Abstract
Clinical Impact
Our study demonstrated the clinical impact in real-world practice of using In-situ fenestration TEVAR with the innovative dedicated perforation-needle technique, which is characterized by an immediate availability as off-the-shelf device, compatibility with the various pathologies and anatomies, as well as minimal invasiveness in comparison to the debranching bypass-procedure for the preservation of the supra-aortic vessels during the endovascular repair of aortic arch pathologies. According to center experience, this approach can applied in elective cases, however, due to its practicability, it can be especially valuable in emergencies, when the other methods are considered as an unfavorable.
Keywords
Introduction
During the thoracic endovascular aortic repair (TEVAR) of thoracic aortic aneurysms (TAA) or staged repair of thoracoabdominal aortic aneurysms (TAAA), the revascularization of the left subclavian artery (LSA) is routinely needed and performed because of the compromised proximal landing zone (PLZ). 1
Besides the conventional left carotid-subclavian bypass, different endovascular approaches have been evolved in the last years, including the Chimneys and the customized fenestrated and branched devices. Many manufacturers developed retro- and antigrade branched arch systems to landings zone 0 and 2. A single-branch thoracic endoprosthesis (the Gore Thoracic Branched Endoprosthesis, W.L. Gore and Associates, USA) for patients requiring zone 2 treatment recently received the MDR CE mark approval.
To preserve the LSA, the in situ fenestration (ISF) technique has become an increasingly attractive option over the recent years. Numerous technical methods were previously used, such as the laser or the needle to perforate the fabric, dilate the perforation, subsequently inserting the bridging grafts into the thoracic grafts which were implanted, so that the orifice of one or more of the supra-aortic vessels were covered.2 –6
In 2016, Wang et al 7 reported the implementation of a dedicated adjustable needle device (Futhrough, Lifetech Scientific Inc., Shenzhen, China) to improve the safety and efficacy of the ISF TEVAR and moreover to establish it as a standard procedure. This system received the CE market license in 2020. Since then, the device has now been used routinely and increasingly in Europe.
The aim of the present study was to evaluate the efficacy as well as the outcomes of this novel technique to treat all patients with thoracic aortic pathologies, which involve the supra-aortic vessels in high-volume territory aortic center.
Methods
Between July 2021 and February 2024, consecutive patients who underwent elective and urgent stent grafting using ISF TEVAR with Ankura TAA Stent Graft System and Futhrough needle device (Lifetech Scientific Inc., Shenzhen, China) were enrolled.
The patients were informed about the treatment and written informed consent was obtained prior to undergoing the repair. Furthermore, we obtained the approval of the ethical board at our institution as well as the consent of each individual patients to participate in this study.
The preoperative imaging included ECG-gated high-resolution contrast-enhanced computed tomography angiography (CTA) with 1 mm sections of the entire aorta from the neck to the groin to evaluate the aortic pathology, the supra-aortic vessels, and the surgical access via the iliofemoral vessels. If ISF of the carotid artery was planned, we performed an additional cranial CTA to assess the intracranial perfusion.
The endovascular procedures were performed under general anesthesia in operating theater equipped with high-resolution imaging. An intraoperative electroencephalography (EEG) was routinely used for all patients as neuro-monitoring.
All procedures were performed in a similar treatment strategy. The thoracic stent grafts (Ankura TAA Stent Graft System, Lifetech Scientific Inc., Shenzhen, China) were delivered through a percutaneous femoral access. The supra-aortic vessels were frequently accessed via cut down. An angiography pigtail catheter was inserted from above via the subclavian artery into the ascending aorta. After positioning the thoracic stent graft into the distal aortic arch, an angiography was performed in left anterior oblique projection (between 45° and 65°). The main graft was precisely implanted, usually distal of the left common carotid artery (LCCA) orifice, covering the LSA. The 8 Fr Futhrough perforation device (Lifetech Scientific Inc., Shenzhen, China) was inserted retrogradely via the steerable 10 Fr Fustar sheath (Lifetech Scientific Inc., Shenzhen, China) to achieve a 90-degree angulation to the thoracic main graft. After the puncture, a 0.018 inch guidewire (V-18 Control Wire; Boston Scientific, Natick, Massachusetts) was inserted into the main graft. We performed a pre-dilation of the fenestration using a low-profile 3 mm coronary angioplasty balloon (Pacific Plus, Medtronic, Minneapolis, Minnesota), followed by a 6 mm angioplasty balloon (Mustang; Boston Scientific) to enlarge the fenestration. We used a conventional balloon-expandable grafts as bridging stents into the supra-aortic vessels because of its radial force, which included Advanta V12 (Atrium Medical, Hudson, New Hampshire), i cover (I vascular, Barcelona, Spain), and Bentley’s BeGraft Stent Graft System (Bentley Innomed GmbH, Hechingen, Germany).
Regarding the anticoagulation regime, all patients received a continuous intravenous infusion of unfractionated heparin monitored by aPTT (activated partial thromboplastin time) postoperatively. After 24 hours, a dual platelet inhibition (aspirin and clopidogrel) was initiated additionally for a postoperative duration of 3 to 6 months. Thereafter, the dual platelet inhibition was discontinued and replaced by either aspirin or clopidogrel as a monotherapy.
The postoperative imaging protocol consisted of triple-phase CTA. The patients were entered into a follow-up program with laboratory, clinical and imaging (CTA) examinations at 3 and 6 months with yearly repetitions thereafter. A post-processing analysis was performed based on the postoperative and follow-up imaging data by 2 independent physicians experienced in 2D/3D post-processing using the Aquarius workstation (TeraRecon, Frankfurt, Germany). Statistical analysis was performed with SPSS software (SPSS 23.0; SPSS Inc, Chicago, Illinois).
Results
Twenty-six patients (24 men; mean age: 69 years; range: 59–82 years) were included. All patients had a pathology of the thoracic or thoracoabdominal aorta with lack of PLZ distal of the LSA (length <1 cm) or with involvement of one or more supra-aortic vessels.
The predominant indication (62 % of cases) was an aneurysmal pathology (16/26). Ten patients had a thoracic TAA >5.5 cm and 6 patients had thoracoabdominal aortic aneurysms TAAA >6 cm.
Six patients (23%) had a type B aortic dissection; one of them had a non-A-non-B dissection. The 4 remaining patients (15%) had a penetrating aortic ulcer (PAU; diameter >20 mm and/or an ulcer depth >20 mm).
Seven of the patients (27%) were treated because of urgent or emergent indications. Three of them presented with complicated dissections, 3 had symptomatic aneurysms/PAUs and one with contained ruptured saccular aortic arch. Four of the 5 TAAA patients needed a staged extensive repair, combining the ISF TEVAR as the first step and branched TEVAR or hybrid thoracoabdominal repair in interval (Figure 1).
(A) Operative steps during the in situ fenestration (ISF) of the left subclavian artery. (B) Staged total endovascular TAAA repair using ISF TEVAR, multibranched stent graft, EVAR, and IBD. (C) Staged hybrid TAAA repair using ISF TEVAR and renovisceral debranching.
The patient’s demographics, aortic characteristics, and indications are shown in Table 1.
The Patient’s Demographics, Aortic Characteristics, and Indications.
Operation, Clinical, and Radiological Outcomes
The majority of the cases (21 patients, 81%) received TEVAR of the Ishimaru’s Z2 using the ISF for the LSA. Whereas a double ISFs of both LCCA and LSA (Ishimaru’s Z1) was a rare indication, performed only in 2 cases because of the absent distance between the 2 vessels (<1 cm). A total endovascular arch repair with 3 fenestrations (LSA, LCCA, and brachiocephalic trunk [BC]) was performed in 3 patients, either as one of the patients rejected the conventional arch surgery himself or because the other 2 were classified as high risk and unsuitable for open repair (Figure 2A, B, and C). Operative and technical details are summarized in Table 2.
(A) ISF of the left common carotid artery. (B) ISF of the left subclavian artery. (C) ISF of the brachiocephalic trunk. (D) The temporary endoluminal shunting during total endo arch repair using ISF, the yellow arrows show access of right subclavian and right common carotid arteries, the red arrow shows the perfusion direction to perfuse the right carotid artery (E) and (F) final angiogram and postoperative CT-controlled 3D reconstruction.
The Operative and Technical Details of the 26 ISF TEVAR Procedures.
The technical success, defined as endovascular exclusion of the aortic arch pathology and preservation of the LSA using ISF, was achieved in 92% (24/26 patients). Due to the difficult morphology of the supra-aortic vessels, the needle device failed to perforate the thoracic aortic grafts in 2 of the patients. A chimney graft had to be implanted to salvage the flow of the LSA. Two anatomical restraints, which had a take-off angulation of <45° and a wide basis >14 mm of the supra-aortic vessels, have been identified as potential causes of failed ISF.
One patient presented with non-A-non-B dissection was treated using a double ISF of the LCCA and LSA. An endoleak type Ia was revealed in the final intraoperative angiogram as well as in the postoperative CTA. We decided to wait and monitor the patient closely. The endoleak was resolved without any re-intervention after a month.
The 2 mortalities of this series were registered in the triple ISF TEVAR group, representing the high-risk character of this complex repair. We considered this procedure as a bailout for the emergent/urgent cases only. One old patient was presented with contained rupture of the aortic arch saccular aneurysm, the other 2 were symptomatic.
Besides the EEG (electroencephalography) and the controlled hypertension, we have also considered an endoluminal temporary shunting of the covered supra-aortic vessels as intraoperative protective procedure to restore the cerebral perfusion during the ISF. We start routinely with the LCCA to keep the cerebral ischemia as short as possible (Figure 2D). Despite these protective measures, including rapid and successful fenestration of the all vessels, the triple ISF was marked by a very high stroke rate (2/3 patients; 67%). The patient with ruptured aneurysm died on the second postoperative day due to multiple organ failure. The second mortality was because of a major stroke and the patient died 8 days after the surgery.
In total, the early perioperative neurological events occurred in 3 patients (11, 5%). One patient had a transient ischemic attack (TIA) and 2 of them suffered a major stroke (8%). One of them died as mentioned above, the second, however, developed an aphasia, which partially improved after several months.
The mean follow-up period was 18 months (range: 2–32). During the follow-up, 3 patients with TAAAs were re-intervened successfully due to our selective TAAA protocol in staged manner. For the second step of thoracoabdominal aortic repair, 2 of these patients received a bTEVAR and an EVAR and the third patient was treated with visceral debranching and TEVAR. Two patients (8%) underwent late unplanned re-intervention. One patient was re-admitted because of TIAs, where a large occlusive thrombus deposits on the bare springs of the aortic graft in the orifice of the LCCA (after ISF TEVAR of the LSA) were detected via CT scan. The orifice of the LCCA was not covered. The patient received a successful interventional thrombectomy of the LCCA via left transcarotidal approach and stent grafting of the proximal LCCA as it was considered to secure the vessel and cover the wall adherent thrombus following the thrombectomy. The patient recovered completely and was discharged without any further neurological complications.
One patient with LSA ISF required a distal extension using a thoracic stent graft after 1 year as a late unplanned re-intervention because of endoleak Ib.
During the maximum follow-up period of 32 months, 2 patients died because of non-aneurysm-related causes (bronchial cancer and myocardial infarction). All remaining patients were doing well. No further endoleaks were registered. All branches were patent, no dislocations or breaks of the bridging stent grafts, and no fabric tears of the thoracic stent grafts were detected so far at the last follow-up using CT scans. The perioperative and follow-up details are shown in Table 3.
The Perioperative and Follow-up Outcomes.
Discussion
During TEVAR, the preservation of the LSA is clearly recommended in the guidelines and has become an established practice. 8 Apart from the conventional surgical left carotid-subclavian bypass, numerous less invasive endovascular techniques for preserving the LSA have been used and practiced divergently, depending on the institution’s and surgeon’s experience. Various methods such as implantation of chimneys and use of physician-made or customized fenestrated or branched stent grafts are available.9,10 The application of ISF using either laser or perforation devices has been first reported in 2004 and has become widely accepted, as the piercing’s techniques have been refined und developed over the years.4,5,11
After different experiences with various puncture instruments, which were not actually made for this purpose, an adjustable puncture needle system in combination with steerable sheath (Lifetech Scientific Inc., Shenzhen, China) was designed by W. Fu et al 7 in China as a dedicated device for the ISF TEVAR treatment of the aortic pathologies involving the aortic arch branches. Thereafter, a Chinese multicenter midterm outcome experience with this system was recently reported. 12 The Futhrough ISF device was approved in Europe and has been marketed exclusively in combination with Ankura TAA Stent Graft System (Lifetech, Shenzhen since 2020, China) by the same manufacturer.
After a careful preliminary experience with selected TEVAR cases using ISF of the LSA, we subsequently introduced this novel technique increasingly in our institution for the different aortic arch pathologies. During the initial learning period, we encountered 2 failures as the surgeons were not able to position the needle device correctly against the TAA SG to obtain the optimal 90-degree angulation to perforate the graft with “push” in a vertical axis. This technical issue has already been accurately reported by the Chinese group, as the sharp take-off angles and the type III aortic arch impeded the needle perforation. 12 Due to our limited experience, we considered that a wide take-off base of the LSA >14 mm may also present a further anatomical constraint since the tip/balloon of the Futhrough device would be destabilized at the correct vertical perforating position when there is a lot of space.
These pitfalls could be avoided over time based on the learning curve, including the recognition of the above-mentioned anatomical restrictions, forcing of better vertical device’s position and getting a different projection of the C-arm. Despite the above-mentioned constellation, the authors are of the opinion that this novel technique has yet to reach its final developmental stage. A further technical refinement concerning pushability, flexibility, and its total functionality may be needed not only to move the procedures’ feasibility forward but also to cover the various types of the arch anatomies.
Notable advantages of this technique, compared with the customized arch devices, were cost saving, avoidance of the associated risk of rupture during the manufacturing time, and the compatibility with the different arch morphologies.
In this series, we repaired 4 ISF TEVARs in combination with endovascular thoracoabdominal repairs (1 Hybrid, 3 bTEVARs) in stages. A further beneficial aspect to preserve the antegrade LSA was the access to the renovisceral aorta after previous endovascular arch repair. Considering a partial hybrid arch repair (left carotid-subclavian bypass) or Chimney TEVAR, the left arm would no longer be accessible for the downstream aorta.
Considering this novel technique, the most significant advantage that we found was its availability as off-the-shelf device, which can be applied promptly for urgent or emergent setting. About third of our series (27%) was treated due to acute indications. The experience would correlate with other series and reports of the ISF TEVAR.3,4
Of note, for emergent TEVAR procedures, this novel ISF replaced gradually and to a large degree the chimney TEVAR of the acute endovascular aortic arch repair in our institution. Although it is technically more difficult, we favored the ISF TEVAR for emergencies because we believe that better sealing of the pathology and less endoleaks could be achieved compared with Chimneys. Whereas the gutter endoleak does represents a major drawback. 13
Stroke is the most feared complication and is strongly associated with perioperative death following TEVAR. 14 The more proximal the TEVAR in regard to LZ (Ishimaru’s Z0), the higher the stroke rate. 15
For the elective setting, if the endovascular total arch repair is indicated and the conventional open repair is hampered, it would be our policy to consider a customized branched arch device. In this series, we performed a 3 endovascular total arch repair with ISF of the BC, LCCA, and LSA due to urgent indications. This approach was performed highly complicated by stroke/mortalities. Although a temporary shunting was used, a cerebral embolism could not be prevented. A significantly less mortalities and stroke rates were clearly shown if a mono ISF of the LSA has been fenestrated compared with triple ISF.
During this procedure, an uncontrolled irregular fabric fenestration may be the result of ballooning after the puncture. As such of the potential damage (fabric tearing, fraying, or even graft rupture) of graft textile, the long-term durability of ISF is yet to be determined. In this context, the role of laser versus needle ISF, bare metal versus covered bridging stents, Dacron versus polytetrafluorethylene (PTFE) thoracic grafts, and the real clinical impact of fabric damage remain unclear. Luo et al 16 reported that 8% of 50 patients had endoleak type III in their midterm retrospective review. Similar to our experience, the majority of reported studies demonstrated so far acceptable outcomes in terms of branch-related complications or endoleaks.3,5,12,16 Of note, the primary scope of this report is to share our “real-world” experience to the vascular community. However, we strongly advocate a close patient surveillance and further extension of the follow-up as well as initiation of a multicenter study. Although other working groups used the self-expandable bridging grafts, 16 we preferred the use of balloon-expandable stent grafts in our series, because of its radial force, to avoid any kinking or stenosis at the site of the perforation. Self-Expanding or Balloon-Expandable should have better patency outcomes after ISF TEVAR, yet to be clarified and the selection would be depend on the center experience.
Limitations
There are, of course, several limitations to this series. First, this is a single-physician experience involving only ISF TEVAR patients but different indications with different arch involvement. The follow-up, like most of other reported studies, is limited, particularly in terms of fenestration-related endoleaks and fabric stability.
Conclusion
In our experience, the use of dedicated needle device is effective. Based on careful patient’s selection and consideration of the anatomies, the ISF TEVAR may serve as an initial approach as off-the-shelf endovascular treatment of the aortic arch pathologies, especially in the acute situations. Larger series and multicenter studies are of course warranted to corroborate these results.
Footnotes
Acknowledgements
M.Y. receives research funding via ASKLEPIOS Proresearch from Lifetech Inc. The other authors declare no associations with any individual, company, or organization having a vested interest in the subject matter/products mentioned in this article.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
