EDITORIAL

To Split or Not to Split: That Is the QuestionRiccardo SuperinaDivision of Transplant Surgery, Department of Surgery, Northwestern University Feinburg School of Medicine,Chicago, IL

Received January 19, 2012; accepted January 20, 2012.

See Article on Page 413

In this issue of Liver Transplantation, Sepulveda et al.1

from France report their results for a series of 36 splitliver transplants in adults. They describe the complica-tions suffered by adult recipients of a right lobe andsegment IV [S4; ie, an extended right graft (ERG)] afterthe division of an organ, with the segment II-III portionbeing transplanted into a child.

The concept of dividing a liver into 2 portions is byno means new, but the utilization of split liver trans-plantation has remained limited despite its potentialfor significantly enhancing the number of potentialdonor organs. Originally described in 1988, split livertransplantation was used first in Europe, where theinitial graft and patient survival outcomes were com-pared to the experience with whole liver transplantsand found to be equivalent.2

In this most recent experience from France, 36patients who received an ERG experienced a disap-pointingly high rate of complications. The authorsreport S4 ischemia as the root cause of serious com-plications in 8 patients (22%), but primary hepatic ar-tery thrombosis also occurred in 3 patients; the over-all rate of significant surgical complications was 39%.Only 21 patients had a postoperative course relativelyfree of complications.

Two of the 8 patients with S4-related complicationssuffered from a septic arterial rupture, and 1 patientsuffered from secondary hepatic artery thrombosisrelated to an infected S4-related periarterial collec-tion. Six patients in the ERG group required retrans-plantation. Graft survival at 1 year was significantlylower in the group with S4-related complications (50%

versus 85.6%), and patient survival was also lowerbut not significantly so.

The authors have been able to document anddescribe ischemic S4s in great detail and offer labora-tory guidelines that are predictive of patients who willdevelop S4-related complications. However, they offerlittle in the way of concrete hypotheses about whythis is such a common occurrence in their hands orwhat can be done to diminish the incidence of thisproblem. The donor selection process was careful,and the criteria for splitting donor livers were verysimilar to current United Network for Organ Sharing(UNOS) guidelines. The recipient selection processalso excluded patients who were very sick, and half ofthe recipients were patients with hepatocellular carci-noma and no portal hypertension. Despite these rela-tively conservative practices, S4-related complicationswith accompanying biliary leaks, perihepaticabscesses, and serious arterial sequelae occurred toofrequently. Surprisingly, the diagnosis of S4-relatedcomplications in the 8 patients occurred relatively latewith a median delay of 22 days after transplantation.The authors do suggest that with the earlier diagnosisof S4 complications and more aggressive surgical de-bridement of infected material, the results for adultrecipients of ERG grafts could be improved.

Perhaps more attention should be paid to the arte-rial supply of S4. In our experience, the arterial sup-ply of S4 is preserved whenever possible because thedivision of the parenchyma just to the right of the fal-ciform ligament removes all portal blood flow to S4and thus leaves the artery as the sole supplier of oxy-gen. In pediatric liver transplantation (in which reduc-tion techniques have a longer history), bile leaks as afunction of both the raw surface and the often

Abbreviations: ERG, extended right graft; S4, segment IV; UNOS, United Network for Organ Sharing.

Address reprint requests to Riccardo Superina, M.D., F.A.C.S., F.R.C.S(C), Division of Transplant Surgery, Department of Surgery,Northwestern University Feinburg School of Medicine, 700 West Fullerton Street, Suite N745, Chicago, IL 60614. Telephone: 773-883-6187;FAX: 773-880-4588; E-mail: rsuperin@childrensmemorial.org

DOI 10.1002/lt.23397View this article online at wileyonlinelibrary.com.LIVER TRANSPLANTATION.DOI 10.1002/lt. Published on behalf of the American Association for the Study of Liver Diseases

LIVER TRANSPLANTATION 18:389-390, 2012

VC 2012 American Association for the Study of Liver Diseases.

separate bile ducts from segments II and III have beenhandled aggressively and have not affected graft orpatient survival.3

Because of the diminished graft survival of the ERGgroup, the net benefit gained as a result of liver split-ting practices was reduced and theoretically could benullified altogether if the retransplant rate were torise. Certainly, the survival of grafts in this series jus-tifies the practice, but modeling could be used tomore precisely quantify the increase in the number oftransplant patients and to more exactly calculate theactual benefit in lives saved and organs gained.

Interestingly, no comparison is made with currentwhole liver transplant results at this center, and it isnot possible to determine from the results whethercomplications have diminished as part of a learningcurve. Fortunately, as the authors point out, othercenters have reached equivalent patient and graft sur-vival for recipients of whole livers and recipients ofERG livers, and it is likely that results will improve ifsplit liver graft utilization increases. It has long beendemonstrated in pediatric transplantation that sur-vival is not so much a function of the type of graft asit is a function of the condition of the patient under-going transplantation.

The authors are to be applauded for supporting thepractice of split liver transplantation and making themost of a scarce resource. In the United Statesbetween 2002 and 2009, more than 29,000 wholeliver transplants were performed, but only 288 splitgrafts were performed in adults (ie, less than 1% ofthe total number of transplants). It has been esti-mated that approximately 20% of all deceased donorsmeet UNOS guidelines for split liver utilization. In ourown organ procurement organization between 2006and 2009, only 12 of 128 livers from donors meetingUNOS split criteria were actually divided, and most ofthese originated from pediatric centers (ie, an ERGwas offered after an organ from an adult donor wasallocated to a small child).

Organ Procurement and Transplantation Networkregulations governing the allocation of livers dictateand monitor the placement of an EGR when an adultliver is accepted for transplantation into a child, butthey do not compel or even encourage the donation ofa segment II-III graft from a liver that has been allo-cated primarily to an adult recipient. The recent addi-tion of a committee-sponsored alternative allocationsystem for segmental liver transplantation at leastintroduces the concept of the donation of a segmentalgraft from a liver allocated primarily to an adult, butthe regulations do not reward or compel considerationeven for the grafts that meet the criteria for splitting.

In France, as reported by the authors, the allocationpolicy dictates that livers from all donors less than 30years old should be directed to children first with thestipulation that each liver should be split and theERG should be shared with an adult recipient. Thispolicy, if adopted in the United States, would make

more grafts available to children, who still suffer fromthe highest mortality rates on the waiting list. In2008, 18% of the children who were listed for a livertransplant died without a chance at transplantation,and infants less than 1 year old are at the highestrisk of dying before an organ becomes available. In2004, an American study predicted that despite whatmight arguably be a higher rate of retransplantation,split liver transplantation would result in more lifeyears gained for adults and satisfy the demands ofchildren, and the waiting list would thus be virtuallyeliminated.4

Directing all livers from donors less than 30 yearsold to children would mirror the proposed policy gov-erning the allocation of kidneys in this country andstill make ERGs available to waiting adults. Withoutcompromising the availability of organs to adults, theextra organs for children would satisfy the require-ments of children waiting for organs. This would alsoconsolidate networks among pediatric centers andadult institutions that are comfortable in making thenecessary technical refinements to successfully trans-plant ERGs and thereby potentially make even moreorgans available to their patients from younger, sta-ble, and higher quality donors. Children make up asmall proportion of all patients on the liver waitinglist. More than 6000 liver transplants are performedannually in this country, but there are normally justover 300 children waiting nationally. If most adultliver transplant centers will not consider the splittingof livers that meet the UNOS split criteria to makesegmental II-III grafts available to children, then theallocation rules should be changed to steer moreorgans from young adult donors to children with theproviso that ERGs will be made available to adults atcenters willing to accept them.

It is clear to me that the French experience reportedhere should raise the enthusiasm for splitting organsin order to meet the rising needs of the transplantpatient population and to alleviate the organ shortagefor children, who represent the segment of the patientpopulation at the greatest disadvantage for receivingan organ in a timely fashion.

REFERENCES

1. Sepulveda A, Scatton O, Tranchart H, Gouya H, PerdigaoF, Stenard F, et al. Split liver transplantation usingextended right grafts: the natural history of segment 4and its impact on early postoperative outcomes. LiverTranspl 2012;18:413-422.

2. de Ville de Goyet J. Split liver transplantation in Europe—1988 to 1993. Transplantation 1995;59:1371-1376.

3. Salvalaggio PR, Whitington PF, Alonso EM, Superina RA.Presence of multiple bile ducts in the liver graft increasesthe incidence of biliary complications in pediatric livertransplantation. Liver Transpl 2005;11:161-166.

4. Merion RM, Rush SH, Dykstra DM, Goodrich N, FreemanRB Jr, Wolfe RA. Predicted lifetimes for adult and pediatricsplit liver versus adult whole liver transplant recipients.Am J Transplant 2004;4:1792-1797.

390 SUPERINA LIVER TRANSPLANTATION, April 2012