HOW I DO IT

Salvage of Thrombosed Forearm PolytetrafluorGethylene Vascular Access Grafts by Reversal of Flow Direction and Venous Bypass Grafting James A. Schulak,

MD,

Matthew L. Lukens,

A technique is described for salvage of looped forearm polytetrafluoroethylene (PTFE) vascular arcess grafts that fail because of thrombosis due to cephalic vein outflow obstruction. It entails reversal of blood flow direction through the graft and construction of a new venous outflow in the medial upper arm. This procedure was performed in nine patients and, at the present time, has increased the graft life by an average of 6.2 months (range: 2 to 14 months) in eight. We conclude that this is a useful alternative to abandoning failed looped forearm FTFE grafts that have cephalic vein outflow obstruction.

ML),

James T. Mayes,

MD, CI~~&~~, ohlo

this may be accomplished by inserting an extension graft that is tunneled just anterior to the humoral condyle to a new anastomotic site on the basilic vein in the upper arm. However, when venous outflow of the original graft at the antecubitis is into the cephalic vein, a bypass graft would cross the antecubital space in an oblique fashion, thereby being subject to kinking and thrombosis with arm flexion. In this report, we describe a technique for salvage of PTFE grafts with cephalic vein outflow that obviates the problem of graft kinking. This operation includes reversal of blood flow direction in the graft and subsequent venous bypass into the upper arm basilic vein. TECHNIQUE

hen inserting a polytetrafluoroethylene (PTFE) graft for hemodialysis vascular access, we initially W favor a forearm loop because it provides excellent highflow vascular access, is conveniently located for ease of puncture, and spares the upper arm for subsequent access surgery. Unfortunately, the majority of PTFE grafts will thrombose in less than 2 years because of venous outflow obstruction secondary to neointimal hyperplasia [I-5]. Although approximately one third of these thrombotic episodes can be treated successfully with simple thrombectomy, the other two thirds require graft revision [2]. This can usually be accomplished by inserting a PTFE venous outflow patch if the stenotic segment is relatively short (2 to 4 cm). However, if the stenotic segment is long, bypass to a more proximal vein is required. When the original venous anastomosis is positioned medially, From the Department of Surgery, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, Ohio. Requests for reprints should be addressed to James A. Schulak, MD, Department of Surgery, University Hospitals of Cleveland, 2074 Abington Road, Cleveland, Ohio 44106. Manuscript submitted January 4, 1990, and accepted in revised form April 24, 1990.

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The operation is performed either with regional nerve block anesthesia or with local anesthesia and intravenous sedation. Although general anesthesia could be used, we generally have not found this to be necessary. First-generation cephalosporin antibiotic therapy is administered intravenously just prior to starting the procedure to provide prophylaxis against subsequent wound infection. An incision is made in the antecubital fossa sufficient to expose both the arterial and venous limbs of the graft, which is usually accomplished by incising along the course of the previous surgical scar. Attention is first directed to the venous limb, where an attempt at simple thrombectomy is made and the anastomosis is evaluated for insertion of a patch to widen the stenosed venous outflow. If this is not feasible either because of long-segment neointimal hyperplasia or because a patch had been placed previously, plans are then made to proceed with the operation described herein, providing that the arterial limb thrombectomy has been successful in re-establishing arterial inflow. At this point, a second incision is made on the medial aspect of the upper arm just above the elbow in order to isolate the basilic vein. It is important to determine that an adequate vein is present before proceeding further with the operation. This can be accomplished by performing a longitudinal venotomy and flushing the vein with a saline-heparin solution to demonstrate satisfactory flow. Alternatively, an intraoperative venous angiogram can be obtained to demonstrate adequate runoff without proximal stenosis. Once vein suitability has been established, arterial flow direction can then be changed. The arterial and venous limbs of the graft are dissected circumferentially for a length of approximately 3 to 4 cm. It is not necessary to dissect the actual arterial anastomosis if complete thrombus removal has been achieved and arteJOURNAL

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igure 1. Right-forearm looped arteriovenous PTFE graft with cephalic vein venous outflow obstruction (shaded areas). The proposed sites of transection are marked between segments A-B and C-D, and blood flow direction is indicated by the arrow.

rial inflow is satisfactory. The grafts are then transected approximately 3 cm from their respective vascular anastomoses (Figure 1). The proximal venous segment of graft (Figure 2, A) is excised, and the vein is closed by either ligation or suture. The proximal arterial limb of the graft (Figure 2, C) is then moved laterally and anastomosed end-to-end to the remaining venous limb (Figure 2, B ). Next, a segment of PTFE graft, using the same diameter as the original graft, is anastomosed end-to-side to the basilic vein in the upper arm wound. A third incision is then made over the medial portion of the graft just below the elbow and the graft again transected. The short segment of disconnected graft is then removed, and the bypass segment of the graft previously anastomosed to the basilic vein in the upper arm is tunneled subcutaneously just anterior to the humoral condyle to this third incision. The operation is completed by performing an end-to-end anastomosis between the remaining ends of the old and new graft. The revised graft continues to have 486

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Figure 2. Right-forearm looped PTFE arteriovenous graft after revision. Point B of the previous venous outflow limb has been anastomosed to point C of the arterial limb in order to change blood flow direction as Indicated by the arrow. Usually segment A is removed. The operation is completed by performlng a venous bypass extension (stippled segment of gratt)from point D to the basilic vein in the upper arm.

a lower arm brachial artery inflow, retains its forearm loop configuration but with a reversed direction of blood flow, and has a new unobstructed venous outflow in the distal upper arm. This technique for PTFE graft salvage has been performed in nine patients over the past 24 months, eight of whom have had their graft life extended by an average of 6.2 months (range: 2 to 14 months). In one patient, recurrent thrombosis due to inadequate arterial inflow occurred several days after revision. This necessitated construction of new access in the contralateral arm. None of these patients developed wound infections despite the extensive nature of the procedure. COMMENTS Many techniques are currently being used to extend the life of thrombosed FTFE vascular access grafts, including balloon angioplasty, infusion of urokinase [6], 161

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and most importantly, surgical revision. The technique of surgical revision described in this report was developed for patients with forearm loop grafts that have cephalic vein outflow obstruction. Although this procedure is somewhat complex and involves crossing the medial aspect of the elbow joint with the venous bypass graft, this is done in a manner that does not adversely affect graft patency. We believe that there are several advantages to the use of this technique for graft revision. First, the graft can be used for hemodialysis immediately after the salvage operation because the major portion of the conduit is the original graft and therefore well incorporated in the subcutaneous tissue. This obviates the need for use of temporary, percutaneously inserted dialysis catheters. Second, the procedure, when successful, conserves other potential vascular access sites for later use. Conservation of potential vascular access sites is an extremely important concept in the surgical treatment of hemodialysisdependent patients, since many of these patients can now expect to live for 10 years or more because of dialysis

therapy. Accordingly, aggressive salvage procedures to extend the life of PTFE vascular access grafts, such as the one described herein, are becoming increasingly warranted. REFERENCES 1. Bell DD, Rosental JJ. Arteriovenous graft life in chronic hemodialysis. Arch Surg 1988; 123: 1169-72. 2. Raju S. PTFE grafts for hemodialysis access. Ann Surg 1987; 206: 666-73. 3. Zibari GB, Rohr MS, Landreneau MD, et al. Complications from permanent hemodialysis vascular access. Surgery 1988; 104: 681-6. 4. Palder SB, Kirkman RL, Whittemore AD, et al. Vascular access for hemodialysis. Ann Surg 1985; 202: 235-9. 5. Etheredge EE, Haid SD, Maeser MN, et al. Salvage operations for malfunctioning polytetrafluoroethylene hemodialysis access grafts. Surgery 1983; 94: 464-70. 6. Davis GB, Dowd CF. Bookstein JJ, et al. Thrombosed dialysis grafts: efficacy of intrathrombic deposition of concentrated urokinase, clot maceration, and angioplasty. AJR Am J Roentgen01 1987; 149: 177-81.

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Salvage of thrombosed forearm polytetrafluoroethylene vascular access grafts by reversal of flow direction and venous bypass grafting.

A technique is described for salvage of looped forearm polytetrafluoroethylene (PTFE) vascular access grafts that fail because of thrombosis due to ce...
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