Utilizing Single-Branched Stent in Combination With Fenestration or Chimney for Endovascular Repair of Aortic Arch Lesions With Aberrant Subclavian Artery

Abstract

Objective:

The study was to figure out the feasibility, efficacy, and safety of a single-branched stent graft, namely Castor, in combination with fenestration or chimney in the context of aortic arch lesions presenting with aberrant subclavian artery (ASA) and/or Kommerell’s diverticulum (KD).

Methods:

All consecutive patients with aortic arch lesions and ASA and/or KD receiving Castor from June 2018 to June 2023 were investigated.

Results:

Incorporating 18 patients, the study encompassed 11 cases with KD, 3 cases with dysphagia; 2 cases of right-sided aortic arch with left-sided aberrant left subclavian artery (ALSA), and 16 cases of left-sided aortic arch with right-sided aberrant right subclavian artery (ARSA). The mean operation time was 132±23 minutes. The mean measured proximal aortic diameter was 30.9±1.6 mm, and proximal diameter of Castor stent was 34 (32, 34.5) mm, with oversize of 9.1±1.6%; the mean measured branch diameter was 8.8±0.97 mm, and branch diameter of Castor stent was 10 (8, 10) mm, with oversize of 0.86±0.57 mm. Technical success rate was 100%, and no in-hospital mortality, no stroke, and no endoleak were identified. One (5.6%) case with spinal cord ischemia and one (5.6%) case with poor healing of operative site were identified. During the follow-up period, no aortic-related death or secondary intervention was recorded. The maximal aortic diameter was significantly reduced at the sixth postoperative month (p_adj=0.031); KD diameter was significantly reduced at the third (p_adj=0.001) and sixth (p_adj<0.001) postoperative month.

Conclusion:

Totally endovascular repair of aortic arch lesions with ASA and KD via Castor stent in combination with fenestration or chimney is feasible, effective, and safe, which can achieve an encouraging medium-term outcome and provide excellent remodeling at the lesions.

Clinical Impact

Single branched stent in combination with fenestration or chimney achieved a sufficient proximal landing zone and provided an encouraging medium-term outcome in this retrospective review of 18 patients receiving endovascular treatment of pathological aortic arch with aberrant subclavian artery and/or Kommerell’s diverticulum. The authors suggest this time-saving and efficient technique to establish systematic experience for the treatment in this kind of patients.

Keywords

aberrant subclavian artery thoracic endovascular aortic repair branched stent Kommerell’s diverticulum

Introduction

Aberrant subclavian arteries (ASAs) denote anomalies involving the aortic arch, with 0.5% to 1% of the population exhibiting a right ASA and a mere 0.05% showcasing a left ASA.¹ The majority of cases bearing ASAs traverse the realms of asymptomatic existence. The cardinal symptoms intricately linked with ASAs encompass dysphagia lusoria, precipitated by esophageal compression, alongside dyspnea, chronic cough, stridor, recurrent pneumonia, obstructive emphysema, or chest pain, stemming from the tracheal compression.² An aberrant right subclavian artery (ARSA) originates from a left-sided aortic arch beyond the left subclavian artery (LSA), coursing either retroesophageally or retrotracheally. Conversely, an aberrant left subclavian artery (ALSA) arises from a right-sided aortic arch beyond the origin of the right subclavian artery. Approximately 60% of ASAs are associated with an aneurysmal dilatation originating from the aortic arch, known as Kommerell’s diverticulum (KD).^3,4 Case with ASA may also experience aneurysmal degeneration in the distal aortic arch. The presence of KD and/or an aneurysmal distal aortic arch can lead to complications, such as dissection, upper extremity ischemia, and rupture.^5,6 Related studies pointed out that ASA typically arises from the distal aortic arch, forming an acute angle with the aortic arch. This configuration weakens the aortic wall at the ASA opening, thereby elevating the risk of aortic dissection.⁵ Therefore, symptomatic patients with ASA should be treated aggressively. However, the infrequency of symptoms associated with ASAs and the substantial diversity in age, symptomatology, and available treatment modalities contribute to fluctuations in reported treatments and outcomes.

Whether ASA is complicated with aortic arch lesions or aortic arch lesions with ASA, thoracic endovascular aortic repair (TEVAR) can be selected. Even though ASA is asymptomatic, its variant anatomical morphology poses great difficulties for TEVAR to treat aortic lesions. The uncertain shape and position of ASA opening and the variability of aortic lesions are the main reasons for the difficulty in management. There is a lack of systematic reports and standardized protocols regarding clinical experience of TEVAR in managing aortic arch lesions with ASA. Direct coverage of ASA aggravates the risk of upper limb ischemia, cerebral infarction, and spinal cord ischemia. The existing reported protocols for preserving ASA during TEVAR therapy involve hybrid ASA bypass, fenestration, and chimney techniques. However, these approaches, documented in limited cases, are intricate and applicable only to relatively straightforward cases.⁷ In this research, it was attempted to delineate our experience and the short-term outcomes derived from treating 18 cases of complex aortic arch lesions associated with ASA/KD spanning from June 2018 to June 2023. The objective was to highlight a discerning perspective for the management of such intricate cases.

Patients and Methods

This investigation received ethical authorization from the ethics committees of multi-center, with the reference number of 2023KY170 on July 20, 2023. Due to the retrospective nature, the informed consent was deemed unnecessary.

Study Population

A comprehensive retrospective analysis was undertaken on cases involving aortic lesions with ASA during the period from June 2018 to June 2023. This multi-center retrospective study encompassed cases treated at 3 medical centers. The focus of the investigation was on those cases who underwent TEVAR with ASA reconstruction utilizing the Castor branched stent technique (Figure 1). Information pertaining to participants’ characteristics, clinical presentation, size of aberrant arteries, laterality, presence of associated KD and/or aortic disease, operative technique, and outcomes was systematically gathered through a comprehensive examination of medical records.

Imaging Evaluation

Computed tomography angiography (CTA) with 3-dimensional reconstruction imaging modality using EndoSize software (version 3.1.36 [5bb19e4]) was carried out to evaluate associated aortic lesions and anatomic subclavian features. Kommerell’s diverticulum was operationally defined as a dilation reaching or exceeding 1.5 times the diameter of the ASA and attaining a minimum dimension of 1.2 cm. This assessment involved measurements taken in the largest transverse plane perpendicular to the aorta, as previously outlined by Ichikawa et al.⁸ All imaging datasets were evaluated rigorously by both a cardiovascular surgical research and a qualified radiologist. Available radiology reports were also reviewed to describe other anatomic aortic pathologies and subclavian features according to the classification system proposed by Plotkin et al.⁹

Castor Device

Castor stent (MicroPort Medical, Shanghai, China) contains an integrated body and a branch designed to preserve the LSA when sealing lesions (Supplementary Figure 1A). The system consists of a woven polyester fabric coverage on self-expanding Nitinol stent without proximal bare zone (Supplementary Figure 1B). Main components of such a delivery system comprises a trigger wire of the main body stent release device (Supplementary Figure 1C-a), a device to control the release of the inner tube (Supplementary Figure 1C-b), the soft sheath (Supplementary Figure 1C-c), and the outer tube (Supplementary Figure 1C-d). To obtain the accessibility of branch segment, a steel ring connected to the traction wire is designed at the beginning of the branch to trigger its release (Supplementary Figure 1D). A “cap” made of polyester fabric is attached to a traction wire and can fold the branch portion, allowing the independent release of the stent trunk and branch.

Operative Approaches

All patients underwent totally endovascular repair of aortic lesions or KD and endovascular reconstruction of ASAs utilizing the Castor simultaneously. The study did not encompass cases involving hybrid repair, where bypass or transposition procedures preceded the application of TEVAR. The procedures were delineated based on the laterality of the ASA and the spectrum of aortic arch lesions. In reality, the methodology does not deviate significantly. The simple manipulation technique of Castor has been detailed in prior research.¹⁰ In simple cases, only Castor stent without additional maneuvers can solve the problem well. In cases of increased complexity, the Castor technique, in conjunction with physician-modified or in situ fenestration, or chimney procedures, becomes imperative. The operative approaches in these cases were classified into 4 scenarios: (1) reconstruction of the ARSA with the Castor branch (Landing Zone 3, Figure 2); (2) reconstruction of the LSA with the Castor branch and in situ fenestration or chimney for ARSA (Landing Zone 2, Figure 3); (3) reconstruction of the LSA with the Castor branch and physician-modified fenestration for ARSA (Landing Zone 2 or Zone 1, Figure 4); and (4) reconstruction of the right subclavian artery (RSA) with the Castor branch and physician-modified fenestration for the ALSA (Landing Zone 2, Figure 5). There is currently no established criterion for decision-making process between the chimney and various fenestration techniques yet. In our study, physician-modified fenestration was considered under the following conditions: patients prone to cerebral infarction, or preoperative CTA suggested distortion or small diameter subclavian artery, which could easily lead to failure of in situ fenestration. In situ fenestration was considered for increasing the stent patency rate and reducing the endoleak rate in aneurysm or large KD patients. Chimney technique was considered for cases where in situ fenestration easily failed due to tortuous and angulated target subclavian vessels.

Take the procedure of situation 2 as an example, the basic description was as follows: (1) The subjects were placed in a supine position under general anesthesia and disinfected in the bilateral inguinal areas, upper limbs, and bilateral necks (if necessary). Subsequently, the bilateral brachial artery (in other cases, the left brachial artery) and the unilateral femoral artery were incised and exposed. A shorter sheath (8F) was used to enter the left brachial artery, then a pigtail catheter (5F) was inserted into the aortic root to perform angiography through an auxiliary percutaneous femoral artery approach. After digital subtraction angiography (DSA) confirmed consistency between pathology and preoperative CTA examination, another 5F catheter was introduced into the right femoral artery through LSA from the left brachial artery and was exteriorized from the exposed main approach of right femoral artery. Then, another pigtail catheter was guided from the right femoral artery to the ascending aorta and exchanged it to a Lunderquist stiff guidewire. Then, we inserted the traction wire into the 5F catheter and exteriorized it from the left brachial artery. The main body of Castor was transported to the descending aorta through the Lunderquist guidewire. Meanwhile, the 5F catheter combined with the traction wire followed the main body of Castor together. (2) The projection angle of LSA and the position of the stent were adjusted based on the measured values of CTA and the marks. Then, the sheath of Castor was removed and the branch was dragged into LSA by pulling the traction wire. Finally, the main body and branch of Castor were deployed by pulling the trigger wire and the traction wire, respectively. (3) Afterward, the projection angle of ARSA was adjusted and the in situ fenestration was performed: the puncture system was introduced from ARSA and the membrane of Castor stent was punctured. Next, the balloon was introduced to expand the in situ fenestration step by step and then the bridging stent was introduced along the guide wire and released to reconstruct the ARSA.

In either case, in order to have sufficient lengths of bridging stents to cover and eliminate ASA lesions, we would implant multiple bridging stents side by side at the distal ASA to increase the coverage length (see Figure 2I). Especially in the patients with dysphagia symptoms, we would pay more attention to this point to keep the aberrant vessels open in the presence of compression of the esophagus as far as possible.

We have developed a postoperative antiplatelet treatment plan for at least 6 months, using clopidogrel (75 mg/day) to prevent branch stent occlusion.

Study Outcomes

Endpoints

The primary endpoints were in-hospital and follow-up mortality. The secondary endpoints were in-hospital complications, graft patency, reinterventions, and diameter changes at the maximal aorta and at the KD.

Patients were subjected to systematic follow-up evaluations, involving CTA of the reconstructed aortic and subclavian artery at 3 and 6 months postoperatively, followed by subsequent annual assessments. The benchmark for patency adjudication was established as the presence of vascular stenosis at 50% or below.¹¹

Reporting items

The presentation of data adhered to the recommended reporting items outlined in the Suggested reporting Items for Lusoria Treatments (SILT checklist).¹² This checklist was designed to enhance the uniformity of reporting in publications concerning the treatment of ASA pathologies.

Statistical Analysis

The collected data were statistically analyzed using SPSS Version 26.0 (SPSS Inc., Chicago, Illinois). Shapiro-Wilk test results were used to determine the distribution of data. The median and interquartile values were utilized for non-normally distributed continuous statistics, whereas the mean±standard deviation (SD) was used for normally distributed continuous variables. The terms number and percentage were used to denote categorical variables. The Kruskal-Wallis test was performed to compare non-normally distributed continuous variables. p<0.05 was considered statistically significant.

Results

Between June 2018 and June 2023, a total of 18 patients with aortic arch lesions and ASA and/or KD received TEVAR with single-branched stent (Castor) or combined in situ fenestration, physician-modified fenestration, or chimney technique by the same surgeon team. Patients’ mean age was 62.4±13.3 (range, 39–82) years. Furthermore, 15 (83.3%) cases were identified with hypertension, 1 (5.6%) case with chronic renal failure, 1 (5.6%) case with prior cerebral infarction, as well as 16 (88.9%) cases with chest pain, of whom there were 13 cases with only chest pain, 2 with dysphagia, and 1 with concurrent dysphagia and asthma. The summary of participants’ baseline characteristics is accessible in Table 1.

Table 1.

Clinical Characteristics of 18 Patients With Aortic Lesion and ASA.

Variable	n (%) or mean±SD
Demographic
Age (years)	62.4±13.3
Male	14 (77.8%)
Hypertension	15 (83.3%)
Smoking	12 (66.7%)
Chronic renal failure	1 (5.6%)
Congestive heart failure	0 (0.0%)
COPD	2 (11.1%)
Diabetes mellitus	5 (27.8%)
Coronary disease	1 (5.6%)
Peripheral vascular disease	0 (0.0%)
Arrythmia	1 (5.6%)
Prior cerebral infarction	1 (5.6%)
Symptoms on presentation	17 (94.4%)
Chest pain	16 (88.9%)
Only chest pain	13 (72.2%)
Chest pain+Dysphagia	2 (11.1%)
Chest pain+Dysphagia+Asthma	1 (5.6%)
Hoarseness+Cough	1 (5.6%)
Asymptomatic	1 (5.6%)

COPD: chronic obstructive pulmonary disease; ASA: aberrant subclavian artery.

The anatomical details from CTA for 18 cases were summarized in Table 2. Two manifested as right-sided aortic arch with left-sided ALSA, and the remaining 16 patients manifested as left-sided aortic arch with right-sided ARSA. Of these 18 patients, 11 (61.1%) cases had KD with the mean KD diameter of 20.0 (19.5, 21.2) mm, and 1 (5.6%) case had bovine arch. All the ASAs were retroesophageal and only 3 (16.7%) patients were symptomatic with dysphagia lusoria. The CTA revealed a mean proximal aortic diameter of 30.9±1.6 mm, and the mean diameter of the branches quantified by CTA was 8.8±0.97 mm.

Table 2.

Anatomical CTA Details of 18 Patients With Aortic Lesion and ASA.

Variable	n (%) or mean±SD or median (Q1, Q3)
Anatomical characteristics
Left-sided aortic arch with right-sided ARSA	16 (88.9%)
Left-sided aortic arch with left-sided ARSA	0
Right-sided aortic arch with right-sided ALSA	0
Right-sided aortic arch with left-sided ALSA	2 (11.1%)
Anatomical course of the ASA
Posterior to the esophagus	18 (100%)
Posterior to the trachea	0
Anterior to the trachea	0
Aortic pathology
Degenerative aneurysm	3 (16.7%)
Type A dissection	1 (5.6%)
Type B dissection	11 (61.1%)
Penetrating aortic ulcer	2 (11.2%)
Intramural hematoma	1 (5.6%)
ASA pathology
KD	11 (61.1%)
KD diameter (mm)	20.0 (19.5, 21.2)
Bovine arch	1 (5.6%)
Measurements (CTA, EndoSize software)
Aortic diameter (mm)
Maximal	48.6±12.5
Proximal	30.9±1.6
Distal diameter	21.4±2.2
*LCCA-LSA spacing or RCCA-RSA spacing	9.5 (7.8, 15.0)
^#LSA-ARSA spacing	9.5 (6.8, 12.3)
LSA proximal diameter	10.3 (8.7, 11.1)
LSA distal diameter	8.8 (7.7, 9.6)
RSA proximal diameter	12.5 (11.2, 13.8)
RSA distal diameter	9.0 (8.3, 9.5)
Diameter of right access road	9.6 (8.6, 10.4)
Diameter of left access road	8.6 (7.9, 10.2)
Effective anchoring zone length	34.3 (29.6, 38.2)

Abbreviations: ASA, aberrant subclavian artery; ARSA, aberrant right subclavian artery; ALSA, aberrant left subclavian artery; RSA, right subclavian artery; LSA, left subclavian artery; LCCA, left common carotid artery; RCCA, right common carotid artery; KD, Kommerell’s diverticulum.

LCCA-LSA spacing in the cases of left-sided aortic arch with right-sided ARSA, RCCA-RSA spacing in the cases of right-sided aortic arch with left-sided ALSA

LSA-ARSA spacing in the cases of left-sided aortic arch with right-sided ARSA

Perioperative details are accessible in Table 3. Three (16.7%) patients with a giant aortic arch aneurysm on the verge of rupture underwent emergency surgery. The mean operation time was 132±23 (range, 81–175) minutes, with radiation dose of 885±101 mGy and contrast agent quantity used of 124±18 mL. The procedure achieved a 100% success rate, with all lesions successfully repaired through endovascular means. A total of 35 branches were reconstructed, comprising 1 left common carotid artery (LCCA), 14 LSAs, 2 RSAs, 16 ARSAs, and 2 ALSAs. Regarding proximal landing, 2 patients underwent straightforward ARSA reconstruction using the Castor branch, with the Castor stent proximal landing situated in zone 3. Furthermore, 15 patients had the Castor stent proximal landing in zone 2, and 1 patient had the Castor stent proximal landing in zone 1. Among the 16 cases with proximal landings in zones 2 and 1, 9 cases were involved in situ fenestration, 5 cases incorporated physician-modified fenestration (4 single fenestrations and 1 double fenestration), and the chimney technique was utilized in 2 cases where in situ fenestration failed due to tortuous and angulated aberrant right subclavicular arteries. Specifically, in 2 cases with a right-sided aortic arch and left-sided ALSA, RSA was reconstructed utilizing the Castor branch, and ALSA was reconstructed by physician-modified fenestration (Landing Zone 2, single fenestration). In 1 case with a left-sided aortic arch and right-sided ARSA, LCCA was reconstructed via the Castor branch, and both LSA and ARSA were reconstructed by physician-modified fenestration (Landing Zone 1, double fenestration) due to insufficient distance between LSA and LCCA for a satisfactory long-term sealing landing zone. In the remaining 13 cases with a left-sided aortic arch and right-sided ARSA, LSAs were reconstructed through the Castor branches, and ARSAs were reconstructed by 9 in situ fenestrations, 2 physician-modified fenestrations, and 2 chimneys (Landing Zone 2, single fenestration).

Table 3.

Perioperative Characteristics of 18 Patients With Aortic Lesion and ASA.

Variable	n (%) or mean±SD or median (Q1, Q3)
Operative details
Planned procedure	15 (83.3%)
Emergency procedure	3 (16.7%)
Success
LSA success (2ALSA+14 regular anatomic LSA)	16 (100.0%)
ARSA success	18 (100.0%)
Proximal landing
Zone 3	2 (11.1%)
Zone 2	15 (83.3%)
Zone 1	1 (5.6%)
Detailed aortic repair technique
LCCA revascularization	1 (5.6%)
Castor branch	1 (5.6%)
LSA revascularization
Castor branch	13 (72.2%)
Physician-modified fenestration (2ALSA+1 regular anatomic LSA)	3 (16.7%)
Without LSA revascularization	2 (11.1%)
ASA revascularization technique
Castor branch	2 (11.1%)
In situ fenestration	9 (50.0%)
Physician-modified fenestration	5 (27.8%)
Single fenestration	4 (22.2%)
Double fenestration	1 (5.6%)
Chimney	2 (11.1%)
Bridging stent information (n=16)
Fluency (BD, USA)	10 (62.5%)
Diameter, mm	10 (9.8, 12)
Length, mm	60 (40, 80)
Viabahn (W.L. Gore & Associates, USA)	6 (37.5%)
Diameter, mm	10.5 (9.8, 11.3)
Length, mm	62.5 (50, 75)
Length of aortic coverage, mm	164.4±28.7
Intra-operative data
Operating time, minutes	132±23
Radiation dose, mGy	885±101
Contrast agent quantity used, mL	124±18

Abbreviations: ASA, aberrant subclavian artery; ARSA, aberrant right subclavian artery; ALSA, aberrant left subclavian artery; LSA, left subclavian artery; LCCA, left common carotid artery.

The mean proximal diameter of Castor stent was 34 (32, 34.5) mm, with oversize of 9.1±1.6%; the mean diameter of Castor stent branch was 10 (8, 10) mm, with oversize of 0.86±0.57 mm. Among 16 patients who experienced fenestration or chimney, 10 (62.5%) patients consumed Fluency bridging stent and each in them consumed a mean of 1.3±0.5 Fluency bridging stents with a mean total length of 88.3±22.1 mm; and the mean diameter of each stent was 10 (9.8, 12) mm with a mean length of 60 (40, 60) mm. Six (37.5%) patients consumed Viabahn bridging stent and each in them consumed a mean of 1.2±0.4 Viabahn bridging stents with a mean total length of 70.0±17.3 mm; and the mean diameter of each stent was 10.5±1.0 mm with a mean length of 62.5 (50, 75) mm. The distal landing zone situated at zone 4 was capable of achieving effective sealing, with the mean length of aortic coverage measuring 164.4±28.7 (range, 120–240) mm.

In-hospital Outcomes

The average duration of hospitalization was 7.6±1.7 days. There were no deaths during the hospitalization, nor aortic rupture, major stroke, subclavian steal syndrome, arm ischemia, endoleak, and reintervention. None of the cases experienced cerebrovascular complications or retrograde dissection. One (5.6%) patient experienced postoperative spinal cord ischemia, manifested as low paraplegia, and subsequently recovered on postoperative day 5 following cerebrospinal fluid drainage and glucocorticoid treatment. Another (5.6%) patient exhibited suboptimal healing of the inguinal incision, while surgical intervention was unnecessary. Prior to discharge, chest pain resolved in all 16 (100%) symptomatic patients, dysphagia only improved in 1 (33.3%) patient, and asthma resolved in 1 symptomatic patient, whereas hoarseness persisted in the symptomatic patient (Table 4).

Table 4.

In-hospital and Follow-up Data of 18 Patients With Aortic Lesion and ASA.

Variable	n (%) or mean±SD or median (Q1, Q3)
In-hospital outcomes
Length of hospital stay, days	7.6±1.7
Complications
Spinal cord ischemia	1 (5.6%)
Poor wound healing	1 (5.6%)
Follow-up data
Length of available follow-up, months	33.8±12.1
Relief from symptoms of dysphagia	3/3 (100%)
Endoleak	0
Reinterventions	0
Major adverse events during follow-up
Aortic-related death	0
Cerebral infarction	1 (5.6%)
Cerebral hemorrhage	1 (5.6%)
Overall death	3 (16.7%)
Maximal aortic diameter (mm) (n=18)
PostM3	41.8 (33.5, 51.3)
Difference (Pre-PostM3)	5.1 (3.9, 5.5)
PostM6	39.5 (33.2, 41.5)
Difference (Pre-PostM6)	6.5 (5.6, 14.1)
KD diameter (mm) (n=11)
PostM3	9.8 (9.5, 10.6)
Difference (Pre-PostM3)	10.0 (9.8, 10.6)
PostM6	9.5 (9.3, 10.6)
Difference (Pre-PostM6)	10.3 (10.1, 10.6)

Abbreviations: KD, Kommerell’s diverticulum; PostM3, the third postoperative month; PostM6, the sixth postoperative month; Q1, the first quartile; Q3, the third quartile.

Follow-up

Outcomes

During a mean follow-up of 33.8±12.1 (range, 9.8–56.8) months, all-cause mortality was 3 (16.7%; Figure 6A). Besides, 1 case died of cerebral infarction at postoperative 14th month. Before discharge and during follow-up, CTA showed no symptoms of cerebral infarction. Sudden hemiplegia and distortion of commissure occurred in this patient at 14 months after TEVAR, and CTA showed the left large cerebral infarction and the stent condition was not abnormal. Another died of cerebral hemorrhage at postoperative 17th month. This patient needed hemodialysis for treatment with chronic renal failure prior to admission. Similarly, before discharge and during follow-up, CTA showed no symptoms of cerebral infarction or cerebral hemorrhage. This patient underwent regular hemodialysis during follow-up. When sudden severe headache occurred at 17 months after TEVAR, CTA showed large hemorrhage in the left brain and subarachnoid space, while the stent condition was not abnormal. This patient was finally considered to die of a cerebral hemorrhage due to chronic hemodialysis. A third patient died of pancreatic cancer at postoperative 34th month. Therefore, none of these deaths were considered to be attributed to aortic-related issues, and there was no need for secondary interventions. All reconstructed branch vessels maintained patency, and the resolution of both dysphagia and hoarseness was found in symptomatic patients (Table 4).

Remodeling at the lesions

In addition, the maximal aortic diameter was not significantly reduced at the third postoperative month versus preoperative (p_adj=0.481) and was not significantly reduced at the sixth postoperative month versus the third postoperative month (p_adj=0.731), whereas significantly decreased at the sixth postoperative month versus preoperative (p_adj=0.031; Figure 6B). The KD diameter was significantly attenuated at the third postoperative month compared with that before surgery (p_adj=0.001), so was that of the sixth postoperative month compared with that before surgery (p_adj<0.001), while the KD diameter at the sixth postoperative month was not significantly lowered compared with that at the third postoperative month (p_adj=1.000; Figure 6C).

Discussion

The ARSA and KD constitute anatomical anomalies frequently accompanied by aortic arch diseases, occasionally presenting symptomatic manifestations. Present recommendations involve the intervention for ARSA and/or KD in cases of symptomatic patients, as well as in asymptomatic cases exhibiting a subclavian artery aneurysm or a KD exceeding 3 cm.¹³ Regarding the treatment options, a large multinational multi-institutional review from the Vascular Low Frequency Disease Consortium confirmed that treatment of simple ASA/KD could be performed safely regardless of the repair strategy.¹⁴ However, given the lower early mortality and reintervention rates, young healthy patients might be considered more suitable for open approaches. In our study, we just discussed the complex ASA/KD cases combined with thoracic aortic lesions including dissection, aneurysm, intramural hematoma, and aortic ulcer. Under this circumstance, endovascular modality showed an irreplaceable advantage, and the management of ASA was different depending on the circumstances.

Total coverage of ASA was sometimes inevitably performed to obtain an adequate landing zone.^15,16 The comprehensive occlusion of the ASA has the potential to trigger ischemia in critical regions, involving brain, spinal cord, and arm, thereby elevating the susceptibility to adverse outcomes, encompassing but not limited to stroke, paraplegia, pulselessness, intermittent claudication in the arm, and a sensation of coldness in the shoulder. Therefore, more and more centers are inclined to completely reconstruct the ASA. As the total open surgery possesses a significant trauma,¹⁷ currently, endovascular reconstruction of ASA is mainly undertaken, including hybrid or total endovascular way: the hybrid technique primarily involves TEVAR encompassing the origin of the ASA, coupled with its ligation or plugging, followed by subclavian artery revascularization through debranching of the ASA or a carotid-subclavian bypass. In addition, the total endovascular approach comprises TEVAR integrated with ASA revascularization via chimney,¹⁸ fenestration,¹⁹ or branched grafts.²⁰ It is noteworthy that there are still some limitations associated with these approaches. Hybrid procedure needs dissection and anastomosis of the target vessels, and numerous potential complications, such as nerve injury, vocal cord paralysis, and lymphatic leakage.^21,22 The problem of endoleak and the long-term patency are worrying after the chimney technique.²³ However, due to a scarcity of relevant research, a consensus on the approach for ASA reconstruction has not been reached.

Therefore, the Castor branched stent graft emerges as a pragmatic and readily accessible alternative option.²⁰ In contrast to the fenestrated endograft, it could be concluded that the Castor single-branched stent possesses noticeable advantages: (1) its unibody design affords a more physiologically aligned structure, (2) the procedural intricacy is diminished, and (3) the incidence of junction site endoleak between the main body and branch portions is mitigated. However, when confronted with aortic arch lesions closely situated to or involving the arch branch, sole reliance on Castor may prove insufficient in addressing the array of challenges. In such instances, the imperative arises to advance the stent to secure an ample landing zone. During this critical juncture, a strategic amalgamation of Castor with fenestration, chimney, and other sophisticated technologies becomes pivotal for resolving the complex issues at hand. This study is first to systematically present outcomes derived from the application of Castor branched stent in combination with fenestration or chimney techniques for the reconstruction of the ASA and aortic arch branches. The primary purpose was to discern and elucidate the multifaceted aspects of feasibility, morbidity, mortality, and medium-term outcomes associated with this comprehensive approach.

In this case series, in 2 cases with sufficient landing distance from lesions to the LSA were involved in the straightforward reconstruction of ARSAs utilizing the Castor branch, and the Castor stent’s proximal landing was positioned in zone 3. The majority of patients in this case series derived benefits from TEVAR with a proximal landing in zone 2. In these cases, the Castor branch was employed to rebuild the LSA, and a combined approach of fenestration or chimney technique was utilized for the reconstruction of ARSA. Even in a scenario where there was insufficient distance between the LSA and LCCA to achieve a satisfactory landing, the LCCA was still reconstructed using the Castor branch, and both the LSA and ARSA were reconstructed through physician-modified fenestration (Landing Zone 1, double fenestration). Notably, the utilization of the Castor combined approach involving fenestration and chimney techniques allows for an attainment of an extended proximal landing zone conveniently, even in scenarios necessitating total aortic arch repair.

Exhibiting a technical success rate of 100% and a notable absence of in-hospital mortality, this study underscored highly encouraging early results. Regarding complications, despite spinal cord ischemia occurred in 1 (5.6%) case during hospitalization, low paraplegia was recovered on postoperative day 5 after cerebrospinal fluid drainage and glucocorticoid treatment. One (5.6%) case had obesity-related poor healing of inguinal incision, but did not require surgical intervention. During the follow-up period, all of the reconstructed branch vessels remained patent, dysphagia and hoarseness disappeared in all symptomatic patients, with no stroke, endoleak, and necessity of reintervention. None of the 3 reported deaths were attributable to aortic-related causes. This outcome instills a sense of optimism and encouragement in the overall assessment. Interestingly, the aberrant arteries were connected with branches or with in situ fenestrations and the pulsatile flow was still maintained to the aberrant arteries. However, dysphagia symptoms alleviated in all 3 patients with dysphagia during follow-up time. We considered the reduced diameter and flow pressure in the KD lumen perhaps explained the alleviation of dysphagia symptoms. Open repair is often touted as the most effective because one can directly resect the ASA, thereby removing the compressive elements on the esophagus.²⁴ The review from the Vascular Low Frequency Disease Consortium pointed out that there was no significant discrepancy between open and endovascular or hybrid procedures in terms of symptom relief.¹⁴ This suggests that perhaps the endovascular method may also relieve the symptoms well.

The bridge stent might cross the esophagus or trachea when the ASA lesion was longer and the bridge stent was longer. However, shorter ASA lesions resulted in shorter implantation of bridging stent, which could be further away or only close to the esophagus or trachea. In other words, the length of the bridging stent we used was determined by the length of the lesion in ASA. In addition, the placement of the bridging stent near or across the esophagus or trachea was also based on the length of the lesion in ASA.

In addition, a certain chance of fistula due to stent long-term erosion of the trachea or esophagus is worthy of our concern. It has been reported that the incidence of aortic-esophageal fistula formation after TEVAR is approximately 1.5% to 2%.²⁵ The potential pathological mechanisms may manifest in the increase of mediastinal pressure and the inflammatory response caused by hematoma and its reabsorption. The radial force exerted by the stent implant on the aortic wall and the changes in the geometry of the aorta after TEVAR are also considered to be potential mechanisms of aortic-esophageal fistula formation. However, in the cases we have studied, there have been no reported complications of aortic or ASA-related tracheal or esophageal fistula so far.

While concerns regarding integrity and durability of the fenestrated Castor stent may arise, both in this study and in other series conducted by our team employing a similar technique, no instances of stent fracture or endoleak have been observed.^26,27 In essence, fenestrations ought to be minimized to mitigate the risk of endoleak. Castor stands out as the sole integrated single-branch stent in clinical practice, presenting a distinct advantage by inherently reducing a fenestration. It is noteworthy that the branch of Castor serves a dual purpose—not only expediting the procedure but also functioning as a marker for fenestration and ensuring the stent’s secure fixation to prevent fenestration displacement. This dual functionality contributes to enhancing the success rate of fenestration. Indeed, managing fenestration displacement can prove to be challenging. The utilization of the fixed branch marker streamlines the process, ensuring a facile, secure, and precise alignment between the fenestration and the target vessel.

Meanwhile, it was attempted to examine the remodeling at the lesions. In this study, the maximal aortic diameter was significantly reduced at sixth postoperative month (p_adj=0.031); the dilated KD was significantly retracted at third (p_adj=0.001) and sixth (p_adj<0.001) postoperative months, suggesting that the reconstruction and remodeling of aortic lesions were stable. These results indicate that this technique not only provides successful reconstruction of the various aortic arch branches but also remodels the aortic lesions surpassingly.

Limitations

Some limitations should be pointed out. First, despite its status as a multi-cardiac center study, the limited number of cases is a consequence of the inherently low incidence of ASA. Second, the absence of a control group and the utilization of compound techniques on Castor stent introduce complexity in comparisons with alternative procedures. Finally, while the medium-term outcomes are promising, it is imperative to conduct a comprehensive long-term follow-up to find out any potential device-related complications.

Conclusion

Employing the Castor stent for addressing pathological conditions in the aortic arch among cases with ASA and/or KD is efficacious, resulting in commendable remodeling at the lesions.

Supplemental Material

sj-tif-1-jet-10.1177_15266028241259391 – Supplemental material for Utilizing Single-Branched Stent in Combination With Fenestration or Chimney for Endovascular Repair of Aortic Arch Lesions With Aberrant Subclavian Artery

Supplemental material, sj-tif-1-jet-10.1177_15266028241259391 for Utilizing Single-Branched Stent in Combination With Fenestration or Chimney for Endovascular Repair of Aortic Arch Lesions With Aberrant Subclavian Artery by Zeng-Rong Luo, Yong-Ping Zhu and Guan-Hua Fang in Journal of Endovascular Therapy

Footnotes

Acknowledgements

The authors acknowledge the contribution by the participators: Xiao-Fu Dai, Dao-Zhong Chen, Zhong-Yao Huang, Xue-Shan Huang, Dong-Shan Liao, Feng Lin, and Qi-Min Wang.

Author Contributions

Zeng-Rong Luo: Conceptualization; Investigation; Methodology; Software; Validation; Writing - original draft; Writing - review & editing.

Yong-Ping Zhu: Data curation; Investigation; Software; Validation.

Guan-Hua Fang: Conceptualization; Investigation; Methodology; Supervision; Writing - review & editing.

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.

Ethical Statement

This study was approved by ethics committee of Fujian Medical University Union Hospital. (Approved number 2023KY170, date: July 20, 2023).

ORCID iD

Guan-Hua Fang

Supplemental Material

Supplemental material for this article is available online.

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