Poor Kidney Transplant Outcomes and Higher Organ Discard Rate Secondary to Macroscopic Arteriosclerosis of Renal Artery: More Evidence Needed to Prove Correlation.

Abstract

We read the outcome of study by Keijbeck et al1 with great interest. The authors have attempted to define the association between macroscopic renal artery arteriosclerosis, donor kidney discard, and transplant outcome. The study concluded that macroscopic arteriosclerosis of the renal artery was independently associated with kidney discard and primary nonfunction of transplant kidney; no effects were demonstrated on delayed graft function, glomerular filtration rate at 1 y, or long-term graft survival. These are indeed exciting findings and encourage the use of marginal kidneys, and the authors need to be congratulated for the timely article with deep clinical significance. We would like to share our views in this regard. This study has a ratio of over 1:7. We would like to know the research methodology used to match the groups to minimize effect estimation bias. In our experience, macroscopic arteriosclerosis is a subjective assessment without an evidence-based grading. This subjectivity and interobserver variation lead to a varied judgment regarding the magnitude of disease among surgeons. The score used by Euro Transplant for estimation Macroscopic Arteriosclerosis of the Renal Artery lacks published evidence of interrater reliability. Despite being widely used, there are no validation studies to prove the clinical validity of the Euro-Transplant score as yet. It would also be interesting to know the Cohen’s kappa statistic of the Euro-Transplant score for reliable use in the wider clinical domain. Contrastingly, Kakuta et al2 have evaluated the impact of microscopic arteriosclerosis and long-term outcome and concluded that although there was increased risk of rejection, the long-term outcome was similar in both the groups. The authors mention that the kidney discard rate due to poor kidney quality was 94.3%. It would be good to know as to how the “poor kidneys” were characterized, what percentage of these poor kidneys had arteriosclerosis, and the analyses of kidneys that were discarded without arteriosclerosis. A wide range of factors influences the decision to accept or discard from extended criteria donor kidneys. These include presence of hypertension, diabetes, history of cerebrovascular accident, duration of the disease, medications, and end organ damage. Additionally, the types of donor (DCD or DBD), cold ischemia time, and associated anatomy of the kidney (kidney perfusion, parenchymal damage, arterial dissection) are critical to decision making. Auglienė et al3 have suggested that in addition to these donor factors, recipients’ age, urinary tract infection, and acute graft rejection episodes after transplantation also have significant negative impact on the renal graft function 1 y after transplantation. Moreover, tools are being developed that include donor and recipient factors to predict graft survival after transplants.4 This indicates that arteriosclerosis in isolation has little contribution to final decision making and predicting the outcome of graft survival. Overall, the study suggests that there is an increased discard rate of arteriosclerotic kidneys but without accounting for other available functional reserves of donor kidneys. We feel that more evidence is needed to justify a change in our clinical practice.