Clinical and procedural impact of aortic arch anatomic variants in carotid stenting procedures

Transradial Approach for Neurovascular Interventions : A Literature Review

The femoral artery is the preferred access route for neurointerventions. The transfemoral approach (TFA) offers advantages such as a large diameter and easy access. However, it also entails disadvantages such as patient discomfort and high risk of complications. Following the initial report of coronary angiography using the transradial approach (TRA) in 1989, cardiologists discovered the advantages of TRA over the TFA and gradually replaced it with the TRA. In 1997, Matsumoto et al. used the TRA for cerebral angiography and neurointervention. Thereafter, the adoption of TRA for neurointervention gradually increased and good outcomes were reported. However, despite these developments, the adoption rate of TRA is relatively low. We reviewed the relevant studies to increase the accessibility of TRA for neurointerventionists.

3D Characterization of the Aortic Valve and Aortic Arch in Bicuspid Aortic Valve Patients

Patients with bicuspid aortic valve (BAV) commonly have associated aortic stenosis and aortopathy. The geometry of the aortic arch and BAV is not well defined quantitatively, which makes clinical classifications subjective or reliant on limited 2D measurements. The goal of this study was to characterize the 3D geometry of the aortic arch and BAV using objective and quantitative techniques. Pre-TAVR computed tomography angiogram (CTA) in patients with BAV and aortic stenosis (AS) were analyzed (n = 59) by assessing valve commissural angle, presence of a fused region, percent of fusion, and calcium volume. The ascending aorta and aortic arch were reconstructed from patient-specific imaging segmentation to generate a centerline and calculate maximum curvature and maximum area change for the ascending aorta and the descending aorta. Aortic valve commissural angle signified a bimodal distribution suggesting tricuspid-like (≤ 150°, 52.5% of patients) and bicuspid-like (> 150°, 47.5%) morphologies. Tricuspid like was further classified by partial (10.2%) or full (42.4%) fusion, and bicuspid like was further classified into valves with fused region (27.1%) or no fused region (20.3%). Qualitatively, the aortic arch was found to have complex patient-specific variations in its 3D shape with some showing extreme diameter changes and kinks. Quantitatively, subgroups were established using maximum curvature threshold of 0.04 and maximum area change of 30% independently for the ascending and descending aorta. These findings provide insight into the geometric structure of the aortic valve and aortic arch in patients presenting with BAV and AS where 3D characterization allows for quantitative classification of these complex anatomic structures.

Medical-Surgical Implications of Branching Variation of Human Aortic Arch Known as Bovine Aortic Arch (BAA)

(1) Background: The aortic arch (AA) branching model is challenging, considering the multiple anatomical variations documented in existing research. The bovine aortic arch (BAA) is the most prevalent anatomical variation among these. This variant of AA branching has long been considered a nonsymptomatic malformation, having been discovered incidentally during imaging investigations for other causes. However, more recent studies have demonstrated that BAA shows a frequent association with coarctation of the aorta (CoA), thoracic aortic disease (TAD), and stroke. At the same time, given the current context of increasing activity in the fields of interventional and surgical procedures in the aorta and its branches, it is very important to know the medical-surgical implications of this anatomical variant. (2) Methods: We conducted a comprehensive review using PubMed and Embase, focusing specifically on randomized trials and cohort analyses that examined the medical-surgical implications of BAA. We assessed information related to studied groups, medical procedures, and study outcomes. Initially, we identified 8454 studies, and after rigorous evaluation, we narrowed down our review to 25 articles. (3) Discussions: The intervention consisted of assessing the risks associated with BAA through different imaging investigation methods such as computer tomographic angiography (CTA), magnetic resonance imaging (MRI), or ultrasonography (US). The following results were evaluated: the prevalence of the BAA, the importance of imaging investigations in establishing the diagnosis and the therapeutic management and monitoring the evolution of patients with the BAA, the association of the BAA with CoA, TAD, and stroke, and the potential risks of interventional treatment in patients with the BAA. (4) Conclusions: The prevalence of the BAA differs both between different ethnic groups and between genders. Advanced imaging methods such as CTA and 4D flow MRI allow detailed descriptions of supra-aortic vascular anatomy and information about blood flow velocities, direction, and turbulence in the AA. US remains an easy and valuable imaging investigation, with the potential to detect and correctly diagnose the BAA and its hemodynamic implications. Anatomical variations in the AA are associated with increased rates of TAD, CoA, and stroke, necessitating early diagnosis and increased supervision of patients with such incidentally observed abnormalities. In addition, there is a need to further develop and refine the surgical techniques used and personalize them to the individual characteristics of patients with the BAA.

Navigating complexity with low-crossing profile dual-layer micromesh carotid stent: implications for contemporary carotid artery stenting outcomes (ROADSAVER study insights)

BACKGROUND

The safety and efficacy of carotid artery stenting (CAS) can be affected by certain technical and anatomical factors. However, it is not known whether the use of a dual-layer micromesh stent (DLMS) with a low-crossing profile could reduce the risks associated with complex vascular anatomies during CAS.

METHODS

This study involved 1965 asymptomatic or symptomatic carotid artery stenosis patients who received the Roadsaver DLMS during CAS, as part of a prospective, multicenter observational ROADSAVER study, conducted from January 2018 to February 2021. The primary outcome was the 30-day rate of major adverse events (MAE; i.e. any death or stroke) after CAS. Procedural details and outcomes were compared between patients with complex anatomical features and those without.

RESULTS

One or more complex anatomical characteristics were identified in 1639 (83.4%) patents. Patients with complex anatomies were older and had a higher prevalence of arterial hypertension, cardiovascular disease, and prior stroke. Between patients with or without complex anatomical features, no significant differences were found either in procedural techniques, or in 30-day MAE (age-adjusted odds ratio (95% CI) for complexities vs. no complexities: 0.76 (0.35, 1.66); p=0.4905) and any stroke (age-adjusted odds ratio (95% CI) for complexities vs. no complexities: 0.89 (0.37, 2.17); p=0.8032) incidence. Furthermore, neither the presence of specific types of anatomic complexity nor their number (per patient) markedly influenced the 30-day MAE and any stroke incidence.

CONCLUSIONS

In this real-world cohort of patients undergoing CAS with the Roadsaver DLMS, no significant difference in the occurrence of 30-day MAE and any stroke was observed between patients with or without high-risk anatomical features.

Right-Sided Aortic Arch: A Computed Tomography Angiography Investigation, A Systematic Review with Meta-Analysis

Background/Objectives: The right-sided aortic arch (RAA) is an uncommon variation of the aortic arch (AA), characterized by the aorta crossing over the right main bronchus. In the RAA, the descending aorta can be found on either the right or left side of the spine. The current study comprises a comprehensive retrospective computed tomography angiography (CTA) investigation into the prevalence of the RAA within the Greek population. Additionally, we will conduct a systematic review and meta-analysis to elucidate both common and rare morphological variants of the RAA. This research is significant as it sheds light on the prevalence and characteristics of the RAA in a specific population, providing valuable insights for clinical practice. Methods: Two hundred CTAs were meticulously investigated for the presence of a RAA. In addition, the PubMed, Google Scholar, and Scopus online databases were thoroughly searched for studies referring to the AA morphology. The R programming language and RStudio were used for the pooled prevalence meta-analysis, while several subgroup analyses were conducted. Results: Original study: A unique case of 200 CTAs (0.5%) was identified with an uncommon morphology. The following branches emanated from the RAA under the sequence: the right subclavian artery (RSA), the right common carotid artery (RCCA), the left common carotid artery (LCCA), and the left vertebral artery (LVA) in common origin with the aberrant left subclavian artery (ALSA). The ALSA originated from a diverticulum (of Kommerell) and followed a retroesophageal course. Systematic Review and Meta-Analysis: Sixty-two studies (72,187 total cases) met the inclusion criteria. The pooled prevalence of the RAA with a mirror-image morphology was estimated at 0.07%, and the RAA with an ALSA was estimated at <0.01%. Conclusions: AA anomalies, specifically the RAA, raise clinical interest due to their coexistence with developmental heart anomalies and possible interventional complications. Congenital heart anomalies, such as the Tetralogy of Fallot and patent foramen ovale, coexisted with RAA mirror-image morphology.

Safety of Tailored Transfemoral Carotid Artery Stenting for Symptomatic Elderly Patients: A Single Center Observational Study

OBJECTIVE

Transfemoral carotid artery stenting (TFCAS) in symptomatic elderly patients (≥70 years old) may have a high periprocedural stroke rate. This study was performed to examine whether tailored TFCAS for symptomatic elderly patients is as safe as that for symptomatic nonelderly patients.

METHODS

The subjects were 185 patients with symptomatic internal carotid artery stenosis. Tailored TFCAS including postoperative management was performed based on preoperative examinations of vascular anatomy, plaque imaging, platelet aggregation activity, and cerebral hemodynamic impairment. The major 30-day perioperative stroke rates were examined.

RESULTS

The patients included 51 (27.6%) <70 (group Y) and 134 (72.4%) ≥70 (group E) years old. Group E included significantly more cases with an elongated aortic arch, tortuous target lesion, and longer plaques (all P < 0.05). Among all cases, 181 (97.8%) procedures were performed as per preoperative planning. Group E had more frequent use of a proximal embolic protection device and a closed-cell or dual-layer micromesh stent (all P < 0.05). Seven patients (3.8%) had major stroke. Rates of major ischemic stroke (2.0% vs. 3.0%, P = 1.00) and intracranial hemorrhage (2.0% vs. 0.8%, P = 0.48) were low and did not differ significantly between groups Y and E.

CONCLUSIONS

Symptomatic elderly patients have several unfavorable factors. However, tailored TFCAS for each patient based on preoperative examinations in symptomatic elderly patients may be as safe as that in symptomatic nonelderly patients.

Hybrid repair of an innominate artery pseudoaneurysm after blunt traumatic injury in a bovine arch

Innominate artery injury is an uncommon consequence of blunt trauma to the neck due to its protected position behind the thorax. A 38-year-old male presented as a trauma with a right-sided pseudoaneurysm emanating from the distal innominate artery after falling from a three-story building. On imaging, he also had a bovine arch. He underwent hybrid repair with covered stent placement from the common carotid into the innominate artery, carotid-subclavian bypass, and plugging of the subclavian artery. The patient recovered with no cerebral insult, neurological deficits, or rupture. Post-traumatic innominate artery pseudoaneurysms can successfully be repaired via a hybrid surgical approach.

Chinese expert consensus on transradial access in percutaneous peripheral interventions

Transradial access (TRA) is a safe and comfortable approach and the preferred access for percutaneous coronary intervention. However, TRA is not widely used for peripheral interventions. Currently, there is a lack of data on patient selection, appropriate medical devices, complication prevention, and TRA adoption. Therefore, the Chinese Society of Interventional Oncology of the China Anti-Cancer Association organized nationwide experts to establish a Working Group of China Expert Consensus on TRA in percutaneous peripheral interventions in 2022, and jointly formulated this consensus to better promote the application of TRA in peripheral interventions to guide clinicians on patient selection, technical recommendations, and physician training. This consensus mainly focuses on the current situation, advantages and limitations of TRA in peripheral interventions, anatomical characteristics of the radial artery, patient selection, technical aspects, prevention and management of complications, radiation dose, and learning curve. A consensus was reached through a literature evaluation and by referring to the opinions of the expert group.

Comparison of treatment outcomes and complications of coil embolization in elderly and very elderly patients with cerebral aneurysms: a propensity score matching analysis

PURPOSE

This single center study aims to compare the treatment outcomes and procedure-related complications of coil embolization in elderly patients (60-79 years) and very elderly patients (aged 80 years or older) with cerebral aneurysms.

METHODS

Data was collected from 504 elderly patients aged 60 years or older who underwent coil embolization for intracranial aneurysms from 2018 to 2021. The study evaluated patient-related and anatomical factors and assessed various outcomes, comparing results between groups using statistical analysis and propensity score matching.

RESULTS

A total of 503 cerebral aneurysms were analyzed from individuals aged 60-79 years (n = 472) and those aged 80 years or older (n = 31). The majority of the aneurysms were unruptured with an average size of 3.5 mm in height and 3.4 mm in width. The patients were compared using 1:1 propensity score matching, and no significant differences were found in factors other than age and aortic elongation. Logistic analysis revealed that being over 80 years old and having a severe aortic arch elongation were identified as risk factors for procedure-related events in both total and unruptured cases.

CONCLUSIONS

The study compared coil embolization treatment for cerebral aneurysms in patients aged 60-79 and over 80, finding no significant difference in treatment outcomes except for procedure-related events. Procedure-related events were associated with severe aortic arch elongation and being over 80 years old. Coil embolization can be considered safe and effective for patients over 80, but further trials are needed for accurate conclusions.

Complications and outcomes of carotid artery stenting in high-risk cases

OBJECTIVES

Carotid artery stenting is sometimes adapted for some at-risk cases; however, appropriate treatment timing with stroke onset is controversial. This study aims to identify factors that have an impact on complications and outcomes, especially in patients at high risk.

MATERIALS AND METHODS

We examined the characteristics of 152 consecutive patients treated by carotid artery stenting between January 2018 and March 2022 and retrospectively analyzed the risk factors for complications and poor outcomes (modified-Rankin-Scale deterioration), such as patient background, carotid artery stenting risks (access route tortuosity, severe calcification, vulnerable plaque, estimated glomerular filtration rate <30 mL/min/1.73 m2, etc.), characteristics of the stenosis, details of treatment, and treatment timing.

RESULTS

The average North American Symptomatic Carotid Endarterectomy Trial criteria score was 68.3% and the lesion length was 20.5±9.7mm. Among patients, 107 (70.4%) had a carotid artery stenting risk. In high-risk carotid artery stenting cases, symptomatic complications occurred in 32 (30.0%), and the 90-day modified Rankin scale score deteriorated in 15 cases (14.0%). Multivariate analysis showed that cases with triple antithrombotic therapy (p=0.003), stenting within 7 days (p=0.0032), and after 28+ days (p=0.0035) of stroke onset were independently associated factors for complications.

CONCLUSIONS

This study showed that among risk factors, triple antithrombotic therapy in particular was a risk factor for perioperative complications. Carotid artery stenting for patients with stroke after 28 days of onset affects the prognosis. Therefore, although further study is warranted, waiting more than one month for treatment in patients requiring carotid artery stenting is a potential risk.

Automated Aortic Anatomy Analysis: from Image to Clinical Indicators

Most cerebrovascular diseases (including strokes and aneurysms) are treated endovascularly with catheters that are navigated from the groin through the vessels to the brain. Many patients have complex anatomy of the aortic arch and supra-aortic vessels, which can make it difficult to select the best catheters for navigation, resulting in longer procedures and more complications or failures. To this end, we propose a framework dedicated to the analysis of the aortic arch and supra-aortic trunks. This framework can automatically compute anatomical and geometrical features from meshes segmented beforehand via CNN-based pipeline. These features such as arch type, tortuosity and angulations describe the navigational difficulties encountered during catheterization. Quantitative and qualitative validation was performed by experienced neuroradiologists, leading to reliable vessel characterization.Clinical relevance- This method allows clinicians to determine the type and the anatomy of the aortic arch and its supra-aortic trunks before endovascular procedures. This is essential in interventional neuroradiology, such as navigation with catheters in this complex area.

Transcarotid versus transfemoral access for cerebrovascular intervention: protocol for a systematic review and meta-analysis

INTRODUCTION

Cerebrovascular intervention is an excellent option to treat cerebrovascular diseases. Interventional access is a prerequisite and a foundation for cerebrovascular intervention, which is crucial to the success of an intervention. Although transfemoral arterial access (TFA) has become a popular and acceptable method of access for cerebrovascular angiography and intervention in clinical practice, it has some drawbacks that limit the usage in cerebrovascular interventions. Therefore, transcarotid arterial access (TCA) has been developed in cerebrovascular interventions. We aim to conduct a systematic review to compare the safety and efficacy of TCA with TFA for cerebrovascular intervention.

METHODS AND ANALYSIS

In this protocol, Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols were followed. PubMed, Embase, Web of Science and the Cochrane Central Register of Controlled Trials will be searched mainly from 1 January 2004, to the formal search date. Additionally, reference lists and clinical trial registries will be searched. We will include clinical trials with more than 30 participants, which reported the endpoints of stroke, death and myocardial infarction. Two investigators will independently select studies, extract data and assess bias risk. A standardised mean difference with 95% CI will be presented for continuous data, and a risk ratio with 95% CI will be presented for dichotomous data. On inclusion of sufficient studies, subgroup analysis and sensitivity analysis will be conducted. The funnel plot and Egger's test will be used to assess publication bias.

ETHICS AND DISSEMINATION

As only published sources will be used in this review, ethical approval is not required. We will publish the results in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022316468.

Aortic Arch Variations and Supra-aortic Arterial Tortuosity in Stroke Patients Undergoing Thrombectomy : Retrospective Analysis of 1705 Cases

PURPOSE

Unfavorable vascular anatomy can impede thrombectomy in patients with acute ischemic stroke. The aim of this study was to determine the prevalence of aortic arch types, aortic arch branching patterns and supra-aortic arterial tortuosity in stroke patients with large vessel occlusion.

METHODS

Computed tomography (CT) and magnetic resonance (MR) images of all stroke patients in an institutional thrombectomy registry were retrospectively reviewed. Aortic arch types and branching patterns of all patients were determined. In patients with anterior circulation stroke, the prevalence of tortuosity (elongation, kinking or coiling) of the supra-aortic arteries of the affected side was additionally assessed.

RESULTS

A total of 1705 aortic arches were evaluated. Frequency of aortic arch types I, II and III were 777 (45.6%), 585 (34.3%) and 340 (19.9%), respectively. In 1232 cases (72.3%), there was a normal branching pattern of the aortic arch. The brachiocephalic trunk and the left common carotid artery had a common origin in 258 cases (15.1%). In 209 cases (12.3%), the left common carotid artery arose from the brachiocephalic trunk. Of 1598 analyzed brachiocephalic trunks and/or common carotid arteries, 844 (52.8%) had no vessel tortuosity, 592 (37.0%) had elongation, 155 (9.7%) had kinking, and 7 (0.4%) had coiling. Of 1311 analyzed internal carotid arteries, 471 (35.9%) had no vessel tortuosity, 589 (44.9%) had elongation, 150 (11.4%) had kinking, and 101 (7.7%) had coiling.

CONCLUSION

With 20%, type III aortic arches are found in a relevant proportion of stroke patients eligible for mechanical thrombectomy. Nearly half of the stroke patients present with supra-aortic arterial tortuosity, mostly arterial elongation.

Patient-Specific 3D-Print Extracranial Vascular Simulators and Infrared Imaging Platform for Diagnostic Cerebral Angiography Training

Tortuous aortic arch is always challenging for beginner neuro-interventionalists. Herein, we share our experience of using 3D-printed extracranial vascular simulators (VSs) and the infrared imaging platform (IRIP) in two training courses for diagnostic cerebral angiography in the past 4 years. A total of four full-scale patient-specific carotid-aortic-iliac models were fabricated, including one type I arch, one bovine variant, and two type III arches. With an angiography machine (AM) as the imaging platform for the practice and final test, the first course was held in March 2018 had 10 participants, including three first-year residents (R1), three second-year residents (R2), and four third-year residents (R3). With introduction of the IRIP as the imaging platform for practice, the second course in March 2022 had nine participants, including 3 R1s, 3 R2s, and 3 R3s. The total manipulation time (TMT) to complete type III aortic arch navigation was recorded. In the first course, the average TMT of the first trial was 13.1 min. Among 3 R1s and 3 R2s attending the second trial, the average TMT of the second trial was 3.4 min less than that of the first trial. In the second course using IRIP, the average TMT of the first and second trials was 6.7 min and 4.8 min, respectively. The TMT of the second trial (range 2.2~14.4 min; median 5.9 min) was significantly shorter than that of the first trial (range 3.6~18 min; median 8.7 min), regardless of whether AM or IRIP was used (p = 0.001). Compared with first trial, the TMT of the second trial was reduced by an average of 3.7 min for 6 R1s, which was significantly greater than the 1.7 min of R2 and R3 (p = 0.049). Patient-specific VSs with radiation-free IRIP could be a useful training platform for junior residents with little experience in neuroangiography.

Preprocedural Imaging : A Review of Different Radiological Factors Affecting the Outcome of Thrombectomy

BACKGROUND

Endovascular treatment (EVT) has strong evidence for its effectiveness in treatment of acute ischemic stroke (AIS); however, up to half of the patients who undergo EVT still do not have good functional outcomes. Various prethrombectomy radiological factors have been shown to be associated with good clinical outcomes and may be the key to better functional outcomes, reduced complications, and reduced mortality. In this paper, we reviewed the current literature on these imaging parameters so they can be employed to better estimate the probability of procedural success, therefore allowing for more effective preprocedural planning of EVT strategies. We reviewed articles in the literature related to imaging factors which have been shown to be associated with EVT success. The factors which are reviewed in this paper included: anatomical factors such as 1) the type of aortic arch and its characteristics, 2) the characteristics of the thrombus such as length, clot burden, permeability, location, 3) the middle cerebral artery features including the tortuosity and underlying intracranial stenosis, 4) perfusion scans estimating the volume of infarct and the penumbra and 5) the effect of collaterals on the procedure. The prognostic effect of each factor on the successful outcome of EVT is described. The identification of preprocedural thrombectomy imaging factors can help to improve the chances of recanalization, functional outcomes, and mortality. It allows the interventionist to make time-sensitive decisions in the treatment of acute ischemic stroke.

Lessons Learned After 760 Neurointerventions via the Upper Extremity Vasculature: Pearls and Pitfalls

BACKGROUND

The radial approach has been gaining more widespread use by neurointerventionalists fueled by data from the cardiology literature showing better safety and overall reduced morbidity.

OBJECTIVE

To present our institution's experience with the radial approach for neuroendovascular interventions in 614 consecutive patients who underwent a cumulative of 760 procedures.

METHODS

A retrospective analysis was performed and identified neuroendovascular procedures performed via the upper extremity vasculature access site.

RESULTS

Amongst 760 procedures, 34.2% (260) were therapeutic, and 65.7% (500) were nontherapeutic angiograms. Access sites were 71.5% (544) via a conventional radial artery, 27.8% (211) via a distal radial artery, 0.5% (4) via an ulnar artery, and 0.1% (1) via the brachial artery. Most of the procedures (96.9%) were performed via the right-sided (737), 2.9% (22) via the left-sided, and 0.1% (1) via a bilateral approach. Major access site complications occurred at a rate of 0.9% (7). The rate of transfemoral conversion was 4.7% (36). There was a statistically higher incidence of transfemoral conversion when repeat procedures were performed using the same access site. Also, there was no significant difference between nontherapeutic procedures performed using the right and left radial access, and conventional versus distal radial access. Procedural metrics improved after completion of 14 procedures, indicating a learning curve that should be surpassed by operators to reach optimal outcomes.

CONCLUSION

Radial artery catheterization is a safe and effective means of carrying out a wide range of neuroendovascular procedures associated with excellent clinical outcomes and an overall low rate of periprocedural complications.

A comparative study of transradial versus transfemoral approach for flow diversion

PURPOSE

Data in neurointerventional literature is extremely limited regarding the safety and efficacy of flow diversion using transradial access (TRA). We aim to demonstrate the safety and efficacy of intracranial aneurysm treatment with the Pipeline Embolization Device (PED) using TRA compared to transfemoral access (TFA).

METHODS

We conducted a retrospective analysis of a prospectively maintained database and identified 79 consecutive patients who underwent neuroendovascular embolization for cerebral aneurysms using the PED from April 2018 through October 2019. Patients were divided into 2 groups: TRA (32 patients) and TFA (47 patients). A comparative analysis was performed between the two groups.

RESULTS

There was no significant difference in postoperative intracranial hemorrhage (p>.99), symptomatic ischemic stroke (p=.512), access site complications (p=.268), or other complications (p=.512). However, there was a significant increase in overall complications (14.9% vs. 0.0%, p=.038) and procedure duration (71.4 min ± 31.2 vs. 58.5 ± 20.3, p=.018) in the TFA group. There was no significant difference in complete occlusion at latest follow-up (19/25, 76.0% vs. 35/40, 87.5%; p=.311), 6-month follow-up (17/23, 73.9% vs. 33/38, 86.8%; p=.303), or 12-month follow-up (8/8, 100.0% vs. 5/6, 83.3%; p=.429). There was also no significant difference in rate of retreatment (p>.99), morbidity (p=.512), mortality (p>.99), latest follow-up (p=.985), or loss of follow-up (p=.298).

CONCLUSIONS

The feasibility and efficacy of flow diversion with the PED via TRA for the treatment of intracranial aneurysms is comparable to TFA. Widespread adoption of this approach may be facilitated by improvements in device navigation and manipulation via radial-specific engineering.

Novel triple coaxial system to navigate 9 French balloon guiding catheter into common carotid artery

Background

It is often hard to navigate a 9 French (F) balloon guiding catheter in patients with type III or bovine aortic arch. Also, a common carotid artery stenosis is challenging, because a guidewire cannot be advanced distally. We developed the combination of a 4F Simmons-type catheter and a 6F distal access catheter as a coaxial inner catheter to navigate a 9F balloon guiding catheter to overcome these difficulties.

Materials and methods

Medical record at our institution was retrospectively reviewed and carotid artery stenting cases in which the 4F Simmons-6F distal access catheter system was employed as a coaxial catheter to navigate a 9F balloon guiding catheter were identified. To construct this system, a 4F 145 cm SY3 (Hanako Medical, Saitama, Japan) and a 6F 118 cm Cerulean DD6 (Medikit Co. Ltd., Tokyo, Japan) were usually employed. A rotating hemostatic valve should be as short as possible and was attached to only a 9F balloon guiding catheter. The length of a 0.035-in. guidewire needed to be 180 cm or longer.

Results

During the study period, 106 carotid artery stenting cases were identified. Of these, this system was employed in 29 cases that included 5 cases with a steno-occlusive lesion at common carotid artery/external carotid artery, 10 with type III or bovine arch, and 11 harboring both. In all the cases, a 9F balloon guiding catheter was successfully navigated.

Conclusion

The 4F Simmons-6F distal access catheter system was useful in navigating a 9F balloon guiding catheter in patients with a common carotid artery stenosis, an external carotid artery occlusion, and an in-stent restenosis, especially when they also harbored type III or bovine aortic arch.

Anatomical Considerations for Endovascular Intervention for Extracranial Carotid Disease: A Review of the Literature and Recommended Guidelines

Patient selection for endovascular intervention in extracranial carotid disease is centered on vascular anatomy. We review anatomical considerations for non-traumatic disease and offer guidelines in patient selection and management. We conducted a systematic literature review without meta-analysis for studies involving anatomical considerations in extracranial carotid intervention for non-traumatic disease. Anatomical considerations discussed included aortic arch variants, degree of vessel stenosis, angulation, tortuosity, and anomalous origins, and atheromatous plaque morphology, composition, and location. Available literature suggests that anatomical risks of morbidity are largely secondary to increased procedural times and difficulties in intervention system delivery. We recommend the prioritization of endovascular techniques on an individual basis in cases where accessible systems and surgeon familiarity provide an acceptable likelihood of rapid access and device deployment.

Aortic arch types and postoperative outcomes after carotid artery stenting in asymptomatic and symptomatic patients

BACKGROUND

The aim of this study was to investigate the influence of the aortic arch type on technical and clinical success of carotid artery stenting (CAS) procedure.

METHODS

Clinical and anatomical data of consecutive patients who underwent CAS from 2010 to 2018 were prospectively collected and retrospectively analyzed. Primary outcome was technical success, define as successful stent delivery and deployment and <30% residual carotid stenosis. Secondary outcomes were death, stroke, myocardial infarction (MI) and transient ischemic attack (TIA) rates at 30 days after CAS. Subgroups analysis with asymptomatic and symptomatic patients were also performed.

RESULTS

During the study period, 523 patients were enrolled and analyzed. Among these, 176 (33.6%) had Type I, 227 (43.4%) had Type II and 120 (23.0%) had Type III or bovine aortic arch (BAA) type. Technical success rate was achieved in 96.0% of cases. At 30 days, if compared with Type I or II, patient with Type III or BAA experienced a higher death rate (0 vs. 0 vs. 1.8%, respectively; P=0.056) and combined postoperative stroke/TIA rate (3% vs. 2.8% vs. 9.9%, respectively; P=0.012). No differences for same outcomes between asymptomatic and symptomatic patients were described, although the latter group experienced more postoperative MI. A multivariate analysis revealed Type III or BAA as an independent risk factor for postoperative stroke/TIA (HR 3.23, IC95% 1.40-7.45; P=0.006).

CONCLUSIONS

In this cohort of patients, death and postoperative neurological complications rates were associated with Type III or BAA, irrespective of symptomatic patients' status. Extremely attention is required during perioperative period in patients who were candidate to CAS and with challenging aortic arch anatomy.

Poor concordance between definitions of type III arch and implications for risk prediction and assessment for carotid artery stenting

OBJECTIVE

The type III arch configuration has been inconsistently reported as a stroke risk factor during carotid artery stenting. However, at least three different methods for the definition of type III arch can be identified in the literature, related to the level of the origin of the innominate artery (IA). According to Casserly's definition, a type III arch presents with an origin of the IA below the horizontal plane of the inner curvature. According to Madhwal's definition, a type III arch has a distance greater than twice the diameter of the left common carotid artery between the highest point of the arch and the origin of the IA. According to MacDonald's definition, a type III arch presents with a distance of ≥2 cm between the highest point of the arch and the origin of the IA. Our aim was to assess the level of concordance between these different methods.

METHODS

Anonymized thoracic computed tomography scans of 100 healthy patients were reviewed. Two of us independently stratified the selected cases as a type I to III arch, according to the three considered definitions. The interobserver level of concordance for each type III arch classification and level of concordance among the three definitions were assessed.

RESULTS

The 100 selected patients (64% male) were 76 ± 7 years old. For each definition, the interobserver repeatability was almost perfect for all three (Madhwal, κ = 0.81; 95% confidence interval [CI], 0.71-0.99; MacDonald, κ = 0.82; 95% CI, 0.72-0.92; Casserly, κ = 0.84; 95% CI, 0.74-0.93). The level of concordance among the different definitions was very low (Madhwal vs MacDonald, 85% [P = .002]; 33% for type III arch; Madhwal vs Casserly, 60% [P < .0001]; 12% for type III arch; MacDonald vs Casserly, 75% [P < .0001]; 12% for type III arch).

CONCLUSIONS

The three definitions of the type III arch have a very low level of concordance, which might account for the varying clinical relevance of this configuration. Our findings have relevant implications for risk prediction for carotid artery stenting based on the presence of a type III arch, for comparisons of the results from different studies, and for comparisons of different datasets from multicenter trials.

Type III Arch Configuration as a Risk Factor for Carotid Artery Stenting: A Systematic Review of Contemporary Guidelines on Management of Carotid Artery Stenosis

BACKGROUND

Type III arch configuration is frequently reported as a stroke risk factor for carotid angioplasty and stenting (CAS). We reviewed contemporary guidelines on management of carotid artery stenosis to assess the clinical relevance attributed to this anatomic feature in current clinical practice.

METHODS

The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. The PubMed, EMBASE, and Web of Science databases were searched to identify all guidelines on extracranial carotid disease published between January 2008 and March 2020. A total of 435 articles were screened. For multiple guidelines from the same writing group, only the most recent updated version was considered. Eighteen documents were identified for qualitative analysis.

RESULTS

Four guidelines specifically reported type III arch as a predictive factor of periprocedural complications after CAS. Two of them also provided a low level of evidence of their recommendation. None of the documents indicated the exact criteria for aortic arch classification. Three different methods to describe type III arch configuration were identified.

CONCLUSIONS

Type III arch configuration is inconsistently included among stroke risk factors for CAS in contemporary guidelines, and variably defined. Further studies on the level of concordance between the 3 existing definition criteria are warranted.

Complexity of Aortic Arch Anatomy Affects the Outcomes of Transcarotid Artery Revascularization Versus Transfemoral Carotid Artery Stenting

BACKGROUND

Transcarotid artery revascularization (TCAR) has been shown to have half the rates of transient ischemic attack (TIA), stroke, and death compared with transfemoral carotid artery stenting (TFCAS). Successful outcomes of TFCAS require careful patient selection. The aim of this study was to determine the outcomes of TFCAS versus TCAR in both simple (type I) and complex (type II and III) aortic arches.

METHODS

A retrospective cohort study was performed comparing the outcomes of patients undergoing TFCAS versus TCAR with simple and complex aortic arches using the Vascular Quality Initiative registry from August 2011 to May 2019. The primary outcome was a composite of in-hospital TIA/stroke/death.

RESULTS

About 6,108 carotid artery interventions were analyzed, including 3,536 (57.9%) patients with type I, 2,013 (33.0%) with type II, and 559 (9.2%) with type III aortic arch. In 3,535 patients with a simple arch, 1,917 underwent TFCAS and 1,619 had TCAR. Mean age was 70.6 (±9.5) years, and 2,382 (67.4%) patients were males. The primary outcome of postoperative TIA/stroke/death was seen significantly less frequently in those undergoing TCAR compared with TFCAS in simple arches (odds ratio [OR], 0.63; 95% confidence interval [95% CI], 0.43-0.94; P = 0.0236). Although the individual outcome of death occurred less often in TCAR (P = 0.0025), there was no difference in the occurrence of in-hospital stroke (P = 0.8836) or TIA (P = 0.4608). On multivariable analysis, TCAR was associated with improved outcomes (P = 0.0062). A worse outcome was associated with increasing age (P < 0.001), a prior stroke (P < 0.0001), and increasing number of stents (P = 0.0483). In 2,572 patients with a complex arch, 1,416 underwent TFCAS and 1,156 had TCAR. Mean age was 73.0 (±9.1) years, and 1,655 (64.4%) were males. In complex arch anatomy, the primary outcome of in-hospital TIA/stroke/death was seen significantly less frequently in TCAR compared with TFCAS (OR, 0.49; 95% CI, 0.31-0.77; P = 0.0022). Again noted was a significant difference in death, with better outcomes in TCAR (P = 0.0133). Although the occurrence of in-hospital TIA was no different between the 2 approaches (P = 0.6158), there were significantly fewer strokes in those treated with TCAR (P = 0.0132). TCAR (P = 0.0146) was associated with improved outcomes. A worse outcome was seen with advancing age (P = 0.0003), prior strokes (P = 0.01), and a left-sided lesion (P = 0.0176).

CONCLUSIONS

TCAR has improved outcomes of TIA/stroke/death compared with TFCAS in both simple and complex aortic arch anatomy. In simple aortic arches, there is no difference in neurologic outcomes between both approaches. In complex arch anatomy, TCAR has fewer strokes.

Impact of Aortic Arch Anatomy on Technical Performance and Clinical Outcomes in Patients with Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Arterial access is a technical consideration of mechanical thrombectomy that may affect procedural time, but few studies exist detailing the relationship of anatomy to procedural times and patient outcomes. We sought to investigate the respective impact of aortic arch and carotid artery anatomy on endovascular procedural times in patients with large-vessel occlusion.

MATERIALS AND METHODS

We retrospectively reviewed imaging and medical records of 207 patients from 2 academic institutions who underwent mechanical thrombectomy for anterior circulation large-vessel occlusion from January 2015 to July 2018. Preintervention CTAs were assessed to measure features of the aortic arch and ipsilateral great vessel anatomy. These included the cranial-to-caudal distance from the origin of the innominate artery to the top of the aortic arch and the takeoff angle of the respective great vessel from the arch. mRS scores were calculated from rehabilitation and other outpatient documentation. We performed bootstrap, stepwise regressions to model groin puncture to reperfusion time and binary mRS outcomes (good outcome, mRS ≤ 2).

RESULTS

From our linear regression for groin puncture to reperfusion time, we found a significant association of the great vessel takeoff angle (P = .002) and caudal distance from the origin of the innominate artery to the top of the aortic arch (P = .05). Regression analysis for the binary mRS revealed a significant association with groin puncture to reperfusion time (P < .001).

CONCLUSIONS

These results demonstrate that patients with larger takeoff angles and extreme aortic arches have an association with longer procedural times as approached from transfemoral access routes.

Procedural success with radial access for carotid artery stenting: systematic review and meta-analysis

BACKGROUND

Femoral access is the traditional approach for endovascular carotid artery stenting. Radial access is increasingly used as an alternative approach due to its known anatomical advantages in patients with unfavorable aortic arch morphology via the femoral approach and its excellent access site safety profile. Our objective was to analyze procedural success using radial access for carotid artery stenting as reported in the literature.

METHODS

Three online databases were systematically searched following PRISMA guidelines for studies (n ≥20) using radial artery access for carotid artery stenting (1999-2018). Random-effects meta-analysis was used to pool the procedural success (successful stent placement with no requirement for crossover to femoral access), mortality, and complication rates associated with radial access.

RESULTS

Seven eligible studies reported procedural success outcomes with a pooled meta-analysis rate of 90.8% (657/723; 95% CI 86.7% to 94.2%; I²=53.1%). Asymptomatic radial artery occlusion occurred in 5.9% (95% CI 4.1% to 8.0%; I²=0%) and forearm hematoma in 1.4% (95% CI 0.4% to 2.9%; I²=0%). Risk of minor stroke/transient ischemic attack was 1.9% (95% CI 0.6% to 3.8%; I²=42.3%) and major stroke was 1.0% (95% CI 0.4% to 1.8%; I²=0%). There were three deaths across the seven studies (0.6%; 95% CI 0.2% to 1.3%; I²=0%). The meta-analysis was limited by statistically significant heterogeneity for the primary outcome of procedural success.

CONCLUSION

Radial access for carotid artery stenting has a high procedural success rate with low rates of mortality, access site complications, and cerebrovascular complications. The potential benefits of this approach in patients with unfavorable aortic arch access should be explored in a prospective randomized trial.

Clinically-relevant morphometric parameters and anatomical variations of the aortic arch branching pattern

INTRODUCTION

The ever expanding advances in various domains of cardiac and endovascular interventions has drawn tremendous attention toward the importance of the anatomical variability and morphometric parameters of the aortic arch (AA) and its branches.

METHODS

The current study delineates the morphometry and anatomical variations of the AA branches by evaluating coronal, axial and sagittal CT multiplanar reformatted three-dimensional angiograms. Correlations between morphometric data as well as the distribution of morphometric data in relation to the anatomical variations were also illustrated.

RESULTS

35% of the examined AA showed abnormal branching patterns, the most common of which was the "bovine arch" (24%), followed by common ostium variant (6%) and aberrant left vertebral artery arising directly from AA (5%). The outer diameter of AA at its origin and its end was 33.83 and 22.06 mm, respectively. The distance between the origin of AA and the origin of brachiocephalic trunk (BCT), left common carotid artery (LCCA) and left subclavian artery (LSA) was 19.59, 23.01 and 26.01 mm, respectively. The outer diameter of BCT, LCCA and LSA was 15.7, 11.42 and 14.02 mm, respectively. The angles between the AA and the BCT, LCCA and LSA were 59.01°, 68.59° and 59.92°, respectively. The mean distance between the BCT and LCCA was 19.59 mm and the distance between the LCCA and the LSA was 23.01 mm. Significant positive and negative correlations between morphometric data as well as the distribution of morphometric parameters in relation to the anatomical variations have been identified.

CONCLUSION

The illustrated anatomical variations and morphometric data provide cardinal information especially for patients undergoing aortic endovascular intervention, principally for choosing the size, shape and type of the angiographic catheters and devices to be delivered.

Feasibility of Using Neck Extension to Overcome a Difficult Aortic Arch and Gain Access to the Carotid Artery

OBJECTIVE

The purpose of this study was to investigate neck movement and various conditions of the aortic arch that may hinder access to the carotid artery during neurointerventional procedures.

METHODS

We reviewed 230 patients who underwent internal carotid artery angiography between February 2016 and October 2016. Use of a Davis catheter (DC) was first attempted and if not possible, movement (right, left, flexion, and extension) of the patient's head was tried before catheter exchange. We analyzed the success rate after neck motion in relation to various aortic arch factors.

RESULTS

Only extension of the patient's neck was effective. Of the 209 patients with right side angiography, 23 had failed access with a DC, but neck extension was effective in 3 patients (13%). Failure to insert a DC was significantly correlated with age, male sex, acute angle, arch elongation, aortic calcification, and carotid artery angulation on the right side, whereas access was not gained in 24 out of 208 patients who underwent left side angiography, and neck extension was successful in 7 patients (29.2%). Also, significant factors determining the catheter exchange were age, male sex, acute angle, arch elongation, and aortic calcification.In the DC access failure group, neck extension was significantly more effective for younger aged patients (P = 0.011).

CONCLUSIONS

Factors such as older age, acute arch angle, higher elongation type, arch calcification, and carotid artery angulation were verified as factors affecting access by a simple catheter; however, neck extension was shown to facilitate access in about 10%-30% of patents.

Reasons for Reperfusion Failures in Stent-Retriever-Based Thrombectomy: Registry Analysis and Proposal of a Classification System

BACKGROUND AND PURPOSE

In 5%-10% of patients with acute ischemic stroke with an intention to treat with mechanical thrombectomy, no reperfusion can be achieved (Thrombolysis in Cerebral Infarction score = 0/1). Purpose of this analysis was a systematic assessment of underlying reasons for reperfusion failures.

MATERIALS AND METHODS

An intention-to-treat single-center cohort (n = 592) was re-evaluated for all patients in whom no reperfusion could be achieved (n = 63). Baseline characteristics of patients were compared between patients with and without reperfusion failures. After qualitative review of all cases with reperfusion failures, a classification system was proposed and relative frequencies were reported. In a second step, occurrence of delayed recanalization at 24 hours after reperfusion failure and dependency on IV-tPA were evaluated.

RESULTS

In 63/592 patients with an intention to perform stent-retriever thrombectomy, no reperfusion was achieved (TICI 0/1, 10.6%, 95% CI, 8.2%-13.1%). Older patients (adjusted OR per yr = 1.03; 95% CI, 1.01-1.05) and patients with M2 occlusion (adjusted OR = 3.36; 95% CI, 1.82-6.21) were at higher risk for reperfusion failure. In most cases, no reperfusion was a consequence of technical difficulties (56/63, 88.9%). In one-third of these cases, reperfusion failures were due to the inability to reach the target occlusion (20/63, 31.7%), while "stent-retriever failure" occurred in 39.7% (25/63) of patients. Delayed recanalization was very rare (18.2%), without dependence on IV-tPA pretreatment status.

CONCLUSIONS

Reasons for reperfusion failure in stent-retriever thrombectomy are heterogeneous. The failure to establish intracranial or cervical access is almost as common as stent-retriever failure after establishing intracranial access. Systematic reporting standards of reasons may help to further estimate relative frequencies and thereby guide priorities for technical development and scientific effort.

Incidentally Found Double Aortic Arch While Treating Posterior Inferior Cerebellar Artery Aneurysm: Conversion from Femoral to Radial Artery Access

BACKGROUND

Asymptomatic double aortic arches are a unique occurrence.

CASE DESCRIPTION

An incidental finding of a double aortic arch in an elderly male was discovered during workup of a transient ischemic attack. The following case presentation details an effective treatment approach in cerebrovascular stenting in a patient with variant aortic arch anatomy. The initial diagnostic cerebral angiogram was performed via transfemoral approach and was quite challenging.

CONCLUSIONS

Faced with challenging anatomy, the radial artery approach is a viable option when navigating into the cerebrovascular anatomy for stenting when proximal variants such as a double aortic arch are identified.

The effect of demographic features on aortic arch anatomy and its role in the etiology of cerebrovascular disease

PURPOSE

The aim of this study was to retrospectively evaluate the distribution of aortic arches, the relationship with demographic characteristics, and the results of carotid and vertebral artery stenting procedures in patients diagnosed with cerebrovascular disease through the intra-arterial digital subtraction angiography (DSA) technique.

METHODS

A retrospective examination was performed on 288 patients diagnosed with cerebrovascular disease, who underwent DSA in the Department of Neurology of Gaziantep University Medical Faculty and Kahramanmaraş¸ Sütçü Imam University Medical Faculty. The patients were examined in respect of demographic features and aortic arch anatomic structure characteristics. All demographic characteristics, DSA, carotid, and vertebral artery stent results were recorded.

RESULTS

The patients comprised 60.1% males and 39.9% females with a mean age of 58.25 years. Type 2 aortic arch was found in 175 (60.7%) patients, Type 2 aortic arch in 99 (34.3%) patients, and Type 3 aortic arch in 14 (4.8%) patients. The right carotid artery stenosis rate was found to be higher in patients with Type 2 aortic arch (P=0.013). When the patients were evaluated according to the presence of a bovine arch, there was no significant difference in terms of age, carotid, and vertebral artery lesions (P>0.05).

CONCLUSION

The aortic arch and its branching properties were not found to have a direct effect on increased risk of cerebrovascular disease or stenting rates. This study can be considered to raise awareness for new studies to demonstrate the effect of aortic arch anatomic differences on cerebrovascular diseases.

Complications of endovascular treatment for acute ischemic stroke: Prevention and management

Endovascular mechanical thrombectomy (MT) for the treatment of acute stroke due to large vessel occlusion has evolved significantly with the publication of multiple positive thrombectomy trials. MT is now a recommended treatment for acute ischemic stroke. Mechanical thrombectomy is associated with a number of intra-procedural or post-operative complications, which need to be minimized and effectively managed to maximize the benefits of thrombectomy. Procedural complications include: access-site problems (vessel/nerve injury, access-site hematoma and groin infection); device-related complications (vasospasm, arterial perforation and dissection, device detachment/misplacement); symptomatic intracerebral hemorrhage; subarachnoid hemorrhage; embolization to new or target vessel territory. Other complications include: anesthetic/contrast-related, post-operative hemorrhage, extra-cranial hemorrhage and pseudoaneurysm. Some complications are life-threatening and many lead to increased length of stay in intensive care and stroke units. Complications increase costs and delay the commencement of rehabilitation. Some may be preventable; the impact of others can be minimized with early detection and appropriate management. Both neurointerventionists and stroke specialists need to be aware of the risk factors, strategies for prevention, and management of these complications. With the increasing use of mechanical thrombectomy for the treatment of acute ischemic stroke, incidence and outcome of complications will need to be carefully monitored by stroke teams. In this narrative review, we examine the frequency of complications of MT in the treatment of acute ischemic stroke with an emphasis on periprocedural complications. Overall, from recent randomized controlled trials, the risk of complications with sequelae for patient from mechanical thrombectomy is ∼15%. We discuss the management of complications and identify areas with limited evidence, which need further research. Search strategy and selection criteria Relevant evidence was found by searches of Medline and Cochrane Library, reference list, cross-referencing and main journal content pages. Search terms included "brain ischemia", "acute ischemic stroke", "cerebral infarction" AND "mechanical thrombectomy", "endovascular therapy", "endovascular treatment", "endovascular embolectomy", "intra-arterial" AND "randomized controlled trial", "non-randomised trials", "observational studies" AND "complications", "procedural complications", "peri-procedural complications", "device-related complications", "management", "treatment", "outcome". The search included only human studies, and was limited to studies published in English between January 2014 and November 2016. The final reference list was selected on the basis of relevance to the topics covered in the Review. Guidelines for management of acute ischaemic stroke by the American Heart Association, the European Stroke Organisation, multi-disciplinary guidelines and the National Institute for Health and Care Excellence (NICE) were also reviewed.

Optimal Guiding Catheter Length for Endovascular Coiling of Intracranial Aneurysms in Anterior Circulation in Era of Flourishing Distal Access System

Purpose

To determine the minimum required guiding catheter length for embolization of various intracranial aneurysms in anterior circulation and to analyze the effect of various patient factors on the required catheter length and potential interaction with its stability.

Materials and Methods

From December 2016 to March 2017, 90 patients with 93 anterior circulation aneurysms were enrolled. Three types of guiding catheters (Envoy, Envoy DA, and Envoy DA XB; Codman Neurovascular, Raynham, MA, USA) were used. We measured the in-the-body length of the catheter and checked the catheter tip location in the carotid artery. We analyzed factors affecting the in-the-body length and stability of the guiding catheter system.

Results

The average (±standard deviation) in-the-body length of the catheter was 84.2±5.9 cm. The length was significantly longer in men (89.1±5.6 vs. 82.1±4.6 cm, P<0.001), patients older than 65 years (87.7±7.8 vs. 82.7±4.2 cm, P<0.001), patients with a more tortuous arch (arch type 2 and 3) (87.5±7.4 vs. 82.7±4.4 cm, P<0.001), and patients with a distal aneurysm location (distal group) (86.2±5.0 vs. 82.7±6.1 cm, P=0.004). A shift in the tip location was noted in 19 patients (20.4%); there was no significant different among the 3 catheters (P=0.942).

Conclusion

The minimum required length of a guiding catheter was 84 cm on average for elective anterior-circulation aneurysm embolization. The length increased in men older than 65 years with a more tortuous arch. We could reach a higher position with distal access catheters with little difference in the stability once we reached the target location.

A systematic review and meta-analysis of variations in branching patterns of the adult aortic arch

OBJECTIVE

The aortic arch (AA) is the main conduit of the left side of the heart, providing a blood supply to the head, neck, and upper limbs. As it travels through the thorax, the pattern in which it gives off the branches to supply these structures can vary. Variations of these branching patterns have been studied; however, a study providing a comprehensive incidence of these variations has not yet been conducted. The objective of this study was to perform a meta-analysis of all the studies that report prevalence data on AA variants and to provide incidence data on the most common variants.

METHODS

A systematic search of online databases including PubMed, Embase, Scopus, ScienceDirect, Web of Science, SciELO, BIOSIS, and CNKI was performed for literature describing incidence of AA variations in adults. Studies including prevalence data on adult patients or cadavers were collected and their data analyzed.

RESULTS

A total of 51 articles were included (N = 23,882 arches). Seven of the most common variants were analyzed. The most common variants found included the classic branching pattern, defined as a brachiocephalic trunk, a left common carotid, and a left subclavian artery (80.9%); the bovine arch variant (13.6%); and the left vertebral artery variant (2.8%). Compared by geographic data, bovine arch variants were noted to have a prevalence as high as 26.8% in African populations.

CONCLUSIONS

Although patients who have an AA variant are often asymptomatic, they compose a significant portion of the population of patients and pose a greater risk of hemorrhage and ischemia during surgery in the thorax. Because of the possibility of encountering such variants, it is prudent for surgeons to consider potential variations in planning procedures, especially of an endovascular nature, in the thorax.