Q&A: Transplants at Duke University Hospital

The average waiting time may reflect many different aspects of the kidney transplant program. If a center does many more living donors, the average waiting time would be lower. If a center is very aggressive in the deceased donor kidneys it accepts, the waiting time might be lower. Waiting times for different blood group organs could impact waiting times as well. If one program had more candidates who were blood group A, as an example (this group has the shortest waiting time), then the waiting time @ that center might be shorter.

Organ allocation is principally determined by time on the waiting list. In the current allocation scheme, a patient’s expected post transplant survival (EPTS) also plays a role as the top 20% of kidney offers are allocated to those patients who are expected to survival the longest with the kidney. Other variables that impact allocation are how sensitized a recipient is, the patient’s blood type, the patient’s age (pediatric patients get preferential treatment), if the recipient has donated previously him/herself.

Patients can list at as many centers as they wish & multi listing does increase the chance that a recipient will get transplanted sooner. This benefit/chance is not as high as it was in the old allocation scheme. To multi list, a patient must do a work up/evaluation at each center.  Additionally, the follow up after transplant is done at the center where the transplant was performed. So, to multi list, patients will often have to travel great distances, which limits some patient’s ability to multi list.

The United Network of Organ Sharing (UNOS) is the group contracted by the US government tasked with organ allocation across the United States. The rules for allocation are unique for each type of organ being offered. For kidney transplant, the “rules” that govern where an organ goes are layered.  For some parameters, there is national priority, for some rules, regional priority is most important.  As an example, a very sensitized patient gets national priority if a match is found. In this sense, an organ from California might get shipped to NC. However, other parameters in the algorithm favor regional matching of the donor & recipient.  In our region, there are 4 transplant centers & we share a common wait list.  When an organ becomes available from a certain blood type, the candidates on the list from the four centers are listed, taking in to account waiting time, EPTS, quality of donated kidney, age of recipient, etc. The centers are then contacted & they start calling in their patients if they are high enough on the list & if the center thinks the type of kidney being offered is a good quality kidney for their recipients. The organ is cross matched (meaning blood from the donor & recipient are mixed to assure there is not a strong immunologic reaction). If negative, then the organ can be used for the recipient @ that center. The algorithm & matching is done through a UNOS computer system. Local organ procurement organizations which contract with UNOS help manage the logistics of packaging & shipping the organs. Each center has surgeons on call who go out & procure the organs.

These changes are an good start to balancing inequities in kidney allocation across the country. The rules/algorithm are complex & modifications will need to be made, but this is the first major overall that has occurred in many years. Benefits include helping sensitized patients & those with blood group B get more offers. It also helps patients who have a lot of dialysis time move up on the list.

In the first year of the allocation scheme, waiting times for highly sensitized patients & those who are on the list with a lot of dialysis time will get transplanted quickly & so the waiting times will drop on average. However, over time, the average waiting time will overall remain about the same, but for specific groups it might move up or down slightly. For younger, healthier patients, the waiting time is expected to decrease slightly. For older or not as healthy patients, the waiting time will likely increase slightly.

Not all centers will consider transplanting patients with different problems. Cut offs for a patient’s body mass index is an example. Different centers use different cut offs. Underlying diseases is also a consideration;  some centers transplant patients with more or different co morbid conditions (different degrees of heart dysfunction, sickle cell anemia, HIV, hepatitis C).  Different centers also approach multi visceral transplant differently (heart kidney, lung kidney, pancreas kidney, liver kidney, etc).  Outcomes at a center might influence patients.  Location of the center relative to a patient’s home (as this will impact how far they have to travel for follow up).  What services the center providers (who their providers are, how their clinics work, other customer services).