Background: Transplant renal artery stenosis is not an uncommon cause of graft failure. It is still controversial regarding the treatment criteria and outcomes of graft after intervention of the stenosis. As devastating complications can occur during intervention, especially acute thrombosis leading to graft loss, the selection for treatment has to be prudent. In a recent systemic review of its management, it appears that endovascular intervention of renal artery yields reasonable patency. However, there is no reports of graft loss in the long-term. This study aims to determine the criteria for intervention and graft failure rate, comparison between suspected and intervened transplant renal artery stenosis.
Method: Nine hundred and fourteen live and cadaveric renal transplants performed at a tertiary hospital from 2011 to 2021 were recruited. A total of 56 patients were identified with transplant renal artery stenosis using the Doppler ultrasonography (US) with peak systolic velocity (PSV) > 250cm/sec. Other factors included systolic blood pressure (sBP) and increased creatinine level. Those who did not fulfil all three criteria were surveyed in three to six months. They were grouped as non-intervention group. Mann-Whitney test was used to compare these parameters between non-intervention and intervention group while Wilcoxon signed-rank test was used to determine the significant improvement of these factors after intervention. Long-term graft failure and patient survival rate in these 56 patients were documented till the censor date on 31 December 2023.
Results: Upon diagnosis, PSV means for non-intervention and intervention groups were 416 ± 113 cm/sec and 532 ± 116 cm/sec respectively (p =0.001). Creatinine increment from baseline value between these two groups was statistically different [non-intervention: 12 (IQR 3-22)micromol/L vs intervention: 30 (IQR 17-77) micromol/L, p = 0.004]. Pre-procedural mean systolic blood pressure of the intervention group was 147 ± 18 mmHg while those in non-intervention group had median sBP of 130 mmHg (IQR: 120-150), p = 0.049. Fourteen grafts had intervention (four balloon angioplasty, seven stenting and two nephrectomy). There were statistically significant reduction of PSV, creatinine level and sBP after treatment (p< 0.001, p = 0.001, p = 0.048 respectively). Only one patient needed re-intervention after two years. Those who had no intervention, the surveillance US showed reduced PSV, 297 ± 137 cm/sec. There was one graft failure (cause was delayed rejection) and one deceased in the intervention group. In the non-intervention group, there were five failed graft (reasons were not renal artery stenosis) and eight mortality within the study period. 
Conclusion: Criteria for intervention from this study in summary are PSV > 400 cm/sec, increased creatinine level of 30micromol/L and sBP > 145mmHg. Intervention of cautiously selected transplant renal artery yields good patency and prolonged graft survival.