Liver Disease
GENERAL PRINCIPLES
Patients with liver disease face increased operative morbidity and mortality in comparison to those with normal hepatic function. Not only does the stress of surgery place them at risk for acute hepatic decompensation, the myriad systemic effects of liver disease result in an increased frequency of complications to multiple other organs as well.
Classification
• Both the older Child-Turcotte-Pugh (CTP) and more recent Model for End-stage Liver Disease (MELD) classification schemes (see Chapter 19, Liver Diseases) are well-validated statistical models for predicting surgical risk in patients with cirrhosis.
î Two different studies separated by 13 years revealed strikingly similar results: a mortality rate of 10% for patients with CTP class A, 30% for class B, and 76%-82% for class C cirrhosis.81,82 Accordingly, it has been suggested that patients with CTP class A cirrhosis can safely undergo elective surgery in general, and those with class C cirrhosis should not under any circumstances.83 However, the distinction is less clear for class B cirrhosis, and the inherent subjectivity of the CTP system limits its discriminatory ability.84
î MELD offers several advantages for calculation of 30-day mortality:
■ Variables are both objective and weighted.
■ It includes serum creatinine, which has been shown to correlate with postoperative mortality.85
■ Predictive performance is equal to if not better than that of CTP.86-88
î Because CTP includes ascites, which is also correlated with poor prognosis in general surgical patients, the two scoring systems could be considered complementary rather than mutually exclusive.89,90
• American Society of Anesthesiologists (ASA) class appears to be the strongest predictor of 7-day mortality in cirrhotic patients undergoing surgery.91 All 10 patients with ASA class V disease died, indicating that ASA class V should be a contraindication to surgery other than liver transplantation.92
DIAGNOSIS
Clinical Presentation
Significant hepatic disease that greatly impacts surgical risk (e.g., acute liver failure, advanced cirrhosis) is usually clinically obvious (scleral icterus, abdominal distention from ascites, florid encephalopathy).
For milder disease, however, more subtle findings such as spider angiomas, palmar erythema, and testicular atrophy may be the only clues. Historical details such as family history of hepatic disease, current or prior alcohol and/or IV drug abuse, and transfusion history may increase clinical suspicion. See Chapter 19, Liver Diseases, for further details.Diagnostic Testing
• Because of the exceedingly low yield of laboratory testing (0.14% in one prospective study enrolling 7620 patients), routine preoperative assessment of hepatic function is not recommended unless clinical findings dictate.83,93
• Those with suspected or known hepatic disease should undergo thorough laboratory evaluation including hepatic enzyme levels, albumin and bilirubin measurement, and coagulation studies along with renal function and electrolytes. If significant laboratory abnormalities (e.g., unexplained transaminase elevation > three times upper limit of normal) are found in patients without known liver disease, surgical intervention may need to be postponed to allow further workup, as the incidence of undiagnosed cirrhosis in this population may be 6% or even higher.83,94
TREATMENT
• Historically, patients with acute viral or alcoholic hepatitis have been observed to tolerate surgery poorly and delaying surgery until clinical and biochemical recovery is recommended.83,95,96
• Patients with mild chronic hepatitis without associated cirrhosis generally tolerate surgery well.97
• For patients with cirrhosis, several steps should be taken to optimize preoperative status:
î Coagulopathy should be treated to minimize risk of hemorrhage. Vitamin K supplementation may be helpful if the INR is elevated. However, in the context of marked hepatic synthetic dysfunction, administration of fresh frozen plasma and/or cryoprecipitate may be necessary. Severe thrombocytopenia should be corrected via transfusion. (See Chapter 20, Disorders of Hemostasis and Thrombosis, under Liver Disease.)
î As cirrhosis is associated with renal dysfunction, intravascular hypovolemia, and extravascular fluid retention, careful attention to volume status is crucial.
Nephrotoxic agents should be used with extreme caution if at all, and free water restriction may be required in patients with serum sodium below 130 mEq/L. However, judicious use of diuretics and/or timely paracentesis may be required to control ascites, particularly if abdominal surgery is being considered.98 Administration of large amounts of crystalloid should be avoided. Despite theoretical benefits, strong evidence for preoperative transj ugular intrahepatic portosystemic shunt to reduce portal hypertension prior to major abdominal surgery remains lacking but may be considered in select circumstances.90î Close attention to nutritional status is warranted in light of the very high incidence of malnutrition in this population.99
î Lastly, encephalopathy frequently complicates surgical intervention.100 Lactulose should be titrated to three to four bowel movements per day, and concurrent rifaximin therapy should be strongly considered.101 Opioid use should be minimized to avoid constipation and ileus, and dose reduction should be considered in light of expected reduced hepatic clearance.