Model for end-stage liver disease (MELD) exception for bacterial cholangitis

Abstract

Patients with structural biliary disease due to sclerosing cholangitis, Caroli’s syndrome, ischemic biliary damage, and other causes carry a high risk of recurrent bacterial cholangitis and septicemia and have a high incidence of morbidity. Because many of these patients have fairly well-preserved hepatic synthetic function, current allocation policy that uses the Model for EndStage Liver Disease (MELD) score alone may not appropriately prioritize these selected groups of patients to avoid a poor outcome. Given the excellent results of liver transplantation (LT) in patients with chronic cholestatic liver disease and the lack of medical therapies available, exceptional status for some of these patients with severe structural damage of the biliary tree should be provided. Similarly, patients with ischemic biliary injury of the liver allograft under immunosuppression carry an even greater increased risk of morbidity and constitute groups that may benefit from exceptional status for timely LT. However, a precise natural history of these conditions has not yet been well defined. The most common disease entity leading to structural damage to the biliary tree is primary sclerosing cholangitis (PSC). This disease is progressive, ultimately leading to secondary biliary cirrhosis and progresses to hepatic dysfunction, portal hypertension, and occasionally the development of cholangiocarcinoma. Although the pathogenesis of PSC is unclear, it is commonly associated with inflammatory bowel disease, most commonly as chronic ulcerative colitis. After diagnosis of PSC, the reported median survival is 12 to 15 years. 1,2 Occasionally, a patient with PSC will develop repeat episodes of bacterial cholangitis, although this is unusual (10%). 3 Although death from bacterial cholangitis itself is rare, complications of septicemia have been reported including endocarditis, osteomyelitis, and hepatic abscess formation. These septic complications can greatly affect overall morbidity and mortality in patients with PSC. In other patients, congential cystic dilatation of the intrahepatic biliary ducts is often associated with congenital hepatic fibrosis. These patients are categorized under the diagnosis of Caroli’s syndrome, which in its end stages is manifested by complications of portal hypertension and repeated bouts of bacterial cholangitis, and can be associated with the development of cholangiocarcinoma. Occasionally, patients with secondary sclerosing cholangitis due to surgical mishap involving bile duct injury can also have repeated episodes of bacterial cholangitis. The natural history of these disorders has not been well established in the medical literature. Finally, there are patients who shortly after LT develop cholestasis, hyperbilirubinemia, an abnormal liver enzyme pattern, and evidence of severe ischemictype biliary tract injury with the development of biliary sludge, casts, and ectasia. These patients also experience repeated bouts of bacterial cholangitis and can in time develop allograft failure. These findings are commonly associated with hepatic artery thrombosis or biliary ischemia. The exact mechanism of ischemic biliary duct injury is not precisely known, although there are some risk factors that have been identified, including the use of extended criteria grafts and prolonged cold and warm ischemic time. In patients who develop structural biliary disease with recurrent bouts of bacterial cholangitis, the underlying severity of liver disease as manifested by hepatic synthetic function appears to affect both the incidence and severity of septic complications. Liver transplantation remains an excellent treatment for patients with structural biliary disease who have recurrent bouts of bacterial cholangitis. 4-9