Received Date: April 11, 2017; Accepted Date: April 21, 2017; Published Date: April 28, 2017
Citation: Manunga J, Sun B. Endovascular Repair of Aortic Arch Aneurysm with Surgeon- Modified Fenestrated Stent Graft. J Vasc Endovasc Surg. 2017, 2:13. doi: 10.21767/2573-4482.100045
Purpose: Early results of endovascular aortic arch aneurysm repair with fenestrated/branched endografts are promising. However, access to these devices in many regions of the world remains limited to a handful of centers participating in government-approved trials. This leaves patients living out of reach of these centers with limited or no treatment options. We describe a technique of treating aortic arch aneurysms with surgeon-modified fenestrated stent graft.
Technique: The technique is demonstrated in an 80-year-old patient with a symptomatic 5.5 cm saccular aortic arch aneurysm that was successfully excluded with a surgeon-modified fenestrated Cook alpha proximal thoracic stent graft. The device comes with laser cut 3.5 mm barbs that do not permit retrograde resheathing. To overcome this, it was deployed, completely removed from its delivery system and a fenestration created to accommodate the left subclavian artery. A nitinol wire was withdrawn and used as a diameter-reducing wire that allowed for the device to be constrained posteriorly. Now mounted on its delivery system, the device was transitioned from a 24 French (Fr) sheath to a 20 Fr sheath to an 18 Fr sheath before advancing it into its original sheath. Under general anesthesia, the device was delivered into the thoracic aorta via a lunderquist wire placed from the right common femoral artery. The fenestration was cannulated from the left brachial artery access following partial device deployment and bridged with an Atrium iCAST stent graft.
Conclusion: Endovascular repair of aortic arch aneurysms with surgeon-modified fenestrated Cook alpha proximal stent graft is feasible. The procedure has a potential for significant complications and should be performed in conjunction with an experienced cardiac surgery team.
Aortic Arch Aneurysm; Surgeon-Modified Stent Graft; Endovascular Repair; Technical Note
Advances in anesthetic techniques, the introduction of cardiopulmonary bypass and hypothermic circulatory arrest have greatly improved outcomes of patients undergoing Open Aortic Arch Reconstruction (OAAR) and made this approach the standard of care. In spite of these advances, the procedure still carries mortality and neurological complication rates as high as 20% and 18%, respectively [1-3]. Inoue et al. reported on the first use of branched endografts for treatment of Arch Aneurysms (AA) . Since then, various device configurations including custom-made scallop, fenestrated and branched (F/B) endografts have been evaluated as alternative options for treatment of High-Risk Surgical Patients (HRSPs) with AA [5,6].
None of these devices is commercially available in the United States (US). There are, however, a few centers investigating arch devices as part of the Food and Drug Administration (FDA) approved clinical trials. For HRSP living out of reach of these centers or those who do not meet inclusion criteria into trials, treatment options are limited. We present a case of a patient with an AA that was successfully excluded using a Surgeon Modified Fenestrated Stent Graft (SMFSG). The patient consented for publication of this manuscript and institution support was granted.
An 80-year-old female presented to her primary care physician with progressive hoarseness. Direct laryngoscopic examination revealed left vocal cord paralysis. A Computed Tomography Angiography (CTA) revealed a 5.5 cm saccular aortic AA (Figure 1). Deemed a poor candidate for OAAR by the consulting cardiothoracic surgeon, she was referred to us for consideration of endovascular repair. Her past medical history was pertinent for tobacco abuse, chronic obstructive pulmonary disease, hypertension, hyperlipidemia, and history of infiltrating ductal carcinoma.
Figure 1: 3D reconstruction CTA of the aortic arch showing a 5.5 cm saccular arch aneurysm. Note the location of the aneurysm-where the ligamentum arteriosum attaches to the aorta. The Left Vertebral Artery (LVA) comes off the aorta just before the left subclavian artery. LVA was not revascularized in this case as the patient was found to have a dominant right vertebral artery and patent basilar artery.
After thorough counseling and discussion of risks associated with the procedure and the lack of long-term data, she was offered repair with a SMFSG using a Cook Alpha thoracic stent graft (Cook Medical, Bloomington, IN).
Before the patient was brought back to the operating room, an Alpha 30 x 100 mm Low Profile Proximal Stent Graft (LPSG) was deployed on a back table under sterile conditions. The LPSG was removal from its delivery system and an 8 mm fenestration created using an ophthalmologic cautery to accommodate the Left Subclavian Artery (LSA) based on measurements obtained using centerline of flow (TeraRecon, Foster City, CA). The fenestration was reinforced with a radiopaque snare using a double-armed 5-0 ethibond locking suture. The device was then reloaded on its original delivery system and one of the 3-nitinol wires withdrawn from the cannula and used as a diameter-reducing wire (Figures 2A-2D). The constraining process was performed as described by Oderich [7,8].
Unlike the old Cook platform (TX2), the new LPSG comes with 3.5 mm laser cut barbs protruding through the fabric making partial deployment and resheathing impossible without tempering with these barbs and thus compromising the integrity of the device. To overcome this, the modified and constrained LPSG mounted on its original delivery system was introduced into a 22 French peel away sheath (Cook Medical, Bloomington, IN) then transitioned into a 20 French sheath and subsequently into an 18 French sheath that was advanced through the valves of the original 16 French sheath (Figures 3A-3D).
Figure 3c: An 18 French peel away sheath is introduced through the valve of the original stent graft sheath. Note that we chose an 18 Fr peel away sheath for a 16 Fr original sheath. This allows for the peel away sheath to stay in the valve allowing only the graft to slide in the original delivery system.
The operation was performed under general anesthesia.
Following percutaneous ultrasound-guided access of the bilateral Common Femoral Arteries (CFA) and exposure of the left brachial artery (LBA), the patient was systemically heparinized achieving an activated clotting time of >300 s. Diagnostic angiography revealed the AA (Figure 4A). The SMFSG was inserted over a lunderquist wire (Cook Medical, Bloomington, IN) through the right CFA and partially deployed under direct visualization. Systolic blood pressure was lowered to 80 mm Hg to reduce the pressure exerted on the graft before cannulation of the fenestration and complete device deployment. The diameter-reducing wire allowed for repositioning of the device in various planes to allow alignment and catheterization of the side branch. A slight forward pressure was maintained on the partially deployed fenestrated stent graft from the right groin to avoid device migration while the fenestration was cannulated using a glide wire (Terumo Medical, Somerset, NJ) and an angled catheter from the LBA access site. A 9 x 38 mm Atrium iCAST stent graft (Maquet, Rastatt, Germany) was delivered over a Rosen wire. The constraining wire and the delivery system were then removed and the SMFSG ballooned using a coda balloon (Cook Medical, Bloomington, IN). The bridging stent graft was deployed and its proximal end flared with a 10 mm x 2 cm angioplasty balloon. Completion angiography (Figure 4B) revealed good perfusion of all arch vessels and exclusion of the aneurysm with no endoleak. CFA were closed percutaneously with Perclose ProGlide devices and the LBA repaired with interrupted 7-0 prolene sutures. Total Fluoroscopy was 417 mGy in 23 min and EBL was <20 mL.
The patient was neurologically intact upon extubation. She was admitted to the floor and discharged home on postoperative day 2. A CTA obtained 3 months postoperatively showed a wellpositioned SMFSG, patent arch vessels and a shrinking aneurysm sac (Figure 4C). Her voice continues to improve but not yet to baseline.
The quest for minimally invasive approaches to the treatment of AA is driven by a simple fact: an increasing number of these patients present with comorbid conditions rendering them poor candidates for OAAR. HRSPs living out of reach of a handful of US centers with access to FDA approved AA devices have limited treatment options that might include chimney technique, in-situ fenestration or SMFSG. In our case, a hybrid approach (LSA to carotid transposition/bypass followed by stent graft placement) was a viable option that was discussed with the patient, but she insisted on a total endovascular approach. In some cases, coverage of the LSA has been well tolerated. In this patient however, LSA revascularization was needed to avoid arm ischemia since the left vertebral artery was coming off the aortic arch and thus covered by the stent graft (Figure 1). Hoarseness in this patient was the result of compression of the left recurrent laryngeal nerve by the aneurysm [9-11].
The chimney technique carries the advantage of being readily available for use since it utilizes off-the-shelf components. However, the technique has a reported type I endoleak rate of 23%, a chimney graft occlusion rate of 11%, and significant stroke rate at follow up [12,13]. Proponents of in-situ fenestration advocate use of this approach for aneurysms located to the inner aortic curve to maximize stent graft apposition to the outer aortic wall and minimize the potential for type III endoleak that might result from the use of a short bridging stent graft . However, long-term results of this technique are lacking.
The use of SMFSG for treatment of complex abdominal and thoracoabdominal aneurysms has been extensively reported . The most commonly used platform for this purpose, Cook TX2, has been discontinued and replaced by the LPSG. The proximal piece of this device comes with protruding barbs that make retrograde resheathing post modification impossible without cutting these barbs-a process that may lead to compromised LPSG integrity. The technique described herein allows one to safely modify the device without cutting proximal barbs.
Lowering systolic blood pressure to ≤80 mm Hg minimizes the force exerted on the device prior to complete deployment and fenestration cannulation. Furthermore, it is extremely important to maintain slight forward pressure on the delivery system of the partially deployed SMFSG to avoid migration while the fenestration is cannulated from the brachial artery access. Only after this maneuver should the entire graft be deployed, the constraining wire removed and the device ballooned. Failure to do so may result in device migration and inability to cannulate the fenestration. In same cases, especially if the device is being deployed in aortic arch zone 0, rapid ventricular pacing may be required to facilitate accurate device landing. In our case, however, lowering systolic blood pressure and maintaining forward pressure on the delivery system was sufficient to overcome aortic pressure since the device was deployed in zone 2.
Treatment of arch pathologies using chimney technique, in-situ stent graft fenestration, custom-made F/B endografts or SMFSG is still in its infancy and requires continued technical refinement to achieve ease of use and decrease the rate of procedure related complications. Patient selection with specific attention to tortuosity of the iliac arteries and aorta as well as the type of arch will prove crucial for a successful and safe implantation of the device. Lastly, these patients require a close follow-up to continue evaluating stent graft performance. In our practice, follow-up consists of a physical examination and a CTA at 3 months, 6 months and yearly thereafter provided there are no concerning signs.
Though feasible, endovascular repair of AA using SMFSG can be a challenging undertaking with potentials for significant neurological complications or even death. These procedures should be performed by an experienced team in collaboration with cardiac surgery at centers with open arch repair expertise after thorough patient selection and counseling.
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