It has been accepted worldwide that the classic internal A-V shunt in the arm constitutes ideal vascular access for performing chronic haemodialysis. When the vessels have been worn out by previous efforts or the veins are not competent, then it is necessary to use special synthetic grafts to bridge the gap between the artery and the vein as they are too far apart. These grafts cannot be the first choice for a vascular procedure in a new patient but must be used in patients who have a certified vascular problem. The A-V grafts are usually placed in the arm between the humeral artery and the axillary vein, either straight or in loop formation in the forearm between the brachial artery and the mesobasilic vein (Figs. 13.1.3-13.1.5).
In rare cases the A-V grafts may be placed in the leg in loop formation between the superficial femoral artery and the major saphenous vein of the same leg (Fig. 13.1.6). They can also be placed suprapubically between the superficial femoral artery of one leg and the major saphenous vein of the other (Fig. 13.1.7). In very rare cases,
where it is not possible to place an A-V graft in either the arm or leg, the graft may be placed like a necklace between the subclavian artery of one side and the subclavian vein of the other (Fig. 13.1.8).
The rate of infection is high and the average time of its function is less than that of the internal A-V shunt. In the first year, their functional time ranges from 65% to 95%. The reasons for their insufficiency are:
• A high percentage of infections
• Stenosis of the venous edge of the anastomosis
• Aneurysm formation.
The most sufficient graft is an autograft from the actual patient (whether it is the saphenous above the knee or the cephalic above the elbow). If it is impossible to use them there are other grafts from modified umbilical veins or synthetic ones from PTFE.
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