MO941CLINICAL OUTCOMES IN KIDNEY RE-TRANSPLANTATION
Authors: Pardinhas Clara , Leal Rita , Caramelo Francisco , Yan Teofilo , Figueiredo Carolina , Nogueira Rui , Rodrigues Luís , Guedes Marques Maria , Romãozinho Catarina , Santos Lidia , Figueiredo Arnaldo , Alves Rui 
Published: May 2021

Abstract

Background and Aims
As kidney transplants are growing in absolute numbers, so are patients with failed allografts and thus potential candidates for re-transplantation. Re-transplantation is challenging due to immunological barriers, surgical difficulties and clinical complexities but it has been proven that successful second transplantation improves life expectancy over dialysis. It is important to evaluate re-transplantation outcomes since 20% of patients on the waiting list are waiting for a second graft. Our aim was to compare major clinical outcomes such as acute rejection, graft and patient survival, between patients receiving a first or a second kidney transplant.

Method
We performed a retrospective study, that included 1552 patients submitted to a first (N=1443, 93%) or a second kidney transplant (N=109, 7%), between January 2008 and December 2018. Patients with more than 2 grafts or multi-organ transplant were excluded. Demographic, clinical and histocompatibility characteristics of both groups were registered from our unit database and compared. Delayed graft function was defined has the need of dialysis in the first week post-transplant. All acute rejection episodes were biopsy proven, according to Banff 2017 criteria. Follow-up time was defined at 1st June 2020 for functioning grafts or at graft failure (including death with a functioning graft).

Results
Recipients of a second graft were significantly younger (43 ±12 vs 50 ± 13 years old, p&lt;0.001) and there were significantly fewer expanded-criteria donors in the second transplant group (31.5% vs 57.5%, p&lt;0.001). The waiting time for a second graft was longer (63±50 vs 48±29 months, p=0.011). HLA mismatch was similar for both groups but PRA was significantly higher for second KT patients (21.6±25% versus 3±9%; p&lt;0.001). All patients submitted to a second KT had thymoglobulin as induction therapy compared to 16% of the first KT group (p&lt;0.001). We found no difference in primary dysfunction or delayed graft function between groups. Acute rejection was significantly more frequent in second kidney transplant recipients (19% vs 5%, p&lt;0.001), being 10 acute cellular rejections, 7 were antibody mediated and 3 were borderline changes. For the majority of the patients (85%), acute rejection occurred in the first-year post-transplant. Death censored graft failure occurred in 236 (16.4%) patients with first kidney transplant and 25 (23%) patients with a second graft, p=0.08. Survival analysis showed similar graft survival for both groups (log-rank p=0.392). We found no difference in patients’ mortality at follow up for both groups.

Conclusion
Although second graft patients presented more episodes of biopsy proven acute rejection, especially at the first-year post-transplant, we found no differences in death censored graft survival or patients’ mortality for patients with a second kidney transplant. Second transplants should be offered to patients whenever feasible.