#1264 Effects of different vascular anastomoses on the transplanted kidney (Inflammation and fibrosis markers from a molecular biological perspective)
Authors: Isoyama Naohito , Hiroyoshi Toshiya , Hitaka Yukihiro , Ogawa Masashi , Yamaguchi Misuhiro , Nakayama Yuki , Nakamura Kimihiko , Shiraishi Koji 
Published: May 2024

Abstract

Background and Aims
Ischemia-reperfusion injury (IRI) is an unavoidable occurrence in kidney transplantation, and the inflammatory response associated with IRI significantly influences allogeneic immunity and transplant outcomes. Minimizing cold ischemia time is essential to reduce IRI, and anastomosis to the internal or external iliac artery is the preferred arterial anastomotic approach. The purpose of this study was to investigate the effect of anastomotic placement on renal function and whether mRNA levels are a factor that may predict renal function decline after transplantation.

Method
This study retrospectively encompassed 65 living kidney transplant procedures conducted from January 2019 to March 2023. The cohort was categorized into two groups using preoperative CT scan assessments of calcification: the internal iliac artery anastomosis group (consisting of 31 patients) with calcification rates below 10%, and the external iliac artery anastomosis group (comprising 34 patients) with calcification rates exceeding 10%. We conducted a comprehensive comparison of preoperative, intraoperative, and postoperative parameters for both groups.
Furthermore, logistic regression analysis was employed to explore the factors influencing renal function. Given the absence of well-defined criteria for assessing renal function post-transplantation, we established a criterion based on the recipient's estimated glomerular filtration rate (eGFR) at discharge, relative to the preoperative donor eGFR. Patients were categorized into two groups, with divisions falling above and below the midpoint of this criterion, and subjected to comparative analysis. In addition, pathology and RNA-seq analysis were performed on protocol kidney biopsies at 3 months and 1-year post-transplant.

Results
Preoperative and intraoperative parameters displayed no significant differences between the two groups, and postoperative renal function remained consistent. Notably, in the external iliac group, one patient required reoperation due to anastomotic hemorrhages, while in the internal iliac group, one patient needed re-anastomosis to the external iliac bone due to insufficient blood flow post-anastomosis. No instances necessitated treatment for rejection. The logistic regression analysis revealed that a lack of prior experience with hemodialysis significantly influenced eGFR in the favorable outcome group. Moreover, RNA-seq analysis and pathology identified mutations in the immune system and TGFβ pathway associated with IRI.

Conclusion
Despite no discernible impact on postoperative renal function attributable to variances in anastomotic arteries, the group with external iliac artery anastomosis exhibited diminished activity in the TGFβ pathway and immune system components associated with fibrosis three months post-operation, hinting at a potentially reduced susceptibility to long-term renal damage. In light of these findings, anastomosing to the external iliac artery appears to be a safe option, and when feasible, it may be the preferable choice for anastomosis in kidney transplantation.