Integer programming approach and application of reformulation-linearization technique to liver exchange problem

Organ transplants are essential for many end-stage organic disease patients. Unfortunately, because of medical or biological incompatibilities, not all donors can donate to their intended recipients. These incompatibilities can be overcome by organ exchange programs, which find new compatible donor–patient pairs by exchanging donors between patients. Organ exchange programs have become prevalent in the last decade for kidneys, and liver exchanges have also been increasing steadily. However, despite the growing number of liver exchanges, since the procedure is relatively new, there is a lack of studies attempting to optimize exchange plans through mathematical programming. This paper develops a new integer programming model for liver exchange programs that takes into account the unique characteristics of liver transplantation. In addition, a new enhanced model is obtained by applying the reformulation-linearization technique (RLT), which provides tight linear programming (LP) relaxation bounds and is computationally efficient.