Child-Pugh and MELD classifications and the mortality following cardiac surgery.

Reviewers: Elmo N. Orlino, MD, Hong Liu, MD
University of California Davis Health System
Sacramento, CA

Patients with moderate to severe cirrhosis undergoing cardiac surgery have a high mortality. It is well known that liver dysfunction increases the risk of perioperative complications after anesthesia. ^1-3 Cirrhotic patients have physiological changes including coagulopathy, malnutrition, relative vasodilation, fluid and electrolyte abnormalities making anesthesia more difficult but especially with the use of cardiopulmonary bypass.

The Child classification system identifies the severity of liver dysfunction from mild, moderate, to severe and has been utilized as a predictor of survival. The class is determined by five graded factors scored from 1 to 3 based on the presence of hepatice ncephalopathy, total serum bilirubin level, presence of ascites, albumin level, and nutritional status with class Abeing a score of 5-6, B 7-9, and C 10-15. These criteria have subsequently been modified by Pugh to create Child-Pugh (CP) class replacing the most subjective factor, nutritional status, with prothrombin time. Another classification system, MELD (Model End Stage Liver Disease) score, has recently been developed to grade the severity of cirrhosis. The MELD score has a range from 6 to 40 and is based solely upon three objective factors, total serum bilirubin, international normalized ratio, and serum creatinine level. It has supplanted Child's criteria for determining the severity of hepatic cirrhosis and the urgency of liver transplantation. Several authors have utilized the MELD score to evaluate surgical risk in cirrhotic patients. ^4,5

To date, the population of cardiac surgical patients with cirrhosis has been sufficiently small which limit the ability to conduct large clinical trials. Several small studies have confirmed that Child-Pugh class B and C patients have a high mortality especially with the use of cardiopulmo-nary bypass. In those studies of cardiac surgical patients (total n = 96), liver dysfunction was classified according to Child/CP criteria and in one study by CP class and MELD score. Reported mortality for mild cirrhosis Child class A range from 0-3% and significantly higher mortality 41-80% for patients with moderate cirrhosis in Child class B. Although very few patients with severe cirrhosis in Child class C received operations, their mortality was 100%.

Klemperer et al 1998 identified 13 patients (8 Child class A, 5 Child class B) in a retrospective study with a preoperative history of cirrhosis. All patients underwent cardiopulmonary bypass for a variety of cardiac procedures. Significant postoperative complications occurred in 25% of Child class A patients and in 100% of Child class B patients. All patients with Child class A cirrhosis survived to discharge from the hospital. There were four deaths in class B patients. The causes of death were due mainly to major infection or hemorrhagic complications and not cardiac performance per se. ⁶ In a series of 10 patients, Kaplan et al reported similar findings with Child class B having a 50% mortality (3 of 6 patients) and no deaths with four class A patients. The causes of death were again not directly related to cardiac failure but rather hepatorenal syndrome, hemorrhage, or sepsis. ⁷ Bizouarn et al reported on early and late outcomes 12 cirrhotic patients (10 class A, 2 class B). In the immediate postoperative period, 50% of class A and 100% of class B patients developed significant complications. There was one death with class B patients and two deaths with class A, however, the two class A patients died during the follow-up period after discharge from the hospital. ⁸

More recently, Hayashida reported on 18 patients (10 class A, 7 class B, and one in class C) undergoing cardiac operations. Fifteen of 18 patients had surgery with CPB while three patients had off pump coronary artery bypass grafting. All patients in Class B and C had major complications including bleeding, infection, renal failure, or respiratory failure. Sixty percent of class A patients had such outcomes. There were no deaths in class A and 50% mortality in class B patients that utilized CPB. All three patients in class B that underwent bypass grafting without the use of cardiopulmonary bypass survived.⁹ Off-pump CABG in moderate to severe cirrhosis may be advantageous as it avoids many of the complications associated with CPB such as poor coagulation profile, decreased vascular tone, massive fluid shifts, and whole body inflammatory response.¹⁰ Suman have published by far the largest study to date with 44 total patients (31 class A, 12 class B, and 1 class C).⁴ They report that Child score and MELD score are significantly associated with hepatic decompensation and mortality. Furthermore, they determined a cutoff Child score of >7 had a sensitivity and specificity of 86% and 92% for mortality, with a negative predictive value of 97% and a positive predictive value of 67%, respectively. Hepatic decompensation is defined by Suman as the appearance of new ascites, portosystemic encephalopathy, jaundice, coagulopathy, variceal bleed, or hepatorenal syndrome within three months following cardiac surgery. Only about 10% (3 of 31) of Child class A patients developed hepatic de-compensation, while 66% (8 of 12) of Child class B and 100% (1 of 1) of Child class C had complications. Mortality in the series was 3% (1 of 31), 41% (5 of 12), and 100% (1 of 1) for Child class A, B, and C, respectively. In their final analysis, Suman suggested that Child score >7 is sufficient to predict a negative outcome after cardiac surgery. Although a similar cut-off value for MELD score is not firmly established, the data show comparable and significant association of Child score and MELD score with hepatic complications and mortality.

There is a paucity of data regarding the effects of cardiac surgery either with or without cardiopulmonary bypass on patients with hepatic cirrhosis. To date, there have been about five studies encompassing 96 patients with cirrhosis of various degrees and etiologies. Overall, these series report mortality for Child class A range from 0-3% and significantly higher mortality 41-80% for patients with moderate cirrhosis in Child class B. Although there is limited data (5 total patients), it is suggested that patients with moderate liver disease have better outcomes undergoing off pump surgery as opposed to CPB. Indeed, the use of CPB with moderate to severe cirrhosis is associated with increased postoperative bleeding, infections, renal failure, respiratory failure, and hepatic decompensation. Clearly, Child class B and C patients are at significant risk for death when undergoing cardiac surgery. Patients with moderate cirrhosis should weigh the benefits and risks of CPB. Patients with severe cirrhosis should not be offered cardiac surgery utilizing CPB. The efficacy of off-pump cardiac procedures for this group is still unresolved. However, the data also strongly supports the relative safety of cardiac surgery in patients with mild liver dysfunction. Child class A patients undergoing cardiac procedures have a reported mortality of 0-3% that is similar to the general population of cardiac surgical patients.

References:

1. Bloch RS, Allaben RD, Walt AJ. Cholecystectomy in patients with cirrhosis. A surgical challenge. Arch Surg. 1985 Jun;120(6):669-72.
2. Aranha GV, Greenlee HB. Intra-abdominal surgery in patients with advanced cirrhosis. Arch Surg. 1986 Mar;121(3):275-7.
3. Ziser A, Plevak DJ, Wiesner RH, Rakela J, Offord KP, Brown DL. Morbid-ity and mortality in cirrhotic patients undergoing anesthesia and surgery. Anesthesiology. 1999 Jan;90(1):42-53.
4. Suman A, Barnes DS, Zein NN, Levinthal GN, Connor JT, Carey WD. Predicting outcome after cardiac surgery in patients with cirrhosis: a comparison of Child-Pugh and MELD scores. Clin Gastroenterol Hepatol.
5. Farnsworth N, Fagan SP, Berger DH, Awad SS. Child-Turcotte-Pugh versus MELD score as a predictor of outcome after elective and emergent surgery in cirrhotic patients. Am J Surg. 2004 Nov;188(5):580-3.
6. Klemperer JD, Ko W, Krieger KH, Connolly M, Rosengart TK, Altorki NK, Lang S, Isom OW. Cardiac operations in patients with cirrhosis. Ann Thorac Surg. 1998 Jan;65(1):85-7.
7. Kaplan M, Cimen S, Kut MS, Demirtas MM. Cardiac operations for patients with chronic liver disease. Heart Surg Forum. 2002;5(1):60-5.
8. Bizouarn P, Ausseur A, Desseigne P, Le Teurnier Y, Nougarede B, Train M, Michaud JL. Early and late outcome after elective cardiac surgery in patients with cirrhosis. Ann Thorac Surg. 1999 May;67(5):1334-8.
9. Hayashida N, Shoujima T, Teshima H, Yokokura Y, Takagi K, Tomoeda H, Aoyagi S. Clinical outcome after cardiac operations in patients with cirrhosis. Ann Thorac Surg. 2004 Feb;77(2):500-5.
10. Downing SW, Edmunds LH Jr. Release of vasoactive substances during car-diopulmonary bypass. Ann Thorac Surg. 1992 Dec;54(6):1236-43.

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Table of Contents:

• President's Message
• Call for Nominations


• Literature Reviews
  • Role of hemodilutional anemia and transfusion during cardiopulmonary bypass in renal injury after coronary revascularization: Implications on operative outcome.
  • Increased prothrombotic state lasting as long as one month after on-pump and off-pump coronary surgery.
  • Characterization of beta3-adrenoceptors in human internal mammary artery and putative involvement in coronary artery bypass management.
  • Aprotinin reduces bleeding and blood product use in patients treated with clopidogrel before coronary artery bypass grafting.
  • Secondary tricuspid regurgitation or dilatation: Which should be the criteria for surgical repair?
  • Stem cells in the dog heart are self-renewing, clonogenic, and multipotent and regenerate infarcted myocardium, improving cardiac function.
  • Overexpression of mitochondrial transcription factor A ameliorates mito­chondrial deficiencies and cardiac failure after myocardial infarction.
  • An essential role for mitochondrial aldehyde dehydrogenase in nitroglyc­erin bioactivation.


• Drug and Innovation Updates
  • Child-Pugh and MELD classifications and the mortality following cardiac surgery.
  • Anesthetic preconditioning and perioperative myocardial protection


• PRO/CON: Conscious Neuraxial Anesthesia is a Viable Alternative to General Anesthesia in Cardiac Surgery.
• Pro - Paul Kessler, MD
• Con - Peggy T. Y. Li, MBChB & Anthony M. H. Ho, MD, FRCPC, FCCP

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