A Novel Endovascular Technique for Exclusion of Inner Curve Aortic Arch Aneurysm

Article Outline

• Abstract
• Introduction
• Procedure
• Discussion
• Conclusion
• Copyright

Abstract 

We present a case of a 78-year-old gentleman who was found to have a large saccular aneurysm of the inner aortic arch after complaining of change in the character of his voice. This lesion was successfully excluded using purely fenestrated endovascular techniques without compromising the origins of supra-aortic vessels. A novel technique with modification of fenestrated design was used to ensure accurate placement of the custom-made endograft. This technique has not been published before.

Keywords: Aortic arch aneurysm, Bovine arch, Endovascular arch repair

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Introduction 

A 78-year-old man who, after complaining of change in the character of his voice for 6 months, underwent a CT scan of the neck and thorax which demonstrated a saccular aneurysm (size 9cm) of his inner aortic arch (Fig. 1). He had a bovine arch anatomy with a common orifice for the left common carotid and brachiocephalic artery with the left subclavian artery being the second of only 2 aortic arch branches.

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• Figure 1 

  A CT scan with reconstructed images demonstrating a saccular aneurysm (size 9cm) of the inner aortic arch.

Because of the particular anatomy, an endovascular graft with a scallop for the bovine trunk and a fenestration for the left subclavian was designed. A novel feature was a perforation proximal to the scallop with a wire through this to anchor the graft at the bovine orifice to ensure accurate placement at the time of deployment (Fig. 2).

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• Figure 2 

  CT scan post-surgery demonstrating the placement of the endoprosthesis following deployment, as well as the left subclavian stent.

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Procedure 

A 7-french Ansel sheath™ was inserted into the right common femoral artery through a transverse incision. A wire was passed through the right femoral artery up into the aortic arch and into the ascending aorta. Following this, a custom-made scalloped (COOK^® Zenith™) Polyester endograft with a fenestration for the left subclavian artery was positioned carefully over the wire and into the aorta. A wire, which was in-built into the endoprosthesis, was then carefully advanced from within the endograft (Fig. 3), through a small opening at the base of the scalloped segment of the graft and into the innominate artery.

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• Figure 3 

  Photographs of the actual custom-made endoprosthesis used. As can be seen, the graft consists of a fenestration to allow for the patency of the left subclavian artery as well as a scallop at the proximal end. A wire can be seen passing through a small puncture at the 12:10 position at the scalloped end.

A right brachial artery cut-down allowed for a snare to be inserted into the innominate artery. The snare captured the in-built prosthesis wire and enabled for it to be passed through the innominate artery and out via the right brachial artery. This wire was carefully maintained at the exact same position with adequate amount of tension so as to prevent the endograft from migrating when it was deployed. Using this technique the graft was deployed successfully, excluding the aortic arch aneurysm while the fenestration lined up exactly with the origin of the left subclavian artery. Following this a wire was passed through a left brachial artery incision and the left subclavian artery was stented with the proximal end of the stent entering into and ‘anchoring’ the aortic arch prosthesis, thus providing another means of preventing migration of the endograft. Post-deployment on table angiogram showed the aneurysm to be completely excluded with scallop allowing for patency of the innominate artery. The total amount of contrast used for the procedure was 200ml, the radiation exposure time was 24min. The patient was transferred to the High Dependency Unit following the operation and was discharged 3 days later.

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Discussion 

This technique was successful as the patient presented with a bovine arch and saccular aneurysm not involving the supra-aortic vessels. This particular anatomy allowed us to completely exclude the aneurysm endovascularly. In a patient without a bovine anatomy, a second fenestration to maintain patency of the left carotid ostium would have to be designed if the above technique is to be used, making the procedure more challenging, but not impossible in a patient with a similarly situated aneurysm.

One of the major points of debate over the past few years when performing endovascular procedures on the aortic arch is the consequences of occluding the left subclavian artery. However, as demonstrated in this case, subclavian over-stenting is a feasible option. Methods previously used for subclavian revascularisation can be avoided as demonstrated in this particular case.

Several methods have been tried to avoid the ‘wind-sock’ effect that occurs during aortic arch stent graft placement given the high pressure flow in this region. Our technique would reduce or eliminate the need for some of the other options currently considered. Paramount to the success of this procedure is maintaining the wire at the correct length and applying adequate amount of tension to the wire passed through the right arm, which then allows the base of the scallop in the endoprosthesis to be pressed firmly up against the aortic wall near the innominate ostium, thus preventing migration during deployment.

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Conclusion 

Endovascular repair of arch aneurysm is becoming an increasingly recognised technique, which offers a minimally invasive option in lesions, which would, by conventional standards, be treated by using a combination of extra-anatomical bypass and endovascular measures. We describe a unique technique in a patient with very particular anatomy, which enhances the accuracy of placement of an endograft across the aortic arch at the branch orifice ostium and increases the safety of using this purely endovascular option for arch aneurysms.