Abstract: Objective To explore the predictive value of Klotho protein in peripheral blood for arteriovenous fistula (AVF) restenosis in patients with end-stage renal disease (ESRD) after percutaneous transluminal angioplasty (PTA). 
Methods A total of 240 ESRD patients undergoing PTA  in the Second Affiliated Hospital of Xingtai Medical College were selected as the research subjects. The follow-up deadline was December 2022, and they were divided into stenosis group and non-stenosis group based on occurrence of AVF restenosis. The peripheral blood Klotho levels of two groups were detected and compared, and the correlation between peripheral blood Klotho and AVF restenosis and predictive value of peripheral blood Klotho for AVF restenosis were analyzed.  Clinical data of the two groups were collected for univariate analysis and multiple logistic regression analysis to explore independent risk factors for VAF restenosis. 
Results The peripheral blood Klotho in the stenosis group was significantly lower than that in the non-stenosis group, with a significant difference (P＜0.05). There was a negative correlation between peripheral blood Klotho and AVF restenosis (r=-0.039, P＜0.001). The area under the receiver operating characteristic (ROC) of peripheral blood Klotho for predicting AVF restenosis was 0.866 (95%CI: 0.823-0.909), with a cutoff value of 1.35 ng/L. Multiple logistic regression analysis showed that age ≥ 75 years (OR=2.425, 95%CI: 1.054-5.579), glycated hemoglobin ≥ 6.5% (OR=2.570, 95%CI: 1.328-4.975), serum albumin ＜40 g/L (OR=3.105, 95%CI: 1.040-9.269), calcium phosphorus product ＞50 mmol/L (OR=3.804, 95%CI: 1.155-12.524), and Klotho protein ＜1.35 ng/L (OR=2.863, 95%CI: 1.272-6.446) were independent risk factors for postoperative restenosis in ESRD patients undergoing PTA (P＜0.05). 
Conclusion The level of peripheral blood Klotho has a negative correlation with the occurrence of AVF restenosis in ESRD patients after PTA, which has a high predictive value. The decrease in peripheral blood Klotho level, the advanced age, the increase in glycated hemoglobin level, the decrease in serum albumin level, and the increase in calcium phosphorus product are independent risk factors for AVF restenosis. 

Key words: kidney failure, chronic, percutaneous transluminal angioplasty, arteriovenous fistula