Up-and-Over Technique for Implantation of Iliac Branch Devices After Prior Aortic Endograft Repair

Introduction

Iliac branch devices (IBDs) have expanded the indications for endovascular aneurysm repair (EVAR) in patients with aneurysmal common iliac arteries (CIAs). Device designs include bifurcated modular systems with bridging covered stents to preserve flow into the internal iliac arteries (IIAs). ¹ Recent studies have shown that IIA preservation is safe and effective for reducing the risks of pelvic ischemic complications compared to historical results of IIA embolization.^2-4

Commercially available IBDs have been used in Europe for nearly 15 years.^5,6 In 2016, the Gore Excluder Iliac Branch Endoprosthesis (IBE; W. L. Gore & Associates, Flagstaff, AZ, USA) became the first IBD approved for commercial use in the United States. Endovascular IIA preservation is typically performed using bilateral transfemoral accesses with advancement of the IBD from the ipsilateral side and an IIA bridging stent from a contralateral approach.^7,8 In patients who need IIA preservation after prior EVAR with a bifurcated stent-graft, IBDs have generally been performed using brachial access instead of the contralateral femoral access, as the steps of establishing through-and-through guidewire access and large sheath placement can be problematic in patients with prior EVAR. Excessive manipulation of the aortic device can result in endograft movement or damage. Herein is described a technique of “up and over” access for endovascular IIA preservation using an IBD, avoiding the need for brachial access. The technique uses the Gore Excluder IBE [but is not described in the instructions for use (IFU) ⁹ ]. It can also be applied with other modular IBDs that require a bilateral femoral approach.

Technique

Description of the Technique

Bilateral common femoral artery accesses are obtained using a percutaneous technique with ultrasound guidance whenever possible. After preclosing sutures are placed, the patient is systemically anticoagulated and sheath access is obtained over stiff guidewires, which are positioned in the distal descending thoracic aorta. A 12-F DrySeal Flex Introducer Sheath (W. L. Gore & Associates) is advanced via the contralateral femoral approach, while a 16-F DrySeal Flex Introducer Sheath is advanced via the ipsilateral femoral approach (Figure 1; Video). A 7-F Ansel sheath with flexible dilator (Cook Medical, Bloomington, IN, USA) is advanced through the 16-F sheath as a buddy system while maintaining the stiff guidewire in the descending thoracic aorta. A 5-F Kumpe catheter is advanced through the Ansel sheath to guide placement of a 0.035-inch, 480-cm Tracer Metro Direct guidewire (Cook Medical), which has a stiff, kink-resistant core and a softer 5-cm radiopaque tip with a hydrophilic coating. From the contralateral side, the Metro guidewire is snared using an Indy OTW Vascular Retriever (Cook Medical). Once the through-and-through Metro wire is exteriorized and kept stable, the Kumpe catheter is removed, and the dilator of the 7-F Ansel sheath is reintroduced. The Ansel sheath is advanced up and over the bifurcation without difficulty. Once the 7-F sheath is within the contralateral iliac limb, its dilator is removed, and the dilator of the 12-F sheath is replaced. The 12-F sheath is advanced and its dilator “hubbed” inside the 7-F sheath (Figure 2), which creates a smooth transition for advancement.

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Figure 1.

(A) Three-dimensional reconstruction of a computed tomography angiogram demonstrates aneurysmal degeneration of the left common iliac artery distal to the landing zone of the previously placed aortic stent-graft iliac limb. (B) Intraoperative imaging demonstrates the looped position of the contralateral sheath crossing up and over the graft bifurcation, the through-and-through wire (yellow arrows), and the guidewire placed into the internal iliac artery.

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Figure 2.

(A) An illustration of an aneurysm of the left common iliac artery with a type Ib endoleak after prior endovascular aortic repair using a bifurcated endograft. (B) After bilateral access, DrySeal Flex sheaths are placed: 12-F on the contralateral (right) side and a 16-F sheath ipsilateral (left). An over-the-wire Indy snare is advanced on the right. A 7-F Ansel Flexor buddy sheath is placed on the left, with a coaxial 5-F Kumpe catheter and long guidewire. (C) The wire is snared and exteriorized, with a loop formed above the graft bifurcation. (D) The Ansel sheath is advanced, with tension on both ends of the wire to maintain position. (E) The dilator is removed from the Ansel sheath. The 12-F sheath, with its dilator, is advanced and docked into the Ansel sheath. By permission of Mayo Foundation for Medical Education and Research; all rights reserved.

Guidewire tension is maintained by applying surgical clamps on both ends of the wire where it exits the sheaths. As a unit, the mated sheaths are moved together, pushing the 12-F sheath up and over the flow divider, simultaneously pulling the 7-F sheath back (Figure 2). This maneuver is of paramount importance to avoid any movement or damage of the aortic bifurcated device by forceful advancement of the 12-F sheath. By keeping the 2 sheaths together, the interventionist can control their position as they loop over the bifurcation. The push-pull maneuver should be performed with fluoroscopic guidance, and the 12-F sheath is parked within the ipsilateral stent-graft limb, just cephalad to the site of Gore IBE deployment (Figure 3).

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Figure 3.

(A) With sheaths mated and the looped wire held taut, the flexible 12-F sheath is pushed forward as the Ansel sheath is pulled back. (B) The Ansel sheath is removed from the 16-F sheath and the iliac branch component is preloaded with the through-wire into the removable guidewire tube and by placing the stiff aortic wire through the delivery catheter. (C) The constrained iliac branch component is positioned. (D) After the first stage of branched endograft deployment, an 8-F Ansel sheath is advanced through the 12-F sheath, over the through-wire. (E) A hydrophilic guidewire and catheter are placed through the Ansel sheath into the internal iliac artery; the wire is parked in a large posterior division branch (usually the superior gluteal artery). By permission of Mayo Foundation for Medical Education and Research; all rights reserved.

The Gore IBE is then mounted over the stiff aortic guidewire, while the through-and-through Metro guidewire is loaded into the removable guidewire tube, which provides access to the IIA branch. The Gore IBE is advanced into the 16-F sheath over the 2 guidewires and positioned with the portal 1 to 2 cm proximal to the origin of the IIA. This should be confirmed with limited contrast angiography via the 16-F sheath. The Gore IBE first step deployment releases and opens the IIA portal. A contralateral 7-F or 8-F sheath is advanced over the through-and-through wire into the IIA portal. The dilator is removed, and a buddy catheter is used for selective catheterization of the IIA. A short flexible-tip Amplatz or Rosen guidewire is positioned into the posterior branch of the IIA. The Raabe sheath is removed over both the through-and-through and the IIA guidewires. A new 8-F sheath with stiff dilator is introduced into the up-and-over 12-F sheath and advanced into the proximal IIA while the separate through-and-through wire access is maintained. An 8L VBX stent-graft is advanced over the Amplatz guidewire. After limited angiography to demonstrate the distal IIA bifurcation, the VBX stent-graft is deployed to its 8-mm nominal diameter, and the balloon is exchanged for a 14-mm angioplasty balloon. The through-and-through guidewire should be withdrawn prior to postdilation of the IIA portal with a 14-mm balloon to avoid trapping the guidewire between the portal and the balloon-expandable stent. Final dilation is typically done with a “kissing” compliant balloon for the Gore IBE and the 14-mm balloon for the iliac bridging stent (Figure 4).

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Figure 4.

(A) After exchanging for an Amplatz wire, the 8-F sheath is removed from the through-wire and reintroduced over the stiff wire into the target vessel. (B) A balloon-expandable covered stent is deployed into the selected artery seal zone. (C) After removing the through-wire, postdilation is needed where the stent overlaps with the 14-mm branched component. A “kissing” compliant balloon in the other limb protects it from displacement or compression. (D) The through-and-through wire access is reestablished with the snare. The Ansel sheath is then advanced from the ipsilateral side. Sheath removal is accomplished after docking and reversing the push-pull maneuver over the wire. (E) The contralateral leg component is deployed to bridge from the original endograft into the proximal segment of the iliac branch component. (F) Final result. By permission of Mayo Foundation for Medical Education and Research; all rights reserved.

Removal of the 12-F sheath from up and over the bifurcation requires special attention to avoid deforming or displacing the aortic endograft. The 12-F sheath is withdrawn by reversing the placement steps. Alternatively, the 12-F dilator can be advanced, which may move the 12-F into the aorta, facilitating removal of the sheath over its dilator. If needed, a snare is used to reestablish through-and-through access, and the 12-F sheath is engaged into a flexible 7-F sheath. The two are moved across the flow divider as a mated unit. Once the 12-F sheath is removed, a new 27-mm flared iliac limb extension may be deployed to connect the previous iliac limb stent-graft to the new Gore IBE. Imaging documents patency and the absence of endoleaks or stent compression.

Discussion

IBD use for endovascular repair of iliac aneurysms after EVAR (or surgical aortic aneurysm repair ¹⁰ ) has been described. Bisdas et al ¹¹ reported an 18-patient experience implanting the Cook IBD after prior EVAR using axillary artery access to deliver a covered stent through the branch into the IIA. Oberhuber et al ¹² reported implantation of a Jotec E-Iliac Stent System after prior EVAR via a femoral approach using a contralateral steerable sheath and downward traction on a through-and-through wire. Rieß et al ¹³ reported implantation of a Cook IBD via a unilateral approach. Interestingly, their unilateral implantation technique was necessitated after an iatrogenic injury attempting to cross the bifurcation of an aortobi-iliac allograft, highlighting the need for an up-and-over access that does not result in pressure on a graft bifurcation.

The modified up-and-over technique presented here allows implantation of IBDs via bilateral femoral accesses in patients with previous surgical aortobi-iliac grafts or bifurcated stent-grafts. It protects the prosthetic bifurcation as the docked sheaths form a gentle loop above the flow divider and are advanced and withdrawn together. Monitoring this action with fluoroscopy ensures there is no unwanted interaction with or displacement of the existing graft. Subsequently, as the coaxial 8-F sheath and docking stent are delivered, controlled traction on the through-and-through wire in the 12-F sheath keeps the system in a stable position. While this modification of the typical contralateral approach is necessary to negotiate the acute angled graft bifurcation without damaging the existing device, it might not be necessary with a bifurcated unibody device seated on the aortic bifurcation.

Since July 2016, we have successfully completed 12 cases using this technique. It avoids the need for surgical exposure to place a large brachial artery sheath and reduces the risk of cerebrovascular embolization. This up-and-over technique has also been employed for other procedures for which contralateral access is needed, and it can be applied even when the working diameter in the aorta is ≤18 mm.

There are several specific circumstances in which IBD placement with this up-and-over approach may be useful; for one, the treatment of type Ib endoleaks, which are typically associated with inadequate selection of distal landing zones or use of large flared iliac limbs outside the IFU at the time of the initial EVAR. Distal endoleak can also occur if EVAR is performed with undersized iliac components or if there is continued expansion of the diseased CIA into the distal landing zone, leading to loss of distal fixation.

Landing into a CIA seal zone well proximal to the iliac bifurcation can leave an uncovered segment of the CIA. If this segment becomes aneurysmal, secondary treatment may be needed. Also, existing IBDs may need revision due to component separation, fracture, or endoleak at the IIA attachment site. This may become more common as the indications for IBDs are extended to IIA aneurysms; a new type III endoleak from component separation or a type Ic endoleak developing from loss of seal in the IIA may necessitate re-stenting of the IIA branch, which would require up-and-over access.

In patients with a short renal artery to iliac bifurcation distance, there may not be enough room for the IBD and the iliac extension limb that connects to the aortic device. Although the flow divider of the aortic device may be extended proximally toward the renal arteries, one alternative is to first place an iliac limb extension and then to deploy the IBD inside the previously placed limb. This may avoid problems that could occur if the proximal end of the IBD projected well above the aortic bifurcation in a short infrarenal segment.

We found that a coaxial system with balloon-expandable covered stents is preferred for this technique. Use of a single smaller sheath might seem an attractive option, but the coaxial 2-sheath system provides greater stability. The through-and-through wire is maintained until after the bridging stent is deployed into the IIA. Tension on the through-and-through wire is needed to prevent upward displacement of the sheath as the stent is advanced across the apex.

We recommend against using the standard Gore internal iliac component with the up-and-over technique. It may be difficult to advance the larger profile stent over the bifurcation, especially if there is excessive tortuosity. Once the bridging stent is advanced beyond the distal edge of the 12-F sheath, it may not be possible to withdraw it. In the event the bridging stent cannot be advanced into the IIA, it would have to be deployed more proximally within the previous iliac limb or main trunk of the IBD, compromising the repair. Although we have used the iCAST stent (Atrium Maquet Getinge Group, Hudson, NH, USA) with success, the VBX stent-graft is more flexible and easier to negotiate over the flow divider of the aortic device. We do not have experience with the balloon-expandable covered LifeStent (Bard Peripheral Vascular, Tempe, AZ, USA). (Note: the IFU for the iCAST and LifeStent describe postdilation to 12 mm. No IFU guidance is provided regarding postdilation with larger balloons.)

The up-and-over technique is not without potential hazards. Special care is needed in the setting of fenestrated endografts because of risk of damaging the side branch stents (renal arteries) with sheath advancement over the bifurcation of the aortic endograft. It is important to keep the tip of the sheath below the side stents. Finally, patency of the IBD, stents, and outflow vessels should be confirmed using completion angiography and cone beam computed tomography.

Conclusion

The up-and-over technique with a flexible 12-F sheath mated with a 7-F sheath from the opposite side allows bilateral femoral access to be used for IBD placement (and for other procedures requiring contralateral access) after prior aortic endograft procedures that create a higher, acutely angled bifurcation. Use of a through-and-through wire and a coaxial sheath for stent delivery creates a very stable platform for intervention.