Abstract
Background and Aims
Evaluation of kidney donors is a complex process based on the elaboration of clinical, laboratory and imaging data.
Until 2014, the quality of kidney transplant (KTx) was assessed considering standard donation criteria (SCD) or extended donation criteria (ECD).
ECD kidneys (kECD) defined subjects older than 65 years without comorbidities or younger, but with comorbidities, such as hypertension, cerebral stroke, high creatinine level (above 1.5 mg/dL).
The Kidney Donor Risk Index (KDRI) is an estimate of the relative risk of post-transplant kidney graft failure from a particular deceased donor compared to a reference donor.
The value obtained is than converted in a percentage called KDPI (KDPI ≥85% is considered as similar of a kidney from ECD), which represent the percentage of utilized donor in the last year better than the considered.
Italian experience in Donor Cardiac Death (DCD) is growing and doubled last KTx year, reaching 1.1 pmp in 2018, with the 22.5% of donors procured at our center.
Our DCD KTx protocol has been active since November 2017, with promising results. We considered only controlled DCD (cDCD) Maastricht Class III.
Methods
We compared all DCD and DBD KTx performed in the Nephrology Unit of the University Hospital of Modena, Italy, from November 2017 to December 2018. We excluded living donor transplantation and combined liver–kidney transplantation. In this study, only cDCD are considered.
We studied KDPI and KDRI score for both DBD and DCD KTx .
Comparison between data from DCD and DBD was performed with t – Student and Chi Square test, survival analysis according to Kaplan-Meier and a Pearson correlation between KPI-KDRI and one year graft function was elaborated.
ROC curve analysis was performed for KDPI – KDRI and DGF for both groups.
A p lower than 0.05 was considered significant.
Results
A total of 28 DBD KTx, 18 double (64.3%) and 10 single (35.7%) and 7 DCD KTx, 3 double (42.8%) and 4 single (57.2%) were observed during the study. Donors and recipients clinical and immunological characteristics are reported in table1.
All of DCD and 64.3% of DBD donors underwent kidney biopsy (Karpinski values are reported in table 1).
Induction therapy was with aTG in DCD KTx and ECD DBD KTx and with anti-interleukin-2 receptor monoclonal antibodies in SCD DBD KTx. Maintenance immunosuppression consisted in steroid, tacrolimus and mycophenolic acid.
KTx outcomes were reported in table 1 with no differences in both groups between creatinine (p0.3) and eGFR (p0.25).
We analyzed KDPI and KDRI values from DBD and DCD KTx and we stratified them as reported in table 2.
We found 7 DGF in DBD KTx (85% with KDPI >85% and KDRI >1.5) and only 1 DGF in DCD KTx with KDPI>85% and KDRI > 1.5.
We did not find a statistical correlation between KDPI- KDRI and eGFR in both DBD KTx (2 patients died and 3 patients were lost at follow up) (r -0.32, p 0.13; r -0.26, p 0.22) and DCD KTx (r -0.59, p 0.15; r -0.47, p 0.28). (Figure 1)
We performed a ROC curve Analysis to investigate the role of KDPI – KDRI and the risk of DGF. We found no statistical correlation in DCD KTx, considering the small sample size (p 0.61) but we found a significant statistical value in DBD KTx (p 0.03 – p 0.02 with a AUC of 0.77-0.78).
Survival analysis did not show statistical difference between DBD and DCD (p 0.72), no graft loss in the first year, although two DBD (92.8%) recipients died (1circulatory arrest,1 sepsis), no one died in DCD group.
Conclusion
cDCD is a valid resource for KTx, with similar outcomes to DBD. This remarks the importance of a multidisciplinary team and a correct selection of donors. We did not find a correlation between KDPI-KDRI and KTX function after one year of follow up in our population for either group.
Clinical validation of an in-house quantitative real time PCR assay for cytomegalovirus infection using the 1st WHO International Standard in kidney transplant patients
