Bifurcated Abdominal Aortic Endograft Deployment via the Carotid Artery
Article Outline
Background
We report the use of the common carotid artery as an alternate access in endovascular therapy.
Methods/Results
A 77-year-old man with an enlarging abdominal aortic aneurysm in whom previous attempts at standard endovascular repair had failed because of difficult iliac access underwent endovascular repair via the left common carotid artery. A custom-made Zenith infrarenal bifurcated stent graft was reverse-loaded on a thoracic distal delivery device and deployed in a caudal-to-cranial fashion. The patient made an uneventful recovery without any complications. Computed tomography confirmed exclusion of the aneurysm.
Conclusion
This case report highlights the role of the common carotid artery as an access vessel for stent-graft deployment when standard access via the femoral and iliac routes is unachievable.
In a recent report from our institution, the common carotid artery (CCA) was used as an access vessel for the deployment of an aortouni-iliac device to treat an infrarenal abdominal aortic aneurysm (AAA) in a patient with problematic femoral and iliac access.1 We now report on a case where a modified bifurcated Zenith (Cook Medical, Bjaeverskov, Denmark) device was similarly introduced via the CCA and deployed in a retrograde fashion because previous attempts at endovascular aneurysm repair (EVAR) via standard access routes had failed.
Case Report
A 74-year-old man was referred to our institution because a previous attempt at EVAR via the femoral access had failed. The iliac arteries were heavily diseased and small such that attempted angioplasty at that time failed to facilitate access. Computed tomography (CT) at our institution showed an infrarenal AAA of 7.4 cm. This had increased in size by 1.5 cm since his previous scan 6 months previously. The iliac arteries were severely calcified, precluding the option of an iliac conduit (Fig. 1). Cardiopulmonary exercise (CPEX) testing revealed a low anaerobic threshold of 9.4 mL/min/kg and a high ventilatory equivalent ratio, making him an extremely high-risk candidate for conventional open aortic repair.
Fig. 1
Three-dimensional reconstruction of CT scan demonstrating heavily calcified and stenosed iliac arteries.
The patient fulfilled our criteria for a custom-made device since his AAA was rapidly increasing in size and his CPEX put him in a high-risk category for open surgery. After assessing his carotid system and surgically treating a right 70% carotid stenosis by endarterectomy, a custom-made device for delivery via the left CCA was prepared to our specification by Cook Medical.
Device Characteristics
A modified bifurcated Zenith AAA stent graft was commissioned. This consisted of a body with a proximal diameter of 32 mm and two limbs with a distal diameter of 12 mm each. The length of the fabric-covered part of the stent was 82 mm down to the contralateral limb and 112 mm to the ipsilateral limb. This device retained the suprarenal barbed stent and “Z”-stent configuration characteristic of the Zenith system. As previously described,1 this device was reverse-loaded onto Cook's TX2 distal component delivery system with an outer diameter of 7.7 mm (Fig. 2). The bare suprarenal stent was contained in the telescoping handle, which is opened by sliding after removal of the first trigger wire, while the second trigger wire still secures the ipsilateral limb of the graft to the gray introducer rod, preventing cranial migration of the stent graft during this maneuver.
Fig. 2
Aortic stent graft reverse-mounted on a TX2 thoracic delivery device.
Procedure
Endovascular access was obtained via the left CCA and both the common femoral arteries (CFAs). A 5F pigtail catheter was positioned at the suprarenal aorta via a left brachial puncture to allow for digital subtraction angiography (DSA). After systemic heparinization, 10F sheaths were placed in both CFAs and a 7F sheath in the left CCA. A 0.035-inch guidewire (Terumo Medical, Somerset, NJ) was then passed via the left CCA and snared from the left CFA. This was replaced by a Lunderquist wire (Cook Medical, Bloomington, IN), providing a through-and-through wire access (body-floss control) from left CCA to left CFA.
The custom-made reverse-loaded Zenith bifurcated stent graft was then introduced over the Lunderquist wire via the left CCA under fluoroscopic guidance.
Correct positioning of the graft was confirmed using DSA—the gold markers at the proximal end of the fabric just caudal to the renal artery origins and the gold “J” mark of the contralateral limb cranial to the aortic bifurcation. The endograft was then deployed in a caudal-to-cranial fashion; i.e., the two limbs were deployed before the main body, by sliding the sheath until the valve assembly docked with the control handle (Fig. 3). Following angiographic confirmation of the position, the suprarenal bare stent was uncovered, first by removing the “white” trigger wire and then by sliding the telescoping handle together with the gray rod and outer sheath in a cranial direction.
Fig. 3
Fluoroscopic image demonstrating deployment of the reverse-mounted abdominal aortic stent graft.
The green trigger wire was then released, freeing the endograft from the delivery system, allowing the latter to be withdrawn. The arteriotomy in the left CCA was closed using a 5.0 Prolene suture (Ethicon, Cincinnati, OH) after bringing the cranial end of the Lunderquist wire to lie in the aortic arch. Following cannulation of the right limb via the right CFA, 12 mm and 13.5 mm diameter Fluency stents (C. R. Bard, Murray Hill, NJ) were used to bridge the gap between the left and right limbs of the Zenith stent graft and native common iliac arteries, respectively. All landing zones and junctions were expanded using a Coda balloon (Cook Medical, Bloomington, IN). A final angiographic run showed satisfactory positioning of the stent graft. There were no endoleaks except for a late type II endoleak from one of the lumbar vessels. At the end of the procedure there was concern regarding the perfusion of the right leg. Angiography revealed thrombosis of the superficial femoral artery (SFA). The thrombus was retrieved using a Fogarty embolectomy catheter (Edwards Lifesciences, Mississauga, Canada) under fluoroscopic control. Stenoses in the SFA were dilated using a 4 mm angioplasty balloon. The patient made an uneventful postoperative recovery without any transient ischemic attacks or stroke and was discharged home. One-month follow-up CT scan showed exclusion of the aneurysm with resolution of a type II endoleak that was previously noted (Fig. 4).
Fig. 4
Postoperative CT scan demonstrating the infrarenal aortic stent graft in satisfactory position.
Discussion
Patients may be turned down for EVAR because of no suitable landing zone or issues with access. The increasing popularity of fenestrated stent grafts and iliac bifurcated devices has reduced the number of patients being turned down for aortic stent grafting because of short/absent proximal or distal landing zones, respectively. Difficult iliac access may be tackled by using a low-profile device, hydrophilic coating, angioplasty/stenting, or an iliac conduit. Another technique, recently described, is “paving and cracking,” where the iliac arteries are lined with a covered stent graft prior to being overstretched, to intentionally cause rupture, thereby facilitating the introduction of a large-diameter aortic stent graft.2 Despite the above techniques, there are still occasions when EVAR via the iliac vessels is impossible. In such cases, one may look for other alternate routes of access.
To date, at least seven cases have been reported in the literature, where the CCA was used as an access vessel for aortic endografting.1, 3, 4, 5, 6, 7 Only one of these cases was for an AAA, the rest being for the treatment of thoracic pathology. In the previous report on the use of CCA access for infrarenal AAA repair an aortouni-iliac device was used since one iliac system was completely occluded.1 This is the first case to describe the deployment of a bifurcated device in a retrograde fashion using carotid access. Although the iliac systems were both heavily diseased and narrowed such that it was impossible to introduce a main-body device, they still provided sufficient inflow into the lower limb arteries to allow the patient a decent walking distance; hence, a bifurcated device was chosen. The same principles do, however, apply for both thoracic and abdominal aortic pathology. The first step is to ensure that the CCA measures a minimum of 8 mm in diameter without any evidence of significant atherosclerotic disease and the contralateral carotid system must also be disease-free, with a complete and patent circle of Willis on CT angiography. Some authors utilize electroencephalography or transcranial Doppler of the middle cerebral artery intraoperatively, performing test clamping before the introduction of the device, so that if there is any sign of cerebral ischemia they can perform an extra-anatomical bypass, to allow carotid perfusion during the procedure.6 In our patient, the contralateral carotid artery had a significant asymptomatic stenosis, which was treated by carotid endarterectomy prior to the procedure, to maximize cerebral blood flow. Of note, blood flow through the CCA is only interrupted during device introduction and deployment, being immediately restored after withdrawal of the device and closure of the arteriotomy, which with correct planning should take under 10 min. Cannulation of the contralateral limb is performed only after the arteriotomy is closed. A useful technique to employ in such cases is “body-floss” control, where the stiff wire enters the CCA and exits the CFA. We find that this maneuver gives control and stability when introducing and deploying the stent graft, helping us reduce the duration of cerebral ischemia.
The main difference between thoracic and abdominal aortic stent grafting via the cranial route is that for thoracic cases “off-the-shelf” devices can usually be used, whereas in all abdominal cases a custom-made stent graft is required. For both our cases1 weused the Cook Zenith platform, where a slightly modified abdominal stent graft was introduced on a thoracic delivery system. Cook's Z-Track™ plus introduction system for the TX2 distal component has a telescoping mechanism designed to contain the uncovered stent at the distal end of the distal thoracic component. We found this ideal for hosting the proximal uncovered suprarenal stent of a reverse-loaded abdominal device, be it uni-iliac or bifurcated. In view of this, our abdominal devices lost none of the characteristics of the TriFab Flex Body (TFFB) Zenith main body.
We have once again used Fluency covered stents to bridge the area between the bifurcated covered stent graft and the common iliac arteries since in such cases, where the carotid approach is sought, the iliac systems are too diseased to allow passage of standard 16F TriFab Limb Extension (TFLE) Cook limbs. The largest, 13.5 mm, Fluency can be easily introduced via a 12F sheath.
Conclusion
With this report we once again highlight the usefulness of considering an alternate access technique—the carotid approach for EVAR, when standard iliofemoral access is impossible. We recommend the setting up of an international registry for such cases in order to strengthen the evidence for such an approach.
F.F. and F.S.-I. are proctors for Cook Medical.
References
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PII: S0890-5096(09)00335-5
doi:10.1016/j.avsg.2009.09.012
© 2010 Annals of Vascular Surgery Inc. Published by Elsevier Inc All rights reserved.
