BTS 2012 Report – The 2010 National Pancreas Allocation Scheme: A one-year review

by Maria Dalby – The introduction of the NHSBT National Pancreas Allocation Scheme in December 2010 has helped to reduce the waiting time for whole pancreas or islet transplantation without prolonging cold ischaemia times. According to Alex Hudson, statistician at the NHSBT who reviewed the one-year results, the scheme represents a successful integration of whole pancreas and islet allocation which has been able to maintain whole pancreas transplantation activity whilst significantly increasing islet activity and conversion rates.

The National Pancreas Allocation Scheme was created in response to increasing transplant activity in the UK, as well as national commissioning of an islet transplant programme and the introduction of the National Organ Retrieval Programme, with the broad aims of devising a transparent and evidence-based allocation process and improving equity in access to pancreas transplantation. The scheme relies on a complex point scoring system which, importantly, places patients waiting for whole pancreas and islet transplantation on a single list, and similarly makes organs from donors after brain death and circulatory death available on the same list. Whilst the overall objectives of the scheme include minimising very poor HLA mismatches, prioritising patients on dialysis over patients listed pre-emptively, and minimising cold ischaemia time, focus during the first year has been on prioritising patients with long (over 2 years’) waiting times, and on using donor BMI for deciding between whole pancreas or islets.

Overall, the number of whole pancreas transplantations remained stable, from 195 transplantations in the previous year to 194 during the first year of the scheme. The number of islet transplantations more than doubled, from 11 in the previous year to 24 during the first year of the scheme. Importantly, this increase was achieved without increasing the use of circulatory-death donors. Donor BMI proved an effective way of choosing between whole pancreas and islet transplants, with the majority of whole pancreas transplantations coming from donors with low BMI, and the majority of islets coming from donors with high BMI (Figure 1). Islet cells were isolated from a total of 67 donated pancreases, 24 of which were transplanted which represented an increase in the conversion rate from around 15% in the previous year to 36% during the first year of the scheme. Donor BMI significantly influenced the likelihood of transplantation; donor age did not.

The proportion of patients waiting for 2 years or more for a pancreas transplantation went from 21% in the previous year to 12% during the first year of the scheme; in the same period, the proportion of patients waiting for less than 1 year increased from 46% to 61%. Another finding during the first year of the scheme included a reduction in very poor HLA mismatches from 34% to 26%, whilst no change was seen in cold ischaemia times. Mr Hudson stressed that it is as yet too early to draw any firm conclusions regarding a scheme that has only been in operation for just over a year, but the early signs are encouraging and suggest that the scheme is on its way to achieving its objectives.

Figure 1. Donor BMI and patient selection for pancreas transplantation.