Chapter 70 Liver and Heart Transplantation
Liver transplantation
1 How many liver transplantations are performed in the United States annually?
Approximately 6000 to 6500 liver transplantations are performed annually in the United States. This includes a small number (3%-5%) from living liver donors. An estimated 17,000 to 18,000 patients are on the waiting list for liver transplantation. Approximately 1600 to 1800 patients die annually while awaiting liver transplantation. One-year, 3-year, and 5-year patient survival after primary transplantation is approximately 88%, 80%, and 74%, respectively.
2 What are the reasons for liver transplantation?
The list of diseases treatable by liver transplantation has expanded steadily over the last decade. Most commonly, the disease process leading to liver transplantation is chronic. Less frequent is acute-on-chronic disease and acute liver failure. Chronic viral hepatitis B or C and alcoholic liver remain the most common reasons for transplantation. Increasingly, nonalcoholic fatty liver disease is an indication for liver transplantation.
Overall, the etiology of chronic liver disease can be classified as follows:
Noncholestatic cirrhosis: Alcohol; hepatitis A, B, C, D; cryptogenic; autoimmune.
Cholestatic cirrhosis: Primary biliary cirrhosis, secondary biliary cirrhosis, primary sclerosing cholangitis.
Metabolic disease: Wilson disease, hemochromatosis, primary oxalosis, glycogen storage disease, α1-antitrypsin deficiency, tyrosinemia, homozygous hyperlipidemia.
Malignant neoplasm: The single most common neoplasm presenting for liver transplantation is hepatocellular carcinoma. Eligibility for transplantation is most commonly based on tumor burden as defined by the Milan or University of California, San Francisco (UCSF) criteria. Cholangiocarcinoma, hepatoblastoma, and hemangiosarcoma are all very rare indications for transplantation.
Miscellaneous: Biliary atresia (in children most common indication), cystic fibrosis, polycystic liver disease, Budd-Chiari syndrome, neonatal hepatitis.
Acute hepatic necrosis: Etiology unknown, drug induced, acute hepatitis, environmental exposure (i.e., Amanita phalloides mushrooms).
The severity of liver disease is calculated on a numeric scale that ranges from 6 (less ill) to 40 (gravely ill). The scoring system, model for end-stage liver disease (MELD), was introduced almost a decade ago and is also used for allocation of organs. The MELD risk score is a mathematical formula that includes creatinine, bilirubin, and international normalized ratio. It does not include the cause of liver disease. Exception points can be earned with hepatocellular carcinoma and comorbidities such as hepatopulmonary syndrome.
Priority exception to MELD is category status 1, which defines acute severe onset of liver failure (fulminant hepatic failure).
3 Why is a patient rejected for liver transplantation?
Reasons to deny transplantation may be due to medical conditions and psychosocial reasons and may vary from center to center. Liver transplantation is considered a medium- to high-risk procedure. Significant coronary artery disease, compromised cardiac function (reduced ejection fraction), and uncontrolled pulmonary hypertension are considered contraindications for liver transplantation. Nevertheless, patients may be eligible once cardiopulmonary disease is adequately treated (i.e., percutaneous transluminal coronary angioplasty). Significant vasopressor support and intubation (other than airway protection) immediately before transplantation may exclude eligibility for transplantation. Uncontrolled infection or sepsis is also considered a contraindication. A positive HIV test, without evidence of AIDS, is not a contraindication, and reasonable survival has been reported. Advanced hepatocellular carcinoma (outside Milan or UCSF criteria) or metastatic disease is generally considered to be a contraindication because of high risk of recurrence and poor 5-year survival. In fulminant hepatic failure, uncontrolled and markedly elevated intracerebral pressure (ICP) is the most common reason for exclusion.
Psychosocial factors such as active drug or alcohol abuse or the lack of a good social support system may lead to the exclusion of the patient from transplantation. Thorough preoperative evaluation and periodic review of the patient’s medical and psychosocial condition are crucial for successful transplantation and long-term survival.
Older age per se is not a reason to deny liver transplantation. Increasingly, patients older than 65 years of age receive liver transplants.
4 What is the patient pathophysiology before liver transplantation?
Every organ system can be affected by end-stage liver disease. Frequently, patients with end-stage liver disease have considerable comorbidities:
Central nervous system: Hepatic encephalopathy (grade I-IV in chronic and acute-on-chronic disease) and elevated ICP in acute hepatic failure.
Cardiac system: Hyperdynamic circulation with high cardiac output and low systemic vascular resistance. This may be blunted in patients receiving nonselective β-blockade for secondary prevention of upper gastrointestinal bleeding; cirrhotic cardiomyopathy.
Hepatic hydrothorax, atelectasis, hepatopulmonary syndrome (orthodeoxia, PaO2 < 70 mm Hg on room air, or A − aO2 gradient > 20 mm Hg, intrapulmonary vascular dilatation).
Portopulmonary hypertension (presence of portal hypertension, precapillary or arteriolar pulmonary hypertension, mean pulmonary artery pressure > 25 mm Hg, pulmonary vascular resistance [PVR] > 240 dyne/second/cm−5). Pulmonary capillary wedge pressure < 15 mm Hg (all at rest and primary pulmonary hypertension ruled out). Estimation of systolic pulmonary pressure on transthoracic echocardiography can be used as a valuable screening tool. Increasingly, the transpulmonary pressure gradient is also used for evaluation.
Gastrointestinal system: Portal hypertension with possible upper gastrointestinal bleeding, (refractory) ascites.
Hematologic system: Anemia, thrombocytopenia (mainly sequestration into the spleen), prolonged prothrombin time–partial thromboplastin time, and decreased fibrinogen. Hypercoagulability (especially in patients with malignant disease).
Renal system: Hepatorenal syndrome type I or II, acute kidney injury.
Miscellaneous: Significant electrolyte disturbances (sodium, potassium, glucose), immunosuppression with increased risk for infection, malnutrition.
5 What are common complications of patients undergoing liver transplantation?
Perioperative complications depend largely on the medical condition and surgical history of the recipient (see question 4). Poor organ quality can also lead to a complicated perioperative course. The organ quality depends on multiple factors including donor age, organ ischemia time, and mechanism of death. Frequently the donor risk index is used to assess donor organ quality. Slow graft function may result in significantly increased resource utilization. Primary nonfunction of the implanted organ, often still manifesting during surgery, requires immediate relisting and retransplantation of the patient.
Overall, hemodynamic instability requiring multiple vasopressors, significant blood loss, severe coagulopathy, electrolyte or glucose abnormalities, renal dysfunction, and respiratory compromise are not uncommon during liver transplantation.
6 What are indicators of good graft function in the immediate perioperative period?
Bile production (during surgery), correction of negative base excess, normalization of prothrombin time, reduction of diffuse bleeding, decreasing fresh frozen plasma (FFP) requirements, and hemodynamic stability after implantation of the liver.
7 Does every patient receiving a liver transplant need to continue to have an endotracheal tube in place and be admitted to the intensive care unit (ICU) after surgery?
Postoperative intubation is not required per se, as long as commonly accepted extubation criteria are followed and good organ function is established. Blood loss alone should not be considered as an indication for postoperative intubation. Patients can have the endotracheal tube removed either in the operating room or shortly after arrival in the ICU.
Most centers still will admit patients to the ICU for monitoring purposes. However, some centers established fast-track protocols admitting patients with uncomplicated cases to the postanesthesia care unit and subsequently discharge them to the ward (step-down unit).
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