Wednesday, July 25, 2018

Kidney Exchange at Methodist of San Antonio

Good matching algorithms and software, innovative histocompatibility tests, recruiting lots of compatible pairs and good surgery and administration combine to make an exemplary single center kidney exchange program:

400 Kidney Paired Donor Transplants at a Single Center; The Methodist San Antonio Experience
A. Bingaman, M. Kapturczak, I. Ashlagi, C. Murphey.

Background: Kidney paired donation (KPD) has become the standard of care for incompatible living donor pairs. Several mature national KPD programs exist yet KPD transplants only represent about 11% of total live donor transplants in the U.S., less than predicted by computer modeling. Methods: We initiated a single center KPD program in 2008. Consenting pairs were entered into our KPD database with blood types, HLA types and unacceptable antigens individually assigned based upon single antigen bead analysis. Results: Between March 2008 and October 2017 our single center KPD program has done 400 KPD transplants, representing 26% of total living donor transplants at our center. These transplants include 57 2-way exchanges, 36 3-way exchanges, 9 4-way exchanges, 6 5-way exchanges, 2 6-way exchanges and 13 non-directed donor (NDD) initiated chains ranging in length from 3-23 recipients. 218 patients were sensitized HLA incompatible with their original donors including 111 (51%) with cPRA >80% and 53 (24%) with cPRA >99%. 62 recipients (15.5%) were re-transplant patients. A total of 43 patients underwent desensitization for positive flow crossmatch or ABO incompatibility. A total of 222 (55%) blood type O donors were utilized of which 212 (95.5%) were transplanted into blood type O recipients or non-O recipients with cPRA >80%. 22 blood type A2 donors were utilized, of which 15 (68%) were transplanted into non-A recipients. 51 compatible pair donors were utilized of which 48 donors (94%) were blood type O or A2, and 3 donors (6%) were blood type A1. Compatible pairs participated in a total of 155 KPD transplants. All compatible pair recipients received kidneys from younger donors. Overall one year graft survival is 98.7%. Conclusions: We report the largest single center KPD program in the world. With limited NDDs, KPD programs must utilize blood type A2 donors and compatible pairs in order to transplant blood type O recipients effectively. To transplant the most highly sensitized patients, combination of KPD and desensitization is very effective with excellent outcomes.
CITATION INFORMATION: Bingaman A., Kapturczak M., Ashlagi I., Murphey C. 400 Kidney Paired Donor Transplants at a Single Center; The Methodist San Antonio Experience Am J Transplant. 2017;17 (suppl 3).

Utilization of Compatible Pairs in a Large Kidney Paired Donation Program

Methodist Specialty and Transplant Hospital, San Antonio, TX
Southwest Immunodiagnostics, San Antonio, TX

Background: Our center has established a very large single center kidney paired donation (KPD) program. A significant barrier to KPD transplant has been the unbalanced blood types in the KPD pool which develops over time, including many blood type O recipient candidates and many non-O donor candidates. Additionally, highly sensitized recipient candidates are in competition for rare donor HLA types. Computer modeling has shown that KPD can be significantly expanded by participation of compatible pairs, particularly to enrich the pool of O donors and utilize donors with rare HLA types. Here we report our experience utilizing compatible pairs as a part of our KPD program. Methods: All recipients with consented incompatible donors were entered into our KPD database. In addition, compatible pairs with older donors that were not HLA identical were approached for consent into the database. Compatible recipients were only offered a kidney from a younger exchange donor. Results: Since February 2009, 23 compatible pairs have been utilized in KPD transplants at our single center, including 14 2-way exchanges, 5 3-way exchanges and 4 chain exchanges (chain lengths 10-23 recipients.) Of the compatible pairs, 8 recipients were blood type O and 15 were non-O; 21 donors were blood type O, 1 was type A2 and 1 blood type A1. In marked contrast, of the incompatible pairs which benefited, 20 recipients were blood type O and 3 were non-O; 10 donors were blood type O, 11 were blood type A1 and 2 blood type B. Of the compatible KPD recipients, none were sensitized, whereas of the incompatible recipients 15 were sensitized, 9 with cPRA >80%. All compatible KPD recipients were transplanted with younger kidney donors. The median age of compatible donors was 57 years whereas the median age of incompatible donors was 29 years. Patient and allograft survival are 100% for both compatible and incompatible groups, median follow up 28 months. The compatible KPD option was viewed as favorable by the majority of pairs approached for consent. Conclusions: This is the largest reported experience of compatible pairs utilized in KPD. When employed in a large KPD program, compatible pairs with O donors significantly expand KPD options for both blood type incompatible pairs and highly sensitized recipients. Utilization of compatible pairs should be expanded nationally to increase the opportunity for incompatible pairs to be transplanted through KPD.

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