Technique for Fenestrated Stent-Graft Implantation as a Proximal Extension to a Previous Fenestrated Endovascular Repair for Abdominal Aortic Aneurysm

Preoperative Planning

In the illustrative case, the first FEVAR procedure (standard Zenith device with 2 fenestrations and 1 scallop) was undertaken in another center, and the initial preoperative images were not available. However, from the postoperative computed tomography angiography (CTA) after the initial repair, the diameter of the thoracoabdominal aortic aneurysm (Crawford type IV) had progressed from 68 to 75 mm within a year.

The device design and planning (Figure 1A) were based on careful analysis of aneurysm morphology using a recent high-resolution CTA. There were 2 concerns: the severe angulation of the distal descending thoracic aorta (the potential proximal landing zone) and the available space within the previous stent-graft due to the existing renal bridging stents protruding into the aorta. The celiac trunk was already occluded, so a 3-fenestration device was chosen.

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Figure 1.

(A) Planning of the case, showing the anatomical characteristics of the aneurysm, the renal arteries, and the superior mesenteric artery. The lower diagrams show the characteristics of (B) the thoracic component and (C) fenestrated component.

A tapered 38/22-×179-mm Zenith custom-made device (Cook Medical, Bloomington, IN, USA) was designed for proximal use (Figure 1B), ideally to be deployed up to the angle of the distal descending thoracic aorta where there was undiseased parallel-walled aorta. A branched device was not chosen because of the severely angled proximal aorta as this would demand potentially difficult manipulation from the upper limb access. For the distal component, a 3-fenestrated, tubular (22-×172-mm) Zenith stent-graft (Cook Medical) was designed (Figure 1C) with 2 premounted wires for the renal arteries and double diameter-reducing ties to allow better handling within the old stent-graft lumen.

Procedure

Under general anesthesia, bilateral percutaneous femoral accesses were established. Each femoral puncture was preclosed using 2 ProGlide devices (Abbott Vascular, Santa Clara, CA, USA). A right brachial artery access was prepared but not used.

Access for the thoracic stent-graft and the main preloaded fenestrated component was through the 22-F sheath (Cook Medical) in the right femoral artery and a 20-F, 25-cm-long Check-Flo introducer. The left femoral artery was used for an angiographic catheter and later for accessing the superior mesenteric artery (SMA) fenestration via a 14-F sheath (Cook Medical, Bloomington) and a 10-F, 30-cm-long Check-Flo introducer.

First, the thoracic stent-graft was deployed at a lower level to avoid the severe angulation of the descending thoracic aorta (Figure 2A). Despite the severe angulation, graft apposition appeared to be good. Then the preloaded fenestrated main component was introduced through the right femoral artery. Longitudinal and rotational orientation was achieved using the markers of the previous fenestrated endograft to align the new fenestrations and the previous bridging stents to the renal arteries (Figure 2, B and C). This produced a double pattern of markers after the introduction of the new fenestrated device. An angiogram verified the position of the SMA. The stent-graft was partially unsheathed, leaving the double diameter-reducing ties in place to allow manipulation. Two 6-F, 90-cm Flexor sheaths (Cook Medical) were advanced on the preloaded wires and positioned at the renal arteries. The deployment sequence for a preloaded fenestrated stent-graft has been described. ¹¹

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Figure 2.

(A) Thoracic stent-graft deployment at a lower level to avoid the severe angulation of the descending thoracic aorta. (B) Longitudinal and rotational orientation was achieved using the markers of the previous fenestrated endograft to align the new fenestrations and the previous bridging stents to the renal arteries. (C) There is a double pattern of markers (colored red and yellow) after the introduction of the new fenestration device. (D, E) A Gooseneck snare (green color) was introduced from the left femoral side and positioned between the grafts outside the new fenestration distally to the left renal artery (LRA; blue sheath). A catheter and hydrophilic wire (brown color) was passed through the loop of the snare and catheterized the old bridging stent in the LRA. The hydrophilic wire was exchanged for a Rosen wire and positioned in the main stem of the LRA. From the right femoral sheath (red color) for the LRA the new LRA fenestration was passed in the usual manner and a hydrophilic wire (pink color) was forwarded outside the fenestration into the loop of the Gooseneck snare. This hydrophilic wire was then fixated by the snare along with the Rosen wire, and the Rosen wire was pushed further into the target vessel, thereby leading the hydrophilic guidewire into the bridging stent. (F) Final angiography confirmed unimpeded perfusion to all target vessels without detectable damage to the left renal artery.

The right renal artery (with the previous stent as a guide) and the SMA were catheterized unremarkably, but the catheterization of the left renal artery (LRA) proved to be impossible even though various catheters and guidewires were used by an experienced operator. Rotational misalignment between the new and old fenestrations with the stented LRA was considered a cause of this problem, combined with the limited distance between the new main body and the aortic opening of the previous bridging stent. A maneuver was attempted whereby a 12-mm angioplasty balloon was introduced from the left femoral access and inflated between the lumen of the old stent-graft and the outer surface of the new one in order to displace the new stent-graft to allow catheterization. However, because of the small space and the rigidity of the area between the old and new devices, this effort was unsuccessful.

In order to proceed with the LRA cannulation, an additional access from the left femoral side was opened to introduce a guidewire and a Gooseneck snare, which was positioned between the grafts outside the new fenestrated stent-graft distally to the LRA. A catheter and hydrophilic wire were passed through the loop of the snare and catheterized the old bridging stent in the LRA. The hydrophilic wire was exchanged for a Rosen wire, which was positioned in the main stem of the LRA. The new LRA fenestration was passed from the right femoral sheath in the usual manner, and a hydrophilic wire was advanced outside the fenestration into the loop of the Gooseneck snare. This hydrophilic wire was then fixated by the snare along with the Rosen wire, and the Rosen wire was pushed further into the target vessel, thereby leading the hydrophilic guidewire into the bridging stent (Figure 2, D and E). A catheter was advanced over the hydrophilic wire, and partial opening of the snare allowed further distal catheterization into the LRA. The hydrophilic wire was exchanged for a Rosen wire now to stabilize the distal LRA position. After removal of the catheter, the preloaded long 6-F sheath from right femoral side was advanced with its dilator into the LRA bridging stent while the snare again held the wire. After the 6-F sheath was on its intended course from the right femoral access to inside the LRA, the Rosen wire from right femoral access was partially withdrawn so that the Gooseneck snare and its Rosen wire could be withdrawn.

The remaining Rosen wire was reestablished in its stable distal position and a covered bridging stent was loaded into the 6-F sheath. The procedure was then continued in the usual manner by catheterization of the remaining fenestration and the SMA, final opening of the main body, balloon dilation with a compliant balloon, deployment and flaring of the bridging stents [a 6-×22-mm Advanta V12 (Atrium Maquet Getinge Group, Mijdrecht, the Netherlands) in each renal artery and an 8-x38-mm Advanta V12 with a Protégé-Everflex stent (Medtronic/Covidien, Minneapolis, MN, USA)] in the SMA]. Final angiography (Figure 2F) confirmed unimpeded perfusion to all target vessels without detectable damage to the LRA.