Overview

Over 6000 LDLT have been performed worldwide. Milestones include the first successful LDLT (adult-to-pediatric) in 1989 and the first successful adult-to-adult LDLT in 1997. LDLT significantly increase the donor pool. For adult recipients, the patient and graft survival rates after LDLT are comparable, or better than, DDLT.

Advantages of a LDLT (over a DDLT)

• Surgery is performed electively – no waiting time, optimal time is chosen for the transplantation (i.e. before the recipient becomes too sick).
  
• Liver graft is in excellent condition (pre-selected organ quality, decreased ischemia time).
  
• The possibility of saving the recipient from waiting-list mortality.

Basic principles of live liver donation (Vancouver Forum Criteria)

• Live liver donation to be performed only if the donor risk is justified by expectation of an acceptable recipient outcome.
  
• Patient and graft survival of a LDLT should approximate the expected outcome for a recipient (with the same disease etiology) undergoing a DDLT.
  
• Indications for LDLT should be the same as those established for DDLT.
  
• LDLT should offer an overall advantage to the recipient when compared with waiting for the availability of a DDLT.
  
• Any outcome that penalizes living donors for the act of donation is not acceptable.

Benefits to the donor

• Psychologic – the concept of altruism; the traditional end-points of medical and surgical therapy do not apply to living donors.

Donor selection criteria

• Age between 18 and 55 years.
  
• Presence of donor–recipient genetic and/or emotional relationship.
  
• ABO compatibility.
  
• Absence of medical contraindications or prior major abdominal surgery.
  
• BMI not greater than 28–30 kg/m².
  
• Free from coercion to donate.

Types of donation

• The selection of recipient eligibility for LDLT should be similar for those being evaluated to receive grafts from deceased donors.
  
• HCCs should still be within the Milan criteria.
  
• An elevated MELD score (e.g. above 25) and/or increased portal hypertension may preclude eligibility for LDLT since the effects of advanced liver dysfunction may not be relieved by a partial graft immediately post-transplantation. However, this decision is not universal and will be determined by each transplantation center performing LDLT.
  
• In the USA, it is currently not the standard practice to perform LDLT for patients with ALF due to the low benefit:risk ratio.
  
• To avoid selection bias and to protect donor welfare, separate teams (medical and surgical) are maintained for evaluation of both potential recipient and donor.
  
• In donors with relative contraindications for donation that can be decreased/reversed (e.g. fatty liver disease, current smoking and alcohol use), and if the potential recipient has the time to wait, individualized management strategies (e.g. weight loss, cessation of smoking and alcohol use) can be formulated. The donor can then be re-assessed periodically to determine the suitability for donation.
  
• Before making a decision to donate, the donor should be aware of the potential recipient’s chance of survival post-transplantation. For example, HCC and viral hepatitis may recur after the transplantation.

Donor evaluation

• The main priority for the donor team is to ensure donor safety.
  
• Blood tests: CBC, basic and liver chemistries, prothrombin time/INR, blood type and screen, viral serologies, HIV, iron studies, urinalysis, urine toxicology screen, serum ethanol, pregnancy test (if indicated).
  
• Evaluations: hepatologist, transplantation coordinator, social worker, psychiatrist, ethicist, cardiologist, surgeon.
  
• Imaging studies: volumetric imaging, delineation of vascular and biliary anatomy. The donor must have >30% residual liver volume post-hepatectomy and the graft-to-recipient weight ratio (in g/kg) must be at least 0.8–1.0. This ratio corresponds to 40–50% of the standard recipient liver volume and generally fulfills the metabolic requirements of adequate liver function in the recipient post-transplantation. SFSS is a condition that occurs when the recipient has a small graft, resulting in delayed graft function (e.g. hyperbilirubinemia, coagulopathy, ascites, hepatic encephalopathy) or a lack of it. The risk of developing SFSS is seen when the graft-to-recipient weight ratio is less than 1.0. An “all-in-one” multidetector CT scan has the advantage over MRI in assessing the biliary anatomy accurately. Fatty liver detection in imaging studies has improved and may obviate the need for assessment through a liver biopsy.
  
• Liver biopsy: if indicated (e.g. to assess for etiology of abnormal liver chemistries, steatosis, familial liver disease).
  
• Informed consent: to understand the risks of liver donation and the possible benefits/outcomes of the recipient.
  
• Medical out – “time-out” period after evaluation completion and date of surgery; the donor may opt out of donation at any time and be offered a “medical out” as a reason for withdrawing. Up to 40% of living donors are eventually excluded from liver donation. Withdrawal from the evaluation process and recipient death (while donor evaluation is ongoing) are the most common reasons.