**2.3 Arteriovenous fistula creation**

Appropriate and efficient vascular access is necessary for a successful HD. According to the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) guidelines, the ideal vascular access is described as one which can deliver an adequate flow rate along with durability and a low complication rate. An arteriovenous fistula (AVF) is usually considered to be the best access for HD in adults and, as commented on by an emerging body of evidence, that it is the same also in children [12].

It has been seen that children's vascular biology is not the same as that of adults; henceforth, the ideal size of the vein and artery, anastomosis maturation time, and volume flow rates for a functional fistula in children on HD are not known. Since its inception, advances in AVF creation, especially with improved surgical experience, primary failure rates have been gone down to as low as 5%. For an AVF creation, the preferred sites include, in order, the radial artery to cephalic vein (radiocephalic), brachial artery to cephalic vein (brachiocephalic), and brachial artery to basilic vein (brachiobasilic, with or without transposition). Alternatively, an ulnar artery to basilic vein AVF can be created. Though rarely utilized, an AVF between femoral artery to saphenous vein has also been described. Although there are no guidelines regarding ideal/minimum vessel size in the literature, the general consensus is a minimum venous diameter of 2.5 mm. The essential information before AVF creation includes adequate vessel size; venous stenosis/occlusion can be obtained by duplex ultrasound scanning or venography and is necessary to be carried out in children to decide on the best vessels for AVF creation [13]. Complications of AVF creation include stenosis/ occlusion, thrombosis, steal syndrome, and possible discrepancy in limb length if the AVF is placed in the lower extremity. Time for anastomosis maturation may be prolonged, with reports of up to 6 months.
