The impact of Arteriovenous fistula anastomosis angle and diameter on steal syndrome: Ultrasound assessment: pilot study
Abstract
Abstract:
Introduction:
Distal hypoperfusion ischemic syndrome (DHIS) or as it is commonly known as steal
syndrome. Steal syndrome is a common problem of arteriovenous access patients. It causes
hypoxia, distal hypo-perfusion, tissue necrosis, gradual finger loss, and eventual peripheral
ischemia when it is reversed from arterial distally to the anastomosis bed. The common cause
of this phenomenon includes proximal or distal stenotic lesion, DM, and lack of collaterals.
However, there are insufficient studies about the angle of anastomosis or diameter and how
they influence steal syndrome. Therefore, we believe there is a correlation between the
anastomosis angle and diameter with DHIS in ESRF patients.
Method: A pilot retrospective study will involve three groups, 29 patients with Steal
syndrome, and the control group will be 61 patients without steal syndrome and 90 patients
with ESRD before fistula creation. Patients data will be collected from the vascular
laboratory at Hammersmith hospital. Several parameters will be assessed, such as
anastomosis angle, VF, and diameter. In addition, the diameter and VF of the artery which
used for the creation of the fistula. Clinical history and data demographics will be recorded
for analysis. Then analysis and comparing between positive and negative steal anastomotic
and volume flow ratio.
Results: The results showed that there was no significant association between the angle of
anastomosis and developing steal syndrome when the angle is ≥45° with a p-value >0.05 and
an angle between 45°-90° showed the lowest percentage of steal syndrome associated in
comparisons with other angels. In terms of risk factors, our results showed that
Hypercholesteremia and family history of CVD were the major risk factors associated with
developing steal syndrome. Moreover, our results suggest that age and gender have an impact
on developing steal syndrome as it was associated with >60% with age group above 60 and
especially with the female gender.
The anastomosis diameter and anastomosis ratio were shown to be extremely significant in
steal patients compared to non-steal patients, with a p-value of <0.005. Furthermore, patients
with steal syndrome had a significantly higher volume flow and volume flow ratio than the
control group, with a p-value of <0.005.
Conclusion: This study suggests that patients with anastomosis diameter >3 mm or an
anastomosis ratio of ≤1.7mm have a greater chance of developing steal syndrome than those
patients with anastomosis diameter of <3 mm or anastomosis ratio of ≥ 1.8mm. In addition,
patients with volume flow in the outflow vein exceeding 800 ml/min or volume flow ratio
≥0.95ml/min are more prone to develop steal syndrome than patients with a volume flow rate
in the outflow vein < 700 ml/min or volume flow ratio ≤0.7ml/min. Our results showed an
angle between 45°-90°, considered preferable as it showed the lowest percentage of steal
syndrome associated in comparisons with other angels.