Page 382 - Libro 2

362 PART 5 — ABDOMINAL LIVERTRANSPLANTATION
The first successful liver transplant was performed by Dr. Thomas Starzl in 1967. Since then, the liver has become the second most common organ to be trans- planted after the kidney. It is estimated that about 6,000 liver transplants are performed every year in the United States, and that there are approximately 17,000 patients on the liver transplant waiting list. Approximately 104,000 liver transplants have been performed since 1988.1
For patients with either acute or chronic end-stage liver failure who are unresponsive to medical therapy, liver transplantation is the only available option. For such patients, organ availability is the rate-limiting factor. US is the initial imaging modality of choice for the evaluation of complictions following liver trans- plantation. US is portable, readily available, with- out risk or contraindications, and is a very sensitive test for the detection of vascular complications and postop fluid collections and biliary complications. However, US is also extremely user dependent and requires an in-depth knowledge of the principles of vascular technology, abdominal anatomy, and gen- eral liver transplant physiology. Liver transplant ultrasound is performed bedside in the immediate perioperative/postoperative phase for routine sur- veillance or when there are clinical indications of suspected graft failure or vascular complications.
There are several conditions that can lead to liver failure and, subsequently, liver transplantation. Table 23-2 lists the most common indications for liver transplantation.
Patients with life-threatening liver disease are only placed on the transplant waiting list if they meet the established Model for End-Stage Liver Disease (MELD) criteria or have a high Child-Pugh score. The Child-Pugh score is used routinely by
TABLE 23-2
Most Common Indications for Liver Transplantation
Hepatitis C
Alcoholic liver disease
Cryptogenic cirrhosis
Primary biliary cirrhosis
Primary biliary sclerosing cholangitis Budd-Chiari syndrome Hemachromatosis
Wilson’s disease
Autoimmune hepatitis
Acute or fulminant liver failure Hepatocellular carcinoma (early stage)
TABLE 23-3
Contraindications or Exclusion Criteria for Liver Transplantation
Extrahepatic malignancy
Untreated infection
Anatomic abnormaltiy
Hepatocelluar carcinoma that has metastasized or is
larger than 5 cm
Advanced cardiopulmonary disease Active substance abuse
End-stage hepatitis B
Advanced age Cholangiocarcinoma
gastroenterologists to assess liver disease. These cri- teria are used to rank patients on the waiting list for liver transplants based on the severity of illness and the eligibility of a patient. These criteria evaluate critical markers such as serum bilirubin, which in- dicates how well the liver excretes bile; international normalized ratio (INR) clotting time, which assesses adequacy of liver function; creatinine, which assesses kidney function; and mental function. There are a few pathologies for which the MELD criteria does not apply, such as hepatocellular carcinoma, hepato- pulmonary syndrome, familial amyloidosis, and pri- mary oxaluria. In the event that a patient’s medical urgency does not fall under the MELD score, one can apply for a MELD exception.1
There are criteria used to exclude patients from liver transplantation. Table 23-3 lists several of the contraindications for liver transplantation.
THE OPERATION
Most commonly, the liver transplant recipient receives a whole liver from a DD. This is referred to as an orthotopic liver transplant (OLT), which means that an organ is transplanted into its normal anatomic position in the recipient. Due to organ shortage, partial liver transplants from an LRD are now increasingly performed. Usually, the right lobe is transplanted. Occasionally, a liver from a DD is divided between two recipients—one receiving the right lobe and the other the left lobe. Children, in particular, often undergo partial or split liver trans- plantation.
The precise vascular and biliary anastomoses created depend on the type of transplant as well as the donor and recipient anatomy (Fig. 23-27). Congenital anomalies of the hepatic vasculature and biliary tree are relatively common. Hence, there is wide variation in postsurgical anatomy. Most vessels