In Situ Needle Fenestration during Thoracic Endovascular Aneurysm Repair: Successful Fenestration of Two Overlapping Thoracic Stent Grafts

Introduction

The gold standard treatment for aortic arch pathologies such as aneurysms and dissections traditionally involved conventional open total arch replacement. However, in the era of endovascular techniques, thoracic endovascular repair (TEVAR) has emerged as the first-line treatment modality for diseases affecting the thoracic aorta. Aortic arch pathology presents unique challenges for endovascular treatment due to its intricate structure and diverse variations. ¹ Conventional endovascular devices and techniques, unfortunately, cannot simultaneously guarantee adequate blood flow to maintain perfusion in the supra-aortic arteries and provide a suitable proximal landing zone. ² Advancements in endovascular aortic arch treatment have expanded the treatment options for aortic arch pathologies. These include innovative approaches such as parallel stenting methods (such as chimney and snorkel techniques) and custom stent grafts with side branches.^2-6.However, it’s important to note that the chimney approach has a potential drawback: inadequate sealing leading to proximal endoleak (type Ia). While custom-made branched stent-grafts offer an appealing solution for complete endovascular repair of the aortic arch, their fabrication typically takes more than six weeks, and they are not readily available at most medical centers.

The in-situ fenestration (ISF) technique, utilizing either a retrograde needle (ISNF) or an energy-based device (such as radiofrequency or laser), was initially introduced by McWilliams in 2004 for treating complex pathologies of the aortic arch. ⁷ The ISF technique can be applied to off-the-shelf devices, offering a rapid and reproducible method for fenestrating the stent-graft without requiring additional manufacturing time. One notable advantage is its versatility across a wide range of thoracic aortic anatomies. Unlike traditional approaches, the fenestrated stent graft is not limited by the length of the proximal landing zone. This innovative technique provides an alternative solution to maintain blood perfusion in the supra-aortic branches of the aortic arch. After deploying the main aortic stent-graft, ISF is performed, followed by the placement of covered or uncovered bridging stents through the fenestrations to ensure continued perfusion of the branch vessels. Recent studies have predominantly focused on ISF using laser or radiofrequency devices and ISNF.^8-11

We report a case of acute type B thoracic dissection that was managed using two overlapping thoracic stent grafts after the initial stent graft migrated. Successful ISF was performed on both stent grafts. Informed consent has been obtained from the patient for publication of the case report and accompanying images.

Patient

A 65-year-old male presented to the emergency department with severe chest and back pain. He had a 30-year history of smoking and no history of diabetes or hypertension. On examination, all peripheral pulses were equally palpable. The patient underwent high-resolution computed tomography angiography of the thoracic aorta, including its branches. The imaging revealed a type B aortic dissection extending from the left subclavian artery (LSA) to the right common femoral artery. The dissection flap extended into the origin of the subclavian artery and the celiac artery (Figure 1). Additionally, a semilunar thrombus was observed on the posterior wall of the aneurysmatic infrarenal abdominal aorta. Fortunately, there was no evidence of end-organ ischemia. Upon admission, the patient presented with an aneurysm expansion of the descending thoracic aorta measuring 40 mm in diameter. Given the substantial risk of thoracoabdominal aneurysm progression, an endovascular treatment for the dissection was selected. The operation was conducted 40 days after the initial presentation

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Figure 1.

Sagittal preoperative Computed Tomography Angiography (CTA) shows thoracic aorta dissection type B, yellow arrow shows the dissected intimal layer in thoracic aorta, red arrow shows the dissection extension to LSA. Abbreviation: LSA, left subclavian artery.

Procedure

A precise assessment was conducted to measure the diameters of the LSA and thoracic aorta, as well as the distances between the brachiocephalic trunk and the left common carotid artery (LCCA), and between the LCCA and the LSA. Additionally, we determined the origin of each vessel in relation to its position on the aorta. Volume rendering techniques were employed to optimize the placement of the C-arm and assess the tortuosity of the aortic arch. Based on these measurements, we selected a 34mm-200 mm thoracic stent graft Lifetech Ancura (Lifetech Scientific, Shenzhen, China) for the aorta and a balloon-expandable covered stent (Lifestream Bard) measuring 12 × 60 mm for the LSA

The patient underwent an intervention performed under general anesthesia. Arterial access was obtained via a femoral cutdown, utilizing the right common femoral artery. A pigtail angiographic catheter was advanced in the aorta. An extra-stiff 0.035″ guidewire (“Lunderquist”) was then advanced through the catheter, reaching up to the aortic arch. Retrograde access was established through the left brachial artery at the ostium of the LSA. The thoracic stent graft (34 mm-200 mm) was advanced and deployed with the guidance of angiography, positioned just distally from the origin of the left carotid artery. It effectively covered the ostium of the LSA. However, angiography revealed blood flow through the LSA. To optimize stent placement, a gentle balloon dilatation of the stent graft was performed using a 40 mm compliant balloon, resulting in the stent graft migrating 1 cm distally. Another stent graft (34 mm-160 mm) was introduced via the right common femoral access. Under precise angiographic guidance, the stent graft was deployed proximally. Angiography revealed a blockage of the LSA.

Then a steerable (FustarTM—Lifetech Scientific; Shenzhen, China) sheath was advanced through the left brachial artery access to be positioned as perpendicular as possible to the greater curvature of the aortic arch, in direct contact with the outer curvature of the endograft. In situ fenestration was meticulously performed using the puncture system (FuThroughTM—Lifetech Scientific; Shenzhen, China, Figure 2). Due to the presence of two overlapping stent grafts, a dense stent mesh was observed. To perform the puncture, we utilized magnification and identified a point without any stents (Figure 3A). The perforation was gradually dilated using 3 mm, 5 mm, and 8 mm balloons. Finally, a balloon-expandable 12 × 60 mm covered stent (Lifestream Bard) was deployed to branch the perforation site into the subclavian artery while ensuring the preservation of the left vertebral artery (Figure 3B and C). A thorough aortic branch angiography confirmed excellent patency of the branch vessels and no signs of endoleak. The arteriotomies were meticulously closed to complete the procedure. After the procedure, the patient made a successful recovery and received antiplatelet therapy. A follow-up computed tomography scan performed at the end of one month revealed no signs of endoleak (Figure 4).

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Figure 2.

The Futhrough™ Endovascular Needle System is an In-situ fenestration device for puncturing the stent graft at the ostium of the revascularized artery using the fenestration technique. It consists of a catheter and a puncture needle.

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Figure 3.

(A) Following the deployment of the two stent grafts, a dense mesh of stents posed challenges for needle perforation. To overcome this, we employed magnification to identify an unstented area and proceeded with the puncture. The perforation was gradually dilated using 3 mm, 5 mm, and 8 mm balloons. (B and C) A balloon-expandable 12 × 60 mm covered stent (Lifestream Bard) was deployed to branch the perforation site into the subclavian artery while ensuring the preservation of the left vertebral artery (Figure 3).

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Figure 4.

The postoperative CTA, revealed good apposition of the endograft and no signs of endoleak.

Discussion

TEVAR has revolutionized the management of aortic pathologies, providing a less invasive alternative to open surgery. However, challenges arise when dealing with complex anatomies, particularly involving the aortic arch and its branches. In such cases, revascularization of the LSA becomes crucial to prevent neurological complications. During the TEVAR procedure, the stent graft is deployed, and a fenestration is created within the graft material to accommodate the LSA. This technique preserves blood flow to the LSA while effectively excluding the aortic pathology. It’s important to note that commercially available stent grafts exhibit varying behavior during in situ fenestration. As demonstrated in in-vitro study the quality of fenestrations is influenced by the materials and structures of these stent-grafts. Specifically, ePTFE stent grafts demonstrated larger fenestration areas with clearer margins. Additionally, the use of sequential balloon dilation plays a crucial role in achieving high-quality fenestrations. ¹² Theoretically, in situ fenestration is feasible with all stent grafts. However, further clinical studies are necessary to evaluate which stent grafts yield optimal clinical outcomes using this technique. In the existing literature, mechanical fenestration has been employed in 60% of cases, while thermal methods have been utilized in 40%. Needle fenestration is the predominant mechanical technique, accounting for 90% of cases. Clinical success rates have been reported at 95.6%. Notably, the analysis of clinical trials indicates that there is no significant difference in success rates based on graft material (PET at 94.3% vs ePTFE at 93.4%) or fenestration method (mechanical at 96.3% vs thermal at 95.3%). ¹³ There is no discernible superiority between needle techniques and thermal techniques in terms of clinical efficacy. Both methods have demonstrated highly satisfactory immediate clinical outcomes. However, further long-term studies are necessary to assess their efficacy over extended periods. Ultimately, the choice of method hinges on material availability and the surgeon’s experience

The Ankura stent graft offers an innovative solution through in situ fenestration. According to an in vitro study, the Ankura stent graft consistently exhibited the best quality fenestrations, which were either circular or square, without any fabric tears. Recent studies have reported excellent technical success rates, with over 99% achieving successful aortic arch exclusion and LSA preservation. Immediate complications, such as endoleaks, are minimal with the in-situ needle fenestration approach. Long-term follow-up demonstrates durable LSA patency and comparable survival rates. In situ fenestration with the Ankura stent graft represents a promising strategy for managing complex aortic pathologies, offering improved outcomes and minimizing the need for additional bypass procedures.^14,15

During this procedure, achieving precise needle catheter placement perpendicular to the stent graft is crucial for successful perforation. A thorough preoperative CT scan examination is mandatory. However, when severe tortuosity or kinking of the subclavian artery is observed, achieving this perpendicular alignment can be challenging. In cases with complex anatomy, alternative treatment options should be considered. These options include specialized endovascular devices designed for subclavian artery use, subclavian artery transposition, or carotid-subclavian bypass with subclavian artery occlusion. Notably, the needle device used in our case features a distal balloon to facilitate needle perforation. When the balloon is inflated, the needle stabilizes in a perpendicular position. Confirmation of successful perforation and wire placement in the stent graft is essential through C-arm rotation. The feasibility of TEVAR using the Ankura™ endograft with ISF using a self-centering adjustable needle system is reported to be 61.5% with LSA angulation being the most important and limiting anatomical constraint. ¹⁵

In our specific case, we accomplished a successful in situ needle fenestration involving two overlapping stent grafts within the aortic arch. Initially, during balloon dilatation, the first stent graft experienced migration. Typically, balloon dilatation is discouraged during TEVAR for aortic dissection. However, due to incomplete exclusion of the LSA following stent graft deployment, we opted for a cautious balloon dilatation. Regrettably, this maneuver led to distal migration of the stent graft. To rectify the situation, we proceeded to deploy a second graft, ensuring effective sealing of the primary entry tear.

Following the deployment of the two stent grafts, a dense mesh of stents posed challenges for needle perforation. To overcome this, we employed magnification to identify an unstented area and proceeded with the puncture. Steerable catheters ensure that the endograft surface and the fenestration tool tip are aligned perpendicularly by controlling their orientation and direction. After successfully puncturing the stent graft, we confirmed the advancement of the 0.014-inch wire into the stent graft. Sequentially, we advanced the wires and balloons to create the fenestration. Ultimately, we successfully deployed the stent graft into the subclavian artery while ensuring the preservation of the left vertebral artery.

In the context of thoracic endovascular aortic repair, in situ fenestration is designed to leverage off-the-shelf devices while preserving perfusion to the supra-aortic branches. This approach maintains the benefits of minimal invasiveness. By creating an ISF after stent graft deployment, surgeons can customize stent-grafts based on individual patient arterial anatomy. Remarkably, in situ fenestration remains feasible even when deploying two overlapping stent grafts, as demonstrated in our patient’s case.

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. The authors declare that that there is no conflict of interest. A written informed consent was obtained from the patient. For this case report, obtaining approval from the local Ethics Board or Committee is not required.