Living Liver Donor Evaluation and Right Lobe Surgery

Living liver donor evaluation has three parts, medical, ethical and documentation, and ends with approval by a government-appointed authorisation committee before surgery. The medical work-up confirms a compatible blood group, a healthy liver with low fat on CT, suitable vascular and biliary anatomy, and enough liver volume for both donor and recipient. Any doubt at any step means the donor is declined.

For Dr. Sandeep Jha, Consultant, Liver Transplantation, Shalby Sanar International Hospital, Gurugram, India, donor evaluation is the most important aspect of a living donor liver transplant. The reason is structural: if donors come to harm, families stop volunteering and the programme fails. He pointed to the United States, where living donor liver programmes contracted after donors died and are only now returning because of the shortage of deceased organs. The lesson he drew is that no donor should have problems after donation, and strict protocols exist to ensure it.

Living liver donor criteria

Dr. Jha's criteria for a potential donor:

• Age 18 to 55.
• No known medical disorders.
• Lean build.
• Capacity to consent: the donor must understand the process of living donation and give informed consent.
• Commitment to follow-up: the donor must be able to comply with long-term follow-up.
• Relationship to the recipient: Dr. Jha explained that Indian law requires the donor to be related to the recipient; only then is ethical and legal clearance granted.

A multidisciplinary team examines every donor: a liver transplant surgeon, a hepatologist, a gastroenterologist, an anaesthetist, a cardiologist and a pulmonologist, with a gynaecologist added for female donors.

The conversation before any test

Before the evaluation begins, the team sits down with the prospective donor. The donor must understand every aspect of liver donation: that it is a good deed, that it carries a small risk to life, and what to expect in the long term. Dr. Jha put the risk to the donor's life at 0.5%, a figure he described as old data given the safety standards now applied. The donor is also told that the gallbladder will be removed. It is attached to the underside of the liver, so once the liver is cut in two the gallbladder is useless and could cause problems; it is taken out during the donor hepatectomy (the removal of part of the donor's liver).

The living liver donor evaluation pathway

Dr. Jha's flowchart for donor evaluation has three components:

1. Medical evaluation.
2. Ethical evaluation.
3. Documentation.

All three go to an authorisation committee headed by government officials. Only after it grants authorisation can the surgical team proceed, and a problem at any step stops the donation.

Blood group compatibility

Compatibility depends on the ABO blood group alone; Rhesus status, positive or negative, does not matter.

Triple-phase CT for a liver donor: mapping the anatomy

The most important element of surgical planning, in Dr. Jha's words, is a contrast-enhanced CT scan performed in three phases:

1. Arterial phase: maps the hepatic arteries.
2. Portal venous phase: captures contrast flowing through the portal vein.
3. Delayed venous phase: captures contrast in the hepatic veins.

Together these images define the anatomy of the donor's liver and show whether the operation is feasible. One example he gave: the right portal vein must be divided at a specific point, and if the remaining stump would be too short, the donor cannot be taken for surgery. The same scan, combined with CT volumetry (calculating the volume of each part of the liver from the images), tells the team how much liver the recipient will receive and how much the donor will keep.

Biliary anatomy is mapped separately with magnetic resonance cholangiopancreatography (MRCP), an MRI technique that images the bile ducts. Variations in the arterial supply and the bile ducts are common, and they form part of the decision on whether a donor is fit.

Liver attenuation index: the fatty liver threshold for donors

Some prospective donors have fatty livers, and graft quality is the foundation of the whole operation. Dr. Jha's team screens for steatosis on a non-contrast CT scan by calculating the liver attenuation index, which compares the density of the liver with that of the spleen. If the index is below zero, the donor is declared unfit.

Practice varies between centres: MRI is increasingly used to quantify liver fat, while his team relies on CT. In doubtful cases the team turns to MRI or a liver biopsy. Biopsy is needed in only a few donors, but when there is uncertainty about the quality of the liver, it is the way to settle it. The stakes run in both directions: if the quality of the donor liver is not good, the donor will have problems and so will the recipient.

Graft-to-recipient weight ratio (GRWR) and donor remnant volume

The graft must be large enough for the recipient and the remnant large enough for the donor. Two measures govern this:

• Graft-to-recipient weight ratio (GRWR): the weight of the graft as a percentage of the recipient's body weight. A GRWR of at least 0.8% is the widely used minimum; below it, the risk of small-for-size syndrome, in which too little liver tissue fails to meet the recipient's needs, rises.
• Donor remnant volume: the liver left behind should be at least about 30% of the donor's total liver volume, the standard safety margin for the donor.

Triple-phase CT with volumetry supplies both numbers, and together they decide whether to proceed.

Right lobe vs left lobe liver donation

The liver is divided into eight Couinaud segments. In an adult recipient, Dr. Jha's team removes the donor's right lobe, segments 5, 6, 7 and 8, which together make up around 60 to 70% of the total liver volume. The left lobe is much smaller in every individual, so adults, who need more liver mass, receive the right lobe. Children, whose metabolic demand is lower, receive a left lateral segment or the left lobe.

Asked in the discussion whether right and left lobe grafts differ in outcome, Dr. Jha was clear: if the technique is good, there is no difference. The difference lies with the donor. Removing the smaller left lobe allows slightly faster recovery and slightly fewer complications; right lobe donors recover a little more slowly, because the right lobe forms the bulk of the liver and the remnant has to grow to compensate.

Inside the donor hepatectomy

The line of division follows Cantlie's line, an imaginary plane running from the gallbladder bed to the inferior vena cava, which separates the right and left halves of the liver. From the front, only segments 5 and 8 of the right lobe are visible; segments 6 and 7 lie behind.

The steps Dr. Jha described:

1. Marking the line of transection on the liver surface, the ischaemic line that appears once the blood supply to one side is controlled.
2. Dividing the liver along the middle hepatic vein, separating the right lobe from segment 4 and the left lobe.
3. Dividing the right portal vein, right hepatic artery and right bile duct to free the graft.
4. Retrieving the right lobe for implantation.

Implanting the graft

In the recipient operation, the sequence runs: removal of the diseased liver, retrieval of the graft from the donor, bench preparation of the graft, implantation and reperfusion. The connections are:

• the graft's right hepatic vein to the recipient's inferior vena cava;
• the graft's portal vein to the recipient's portal vein;
• the graft's right hepatic artery to the recipient's hepatic artery;
• the graft's bile ducts to a Roux-en-Y loop of small intestine, into which they drain.

At the end of the transplant, a Doppler ultrasound checks the hepatic artery, the hepatic veins and the portal vein. Only when all three are functioning properly is the operation completed.

Liver donor recovery after surgery

Asked about the fate of the donor, Dr. Jha's answer was that after a complete evaluation the donor is absolutely fine. Donors are up and about two to three days after surgery, walking and eating, and are discharged by day six or seven. They are able to travel from day 10, and most travel back to their home country between 10 days and about two to three weeks after the operation. They can return to office and computer work and light household work, but not heavy exertion. The only formal restriction is no heavy lifting for three months, after which they can lift any weight and do anything.

Published studies describe a return to normal activity by six months; in Dr. Jha's practice, donors are back at their jobs within about a month. To make the point in the masterclass, he showed two of his donors: one who went on with a successful modelling career, and a man photographed just after surgery and again a year later.

What happens to the recipient after the graft is in place, from the intensive care unit to long-term immunosuppression, is covered in liver transplant complications, from ICU care to long-term follow-up. The donor questions raised by referring doctors are in the Live Discussion, and a separate guide covers who can donate a liver from another surgeon's perspective.