L (2 mg/dL) in any measurement during the postoperative period. Our goal was to determine the risk factors associated with hepatic dysfunction in patients undergoing open-heart surgery with cardiopulmonary bypass. The collected parameters include; alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), total bilirubin (TBIL), and gamma-glutamyl transpeptidase (GGT) and albumin preoperatively and on postoperative days 1, 3 and 7. Possible preoperative, intraoperative, and postoperative risk factors were investigated. Logistic regression analysis was done to identify the risk factors for postoperative hyperbilirubinemia.

There are a series of pathophysiological changes in patients undergoing open-heart surgeries with cardiopulmonary bypass (CPB) that causes liver hypoperfusion, centrilobular sinusoid ischemia, and subsequent reperfusion injuries, hemolysis, or systemic inflammatory response. These events may eventually lead to various forms of hepatic dysfunction in patients during the postoperative period after open-heart surgeries. An increased incidence of liver function test abnormalities were reported, and the rates vary between 10 % and 40%. The occurrence of postoperative hyperbilirubinemia is crucial in increased morbidity and mortality after open-heart surgery with CPB. There are several reports of the possible risk factors that are associated with hepatic dysfunction. In previous studies, the incidence of postoperative hyperbilirubinemia was between the range of 20% up to 51% in open-heart surgeries with CPB. The causes of this higher incidence were related to the presence of various possible risk factors, and these include; valvular heart disease and related low cardiac output states, and low ejection fraction. Other important risk factors for postoperative hepatic dysfunction after open-heart surgery with CPB were longer operative time and a larger volume of blood transfusion. However, CPB itself is not a significant constituent in the postoperative development of hyperbilirubinemia. Splanchnic ischemia before or during operation and in the postoperative period appears to be an essential cause. Other risk factors that were identified as possible risk factors for postoperative hepatic dysfunction. We can list these factors as; poor preoperative heart function, hemodynamic instability, emergency surgery, and preoperative liver dysfunction. Our goal was to determine the possible risk factors associated with hepatic dysfunction in patients undergoing open-heart surgery with CPB.

Eligibility Criteria:
Inclusion Criteria:

* Patients undergoing open-heart surgery with CPB,
* Patients between the ages of 19 to 80,
* American Society of Anesthesiologist (ASA) status of 2 and 3,
* Preoperative ejection fraction (EF) greater than 30%.
* There were five different open-heart surgery group of patients in this study. The groups include; coronary artery bypass grafting (CABG), mitral valvular replacement, aortic valvular replacement, combined mitral and aortic valve replacement, combined mitral, aortic and/or tricuspid valve replacements.

Exclusion Criteria:

* Both CABG and valve replacement,
* Resection of a ventricular or aortic aneurysm,
* Transplantation or another surgical procedure,
* Reoperation of valvular repair surgery, patients with preoperative ejection fraction less than 30%,
* Preoperative hyperbilirubinemia defined as total bilirubin concentration of more than 3 mg/dL,
* Preoperative congestive heart failure, preoperative renal dysfunction (serum creatinine greater than 1.3 mg/dL),
* Chronic oliguria/anuria requiring dialysis,
* Preoperative American Society of Anesthesiologist (ASA) status of 4,
* History of pancreatitis or current corticosteroid treatment.