Potential Impact of in Situ Liver Splitting on the Number of Available Grafts. Transplantation 2002; 74: 222.

Limitations to split-liver transplantation: the donor or the surgeon? The shortage of cadaveric liver grafts is inherent in the success of liver transplantation. Over the past 10 years, this deficit has accumulated to a point that will require drastic measures to overcome. The most visible consequences of this shortage are patients’ mortality and time spent on the waiting list. The least visible consequence is that some centers have limited patients’ access to the center’s already large transplantation waiting lists. The most controversial issues are the reluctance to perform transplantation in nonresidents, or for specific indications, and the development of living-related liver transplantation. Several measures have been implemented to overcome this shortage. Some measures are administrative, occurring at national levels, and aim at a more efficient identification of donors and allocation of grafts. The best example is Spain’s policy of systematically identifying brain-dead donors, a policy that has resulted in an increase in the harvesting of grafts to 34 per million inhabitants (pmi), which is more than twice that of other European countries and Canada (13–17 pmi) and 1.5 times that in the United States (22 pmi) (1). The use of previously unused donors, such as marginal, living-unrelated donors (“domino” transplantation), or living-related donors, represents another set of measures that can increase the donor pool. These measures, however, can be made only by each unit or even by individual surgeons, although the measures require official, prospective evaluation. The last option is optimizing available grafts through the practice of splitting. Such practices are currently also left to the discretion of individual centers, but there is evidence that some form of administrative enforcement will be necessary and is already in a preparatory process. Toso et al. are the first to try to quantify the extent to which a systematically followed policy of splitting optimal brain-dead donors would increase the number of grafts, at the national level of Switzerland. Their result is at least a 15% increase in the number of grafts; and they conclude that splitting could fulfil all the needs for pediatric transplantation and, more generally, that transplantation of livers as whole grafts is a waste of resources. Their figure is more realistic than the previous estimates of 20% to 25% (2,3), yet far from the current application of split grafts that, overall, accounted for only 2.1% (459 of the 21,819) and 4.7% (925 of 19,667) of the transplantations performed during the past 5 years in the United States (based on OPTN data as of December 7, 2001) and Europe (4), respectively. This discrepancy suggests that limitations other than donor conditions should also be considered and that unless they are motivated—or forced to do so—many surgeons may prove reluctant to apply the authors’ conclusions. The split-liver transplantation technique has been used in Europe and the United States since the early 1990s. The conventional technique in which a child received the left lateral segment and an adult received the right liver was initially associated with poor results, particularly for the adult recipient of the right lobe. However, avoiding high-risk recipients, the development of the in situ split, and improvement in expertise have led to improved outcomes almost comparable to outcomes of whole grafts. Split grafts, therefore, are used, although to a variable extent, by all active pediatric transplant programs as an alternative to using reduced-size grafts, a practice that has fallen into disfavor. Implementation of a split-graft policy has decreased the waiting time in pediatric transplant patients to less than 1 month in some units (3) and almost suppressed the shortage of grafts for pediatric recipients at national levels, with, however, minimal impact on the adult waiting lists. In fact, pediatric transplantations accounted for only 8% of all transplantations performed in Europe during the past 2 years and only 25% to 30% of these pediatric grafts have been performed with split grafts (4). Providing only split grafts to pediatric recipients, as suggested by Toso et al., theoretically would increase the proportion of grafts available to adults to 8%. Yet, donors less than 10 years old cannot be split and are, or should be, preferentially allocated to pediatric recipients; this would cover 20% of the pediatric demand. In addition, in 2001, living-related transplantation accounted for 12% of pediatric transplantations in Europe, a figure that is more likely to increase than to decrease because it is associated with improved patient and graft survival (5). The only effective means for observing a significant impact of splitting in adult recipients, therefore, would theoretically be to develop the in situ full-right–full-left division along the main portal fissure, generating a left graft that can also be transplanted into an adult recipient. This technique recently has been standardized (6) and is actively promoted by some groups; yet, although appealing, this technique does not seem to have come to current practice. Only 13 such procedures were performed in the United States last year (based on OPTN data as of December 7, 2001), a 0.3% contribution to the number of grafts transplanted in adults, which is far from the minimal 8.6% increase in adult transplantations calculated by Toso et al. This figure could be refined to take into account the fact that these adult recipients of the left graft would need to be relatively small, in good general condition, with relatively preserved liver function, and experience no anticipated difficulties during recipient hepatectomy to avoid undue prolongation of cold ischemia to an already small graft. However, some Japanese groups perform adult living-related liver transplantation using exclusively left livers (7). The limitation, therefore, lies elsewhere: it is neither in the donor nor in the recipient selection but probably on the medical side. Indeed, how many transplant surgeons are willing to use split grafts? Initial experience with ex situ splitting when the technique was not standardized and the donor–recipient selection was inaccurate was often disappointing if not disastrous. Those who have not pursued and noticed the improved outcome might not be encouraged to do so (the European Liver Transplant Registry reports significantly lower graft survival rates in recipients of split grafts (4)), without considering that these comparisons are not stratified for donor or recipient’s conditions. Indeed, how many units are able to provide a senior surgeon for performing the in situ split, in addition to the more junior surgeon who usually performs the standard harvesting procedure? The requirement of a senior surgeon is necessary not only because in situ splitting is technically demanding but also to justify the 3 to 4 hours added to the procedure that delay the other harvesting teams, and potentially put the heart and lung grafts at risk. In addition, how many of these surgeons will accept performing this delicate surgery outside university hospitals where necessary equipment may not be available? How many of these units have the backup operating room and medical staff to transplant both grafts and the ability to perform another transplantation the following day if a new donor becomes available? If this is not the case, and the unit ends up with a single graft while shipping the other half, what will be the motivation for performing a more complex harvesting and transplant procedure that will result in their patient staying longer in the ICU than if they had used the whole graft? This is especially true considering that the most active units (those able to perform or use split livers) are also those that are performing the more complex, living-related procedures, and are currently faced with an increasing proportion of high-risk recipients. There also exists the concept, as Oscar Wilde recounted, that, “There are many things that we would throw away if we were not afraid that others might pick them up.” In fact, the incidence of optimal donors identified by Toso et al. is reassuring because it indicates that the barriers to split-liver trans-plantation will have to be broken for only 1 in 10 donors. This may speed up administrative enforcement through preferential allocation of optimal grafts to units that are ready to split them—a policy that has actually begun in France at a regional level. Such programs will have a much lower impact on the number of transplantations performed than a better identification of potential donors. Yet, these programs will not decrease living-donor or brain-dead donor transplantation and may only prove detrimental for the smallest centers. Sharing, however, is as inherent to the concept of transplantation as shortage.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.