Sunday, July 28, 2013

First Kidney Exchange in Portugal:

Ana Viana writes from Portugal about the first kidney exchange there, which she and other Operations Researchers helped bring about with some integer programming formulations that they've also written about:

"I am happy to inform you that the first successful kidney exchange in Portugal took place in April.
This was performed under the "Program Nacional para Doação Renal Cruzada" (National Program for Kidney Paired Exchanges), supervised by the Portuguese Institute for Blood and Transplantation (

Below you can find a partial translation of news on the subject that I took from Internet.

To help the decision process the program is using a MIP model developed by myself and my colleagues. It's just the beginning but we are very excited with it!

Best regards,


"The two patients who received in April the kidneys from two living donors in the first kidney exchange transplant in Portugal crossover are well, said to LUSA the doctor responsible for the double intervention.
Five additional pairs are currently under study and it is possible that very soon additional transplants can be done, said surgeon Alfredo Mota from Centro Hospitalar da Universidade de Coimbra(CHUC).
The people involved in the first transplant of its kind in Portugal are a brother (donor) and a sister (patient) and husband (donor) and wife (patient).
The intervention took more than six hours and involved 12 surgeons, 4 anesthesiologists, 12 nurses and 4 technicians, using four operating rooms at the same time.
This type of intervention is "a breakthrough for the country, placing it at the forefront internationally and with greater opportunity to increase kidney transplants," said the same official.

A video can also be found in "
The video is just over two minutes, and it is in Portuguese, with some good shots of both a nephrectomy and a transplant.

Here is a paper by Ana and her colleagues, which is already available online and is listed as (forthcoming) in November 2013 in the European Journal of Operational Research, Volume 231, Issue 1, 16 November 2013, Pages 57–68:

New insights on integer-programming models for the kidney exchange problem
by Miguel Constantino,  Xenia Klimentova, Ana Viana, Abdur Rais,

In recent years several countries have set up policies that allow exchange of kidneys between two or more incompatible patient–donor pairs. These policies lead to what is commonly known as kidney exchange programs.

The underlying optimization problems can be formulated as integer programming models. Previously proposed models for kidney exchange programs have exponential numbers of constraints or variables, which makes them fairly difficult to solve when the problem size is large. In this work we propose two compact formulations for the problem, explain how these formulations can be adapted to address some problem variants, and provide results on the dominance of some models over others. Finally we present a systematic comparison between our models and two previously proposed ones via thorough computational analysis. Results show that compact formulations have advantages over non-compact ones when the problem size is large.

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