Minimum graft volume for successful adult-to-adult living donor liver transplantation for fulminant hepatic failure

Changes in liver regenerative factors in a case of living-related liver transplantation

Liver regeneration in a patient with fulminant hepatic failure (FHF) who underwent living-related partial liver transplantation (LRLT) was investigated regarding hepatic growth factors. The patient was a 16-yr-old Japanese male who developed severe subacute FHF. LRLT was performed using an extended left lobe of the ABO matched patient's mother. In the recipient, the pre-transplant levels of both plasma hepatocyte growth factor (HGF) and transforming growth factor (TGF)-beta were extremely high and rapidly decreased following the liver replacement. The liver volume evaluated using a CAT scan increased 195% after 2 wk in graft liver and 110% after 2 wk in the hepatectomized donor. The explanted liver (FHF liver), the liver from donor (normal liver), and the graft liver [the 3rd post-transplant day (POD 3)] were all investigated immunohistochemically. FHF liver: No liver regeneration was observed [proliferative cell nuclear antigen (PCNA) labeling index (L.I.): 0%]. In the liver, both HGF in the hepatocytes and c-met on the membrane of the hepatocytes were positive. TGF-beta was positive in the hepatocytes and no apoptosis was detected by the TUNEL method. Donor liver (POD 0): Few PCNA stained hepatocytes were detected. No HGF was detected but c-met was clearly detected on the cell membrane of the hepatocytes. Neither TGF-beta nor apoptosis was detected. Graft liver (POD 3): The PCNA L.I. was conspicuous at 40%. HGF was positive in non-parenchymal cells and c-met was positive in the cytoplasm of the hepatocytes. TGF-beta was negative while apoptosis was positive in the zone 3 hepatocytes. In conclusion, these findings suggested that the liver of the patient with FHF did not respond to liver regenerative stimulus, in part, through involvement of inhibitor TGF-beta. On POD 3, the transplanted graft was in a vigorous regenerative status in comparison to that in the hepatectomized donor. The HGF/c-met system is thought to be involved in the mechanism of regeneration. Intrahepatic apoptosis was detected in the graft on the 3rd post-transplant day probably due to transient ischemia in the liver, which was not related to the Fas/Fas-ligand system.

Minimum graft size for successful living donor liver transplantation

BACKGROUND

The extension of living donor liver transplantation to adult recipients is limited by the adequacy of the size of the graft. We evaluate the effect of the graft size on the survival of the recipient in order to establish a clinical guide for the minimum requirement.

METHODS

The clinical records of 14 adults and 11 children (body weight 6.1-100 kg) who underwent living donor liver transplantation for chronic or acute liver failure were reviewed. The effect of the graft weight ratio (graft weight divided by standard liver weight of recipient) on graft function and survival was studied.

RESULTS

The graft weight ratio ranged from 31 to 203%. The overall graft and patient survival rates were 84% at a median follow-up of 29 months. The survival rate was 95% for recipients with a graft weight ratio >40%, and 40% only for those with a ratio < or =40% (P = 0.016). It was 88% (7/8) when the ratio was >100%, 100% (5/5) when the ratio was 71 to 100%, 100% (7/7) when the ratio was 41 to 70%, and 40% (2/5) only when the ratio was < or =40%. When the graft weight ratio was < or =40%, early graft dysfunction was evident and contributed to the causes of death in three patients.

CONCLUSIONS

Preoperative computed tomographic measurement of liver size of a living donor is essential. A graft that represented 40% or less of the recipient's standard liver weight should be regarded as a marginal graft with a lower success rate.

Split liver transplantation

OBJECTIVE

This study reviews the indications, technical aspects, and experience with ex vivo and in situ split liver transplantation.

BACKGROUND

The shortage of cadaveric donor livers is the most significant factor inhibiting further application of liver transplantation for patients with end-stage liver disease. Pediatric recipients, although they represent only 15% to 20% of the liver transplant registrants, suffer the greatest from the scarcity of size-matched cadaveric organs. Split liver transplantation provides an ideal means to expand the donor pool for both children and adults.

METHODS

This review describes the evolution of split liver transplantation from reduced liver transplantation and living-related liver transplantation. The two types of split liver transplantation, ex vivo and in situ, are compared and contrasted, including the technique, selection of patients for each procedure, and the most current results.

RESULTS

Ex vivo splitting of the liver is performed on the bench after removal from the cadaver. It is usually divided into two grafts: segments 2 and 3 for children, and segments 4 to 8 for adults. Since 1990, 349 ex vivo grafts have been reported. Until recently, graft and patient survival rates have been lower and postoperative complication rates higher in ex vivo split grafts than in whole organ cadaveric transplantation. Further, the use of ex vivo split grafts has been relegated to the elective adult patient because of the high incidence of graft dysfunction (right graft) when placed in an emergent patient. Reasons for the poor function of ex vivo splits except in elective patients have focused on graft damage due to prolonged cold ischemia times and rewarming during the long benching procedure. In situ liver splitting is accomplished in a manner identical to the living donor procurement. This technique for liver splitting results in the same graft types as in the ex vivo technique. However, graft and patient survival rates reported for in situ split livers have exceeded 85% and 90%, respectively, with a lower incidence of postoperative complications, including biliary and reoperation for bleeding. These improved results have also been observed in the urgent patient.

CONCLUSION

Splitting of the cadaveric liver expands the donor pool of organs and may eliminate the need for living-related donation for children. Recent experience with the ex vivo technique, if applied to elective patients, results in patient and graft survival rates comparable to whole-organ transplantation, although postoperative complication rates are higher. In situ splitting provides two grafts of optimal quality that can be applied to the entire spectrum of transplant recipients: it is the method of choice for expanding the cadaver liver donor pool.

Impact of graft size mismatching on graft prognosis in liver transplantation from living donors

BACKGROUND

Although living donor liver transplantation for small pediatric patients is increasingly accepted, its expansion to older/larger patients is still in question because of the lack of sufficient information on the impact of graft size mismatching.

METHODS

A total of 276 cases of living donor liver transplantation, excluding ABO-incompatible, auxiliary, or secondary transplants, were reviewed from graft size matching. Forty-three cases were highly urgent cases receiving intensive care preoperatively. Cases were categorized into five groups by graft-to-recipient weight ratio (GRWR): extra-small-for-size (XS; GRWR<0.8%, 17 elective and 4 urgent cases), small (S; 0.8< or =GRWR< 1.0%, 21 and 7), medium (M; 1.0< or =GRWR<3.0%, 119 and 19), large (L; 3.0< or =GRWR<5.0%, 67 and 10), and extra-large (XL; GRWR> or =5.0%, 9 and 3).

RESULTS

Smaller-for-size grafts were associated not only with larger and older recipients, but also with rather older donors. Posttransplant bilirubin clearance was delayed and aspartate aminotransferase corrected by relative graft size was higher in XS and S. Posttransplant hemorrhage and intestinal perforation were more frequent in XS and S, and vascular complications and acute rejection were more frequent in larger-for-size grafts. Consequently, graft survival in XS (cumulative 58% and actuarial 42% at 1 year) and S (76% and 74%) was significantly lower compared with that in M (93% and 92%) in elective cases. Graft survival in L (83% and 82%) and XL (75% and 71%) did not reach statistical significance.

CONCLUSIONS

The use of small-for-size grafts (less than 1% of recipient body weight) leads to lower graft survival, probably through enhanced parenchymal cell injury and reduced metabolic and synthetic capacity. Although large-for-size grafts are associated with some anatomical and immunological disadvantages, the negative impact is less pronounced.

Applicability of living donor liver transplantation to high-urgency patients

BACKGROUND

Cadaveric liver donors are scarce in Hong Kong, and the application of liver transplantation to high-urgency patients is limited. We evaluated the use of grafts from living donors in this setting.

METHODS

From July 1994 to January 1998, 49 consecutive adult patients who were intensive care unit-bound because of acute or chronic liver failure were put on a high-urgency list for liver transplantation. Family members were not solicited for living donation, and the initiation and decision for living donor liver transplantation (LDLT) was based on the donor's voluntary intent. Assessment of the living donor, including blood tests, computed tomographic volumetry, and angiography, was performed only after informed consent was executed.

RESULTS

In 25 of 49 (51%) patients, no family member volunteered as living donor; 23 died awaiting donor organs, and 2 received a cadaveric graft. Twenty-four (49%) patients had 36 family members who volunteered as living donors. Before evaluation of living donor was completed, two patients received a cadaveric liver transplant. LDLT was not performed in nine patients because of recipient contraindications (n=4), ABO blood group incompatibility (n=3), and withdrawal of donor (n=2). Eight of these nine patients died, and one received a cadaveric liver graft. The remaining 13 (27%) patients received grafts from living donors. Four of 5 (80%) patients who underwent cadaveric liver transplantation and 11 of 13 (85%) who underwent LDLT survived. Thus, emergency transplantation from living donors increased the applicability of liver transplantation from 10% to 37%, and the survival rate after emergency LDLT (85%) was superior to that of the remaining patients (11%).

CONCLUSIONS

When cadaveric organ donation is scarce, emergency liver transplantation from living donors can be applied to high-urgency adult patients.

Auxiliary partial orthotopic liver transplantation from living donors: significance of portal blood flow

BACKGROUND

Auxiliary liver transplantation has several advantages over standard orthotopic liver transplantation. However, functional competition has been reported even in auxiliary partial orthotopic liver transplantation (APOLT). We evaluated herein the interaction in APOLT between the native liver and the graft in terms of portal blood flow and regeneration. The need for diversion of the portal blood flow to the graft was also assessed.

METHODS

A total of 15 patients received APOLT from living donors. Portal blood flow to the native liver was preserved in 6 patients, and the portal vein to the native liver was preemptively transected at the time of transplantation in 9 patients.

RESULTS

Of the patients with preservation of the portal blood flow to the native liver, two showed inadequate graft portal blood flow just after operation, and in the other three patients the graft portal blood flow decreased or the graft atrophied after deterioration of the graft function. In the patients with preemptive transection of the portal vein to the native liver, optimal graft portal blood flow was obtained, and the native liver, supplied only by arterial inflow, supported a small-for-size graft until the graft regenerated. The damage to the native liver was minimal.

CONCLUSIONS

Functional competition may occur in APOLT with preservation of the portal blood flow to the native liver, whereas preemptive transection of the native liver portal vein is a safe procedure and effectively prevents the portal steal phenomenon.

Adult-to-adult living donor liver transplantation using extended right lobe grafts

OBJECTIVE

The authors report their experience with living donor liver transplantation (LDLT) using extended right lobe grafts for adult patients under high-urgency situations.

SUMMARY BACKGROUND DATA

The efficacy of LDLT in the treatment of children has been established. The major limitation of adult-to-adult LDLT is the adequacy of the graft size. A left lobe graft from a relatively small volunteer donor will not meet the metabolic demand of a larger recipient.

METHODS

From May 1996 to November 1996, seven LDLTs, using extended right lobe grafts, were performed under high-urgency situations. All recipients were in intensive care units before transplantation with five having acute renal failure, three on mechanical ventilation, and all with hepatic encephalopathy. The median body weight for the donors and recipients was 58 kg (range, 41-84 kg) and 65 kg (range, 53-90 kg), respectively. The body weights of four donors were less than those of the corresponding recipients, and the lowest donor-to-recipient body weight ratio was 0.62:1. The extended right lobe graft was chosen because the left lobe volume was <40% of the ideal liver mass of the recipient.

RESULTS

Median blood loss for the donors was 900 mL (range, 700-1600 mL) and hospital stay was 19 days (range, 8-22 days). Homologous blood transfusion was not required. Two donors had complications (one incisional hernia and one bile duct stricture) requiring reoperation after discharge. All were well with normal liver function 5 to 10 months after surgery. The graft weight ranged from 490 g to 1140 g. All grafts showed immediate function with normalization of prothrombin time and recovery of conscious state of the recipients. There was no vascular complication, but six recipients required reoperation. One recipient died of systemic candidiasis 16 days after transplantation and 6 (86%) were alive with the original graft at a median follow-up of 6.5 months (range, 5-10 months).

CONCLUSIONS

When performed by a team with experience in hepatectomy and transplantation, LDLT, using an extended right lobe graft, can achieve superior results. The technique extends the success of LDLT from pediatric recipients to adult recipients and opens a new donor pool for adults to receive a timely graft of adequate function.

Extending the limit on the size of adult recipient in living donor liver transplantation using extended right lobe graft

The feasibility of adult-to-adult living donor liver transplantation (LDLT) is restricted by the adequacy of the graft size. A left lobe graft from a relatively small donor will not meet the metabolic demand of a larger recipient. We report a successful LDLT performed on a 90-kg man using an extended right lobe graft weighing 910 g from his relatively smaller-size brother. The donor-to-recipient body weight ratio was only 0.82. No homologous blood transfusion was required for the donor, and the donor recovered uneventfully except for mild transient hyperbilirubinemia. The graft provided adequate function for the metabolic needs of the recipient despite postoperative septic complications. Both donor and recipient were well with normal liver function at 4 months after operation. LDLT using the extended right lobe liver graft can extend the limit on the size of the adult recipient and may be a viable option even when the donor is relatively small compared with the recipient.