Assessment of the Combined Effect of Plasma Exchange and Plasma Perfusion on Patients with Severe Hepatitis Awaiting Orthotopic Liver Transplantation

Coagulopathy in liver disease

The liver plays a central role in hemostasis, as it is the site of synthesis of clotting factors, coagulation inhibitors, and fibrinolytic proteins. The most common coagulation disturbances occurring in liver disease include thrombocytopenia and impaired humoral coagulation. Therapy's overall goal is not to achieve complete correction of laboratory value abnormalities but to gain hemostasis. Therapy with vitamin K may be a useful option in patients with increased prothrombin time due to vitamin K deficiency; in patients with malnutrition; in patients using antibiotics; and in patients with cholestatic liver disease, particularly prior to invasive procedures. Infusion of fresh frozen plasma is more often effective and is recommended in patients with liver disease before invasive procedures or surgery, as such patients require transient correction in their prothrombin time. Therapy with plasma exchange may be considered in patients who cannot be treated with fresh frozen plasma due to volume overload risk. In patients with severe coagulopathy and hypofibrinogenemia, cryoprecipitate therapy is ideal. Therapy with prothrombin-complex concentrate is seldom pursued in patients with liver disease due to high risk of thrombotic complications. Transfusions of platelets are appropriate for patients with thrombocytopenia (< 50,000/mm(3)) associated with active bleeding or before invasive procedures in which a short-term platelet count increase is noted. Trial with desmopressin may be considered before invasive procedures in patients with liver disease and with refractory and prolonged bleeding time. Recombinant activated factor VIIa administration is suggested for patients with significantly prolonged prothrombin time and contraindications to fresh frozen plasma therapy; however, this is expensive. Thrombopoietin and interleukin-11 are currently investigational for patients with thrombocytopenia of chronic liver disease. Liver transplantation completely restores impaired coagulation abnormalities and is the ultimate intervention that corrects coagulopathy of advanced liver disease and liver failure.

Artificial liver support system in China: a review over the last 30 years

Severe viral hepatitis with high mortality is the most common cause of liver failure in China. Treatment of severe viral hepatitis by hemoperfusion was initially adopted in the late 1970s and early 1980s. Following 10 years of development in China, a plasma exchange (PE)-centered artificial liver support system (ALSS), principally dependent on PE technology was developed. Based on the condition and symptoms of each patient, PE was given alone, or combined with hemodialysis, hemofiltration, hemodiafiltration, hemoperfusion, or plasma perfusion. In the late 1990s, training courses for ALSS were developed, and ALSS began to be carried out across China. Guidelines for artificial liver therapy were formulated and published by the Artificial Liver and Liver Failure Group of the Chinese Society of Infection. In recent years, new methods have been attempted, including small pore-size plasma separators, a molecular adsorbent-based recirculating system (MARS), and a continuous albumin purification system (CAPS). According to a retrospective analysis published in 2004, ALSS therapy significantly (P < 0.001) improved the survival rate of patients with severe hepatitis compared with patients who received only medicines (43.4%, 157/362 vs. 15.4%, 55/358 in chronic patients and 78.9%, 30/38 vs. 11.9%, 5/42 in acute and subacute patients). Furthermore, ALSS has also proved valuable as a bridge to liver transplantation in the treatment of patients with end-stage severe hepatitis in China. More recently, ALSS has been used in the treatment of drug-induced liver failure, acute fatty liver during pregnancy, and other difficult-to-treat disorders in China.

Hemostatic defects in end stage liver disease

End stage liver disease results in a complex and variably severe failure of hemostasis that predisposes to abnormal bleeding. The diverse spectrum of hemostatic defects includes impaired synthesis of clotting factors, excessive fibrinolysis, disseminated intravascular coagulation, thrombocytopenia, and platelet dysfunction. Hemostasis screening tests are used to assess disease severity and monitor the response to therapy. Correction of hemostatic defects is required in patients who are actively bleeding or require invasive procedures. Fresh frozen plasma, cryoprecipitate, and platelet transfusion remain the mainstays of therapy until larger trials confirm the safety and efficacy of recombinant factor VIIa in this population.