[Liver transplantation: deciding between need and donor allocation]

[Allocation systems in transplantation medicine: Advantages and disadvantages]

Donor organs for transplantations are a scarce commodity; therefore, allocation systems are needed that guarantee an ethically acceptable distribution to patients on the waiting list (equal treatment and fairness) but also take the probability of survival of the transplant in each recipient into consideration. In this article the allocation systems for lung, liver, kidney and pancreas transplants are presented.For lung transplantations an allocation system based on the lung allocation score (LAS) is currently used. The LAS predicts the probability of survival on the waiting list and the survival rate following transplantation. Organs with a limited range of utilization are distributed in a so-called mini-match procedure.For post-mortem kidney and pancreas transplantations a relatively complex but transparent allocation system has been created in which patients are subdivided into groups, each of which has its own allocation rules. The allocation is principally carried out according to criteria of fairness of distribution and according to the prospects of success. The probability of a mismatch also plays a role. The urgency is important for children and for patients who do not have the possibility of dialysis. Combined pancreas and kidney transplantations have priority over kidney transplantations alone.The criterion for the urgency of liver transplantation in Germany is currently the model for end-stage liver disease (MELD), which aims to reduce the waiting list mortality and to prioritize transplantations for those most in need. Because the system insufficiently describes the priority of transplantation for patients with tumors or genetic liver diseases, there is an additional set of rules for so-called standard exceptions.

Autoimmune hepatitis

Autoimmune hepatitis (AIH) was the first chronic liver disease in which remission was achieved by immunosuppression. Prognosis is poor when left untreated. Since the original description in 1950 by Waldenström, the initially reported treatment option has remained until today and is the core of the basic therapeutic strategy of inducing remission with steroids and azathioprine. Immunosuppression as a treatment concept spans different situations including the induction and maintenance of remission, treatment of nonresponders, avoidance of side effects, perioperative treatment of liver transplantation candidates and the issue of withdrawal. Alternative immunosuppressive drugs such as transplantation immunosuppressants have been administered and reported in small series. In an attempt to optimize side effect management, a recent large multicenter prospective treatment trial suggests that budesonide may offer an alternative for noncirrhotic AIH patients with lower steroid side effects. With an early diagnosis and effective therapy, only 4% of transplant candidates are transplanted for AIH. After liver transplantation there is a considerable risk for graft loss because of recurrent AIH, and lifelong vigilance and therapeutic attention is important.

Therapy of autoimmune hepatitis

Autoimmune hepatitis was the first chronic liver disease with a favourable response to drug therapy and a dismal prognosis when left untreated. Since its original description in 1950 and first treatment studies the basic therapeutic strategy of inducing remission with steroids and azathioprine has not been modified in principle. A timely diagnosis before cirrhosis develops, the avoidance of immunosuppressant side effect, non-responders to standard induction therapy, and adherence to therapy are the greatest challenges. Alternative immunosuppressive drugs have been tested in small series and include transplant immunosuppressants. A recent large multicenter prospective treatment trial suggests that budesonide may offer an alternative in non-cirrhotic AIH patients capable of minimizing unwanted steroid effects. The ultimate treatment approach upon drug treatment failure is liver transplantation. Only four percent of transplant candidates are transplanted for AIH but the risk for graft loss because of recurrence has to be considered and recurrent AIH treated after transplantation.

Autoimmune hepatitis

Autoimmune hepatitis is a chronic inflammatory disease of the liver with a dismal prognosis when left untreated. Key for the improvement of prognosis is a timely diagnosis before cirrhosis has developed. This is reached by the exclusion of other causes of hepatitis, elevated immunoglobulin G, autoantibody profile and histological assessment. Treatment achieves remission rates in 80% of individuals and consists of immunosuppression with corticosteroids and azathioprine. A recent randomised controlled multicenter trial has added budesonide to the effective treatment options in non-cirrhotic patients and leads to a reduction of unwanted steroid side effects. Autoimmune hepatitis is an autoimmune disease of unknown aetiology. Association studies of major histocompatibility complex and other genes demonstrate an influence of immunogenetics. However, apart from the autoimmune polyglandular syndrome type 1, in which 10% of patients suffer from an autoantibody-positive autoimmune hepatitis linked to mutations of the autoimmune regulator gene, there is no clear evidence for a hereditary aetiology of this disease.

[Liver transplantation: indications and results]

After around 64,000 transplantations in Europe since 1988 liver transplantation has emerged as a standard treatment option for otherwise incurable chronic liver diseases. Cirrhosis of different etiologies represents the most frequent transplant indication. Overall survival in this group amounts to 72% after 5 years, and 62% after 10 years. In Germany, the main indications include alcoholic liver cirrhosis, tumors with increasing numbers in recent years, as well as viral diseases leading to cirrhosis. Since December 2006 the priority for liver transplantation is determined by the model for end stage liver disease (MELD) and not by the length of waiting time. MELD is a statistical model based on serum creatinine, serum bilirubin and coagulation, which describes the probability of 3-month mortality of a potential transplant candidate. Not all liver diseases are adequately represented by MELD necessitating the additional use of a defined number of standard exceptions that have been last updated in 2008. As a consequence of these developments indications, selection of recipients and the management of the waiting list have seen profound change.

Prediction of survival after liver transplantation by pre-transplant parameters

OBJECTIVE

Score-based medical urgency criteria are used for necessity-oriented liver transplantation (OLT) but lead to an increasing number of complications in patients with reduced post-OLT survival. A prediction of outcome would improve preoperative patient selection and management.

MATERIAL AND METHODS

One-hundred-and-thirty-three consecutive adult patients (63.9% men, mean age 47.4+/-11.2 years) given transplants between May 2004 and November 2005 at the Hannover Medical School were analysed retrospectively using univariate and multivariate methods.

RESULTS

Indications were: 27.1% viral hepatitis, 19.6% primary sclerosing cholangitis, 15.0% alcoholic liver disease, 7.5% metabolic liver disease, 6.8% primary biliary cirrhosis. Overall, 12-month patient survival was 81.2%. The mean MELD score at OLT was 14.5+/-5.3 and 12-month survival with MELD >16 (71.7%) and <16 (86.2%) differed significantly (p=0.041). Predictors of 12-month mortality included age (53.2+/-9.4 versus 46.1+/-11.2 years; p=0.004), lower cholinesterase (2.9+/-1.88 versus 3.7+/-2.02 kU/l; p=0.026) and serum creatinine (160.4+/-186.8 versus 77.7+/-31.6 micromol/l; p=0.007), with creatinine and cholinesterase as independent parameters. Based on these parameters, a model for predicting patient survival after liver transplantation was calculated and validated in a second independent cohort of 87 OLT patients. This score identified a high-risk group and a low-risk group (overall survival 47.4 versus 91.2%; p<0.001) with a specificity of 87.3% and a sensitivity of 68.75%.

CONCLUSION

Age, pre-OLT creatinine and cholinesterase are predictors of short-term post-OLT survival and may be helpful as a bedside score in pre-OLT clinical management, outcome prediction and decision-making.

[Sequelae of organ transplantation]

Transplant medicine has significantly changed the prognosis of diseases leading to terminal organ failure. It has evolved from an experimental procedure to standard therapy for liver, kidney and cardio-vascular diseases. Transplant medicine combines operative organ replacement with the management of severely ill patients before transplantation, as well as life-long follow-up of organ graft recipients. Ten year survival rates of 65% to over 90% have led to a steady increase of transplanted patients seen by general medical care providers which represents a challenge for practicing internists. Apart from organ-specific conditions, infectious, immunosuppressant-associated and metabolic consequences determine long-term survival. These include virus reactivation, graft rejection, anastomotic problems but more importantly general mortality determining factors such as diabetes, renal insufficiency and hypertension, which are often a consequence of immunosuppressant administration. They directly impact long-term survival. The awareness and treatment of these secondary conditions of organ transplantation in routine medical practice contributes significantly to secure the long term success of transplant medicine.

[Infections after organ transplantation]

Early postoperative infections after transplantation vary according to the transplanted organ. During the subsequent course opportunistic infections such as cytomegalovirus reactivation, Pneumocystis jiroveci pneumonia, invasive pneumococcal infection and mould infections predominate. Reactivated tuberculous infection appears to become more prevalent. Some of the opportunistic infections are preventable by chemoprophylaxis; others can be managed very effectively by monitoring and early preemptive therapy. Physicians caring for patients after organ transplantation need to early consider in the differential diagnosis rare pathogens which are often overlooked with standard diagnostic procedures.