*4.2.5 Steal syndrome*

Distal hypo-perfusion of the limb in case of severe peripheral vascular disease due to pulling of arterial blood flow in AVF causes steal syndrome. Failure of adequate collateral formation and/or excessive blood flow is the main causes of symptomatic steal. About 3 to 8% cases may present with steal syndrome [7]. Brachiocephalic AVF tend to cause steal more than radio-cephalic AVF. Hand ischemia, pain, numbness are some of the symptoms where steal syndrome may be present. AVF shows normal color flow and high PSV.

For arterial steal, radial artery at wrist is usually examined. In complete arterial steal, direction of flow distal to the graft is reversed, however in partial steal, the spectral waveform becomes biphasic. Steal syndrome is confirmed if gentle compression of graft reverses the direction of flow and normal spectral waveform is achieved (**Figure 12**). Symptomatic steal may require graft ligation. However, asymptomatic steal is also seen which warrants no clinical significance.

#### **Figure 12.**

*(a) CDI image showing antegrade flow during systole and retrograde flow during diastole in radial artery distal to anastomosis (b) on gentle compression of AVF, elevated systolic flow and diastolic flow is noted confirming arterial steal syndrome [8].*

*Hemodialysis AV Fistula: What a Radiologist Should Know? DOI: http://dx.doi.org/10.5772/intechopen.100485*

Other complications like cardiac failure, venous hypertension and median nerve injury are also noted in relation to AVF. However, they are not very common and role of radiology is not prevalent. Venous hypertension may be seen as reversal of blood flow in color doppler study. Median nerve injury may occur from ischemic injury due to steal syndrome or direct compression of median nerve due to hematoma or amyloid deposition in late phases of AVF. In such cases, radiology can evaluate the primary etiology.
