Access Blood Flow as a Predictor of Early Failures of Native Arteriovenous Fistulas in Hemodialysis Patients

Abstract

Blood flow imaging using color doppler has proven effective in predicting graft failures in hemodialysis patients, but its effect on native arteriovenous fistulas (AVF) is not well known. This study was performed to investigate whether measurements of the access blood flow can be used as predictors of an early failure of a native AVF in hemodialysis patients. Fifty-three consecutive patients who received native AVF operations were included in this study. Access blood flow was measured at 1 week after operations, and AVF function was followed for 4 months. During the follow-up, access failures developed in 10 patients at 9.8 ± 3.5 weeks. AVF blood flow was significantly lower in the failure group (n = 10) than in the patent group (n = 43) (450 ± 214 vs. 814 ± 348 ml/min, p = 0.003). The incidence of access failures was higher in the patients with a flow <350 ml/min (n = 9) compared to the patients with a flow >350 ml/min (n = 44) (55.5 vs. 11.3%, p = 0.008). The diameters of veins were significantly smaller in the failure group than in the patent group (3.5 ± 0.5 vs. 4.1 ± 0.7 mm, p = 0.018). The incidence of diabetes mellitus was higher in the failure group than in the patent group (90 vs. 51%, p = 0.025). However, age, sex, duration from an operation to first cannulation, and different AVF sites did not make a significant difference between the two groups. Our data suggest that access blood flow measurements using color doppler ultrasound during early postoperative periods are useful parameters in predicting an early failure of a native AVF in hemodialysis patients.

Color Doppler ultrasound and arteriovenous fistulas for hemodialysis

“…To this end, the international guidelines recommend a specific protocol for vascular access monitoring (physical examination of the AVF before each dialysis session) and surveillance (assessment of recirculation, venous/arterial pressures, calculation of flow volume and other parameters, which provide information on AVF function and should be evaluated on a monthly basis) [24]. Measurement of blood flow is now considered the best means of surveillance for a vascular access [24]: reduced flow volumes or values that decrease over time are predictive of thrombosis for both native and prosthetic AVFs [32,34,35]. There are several methods for calculating AVF flow (DUS, MR angiography, the ultrasound dilution technique, the Crit-line monitor, glucose infusion, differential conductivity, ionic dialysance), and none is considered unequivocally superior to the others in the main international guidelines [12,24].…”

“…Values of \500 ml/min [13,24] and \300 ml/min [13,32] are considered predictive of access dysfunction and imminent thrombosis, respectively. Aside from these absolute values, subsequent studies have shown that, in a vascular access that has previously been stable with flow volumes of [1,000 ml/min, further investigation is warranted when consecutive monthly measurements reveal a decrease in flow volume of [25 % over a relatively short period of time (1-4 months) since these findings are predictive of stenosis and vascular access thrombosis [15,24,34,35]. DUS calculation of AVF flow volume can also be useful for assessing the effectiveness of a therapeutic intervention carried out to resolve a complication.…”

Arteriovenous fistula for dialysis — what do we know today?

“…Elderly people and diabetic patients are more prone to early complications [28]. Too early attempts of needle insertion to the fistula, in particular within 14 days of its formation, increase the risk of complications and shorten AVF survival [4].…”

“…It is well-established that anticipative management strategies bring more benefits than any other treatment following thrombus formation. The first check of a newly formed AVF is performed within a month of its creation [28,32,34]. Postoperative wound healing is assessed and infection or venous thrombosis ruled out.…”

“…Wang et al recommend follow-up examinations on day 1, week 1 and 12 weeks of vascular access surgery [28]. Duplex Doppler ultrasonography is a method of choice to assess anastomosed vessel morphology.…”