Morphology of the aortic arch branching pattern in raccoon dogs (Nyctereutes procyonoides, Gray, 1834).

BACKGROUND: Aortic arch (AA) branching patterns vary among different mammalian species. Most previous studies have focused on dogs, whereas those on raccoon dogs remain unexplored. OBJECTIVES: The objective of this study was to describe the AA branching pattern in raccoon dogs and compare their morphological features with those of other carnivores. METHODS: We prepared silicone cast specimens from a total of 36 raccoon dog carcasses via retrograde injection through the abdominal aorta. The brachiocephalic trunk (BCT) branching patterns were classified based on the relationship between the left and right common carotid arteries. The subclavian artery (SB) branching pattern was examined based on the order of the four major branches: the vertebral artery (VT), costocervical trunk (CCT), superficial cervical artery (SC), and internal thoracic artery (IT). RESULTS: In most cases (88.6%), the BCT branched off from the left common carotid artery and terminated in the right common carotid and right subclavian arteries. In the remaining cases (11.4%), the BCT formed a bicarotid trunk. The SB exhibited various branching patterns, with 26 observed types. Based on the branching order of the four major branches, we identified the main branching pattern, in which the VT branched first (98.6%), the CCT branched second (81.9%), the SC branched third (62.5%), and the IT branched fourth (52.8%). CONCLUSIONS: The AA branching pattern in raccoon dogs exhibited various branching patterns with both similarities and differences compared to other carnivores.

A thyroidea ima artery variation providing collateral circulation to the mediastinum.

The thyroidea ima artery (TIA) is a highly variable arterial deviation of the blood supply to the thyroid gland with critical implications for surgical neck procedures such as tracheostomy. Though relatively common in the population at large (~ 4%), most TIA variations are related to the origin of the artery and whether it emerges from the common sites of the brachiocephalic trunk, aortic arch, and right common carotid artery, or another more unique vessel-as opposed to its dispersion pattern. TIA variants generally supply the thyroid gland, occasionally co-occurring with absent thyroid arteries. Here, we report on a unique case of a four-pronged variation of the TIA discovered during an anatomy laboratory dissection of first-year medical students. This variant originated from the brachiocephalic trunk and had three branches terminating in the thyroid gland and a fourth branch traveling into the thorax to provide accessory circulation in the mediastinum. Specifically, small arterial branches from the inferior TIA branch supplied the anterior pericardium and surrounding adipose tissue, in addition to normal pericardiacophrenic circulation. We discuss the potential embryological and clinical relevance of this unique variation and voice further support for imaging as a requirement before surgical neck procedures to prevent catastrophic bleeding in the event of a TIA variant.

Morphology of aortic arch branching patterns in the Eurasian Otter (Lutra lutra, Linnaeus, 1758).

In this study, we investigated the aortic arch (AA) branching pattern in the Eurasian otter (Lutra lutra). We performed arterial silicone casting of the AA of 18 Eurasian otters (8 males and 10 females). We analyzed the AA branching pattern at three levels: the AA, brachiocephalic trunk (BCT), and subclavian artery (SB), using different classification methods at each level. We introduced new criteria for classifying the SB branching pattern applicable for Eurasian otter and other carnivores based on the sequence of the four main branches: vertebral artery (VT), internal thoracic artery (IT), costocervical artery (CCT), and superficial cervical artery (SC). In all Eurasian otters, two major branches emerged directly from the AA, i.e., the BCT and left SB. The BCT branched off the left common carotid artery and terminated in the right common carotid artery and right SB in 17 of 18 Eurasian otters; the BCT formed a bicarotid artery in the remaining case. The SBs showed various branching patterns, with the main branching pattern involving branching to the VT and IT at the same position, followed by the CCT and SC. The SB branching pattern in the Eurasian otter differed from that in dogs in that the two first branching arteries were VT and IT, rather than VT and CCT. Here, we present the anatomical characteristics of the AA branching patterns in the Eurasian otter and new analysis methods applicable for comparative studies of other carnivores.

Optimal guiding catheter position during advancement of the guiding catheter into the carotid artery from the aortic arch via transfemoral approach.

BACKGROUND: Guiding catheter (GC) advancement into the target carotid artery is a crucial step in neuroendovascular therapy. In difficult anatomies, alternative methods have been reported to overcome difficult carotid access for swift GC advancement. However, studies focusing on the positional relationship between the GC and inner catheter (IC) at the aortic arch are lacking. METHODS: We evaluated the impact of the positional relationship between the GC and IC on whether the GC position affects catheter support or system straightening. We retrospectively reviewed 89 patients who underwent neuroendovascular therapy. We assessed the time to carotid access across difficult arch anatomies. The GC position was divided into Position 1, descending aorta level; Position 2, aortic arch level; and Position 3, origin of the left common carotid artery or innominate artery. We also evaluated the GC support and straightening effects in an in vitro vascular model study. RESULTS: The coaxial catheter flexion angle at the aortic arch was significantly larger when the GC was set to Position 3 (p < 0.0001). A significantly shorter time to carotid access was observed with Positions 2 and 3 than with Position 1 in the difficult arch anatomy group. In the in vitro vascular model evaluation, the catheter support effect significantly increased as the GC position became closer to the IC tip (p < 0.0001) and straightening effect significantly increased as the GC moved to Position 2 from Position 1 (p < 0.0001). CONCLUSION: During GC advancement, the GC positional relationship changed the support of the coaxial system with system straightening. The optimal GC position, Position 3, facilitated swift GC advancement.

Morphology of the pattern of branching of the aortic arch (Arcus aortae) in Syrian hamsters (Mesocricetus auratus).

The branching patterns of the aortic arches of 28 adult male and female Syrian hamsters (SH) were thoroughly examined under a stereomicroscope for the first time by using latex injection and corrosion casting to determine their general arrangements and morphological variations as well as their differences and similarities to other rodents and rabbits. Three major arteries, namely, the brachiocephalic trunk (BC), left common carotid artery (CC) and left subclavian artery (SA), originating from the aortic arch (AR), were uniformly noted in SH. The BC was consistently divided into the right SA and the right CA. SA in SH normally releases the internal thoracic, deep cervical, dorsal scapular, vertebral, superficial cervical and supreme intercostal arteries. The costocervical trunk typically consisted of supreme intercostal and internal thoracic arteries and a common trunk for dorsal scapular and deep cervical arteries. To comprehend the comparative morphology of the pattern of branching of AR more completely, our results were compared with previous studies in rodents and rabbits. (1) The general morphology of the great arteries from AR in SH was similar to that in mole rats, rats, mice, porcupines, and gerbils but was essentially different from that in rabbits, guinea pigs, red squirrels, ground squirrels, pacas and chinchillas. (2) The typical pattern of the branching of the subclavian arteries in SH was similar to that in guinea pigs, rats, and rabbits but was different from that of the reported rodents regardless of the origins of the bronchoesophageal and internal thoracic arteries and the composition of the costocervical trunk.

The Wandering Nerve: Positional Variations of the Cervical Vagus Nerve and Neurosurgical Implications.

BACKGROUND: The vagus ("wandering") nerve is the longest cranial nerve with the largest territory of innervation in the human body. Injury during various operative procedures involving the anterior or lateral neck may lead to serious complications. Per "textbook" descriptions, the cervical vagus nerve (CVN) commonly locates within the carotid sheath, in between the common carotid artery (CCA) and internal jugular vein (IJV). However, anatomic variations in its positioning may occur more often than expected and intraoperative identification may anticipate potential surgical pitfalls. METHODS: A literature review was conducted per PRISMA guidelines for all studies describing positional variations of the CVN within the carotid sheath. A rare and potentially dangerous variation, occurring in only 0.7% of all reported cases, is illustrated with a cadaveric case. RESULTS: Overall, 10 anatomic CVN variations have been described across 971 specimens. The non-textbook variations (26.5%) consist of: lateral (4.7%), anterolateral (8.7%), posteromedial (0.2%), posterior (5.8%), anterior (3.1%), medial (0.7%), and anteromedial (0.4%) to the CCA, as well as posterolateral (0.3%) and posterior (2.6%) to IJV. The "textbook" anatomic location is posterolateral to CCA (73.5%). Moreover, an increase in variability is reported on the left side (17.1%) compared with the right (11.3%). Our cadaveric dissection revealed a right-sided CVN directly medial to the CCA. CONCLUSIONS: Positional variations of the CVN occur in over 26% of patients and may add difficulty to an array of surgical procedures. Knowledge of these variations and their prevalence may aid the surgeon in conducting a more precise dissection possibly preventing significant potential adverse sequelae.

Non-invasive evaluation of the common carotid artery in normal adults using ultrasound radiofrequency data technology.

AIM: To evaluate the changes in CCA-IMT and vascular elasticity in healthy subjects in relation to age using radiofrequency data technology, to produce reference values for potential clinical applications. MATERIALS AND METHODS: The following variables were measured in 160 subjects using radiofrequency data techniques: CCA-IMT, carotid distensibility (CD), local pulse-wave velocity (PWVß), and stiffness (ß). The subjects were divided into four age groups (30-39, 40-49, 50-59, and 60-69 years), with 20 men and 20 women in each group. The above parameters were compared among the different age groups. RESULTS: CCA-IMT increased significantly with age (p<0.05). CD decreased significantly in the 40-49-years compared with the 30-39-years age group (p<0.05). PWVß showed a significant increase in the 30-39-, 40-49-, and 50-59-years age groups (p<0.05). ß increased significantly in the 50-59- compared with the 40-49-years age group (p<0.05). Compared with the 50-59-years age group, CD, PWVß, and ß showed no significant changes in the 60-69-years age group (p>0.05), with mean values of 329.39 ± 102.06 µm, 7.22 ± 1.91 m/s, and 10.04 ± 4.91, respectively. CONCLUSION: Ultrasound radiofrequency data technology provides a non-invasive method for quantitatively and accurately assessing increased CCA-IMT and reduced vascular elasticity in healthy subjects in different age groups. The reference values produced in this study will be useful in clinical practice.

A systematic classification of the left-sided aortic arch variants based on cadaveric studies' prevalence.

INTRODUCTION: Typical branching pattern of the left-sided aortic arch consists of the brachiocephalic trunk (BCT), the left common carotid artery (LCCA) and the left subclavian artery (LSA). Variant patterns have been associated with a broad spectrum of pathologies. The meticulous knowledge of potential aortic arch variants is of utmost importance to radiologists, interventional cardiologists, vascular and thoracic surgeons. The current systematic review collects all aortic arch branching patterns and their frequency as published by various cadaveric studies, calculates prevalence taking into account the gender and the different people background, as well. All extracted variant patterns are classified into types and subtypes according to the number of emerging (major and minor) branches (1, 2, 3, 4 and 5) and to the prevalence they appear. In cases of similar prevalence, total cases were taken into consideration; otherwise the variants were classified under the title "other rare variants". METHODS: A systematic online search of PubMed and Google books databases was performed only in cadaveric studies. RESULTS: Twenty studies with typical (78% prevalence) and variable (22%) branching patterns were included. Types 3b, 2b, 4b, 1b and 5b had a prevalence of 81%, of 13%, of 5%, 0% and of 0%, respectively. Common variants were the brachiocephalico-carotid trunk (BCCT, 49% prevalence), the aberrant left vertebral artery (LVA, 41%) and the aberrant right subclavian artery (ARSA, 8%). LVA of aortic origin was detected in 32%, the bicarotid trunk (biCT) in 5% and the bi-BCT trunk in 3%. Thyroidea ima artery, a minor branch emerging from the aortic arch was found in 2%. Coexisted variants were detected in 4% (ARSA with a distinct RCCA and LCCA origin), in 3% (BCCT with a LVA of aortic origin), in 2% (ARSA with a biCT and a vertebrosubclavian trunk). CONCLUSION: No significant gender or ethnic differences exist among the 5 branching types. The proposed classification scheme aims to become a valuable and easy to use tool in the hands of all physicians involved in diagnosis and treatment of aortic arch pathology. It could be also useful in anatomical education, as well.

Fully Automatic Measurement of Intima-Media Thickness in Ultrasound Images of the Common Carotid Artery Based on Improved Otsu's Method and Adaptive Wind Driven Optimization.

The intima media thickness (IMT) of the common carotid artery (CCA) can be used to predict the risk of atherosclerosis. Many image segmentation techniques have been used for IMT measurement. However, severe noise in the ultrasound image can lead to erroneous segmentation results. To improve the robustness to noise, a fully automatic method, based on an improved Otsu's method and an adaptive wind-driven optimization technique, is proposed for estimating the IMT (denoted as "improved Otsu-AWDO"). First, an advanced despeckling filter, i.e., " Nagare's filter" is used to address the speckle noise in the carotid ultrasound images. Next, an improved fuzzy contrast method (IFC) is used to enhance the region of the intima media complex (IMC) in the blurred filtered images. Then, a new method is used for automatic extraction of the region of interest (ROI). Finally, the lumen intima interface and media adventitia interface are segmented from the IMC using improved Otsu-AWDO. Then, 156 B-mode longitudinal carotid ultrasound images of six different datasets are used to evaluate the performance of the automatic measurements. The results indicate that the absolute error of proposed method is only 10.1 ± 9.6 (mean ± std in µm). Moreover, the proposed method has a correlation coefficient as high as 0.9922, and a bias as low as 0.0007. From comparison with previous methods, we can conclude that the proposed method has strong robustness and can provide accurate IMT estimations.

Transradial Approach as the Primary Vascular Access with a 6-Fr Simmons Guiding Sheath for Anterior Circulation Interventions: A Single-Center Case Series of 130 Consecutive Patients.

OBJECTIVE: In coronary intervention, the transradial approach (TRA) is increasingly used as the primary vascular access because of its numerous advantages over the transfemoral approach. However, in neurointerventions, conventional TRA with a straight-shaped guiding system is used as an alternative vascular access because transradial carotid cannulation can be technically challenging for right common carotid artery (CCA) lesions with steep angulation to the right subclavian artery or left CCA lesions with a nonbovine origin. The purpose of the present study was to evaluate the feasibility and safety of TRA as the primary vascular access with a pre-shaped Simmons guiding sheath for anterior circulation interventions. METHODS: Between June 2018 and September 2019, 130 consecutive patients (75 carotid artery stenting and 55 cerebral aneurysm coiling cases) who underwent TRA as the primary vascular access were included in this study. A 6-Fr Simmons guiding sheath was introduced into the target CCA by selecting a cannulation technique based on preprocedural image assessment. We retrospectively analyzed the carotid cannulation success, procedural success, and periprocedural or vascular access site complications. RESULTS: Carotid cannulation (69 right CCA, 6 left CCA with a bovine origin, and 55 left CCA with a nonbovine origin) and the subsequent procedure were successfully performed for all 130 patients without periprocedural or vascular access site complications. CONCLUSIONS: TRA with a 6-Fr Simmons guiding sheath for anterior circulation interventions is highly successful and safe for all target CCAs and aortic arch types. This method can be utilized as the primary vascular access for anterior circulation interventions.

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.

Variations in the branching pattern of the aortic arch: an African perspective

Variation in the branches of the aortic arch is higher in individuals of African descent. However, published studies are few. The aims were to document variations in the branching pattern of the aortic arch in a South African sample, determine whether these variants are more common than other populations, and determine whether there are any significant differences in the prevalence of variation between males and females. The aortic arch and main branches were dissected in 733 cadavers. All branching patterns were documented and classified as types. Chi-Square tests were used to determine whether there were any significant differences in prevalence of variation between males and females. The diameters of the main branches were measured and compared between sexes.The standard branching pattern was present in 65% of individuals, similar to that reported for other African studies, but lower than other studies from around the world. Variations were more prevalent in males than in females (p = 0.025), while only the diameter of the left vertebral artery, when arising from the arch was significantly larger in females, with no differences between sexes for the other vessel diameters. The results of this study support the hypothesis that variations in the branching pattern of the aortic arch are more common in African individuals. These individuals may be at increased risk of associated although rare, clinical symptoms or iatrogenic injury

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A case of type A acute aortic dissection with a common carotid trunk.

We present a rare case of common carotid artery with acute type A aortic dissection. A 72-year-old woman underwent emergent aortic arch repair using Antegrade selective cerebral protection. Bottom-tapped cannulae were inserted into three orifices of arch vessels, however, regional cerebral oxygen saturation decreased after rewarming. We found that arch branches were in order from front to back, right subclavian artery, common carotid trunk, and left subcravian artery. The patient complicated stroke in the right middle cerebral artery.

Anatomical variations of the aortic arch branches in a sample of Chinese cadavers: embryological basis and literature review.

OBJECTIVES: The aim of this study is to determine the incidence and explore the types of aortic arch branch variations found in our cadavers. METHODS: The types and incidence of aortic branch variations in 120 cadavers were analysed after careful dissection. RESULTS: One hundred and six of 120 cadavers had normal aortic arch branches and gave rise to usual branches, namely the brachiocephalic trunk, the left common carotid artery and the left subclavian artery. The remaining 14 cadavers had 2 basic types of branch variations, thus accounting for an incidence of 11.67%. A total of 9 aortic arches emitted 4 branches; the brachiocephalic trunk, the left common carotid artery, the left vertebral artery and the left subclavian artery (incidence 7.5%). The second subgroup of 5 cadavers also emitted 4 aortic branches: the right common carotid artery, the left common carotid artery, the left subclavian artery and the right subclavian artery (incidence 4.16%). In this group, the right subclavian artery sprung as a distal branch of the aortic arch (descending), thus making a vascular ring that takes a superoposterior course round the back of the trachea and the oesophagus to reach the right side. There was a single cadaver, different from the other 4 aortic branches of the second group which had a common origin for the common carotid arteries, while the left subclavian artery and distally placed right subclavian artery were present. We did not observe any Kommerell's aortic diverticula. CONCLUSIONS: The variations of aortic arch branching are complex and diverse due to varied possible alterations in the embryological processes. There is an imperative need for further research on these variations to elucidate the possible relationships with clinical diagnostic or surgical events.

Common left carotid bifurcation at C7-Th1 level: a rare anatomical variant.

The left common carotid artery usually bifurcates to the internal and external carotids at or near the superior border of thyroid cartilage. In head and neck surgery, the common carotid arteries are important landmarks, defining the plane of dissection during radical neck surgeries. According to the literature, many variations exist regarding the carotid bifurcation. Anatomical knowledge of these variants is important for surgical approaches in the head and neck regions, to avoid devastating complications that may occur, mainly during anterior neck dissections. We report an interesting case of a 75-year-old male patient with low bifurcation of the left common carotid artery, accidentally found during a routine carotid Doppler ultrasonography. Bifurcation was located at the C7-Th1 intervertebral disc height, approximately 4 cm from the aortic arch.

An unusual origin and course of the thyroidea ima artery, with absence of inferior thyroid artery bilaterally.

We report an unusual origin and course of the thyroidea ima artery in a male cadaver. The ima artery originated from the right subclavian artery very close to origin of the right vertebral artery. The artery coursed anteriorly between the common carotid artery medially and internal jugular vein laterally. It then coursed obliquely, from below upwards, from lateral to medial superficial to common carotid artery, to reach the inferior pole of the right lobe of thyroid and branched repeatedly to supply the anteroinferior and posteroinferior aspects of both the thyroid lobes and isthmus. The superior thyroid arteries were normal. Both the inferior thyroid arteries were absent. The unusual feature of this thyroidea ima artery is its origin from the subclavian artery close to vertebral artery origin, the location being remarkably far-off from the usual near midline position, and the oblique and relatively superficial course. This report is a caveat to neck surgeons to consider such a superficially running vessel to be a thyroidea ima artery.

Technical Nuances of Exposing Rat Common Carotid Arteries for Practicing Microsurgical Anastomosis.

BACKGROUND: Animal models are commonly used in training protocols for microsurgical vascular anastomosis. Rat common carotid arteries (CCAs) are frequently used for this purpose. Much attention has been paid to the technical details of various anastomosis configurations using these arteries. However, technical nuances of exposing rat CCAs have been understudied. The purpose of this study is to describe nuances of technique for safely and efficiently exposing rat CCAs in preparation for a vascular anastomosis. METHODS: Bilateral CCAs were exposed and prepared for anastomosis in 10 anesthetized Sprague-Dawley rats through a midline cervical incision. The exposed length of the CCA was measured. Additionally, technical nuances of exposure and surgically relevant anatomic details were recorded. RESULTS: The CCAs were exposed from the sternoclavicular joint to their bifurcation (average length, 19.1 ± 2.8 mm). Tenets important for a safe and efficient exposure of the CCAs included 1) generous subcutaneous dissection to expose the external jugular veins (EJVs), 2) avoiding injury to or compression of the EJVs, 3) superior mobilization of the salivary glands, 4) division of internal jugular veins, 5) opening the carotid sheath at its midlevel and from medial to lateral, and 6) avoiding injury to the vagus nerve or sympathetic trunk. CONCLUSIONS: Using the principles introduced in this study, trainees may safely and efficiently expose rat CCAs in preparation for a bypass.

Analysis of Dynamic Geometric Configuration of the Aortic Channel from the Perspective of Tornado-Like Flow Organization of Blood Flow.

Analysis of the data of morphometry of aortic casts, aortography at different pressures, and multispiral computer tomography of the aorta with contrast and normal pulse pressure showed that geometric configuration of the flow channel of the aorta during the whole cardiac cycle corresponded to the conditions of self-organization of tornado-like quasipotential flow described by exact solutions of the Navier-Stokes equation and continuity of viscous fluid typical for this type of fluid flows. Increasing pressure in the aorta leads to a decrease in the degree of approximation of the channel geometry to the ratio of exact solution and increases the risk of distortions in the structure of the flow. A mechanism of evolution of tornado-like flow in the aorta was proposed.

Branching patterns of the aortic arch in the Siberian roe deer (Capreolus pygargus Pallas, 1771).

This study examined the branching pattern of the aortic arch (AA) and its major branches in the Siberian roe deer (Capreolus pygargus Pallas, 1771) from South Korea. A total of eight of the nine expected types, based on the branching site and bilateral levels of the costocervical trunk (CCT) and subclavian artery (SB), were observed in the arterial silicone casts of 35 deer (16 males, 19 females). This deer has no typical type. The three most common types were present in 28.6, 25.7 and 20.0% of cases and resulted from different branching patterns of the left CCT and left SB. These results suggest that the Siberian roe deer in the Korean peninsula has various AA branching patterns, which differs from other ruminants.