Venous distensibility is more important than venous diameter in primary survival of autogenous radiocephalic arteriovenous fistulas

BACKGROUND: Many studies suggested that the optimal cephalic vein diameter for wrist radio-cephalic arteriovenous fistula construction should be at least 2 mm to predict successful maturation and primary patency. However, our experience has shown that many patients with smaller cephalic vein diameter (≤2 mm) in the neutral state (without a tourniquet) also have good clinical outcomes. The aim of this study was to identify predictors that affect primary survival of new wrist radio-cephalic arteriovenous fistula in patients with cephalic vein diameter ≤2 mm. METHODS: We performed a retrospective review of 50 patients with preoperative cephalic vein diameters ≤2 mm in the neutral state who underwent wrist radio-cephalic arteriovenous fistula construction between September 2016 and October 2019. Internal diameters of the cephalic vein and radial artery, venous distensibility, peak systolic velocity, and resistance index of the radial artery were determined by ultrasound examination before wrist radio-cephalic arteriovenous fistula placement. Patients were divided into two groups: failure and survival. RESULTS: The radio-cephalic arteriovenous fistula survival rate was 68% from the time of radio-cephalic arteriovenous fistula creation until the end of the study. Univariate analysis showed that larger venous distensibility (p < 0.001), non-diabetic kidney disease (p = 0.009), and slower peak systolic velocity of the radial artery (p = 0.033) were predictive factors for primary radio-cephalic arteriovenous fistula survival. Multivariate regression analysis revealed good venous distensibility (odds ratio = 9.637, 95% confidence interval = 1.893-49.050, p = 0.006) and non-diabetic kidney disease (odds ratio = 0.148, 95% confidence interval = 0.033-0.660, p = 0.012) to be independent predictors for primary radio-cephalic arteriovenous fistula survival. Receiver operating characteristic analysis showed that venous distensibility >0.52 mm (sensitivity: 70.6%, specificity: 68.8%) was the best cut-off value to predict primary radio-cephalic arteriovenous fistula survival. CONCLUSION: When cephalic veins with diameter ≤2 mm are found, venous distensibility should be used to aid in the surgery decision-making process. The outcome of wrist radio-cephalic arteriovenous fistula survival would be significantly improved through the use of cephalic vein with venous distensibility >0.52 mm.