The core of a paired donation program is the computer registry of donors and willing, medically suitable but incompatible donors. The computer matches up donors with compatible recipients so that reciprocal pairs can swap their donor’s kidneys (Figure A). If recipient A and donor A are incompatible but recipient A is compatible with donor B and recipient B compatible with donor A, then a straight swap will get both recipients transplanted without desensitization. Both recipients are transplanted with compatible donors.
For this to occur, many incompatible pairs have to enter a registry to generate sufficient matches to be successful. The straightforward swap described in Figure A requires donors to travel and for operations to occur simultaneously, which may be logistically challenging. In the case above, all participants lived close to Cleveland Clinic. To improve transplant rates, chains of non-simultaneous transplants are now acceptable (Figure B). Such chains have improved transplant rates compared with simple paired exchange. Furthermore, instead of donors traveling, the living donor kidney can travel much in the same way as deceased donor organs. In other words, if a recipient from Cleveland finds a donor match in Los Angeles through an incompatibility registry, the donors may donate closer to home and have the kidney travel to the recipient destination.
Nephrologists and urologists at the institute recently have become involved with a paired donor registry known as the National Kidney Registry. Since 2008, this registry reports that 68% of the patients listed have been transplanted. This is the highest percentage of any registry in the United States today. The high transplant rates are due to a very strong computer matching program with careful oversight, the use of chain paired donation, and travel of the kidney instead of the donor. We are beginning to enter pairs in this program now and are already looking at potential transplants for our patients. We hope that this will offer an opportunity at transplantation to an otherwise underserved group of kidney disease patients with willing, medically fit but incompatible donors.
David Goldfarb, MD, is a urologist at the Glickman Urological and Kidney Institute at Cleveland Clinic.