Abstract: Objective  To investigate the effect of overlock suture for vascular anastomosis during internal fistula surgery on postoperative patency of the internal arteriovenous fistula (AVF).  Methods  A retrospective analysis was performed on 256 patients who received vascular anastomosis surgery for AVF construction in our hospital from July 2020 to June 2023. They were divided into two groups according to the stitch method: the traditional manual stitch group using manual stitch (n=178), and the overlock stitch group using a stitch instrument for stitch (n=78). The two groups were matched 1:1 with 64 patients in each group by propensity score matching (PSM) method. The efficacy and complications after the treatment were compared between the two groups. According to the patency of AVF after the surgery for 6 months, the 128 patients were divided into patency group (n=81) and poor patency group (n=47). Univariate and multivariate logistic regression were used to analyze the independent influencing factors for poor AVF patency. A risk assessment scale and risk stratification were conducted, and the predictive value of the risk assessment scale were verified.  Results After the surgery for one month and 6 months, anastomotic diameter (t=22.936 and 24.078, P<0.001), blood flow in AVF (t=12.990 and 14.009, P<0.001) and AVF patency rate (χ2=5.489 and 6.646, P=0.019 and 0.010) were better in the matched overlock stitch group than in the matched traditional manual stitch group. Postoperative complication rate was lower in the matched overlock stitch group than in the matched traditional manual stitch group (χ2=19.384, P<0.001). Multivariate logistic regression showed that mean arterial pressure ≥70mmHg (OR=3.355, 95% CI: 1.502～7.492, P=0.003), preoperative internal diameter of the anastomotic artery <3.5mm (OR=2.344, 95% CI: 1.124～4.888, P=0.023) and preoperative internal diameter of anastomotic vein <3.5mm (OR=2.177, 95% CI: 1.048～4.525, P=0.037) were the independent risk factors for poor postoperative patency of AVF, while hypertension history (OR=0.114, 95% CI: 0.049～0.265, P<0.001), diabetes history (OR=0.357, 95% CI: 0.168～0.759, P=0.007) and blood phosphorus ≤1.78mmol/L (OR=0.501, 95% CI: 0.239～1.047, P=0.006) were the protective factors for postoperative AVF patency. Using scores of 3 points in the risk assessment scale as the optimal cutoff value for diagnosis, the sensitivity and specificity were 79.8% and 73.2% respectively; scores of ≤2.5 points were classified as low risk, 3.0～4.0 points as medium risk, and ≥4.5 points as high risk of poor patency. Using the 120 patients treated between July 2022 to June 2023 to verify the diagnostic value of the assessment scale and showed that the sensitivity, specificity, positive predictive value, and negative predictive value of poor patency were 79.6%, 78.9%, 70.6%, and 85.6% respectively.  Conclusion The overlock suture technique for vascular anastomosis in the surgery of AVF construction can significantly improve the postoperative patency of the AVF. Overlock stitch technique provides a stable and reliable anastomosis and reduces the risk of postoperative complications.

Key words: Overlock suture, Vascular anastomosis, Arteriovenous fistula, Patency, Influence