Abstract: Objectives  To study the pathological course of intimal hyperplasia at the blunt needle buttonhole puncture segments of arteriovenous fistula (AVF), analyze the possible pathogenesis of the intimal hyperplasia, and find out the effective intervention measures.  Methods   Doppler ultrasound was used to observe the intimal hyperplasia at the buttonhole puncture segments of AVF, measure the size of the hyperplastic area, and describe its morphological characteristics. Patients with intimal hyperplasia at the buttonhole puncture segment were divided in to continuous use group and discontinuous use group according to whether or not the puncture was continuously used. The changes of intimal hyperplasia at the puncture segments were dynamically observed. Spearman correlation was used to analyze the correlation between intimal hyperplasia and clinical data of the patients.  Results  A total of 39 patients with 82 buttonholes were included in this study. Ultrasound examinations showed that intimal hyperplasia appeared at the anterior and posterior blood vessel walls of the buttonhole puncture segments with various morphological characteristics. At the initial examination, the incidence of intimal hyperplasia at the blunt needle buttonhole puncture segments was 54.9%, significantly higher than the incidence in the traditional sharp needle puncture group (χ2=103.197, P＜0.001). Spearman correlation analysis showed that the intimal hyperplasia at the buttonhole puncture segments was positively correlated with the puncture time (r=0.211, P=0.001). In the continuous use group, the intimal hyperplasia (n=28) aggravated progressively, with significant increase of length, width and thickness of the hyperplastic area after one year (t=-4.030, -3.093 and -2.454 respectively; P＜0.001, =0.005 and 0.021 respectively). While in the discontinuous use group (n＝21), the intimal hyperplasia subsided gradually, with significant decrease of length and width of the hyperplastic area after one year (t=3.140 and 3.084 respectively; P=0.005 and 0.006 respectively).  Conclusions Intimal hyperplasia is liable to occur at the vascular walls of buttonhole puncture segments, and the degree of intimal hyperplasia gradually increases with the prolongation of puncture time. Discontinuing the puncture is an effective measure to alleviate the intimal hyperplasia.

Key words: Arteriovenous fistula, Buttonhole puncture, Blunt needle, Intimal hyperplasia, Doppler ultrasound