GUIDELINES [ back to index ]
22. Management of ischemia (2)
*1 Surgical banding
• Surgical banding of the access is usually performed close to the arterial anastomosis. A/V fistulas can be banded with non-absorbable sutures, a small calibre interposition graft, or by narrowing the vein with a tight Dacron or PTFE cuff. In prosthetic access, interposition of a short tapered graft segment has been suggested. All these procedures create a reduction in blood flow up the fistula and steal syndrome will disappear after a sufficient reduction in fistula blood flow or cessation of reversal of diastolic retrograde inflow from the distal brachial artery. This can be achieved only when access resistance at least approaches the level of peripheral arterial resistance. Sufficient surgical banding thus means suturing a high grade anastomotic stenosis with the risk of insufficient flow or even access thrombosis 1 2. Therefore, banding should be attempted only with intraoperative monitoring of access flow as well as peripheral circulation (pulse oximetry, continuous transcutaneous pO2 (tcpO2) measurement, digital photoplethysmography, pulse volume recordings or Doppler wrist/brachial pressure index measurement 3 4).
• Despite subtle technique, access banding results in high rates of thrombosis or recurring steal 1.
• See also algorithm: “Management of high flow in A/V fistula and grafts”.
*2 Ligation of distal radial artery
• The easiest way to block retrograde arterial inflow into a distal access at the wrist is to ligate (or embolise) the artery distally to the anastomosis. In radio-cephalic (or ulnar-basilic) fistulae, the effect can be simulated by digital compression of the respective artery at the wrist below the anastomosis. In 1971, Bussell et al. demonstrated an increase in pulse amplitude of the thumb averaging 80 % in compressing the radial artery distal to the anastomosis, thus impairing retrograde inflow 5. By compressing the ulnar artery, a 90 % reduction in pulse amplitude of the thumb was seen.
• Before interventional embolisation of the artery, temporary balloon blockade can serve the same purpose. Pulse oximetry, continuous transcutaneous pO2 (tcpO2) measurement or digital photoplethysmography prior to and after definitive treatment are helpful in quantifying the problem and assessment of the improvement in hand circulation 6.
*3 DRIL procedure
• Arterial ligation distal to the A/V fistula can also be performed successfully in elbow fistulas to treat steal syndrome. Ligation of the brachial artery, however, was felt to enhance the risk of forearm ischaemia. Therefore D istal R evascularisation was added to I nterval L igation of the artery. In this so-called DRIL procedure, the artery is ligated distally to the access anastomosis, and a vein bypass from proximal to the anastomosis to distal to the ligation is inserted. It is recommended that construction of the proximal anastomosis should be a reasonable distance (>5 cm) proximal to the access to prevent diastolic retrograde flow , and thereby recurrence of steal syndrome, within the bypass. Results of DRIL procedure appear reasonable although only a few centres have reported long-term results 1 7.
*4 Distal extension of the access
• Another alternative which does not involve ligation of a normal brachial artery is to take down the fistula at the anastomosis, thereby reconstituting the brachial artery flow and then using a separate segment of vein to extend the fistula vein onto the proximal or distal radial or ulnar artery. This allows fistula inflow from one forearm artery whilst still allowing distal flow down the other. This has not been published in a series but has been effective in a clinical practice.
• Closure of the access is often the only reasonable way to limit severe distal necrotic lesions, especially in cases of major arterial calcification and in patients with significant surgical risk factors. When abandoning the access and creating a new one on the other arm, the high risk of steal syndrome in that extremity must be borne in mind. Some of these patients therefore are candidates for permanent central venous haemodialysis access.