Two-stage Hemodialysis Reliable Outflow (HeRO) graft implantation technique that avoids the use of a femoral bridging dialysis catheter

Introduction

A large number of patients with end-stage renal disease (ESRD) require long-term hemodialysis. Vascular access options for hemodialysis include the placement of arteriovenous (AV) fistulas, AV grafts, and tunneled dialysis catheters (TDCs) (1). The National Kidney Foundation Kidney Dialysis Outcome Quality Initiative (NKF-K/DOQI) recommends autogenous AV fistulae as the first choice of vascular access, followed by prosthetic AV grafts (2). In patients in whom these preferred dialysis access options have been exhausted, TDCs are considered as a last resort, for TDCs are associated with a high incidence of catheter-related infection, central venous outflow obstruction, and less effective dialysis owing to poor dialysis flow rates (3, 4).

One alternative to the TDC is the Hemodialysis Reliable Outflow (HeRO), which was approved by the United States Food and Drug Administration (USFDA) as a graft for use in ESRD in 2008. The HeRO graft consists of two primary components: a conventional expanded polytetrafluoroethylene (ePTFE) graft component and a silicone venous outflow component. The ePTFE graft component is placed in the upper arm and anastomosed to the target artery for arterial inflow; the venous outflow component is placed similar to a TDC with its distal end terminating at the cavo-atrial junction. Two components are placed entirely subcutaneously. When they are brought together via a titanium connector, it results in shunting of arterial blood from the donor artery into the central venous system, thereby bypassing the need of creating a formal venous anastomosis for outflow (4-5-6). Hence, for patients with no adequate upper extremity peripheral venous outflow, the HeRO graft can provide an opportunity for a preferred upper extremity subcutaneous AV dialysis graft.

Furthermore, preliminary studies have shown the HeRO graft has a lower infection rate, improved patency rate, and improved adequacy of dialysis compared with tunneled catheters (5, 6). Despite these advantages, nevertheless, there is one major drawback to the HeRO graft; it may require a temporary bridging hemodialysis catheter until HeRO cannulation, as the HeRO graft needs time to incorporate as with all ePTFE grafts. As described in the series by Katzman et al (5), such concomitant bridging TDCs carry a high infection burden. To avoid the need for a bridging TDC, some have suggested combining early cannulatable dialysis grafts, such as Flixene graft or Vectra graft, with the graft component of the HeRO (7-8-9-10). However, these early-stick grafts may not instantly be accessible, thereby still requiring a temporary dialysis catheter in the setting of urgent need of hemodialysis treatment (8). We present here a novel two-stage HeRO graft implantation technique that not only avoids the use of a femoral bridging catheter but also allows immediate cannulation upon completion of the second stage procedure in the subset of patients with an internal jugular vein (IJV) catheter and contralateral venous occlusion.

Two-stage HeRO implantation technique

The first stage of this technique is to implant the ePTFE graft component. First, two to three incisions are performed in the upper arm ipsilateral to the preexisting IJV catheter: one in the deltoid area, one near the antecubital crease, and one in the axilla. The ePTFE component is then tunneled subcutaneously in a gentle curve or loop through these incisions, from the arterial anastomosis incision site to the connector incision site in the deltoid area. Then, instead of anastomosing to the target artery, the proximal arterial end of the ePTFE component is folded over and placed in the subcutaneous tissue (Fig. 1). The preexisting IJV catheter is maintained to provide continuous dialysis access.

Fig. 1 -

The second stage of the operation is initiated in 4 weeks by reopening the arterial incision site with dissection to free the target artery. The connector incision site is also reopened to dissect this end free. Next, the ePTFE arterial end within the subcutaneous tissue is unfolded. After controlling with vessel loops, the target artery arteriotomy is performed. The ePTFE arterial end is then beveled to appropriate length and dimension, de-clotted using a Fogarty thrombectomy catheter, flushed with heparinized saline, and anastomosed to the artery. A clamp is applied to the graft, restoring flow to the donor artery (Fig. 2a).

Fig. 2 -

The chest wall catheter is then freed up from its exit site, and the jugular entrance site is opened. After clamping the catheter at the entrance site, it is transected, and the external part is cleared from the field (Fig. 2b). A stiff guidewire is then placed through the remaining part of the catheter under fluoroscopic guidance, and the residual catheter is removed. Afterward, the venous outflow component is tunneled from the IJV site to the connector site in a standard fashion (Fig. 2c). In the following step, the dilator peel-away sheath is placed over the wire and serial dilation over the guide wire tract is performed until the peel-away sheath is placed in the superior vena cava. Following clamping the proximal end of the venous outflow component, the wire and dilator are removed. The venous outflow component is then placed through the peel-away sheath until its tip is located at the cavo-atrial junction, confirming with fluoroscopy. Subsequently, the venous outflow component is cut to length, and the clamp on the graft is removed, restoring flow to the graft. Finally, the distal portion of the venous outflow is attached to the ePTFE graft in the standard fashion, completing the HeRO graft implantation in two stages without using a femoral bridging catheter (Fig. 2d).

Discussion

In placing the HeRO graft in patients dependent on IJV hemodialysis catheters with contralateral central venous occlusion, a femoral bridging catheter is required until the HeRO graft becomes cannulatable. However, earlier studies have shown that the IJV site was associated with a significantly lower risk of catheter-related infection than the femoral site. According to the meta-analysis conducted by Katzman et al, IJV TDC catheter-related bacteremia rate was 2.3/1000 catheter days, whereas published bacteremia rates of femoral TDCs ranged from 3.6/1000 catheter days to 6.9/1000 catheter days (5). Considering 4 weeks as an ePTFE prosthetic graft incorporation time, a femoral TDC has 3.6-12.9% higher risk of infection compared with an IJV TDC. As described in a recently developed decision analytic model for selecting hemodialysis access, infection is the primary determinant of the cost of hemodialysis (11). In addition, the Katzman series reported that all HeRO-related infections occurred while a bridging TDC was in use; notably, 59% of their cohorts utilized femoral TDCs during the bridging period (5). These findings suggest that utilizing an existing IJV TDC in catheter-dependent patients, instead of creating a new femoral bridging TDC, would further reduce infection episodes associated with a femoral bridging catheter, thereby reducing morbidity and healthcare costs. Furthermost, by avoiding the need for a femoral bridging catheter placement, lower extremity access sites can be preserved for future dialysis access options.

To obviate the need for a bridging catheter and further to overcome the limitation of ePTFE grafts with respect to early cannulation, some have suggested replacing a portion of the ePTFE graft part of the HeRO graft with an early-stick graft such as Flixene graft or Vectra graft. Combining these early-stick grafts, success of access within 24-72 h after implantation has been documented (7-8-9-10). However, when there is an impending need for commencement of dialysis, even this short 24-72 h wait is not feasible. In such instances, immediate postimplant cannulatability can be achieved using the two-stage technique we present here, which allows time for the ePTFE graft to mature before initiation of the second stage.

In addition to utilizing it for continuous hemodialysis vascular access, a preexisting IJV catheter is used as a conduit to place the guidewire for insertion of the venous outflow component in the second stage. Technically, in this situation in which the catheter’s tip is already placed in the right atrium, insertion of the venous outflow component can be performed with a high success rate. In addition, the IJV that is harboring a TDC is the only accessible central vein in this subset of catheter-dependent patients with contralateral central vein occlusion. Furthermore, previous publications documented successful conversion of existing catheters into a HeRO without any adverse events (8, 12, 13).

This two-stage technique is devised and proposed on the basis of following grounds. First, the first stage procedure is minimally invasive procedure that can be performed on an outpatient basis in less than half an hour. Second, there are no published data to suggest reopening and manipulating a subcutaneously placed prosthetic graft that is not in systemic circulation 4 weeks later would increase the risk of infection.

Some procedure details deserve mention here. Firstly, the ePTFE graft component may also be placed in a straight line in the first stage. The preferable anastomosis may be in the axilla, for this will give a more favorable loop configuration. Secondly, before anastomosing the graft part to a target artery in the second stage, the arterial end of the HeRO graft needs to be evacuated using a Fogarty thrombectomy catheter; in our experience, the removed material was found to be organized fibrin thrombus in the pathologic study. Lastly, with wire access gained to the central venous system prior to preexisting TDC removal, placement of the venous outflow component can be performed routinely without adjunctive technique such as percutaneous transluminal angioplasty.

In conclusion, this novel two-stage HeRO implantation technique is simple, yet allows immediate cannulation upon completion of the second stage procedure while avoiding the need of a femoral bridging catheter in IJV catheter dependent patients with contralateral central venous occlusion, and thus lowering the risk of infection related to a femoral bridging catheter.

The first stage. The ePTFE graft component is tunneled through incisions, folded over, and placed in the subcutaneous tissue.

The second stage. (a) Reopened arterial and connector incision sites; (b) The chest wall catheter is freed and the jugular entrance site is opened; (c) The venous outflow component is tunneled from the IJV site to the connector site in a standard fashion; (d) Coupling of the venous outflow component to the ePTFE component.

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