Guideline recommendations on minimal blood vessel diameters and arteriovenous fistula outcomes

Abstract

Objective: Clinical guidelines provide recommendations on the minimal blood vessel diameters required for arteriovenous fistula creation but the evidence for these recommendations is limited. We compared vascular access outcomes of fistulas created in agreement with the ESVS Clinical Practice Guidelines (i.e. arteries and veins >2 mm for forearm fistulas and >3 mm for upper arm fistulas) with fistulas created outside these recommendations.

Methods: The multicenter Shunt Simulation Study cohort contains 211 hemodialysis patients who received a first radiocephalic, brachiocephalic, or brachiobasilic fistula before publication of the ESVS Clinical Practice Guidelines. All patients had preoperative duplex ultrasound measurements according to a standardized protocol. Outcomes included duplex ultrasound findings at 6 weeks after surgery, vascular access function, and intervention rates until 1 year after surgery.

Results: In 55% of patients, fistulas were created in agreement with the ESVS Clinical Practice Guidelines recommendations on minimal blood vessel diameters. Concordance with the guideline recommendations was more frequent for forearm fistulas than for upper arm fistulas (65% vs 46%, p = 0.01). In the entire cohort, agreement with the guideline recommendations was not associated with an increased proportion of functional vascular accesses (70% vs 66% for fistulas created within and outside guideline recommendations, respectively; p = 0.61) or with decreased access-related intervention rates (1.45 vs 1.68 per patient-year, p = 0.20). In forearm fistulas, however, only 52% of arteriovenous fistulas created outside these recommendations developed into a timely functional vascular access.

Conclusions: Whereas upper arm arteriovenous fistulas with preoperative blood vessel diameters <3 mm had similar vascular access function as fistulas created with larger blood vessels, forearm arteriovenous fistulas with preoperative blood vessel diameters <2 mm had poor clinical outcomes. These results support that clinical decision-making should be guided by an individual approach.

Keywords: Arteriovenous fistula; cohort study; hemodialysis; preoperative diameter; vascular access function.

Figure 1.

Flow chart. The study population was divided according to concordance with the ESVS Clinical Practice Guidelines on minimal blood vessel diameters for arteriovenous fistula creation.

Figure 2.

Duplex ultrasound measurements of arteriovenous fistulas created in agreement with guideline recommendations on minimal blood vessel diameters or not. (a) Brachial artery blood flow measured by duplex ultrasound over time; (b) Diameter of the arteriovenous fistula outflow vein measured by duplex ultrasound over time. Data are presented as means and standard deviations. Differences between time points and study groups were analyzed with repeated measures ANOVA. p Values refer to comparisons between study groups.

Figure 3.

Vascular access function of all fistulas, and separately for forearm and upper arm arteriovenous fistulas created in line with guideline recommendations on minimal blood vessel diameters or not. Bar charts of (a) duplex maturation rate (brachial artery blood flow >500 mL/min and outflow vein diameter >4 mm) determined at 6 weeks after vascular access creation; (b) Vascular access function: for patients on dialysis at the time of vascular access creation or who started dialysis within 4 months after vascular access creation, an optimal vascular access outcome was considered as a functional arteriovenous fistula within 4 months after surgery (cannulation with two needles for at least six hemodialysis sessions at the prescribed access circuit flow in 30 days). For patients who had not yet started dialysis treatment at 4 months after vascular access creation, an optimal vascular access outcome was considered as starting dialysis with the index arteriovenous fistula; (c) Access-related intervention rate. Differences between groups were analyzed with Poisson distribution tests.

Figure 4.

Vascular access function of arteriovenous fistulas created in agreement with guideline recommendations on minimal blood vessel diameters or not. (a) Kaplan-Meier survival curve of time to having a functional fistula (cannulation with two needles for at least six hemodialysis sessions at the prescribed access circuit flow in 30 days). The analysis was restricted to patients on dialysis at the time of vascular access creation. Differences between study groups were analyzed with the log rank test. (b) Bar charts of modality of start of hemodialysis. This analysis was restricted to patients not on dialysis at the time of vascular access creation.