To systematically evaluate the clinical characteristics and treatment prognosis of patients with moderate-to-severe transplant renal artery stenosis (TRAS), and to explore the risk factors of TRAS after kidney transplantation, providing the basis for early prevention, diagnosis, and treatment.

The clinical data of 16 patients who underwent kidney transplantation in Northern Theater Command General Hospital from January 2022 to July 2024 and were diagnosed with moderate-to-severe TRAS during follow-up were retrospectively analyzed, and recipients who received the other kidney from the same donor were selected as the control group. The basic information, clinical manifestations, laboratory test results, treatment methods, and prognosis of the patients were collected. Independent sample t-test, Mann-Whitney U test, or paired sample t-test were used for comparative analysis of measurement data, while chi-square test or Fisher′s exact probability method were applied to count data. Cox proportional hazards regression was used to analyze risk factors for moderate-to-severe TRAS. The receiver operating characteristic curve (ROC) was used to evaluate the predictive performance of risk factors for TRAS.

The incidence of moderate-to-severe TRAS after kidney transplantation was 4.5%, with a median time of 157 days post-transplantation. At the time of TRAS diagnosis, the TRAS group had significantly higher neutrophil ratio, serum urea nitrogen, creatinine, and cystatin levels, and lower hemoglobin levels compared to the control group (all P<0.05). Univariate analysis showed that the TRAS group had a lower body mass index, higher proportion of re-transplantation, more frequent use of mizoribine, and higher serum lipoprotein a levels compared to the control group, with statistically significant differences (all P<0.05). Cox proportional hazards regression analysis showed that re-transplantation (HR=5.772, 95%CI: 1.227-26.684, P<0.05) and high lipoprotein a levels (HR=1.008, 95%CI: 1.002-1.013, P<0.05) were independent risk factors for moderate-to-severe TRAS. ROC curve analysis for lipoprotein a showed that the area under the curve was 0.771 (95%CI: 0.597-0.946, P<0.05), and the optimal cutoff value was 74.95 nmol/L. In the TRAS group, 9 patients were stented, 2 patients were treated with balloon dilatation alone, and 5 patients were treated with balloon dilatation combined with stent implantation; serum creatinine at 3, 7, 14, 28 days and 2, 3 months after interventional therapy was significantly different from that before surgery (t=2.959, 3.354, 2.795, 3.148, 3.040, and 3.721, P<0.05).

Patients with moderate-to-severe TRAS after kidney transplantation exhibit higher neutrophil ratios, more severe anemia, and significantly elevated serum urea nitrogen, creatinine, and cystatin levels. Interventional therapy can significantly improve renal function in such patients. Patients with re-transplantation and lipoprotein a levels >74.95 nmol/L were at higher risk of moderate-to-severe TRAS.