GUIDELINES [ back to index ]
12. Management of A/V fistula stenosis
*1 Relevant stenosis
Stenosis should be treated, if the reduction of diameter exceeds 50 % and is associated with abnormal physical findings, reduction in access flow, measured dialysis dose or previous thrombosis.
A stenotic lesion or vessel segment, induced by intimal hyperplasia, is the most common cause for low flow. In radiocephalic A/V fistulas, 55 - 75 % of these stenoses are located at the A/V anastomosis and 25 % in the outflow tract 1 2 3. In brachiocephalic and / or basilic A/V fistulas the typical location (55 %) is at the junction of the cephalic with the subclavian vein and the basilic with the axillary vein, respectively 1. An arterial inflow stenosis > 2 cm from the anastomosis is rare but may jeopardise flow in the A/V fistula.
*2 Stenosis of the anastomotic area
Primary surgical treatment is indicated in stenoses of the anastomotic area located in the lower forearm. However, PTA is also possible although its results are likely less durable.
Primary interventional treatment is indicated in stenoses of the anastomotic area located in the upper forearm and in the upper arm. However, surgery must be considered in cases of early or repeated recurrences of the lesions.
Dilatation or surgical revision of anastomotic stenoses in upper arm fistulas can result in steal syndrome and hand ischaemia. Prudent dilatation to 5 or 6 mm is recommended first and it is rarely indicated to dilate to more than 6 mm. Nephrologists must be warned to look after the hand of such patients in the days and weeks following the dilatations or surgical revisions.
*3 Outflow stenosis
Percutaneous transluminal angioplasty (PTA) is the first treatment option in outflow vein (cephalic / basilic) stenosis (see appendix for details).
Junctional stenosis, i.e. stenosis at the junction of the superficial vein with the deep venous system, can also be treated by PTA.
Surgical correction may be needed after failed PTA with and without stent placement.
An eventual stent placed in the final arch of the cephalic vein must not protrude into the subclavian vein where it could induce stenosis and preclude future use of the downstream (basilic, brachial, and axillary) veins.
*4 PTA
In order to visualise the stenoses, angiography is performed by puncturing of the brachial artery in case of anastomotic problems or by direct puncture of the vein above the anastomosis if an outflow problem has occurred 4.
It is controversial, whether long stenosis should be treated radiologically or surgically. While some authors recommend surgical intervention in long segment stenoses (longer than 6 cm) 5, either by graft interposition 6 or vein transposition, others recommend radiological intervention also in long stenoses (> 5 cm) 4. Studies proving the superiority of one of the treatment are not available. However, some radiological series recently confirmed that long stenoses (> 2 cm) usually had a poorer outcome 7.
*5 Persistent stenosis
Some stenoses cannot be dilated by balloon angioplasty. These hard stenoses can be treated with atherectomy devices or cutting balloons, first described by Vorwerk et al. 8.
*6 Recurring stenosis
Recurring stenoses can be treated radiologically, with or without a stent, or surgically 4. The decision should be made considering the individual situation of the patient and the invasiveness of surgical treatment.
Despite complete opening of the PTA balloon (without waste) of sufficient diameter, the dilated vessel wall may collapse immediately after removal of the balloon. This elastic recoil can be treated with stent implantation, especially in central veins, as long as the ostia of major side branches will not be covered by the stent. There is no room for stent placement in the needling areas of forearm fistulas except for acute PTA-induced ruptures not controlled by a prolonged balloon inflation.