Congenital external carotid-internal carotid artery anastomosis: a report of three cases and literature review.

PURPOSE: Congenital external carotid-internal carotid artery (EC-ICA) anastomosis is a cervical arterial variation that was initially reported, based on anatomic dissection, from Japan in 2000. The purpose of this report is to show the characteristic radiological findings of this extremely rare cervical arterial variation. METHODS: We analyzed nine cases, including six previously reported cases and three cases that we recently experienced. Three of the six previously reported cases were from Japan, and the remaining three cases were from Korea. MR angiography (4), CT angiography (2), catheter angiography (2) and autopsy (1) were used as diagnostic modalities. RESULTS: The study population included eight men and one woman. Anastomosis was seen on the left side in seven cases and the right side in two cases, and it was located at the level of the C1/2-C2/3 intervertebral space. In all cases, ECA was larger than the ICA at the level of their origins. In four cases, the ICA was extremely small in caliber. In one case, the ICA may have been occluded postnatally, and its configuration was similar to that of the nonbifurcating cervical carotid artery (CCA). With the exception of this occluded case, the carotid bifurcation and EC-ICA anastomosis formed a large arterial ring in all cases. CONCLUSION: EC-ICA anastomosis can be regarded as a variant of the nonbifurcating CCA because if the most proximal segment of the small ICA is occluded, nonbifurcating CCA may form. EC-ICA anastomosis is located between the C1/2-C2/3 intervertebral space and may be formed by the remnants of the proatlantal artery I.

Morphological, embryological, and clinical implications of the bi-carotid trunk, aberrant right subclavian artery, and bilateral linguofacial trunk.

A female cadaver fixated with 10% formalin solution was dissected during a routine undergraduate anatomy class. It was found that both the right and left carotid arteries arose from a bi-carotid trunk as the first branch of the aortic arch. The bi-carotid trunk was followed by the left subclavian artery. The aberrant right subclavian artery (the last branch) had a retro-oesophageal course. These variations were associated with the linguofacial trunk bilaterally. The group of variant anatomy of vessels encompassing the bi-carotid trunk, aberrant right subclavian artery, and the linguofacial trunk is extremely rare. A similar case has not been reported yet in the literature. The anatomic and morphologic variations of the aortic arch and its branches are important for diagnostic and surgical procedures in the thorax and neck region. Thoracovascular surgeons and interventional radiologists should be aware of these anomalies during head and neck surgery, aortic instrumentation, and four-vessel angiography.

MN1 C-terminal truncation syndrome is a novel neurodevelopmental and craniofacial disorder with partial rhombencephalosynapsis.

MN1 encodes a transcriptional co-regulator without homology to other proteins, previously implicated in acute myeloid leukaemia and development of the palate. Large deletions encompassing MN1 have been reported in individuals with variable neurodevelopmental anomalies and non-specific facial features. We identified a cluster of de novo truncating mutations in MN1 in a cohort of 23 individuals with strikingly similar dysmorphic facial features, especially midface hypoplasia, and intellectual disability with severe expressive language delay. Imaging revealed an atypical form of rhombencephalosynapsis, a distinctive brain malformation characterized by partial or complete loss of the cerebellar vermis with fusion of the cerebellar hemispheres, in 8/10 individuals. Rhombencephalosynapsis has no previously known definitive genetic or environmental causes. Other frequent features included perisylvian polymicrogyria, abnormal posterior clinoid processes and persistent trigeminal artery. MN1 is encoded by only two exons. All mutations, including the recurrent variant p.Arg1295* observed in 8/21 probands, fall in the terminal exon or the extreme 3' region of exon 1, and are therefore predicted to result in escape from nonsense-mediated mRNA decay. This was confirmed in fibroblasts from three individuals. We propose that the condition described here, MN1 C-terminal truncation (MCTT) syndrome, is not due to MN1 haploinsufficiency but rather is the result of dominantly acting C-terminally truncated MN1 protein. Our data show that MN1 plays a critical role in human craniofacial and brain development, and opens the door to understanding the biological mechanisms underlying rhombencephalosynapsis.

Carotid artery tortuosity may pose a problem during insertion of the tunneled catheter for hemodialysis.

Tortuosity of the carotid artery is usually an asymptomatic vascular abnormality and is discovered accidentally during cerebral angiography. These vascular changes may aggravate surgical procedures in the neck region. We described a technique of permanent catheter insertion in patients with renal graft failure in whom renal replacement therapy was necessary. Severe tortuosity of cervical arteries may make this procedure more difficult, necessitating a special technique, that is, full image monitoring.

Carotid web prevalence in a large hospital-based cohort and its association with ischemic stroke.

Carotid artery webs are shelf-like protrusions of intimal fibrous tissue arising from the posterior wall of the carotid bulb, found to have a 2.3% prevalence in the United States. Previous studies have demonstrated its association with ipsilateral anterior circulation stroke. The aim of this study is to assess the prevalence of carotid webs in the largest US epidemiologic study to date, and to further characterize the clinical features of carotid web patients. We assembled a cohort of 1467 adult patients with CT angiogram neck from January 1, 2011 to January 1, 2017. CT angiograms were reviewed for diagnosis of carotid web. Demographic and clinical details of web patients were obtained. Differences in demographics and CT angiogram indication between patients with and without carotid web were assessed using appropriate statistical tests. Twenty-four (24/1467 = 1.6%) carotid web patients were identified (mean age: 63 years; 62.5% female; 50% African American). Twelve (12/24 = 50%) had ipsilateral anterior circulation stroke. Of them, 8 were deemed cryptogenic. Four (4/24 = 16.7%) web patients had at least one recurrent stroke in the ipsilateral anterior circulation. One case was reported on the radiology report at the time the study was initially performed. This study confirms a prevalence of 1.6% in our urban, North American cohort. Among carotid web patients, there was a high incidence of ipsilateral anterior circulation stroke, the majority of which were classified as cryptogenic. This study affirms the importance of the diagnosis of carotid web, especially in cryptogenic stroke patients, as a potential unrecognized stroke risk factor.

Persistent Primitive Hypoglossal Artery with Ipsilateral Symptomatic Carotid Artery Stenosis and Cerebral Aneurysm.

OBJECTIVE: Persistent primitive hypoglossal artery (PPHA) is a rare type of persistent carotid-basilar anastomosis sometimes associated with other vascular lesions. We treated an extremely rare case of PPHA with concomitant ipsilateral symptomatic cervical internal carotid artery (ICA) stenosis and unruptured aneurysm. CASE PRESENTATION: A 67-year-old woman visited our institution with acute onset of diplopia. Magnetic resonance imaging revealed multiple acute infarctions in the right anterior and posterior circulations. Digital subtraction angiography demonstrated the right PPHA concomitant with ipsilateral cervical ICA stenosis and an unruptured ICA aneurysm with maximum diameter of 8 mm. The multiple infarctions were considered to result from artery-to-artery embolism due to microthrombi from the ICA plaque passed along the PPHA, so carotid endarterectomy was performed as the first step with preoperative modified Rankin Scale (mRS) grade 1. During the operation, the patient had impaired ICA perfusion due to internal shunt catheter migration into the PPHA followed by acute infarction in the right hemisphere causing mild left hemiparesis. The patient was transferred to the rehabilitation hospital with mRS grade 3. After 3 months of rehabilitation, the patient recovered to mRS grade 1 and clipping surgery for the unruptured right ICA aneurysm was performed as the second step with uneventful postoperative course. CONCLUSION: The treatment strategy should be carefully considered depending on the specific blood circulation for such cases of PPHA with unique vasculature.

Retroesophageal right subclavian artery associated with a bicarotid trunk and an ectopic origin of vertebral arteries.

A rare branching pattern of the aortic arch in a female cadaver is reported. An aberrant right subclavian artery originated from the distal part of the aortic arch and following a retroesophageal course was recognized. Next to it, from the left to the right, the left subclavian artery and a short bicarotid trunk originating the left and the right common carotid artery were recognized. An unusual origin of the vertebral arteries was also identified. The left vertebral artery originated directly from the aortic arch, whereas the right vertebral artery originated directly from the right common carotid artery. Retroesophageal right subclavian artery associated with a bicarotid trunk and ectopic origin of vertebral arteries represents an exceptional and noteworthy case.

Medial type persistent trigeminal artery associated with a saccular aneurysm at its trunk.

There are four types of fetal anastomosis between the carotid and vertebrobasilar arteries at 5 weeks gestation; from caudal to cranial position, these involve the proatlantal intersegmental, hypoglossal, otic, and trigeminal arteries. Excluding otic artery, these arteries may persist rarely. Persistent trigeminal artery (PTA) is the most common carotid-vertebrobasilar anastomosis, and the medial type (intrasellar) PTA is quite rare, accounting for approximately 10% of all PTA cases. An aneurysm is occasionally found at the origin of the PTA. Rarely, an aneurysm arises at the trunk of the PTA. Using magnetic resonance angiography, we identified a case of medial type PTA with an unruptured saccular aneurysm at its trunk.

Absent left common carotid artery in a right aortic arch: Separate origins of left internal and external carotid arteries from brachiocephalic artery.

We present a case of cyanotic congenital heart disease with left common carotid artery agenesis in the setting of the right aortic arch highlighting the potential implications in management.

Comparability of semiautomatic tortuosity measurements in the carotid artery.

PURPOSE: Increased arterial tortuosity has been suggested as a predisposing factor for carotid artery dissection, which is an important risk factor for development of extracranial carotid artery aneurysms (ECAA). Prior to comparison with non-ECAA controls, the optimal measurement technique should be defined. This study describes the difference between software packages in terms of reproducibility and absolute outcome of arterial tortuosity measurements in ECAA patients. METHODS: CT-angiography analysis was performed on 12 ECAA patients selected from our registry, using four software packages: 3mensio Vascular, TeraRecon, Vital Images, and Aycan OsiriX PRO. The tortuosity index (TI) was calculated from the skull base until the carotid bifurcation and aortic arch, and was defined as the centerline's true length divided by the straight line distance. Intraclass correlation coefficients (ICC) with 95% confidence intervals were calculated to quantify inter- and intra-observer variability within one software package, and differences in measured TI between packages. RESULTS: Inter-observer agreement was nearly perfect for 3mensio, excellent for Vital Images and OsiriX, and substantial for TeraRecon, with ICC 0.99 (0.96-1.0), 0.90 (0.69-0.97), 0.84 (0.53-0.95), and 0.72 (0.28-0.91), respectively. Intra-observer agreement ranged from ICC 1.0 for 3mensio to 0.91 for TeraRecon. Agreements in TI ranged from ICC 0.99 (0.98-1.0) for 3mensio vs. OsiriX, to 0.95 (0.82-0.98) for 3mensio vs. TeraRecon. Median time needed to complete one round of measurements was highest for OsiriX (p = 0.013). CONCLUSIONS: Carotid artery tortuosity measurements are reproducible and comparable between current commercially available software packages, with high intra-observer agreement. Although the reproducibility differed per software packages, all packages scored an acceptable inter-observer agreement.

Multimodality and multiterritory vascular imaging in a toddler with acquired, complex, and unusual aortic arch anatomy.

A 20-month-old otherwise well child with no cardiac history presented for evaluation of a recent onset cardiac murmur. His initial examination revealed significant right carotid bruit along with a transthoracic echocardiogram (ECHO) concerning for severe transverse arch hypoplasia with unusual appearance and left ventricular hypertrophy with preserved function. This report demonstrates the utility of various modalities including echo, CT, and MRI to assess vascular structures in different vascular territories in a challenging patient who underwent a satisfactory arch repair with unexpected pathology findings.

Carotid Webs in Cryptogenic Ischemic Strokes: A Matched Case-Control Study.

BACKGROUND: Young individuals with symptomatic carotid webs may be predisposed to ischemic strokes. However, evidence remains scarce. This investigation reports the frequency of carotid webs among patients with cryptogenic strokes compared to a control group. METHODS: Consecutive cryptogenic ischemic strokes and trauma patients were identified. Additional inclusion criteria required age 18-60 years and availability of head/neck computed tomography (CT) angiography. CT angiogram (CTA) neck images were evaluated independently by 2 fellowshiptrained specialists. A carotid web was defined by a shelf-like, linear filling defect in the posterior internal carotid artery bulb. RESULTS: Of 1877 patients presenting with ischemic strokes in 2015-2017, 165 were diagnosed with cryptogenic strokes, 51 of whom met the inclusion criteria of age and CTA availability. Fifty one trauma cases were matched for age and sex. After imaging analysis, 13 carotid webs (25%) were identified in the 51 cryptogenic stroke group versus 0 (0%; P < .001) in trauma subjects. Thirty-nine of the 51 cryptogenic ischemic stroke patients were found with carotid anterior distribution infarcts, of which 9 (23%) were found with ipsilateral carotid webs. There were more proximal large vessel occlusions in the cryptogenic patients with carotid webs, compared to those without (P = .04). All carotid webs led to less than 30% degree of stenosis. CONCLUSIONS: Carotid webs were found at a significantly higher frequency in patients with cryptogenic ischemic strokes compared to controls, indicating a potentially thrombogenic nature of these lesions in young patients. Additionally, intracranial large vessel occlusions were more common in patients with symptomatic carotid webs, presenting with ipsilateral strokes.

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.

Carotid Artery Tortuosity Index Is Associated With the Need for Early Aortic Root Replacement in Patients With Loeys-Dietz Syndrome.

OBJECTIVE: This study aimed to determine if carotid arterial tortuosity represents a marker of disease severity in Loeys-Dietz syndrome (LDS). METHODS: Fifty-four 54 LDS patients (mean age, 17.0 years) who underwent computed tomogram angiography from January 2004 to December 2013 were retrospectively identified. Carotid artery tortuosity index (CATI) was calculated from computed tomogram angiography. Clinical variables were obtained from the medical records. Relationship between CATI and need for aortic root replacement was evaluated with Cox proportional hazard model and Kaplan-Meier analysis. RESULTS: Higher CATI was associated with the need for aortic root replacement (P < 0.001) in the univariate Cox proportional hazard model. Patients were stratified based on both CATI and aortic root size in Kaplan-Meier analysis, and patients with higher CATI were more likely to require aortic root replacement (P < 0.001) in both aortic root size strata. CONCLUSION: Increased carotid artery tortuosity is associated with the need for early aortic root replacement in patients with LDS.

Evaluation of vertebral artery anomaly in basilar invagination and prevention of vascular injury during surgical intervention: CTA features and analysis.

OBJECTIVE: To evaluate vertebral artery anomaly at the craniovertebral junction (CVJ) in patients with basilar invagination (BI) by computed tomographic angiography (CTA), and to discuss the prevention strategy of vascular injury. METHODS: The primary axial, multiple planar reconstruction and volume-rendering cervicocranial CTA images of 39 BI patients were analysed to evaluate vertebral artery anomaly at the CVJ: persistent first intersegmental artery (PFIA), fenestrated vertebral artery (FEN), and extracranial C1/2 origin of posterior inferior cerebellar artery (PICA), high-riding vertebral artery, side-to-side asymmetry and irregular midline carotid artery loop was determined by subjective vision. 100 patients who underwent CTA for reasons other than CVJ deformity were enrolled as normal controls to evaluate the prevalence of vertebral artery anomaly in a normal population. Chi-square test was utilized for comparing the prevalence of vertebral artery anomaly between these two groups. RESULTS: The incidence of PFIA was 25.6% (10/39), FEN was 7.7% (3/39), PICA was 5.1% (2/39), and the total incidence of extraosseous anomalous course of vertebral artery was 38.5% (15/39), significantly higher than that of control group, 7.0% (7/100) (P < 0.01). The incidence of high-riding vertebral artery and side-to-side asymmetry were 61.5% (24/39) and 30.8% (12/39), respectively. An irregular midline carotid artery loop was observed in five patients (12.8%). CONCLUSION: Vertebral artery anomaly, which can be clearly depicted by CTA, is more frequent in BI patients. Preoperative CTA should be performed for this patient population to prevent vascular injury. These slides can be retrieved under Electronic Supplementary Material.

Coexistence of bicuspid aortic valve, aberrant right subclavian artery and common origin of carotid arteries.

BACKGROUND: Prevalence of bicuspid aortic valve (BAV) and right aberrant sub-clavian artery (ASA) separately is relatively common in general population, and much higher in some disorders. Surprisingly, coexistence of both valve and vessel anomalies has only been reported in single cases. MATERIALS AND METHODS: From 2008 to 2016, in a single, high-volume tertiary cardiac centre, patients who underwent chest computed tomography (CT) for various reasons, were retrospectively screened for the presence of right ASA. RESULTS: Seventy-two patients with either right or left ASA were identified by CT. Among them 7 cases of BAV and right ASA coexistence were identified. Additionally, 1 case with coexisting common origin of carotid arteries (COCA) was visualised in this subgroup. CONCLUSIONS: Although coexistence of ASA and BAV has not been reported in paediatric population, it has been diagnosed in very few adults as well as in our series. Additional presence of COCA in this group seems to be very rare. From practical point of view, heart cannulation via the radial artery and subsequent ASA may be challenging. Similarly, COCA presence may have surgical implications during corrective procedures.

Association Between Carotid Bulb Diaphragm and Ischemic Stroke in Young Afro-Caribbean Patients: A Population-Based Case-Control Study.

BACKGROUND AND PURPOSE: Carotid bulb diaphragm (CBD) has been described in young carotid ischemic stroke (CIS) patients, especially in blacks. However, the prevalence of CBD in CIS patients is unknown, and whether CBD is a risk factor for CIS remains unclear. We assessed the association between CBD and incident CIS in a population-based study. METHODS: We selected all young (<55 years) CIS patients from a 1-year population-based cohort study in the Afro-Caribbean population of Martinique in 2012. All patients had a comprehensive work-up including a computed tomographic angiography. We calculated CIS associated with ipsilateral CBD incidence with 95% confidence intervals using Poisson distribution. We then selected age- and sex-matched controls among young (<55 years) Afro-Caribbean stroke-free patients admitted for a road crash who routinely had computed tomographic angiography. Odds ratio (ORs) were calculated by conditional logistic regression adjusted for hypertension, dyslipidemia, diabetes and smoking. RESULTS: CIS associated with ipsilateral CBD incidence was 3.8 per 100 000 person-years (95% confidence interval, 1.4-6.1). Prevalence of ipsilateral CBD was 23% in all CIS and 37% in undetermined CIS patients. When restricted to undetermined CIS, CBD prevalence was 24 times higher than that in controls (adjusted OR, 24.1; 95% confidence interval, 1.8-325.6). CONCLUSIONS: CBD is associated with an increased risk of ipsilateral CIS in young Afro-Caribbean population.

Fast 4D flow MRI intracranial segmentation and quantification in tortuous arteries.

PURPOSE: To describe, validate, and implement a centerline processing scheme (CPS) for semiautomated segmentation and quantification in carotid siphons of healthy subjects. 4D flow MRI enables blood flow measurement in all major cerebral arteries with one scan. Clinical translational hurdles are time demanding postprocessing and user-dependence induced variability during analysis. MATERIALS AND METHODS: A CPS for 4D flow data was developed to automatically separate cerebral artery trees. Flow parameters were quantified at planes along the centerline oriented perpendicular to the vessel path. At 3T, validation against 2D phase-contrast (PC) magnetic resonance imaging (MRI) and 4D flow manual processing was performed on an intracranial flow phantom for constant flow, while pulsatile flow validation was performed in the internal carotid artery (ICA) of 10 healthy volunteers. The CPS and 4D manual processing times were measured and compared. Flow and area measurements were also demonstrated along the length of the ICA siphon. RESULTS: Phantom measurements for area and flow were highly correlated between the CPS and 2D measurements (area: R = 0.95, flow: R = 0.94), while in vivo waveforms were highly correlated (R = 0.93). Processing time was reduced by a factor of 4.6 compared with manual processing. Whole ICA measurements revealed a significantly decreased area in the most distal segment of the carotid siphon (P = 0.0017), with flow unchanged (P = 0.84). CONCLUSION: This study exhibits fast semiautomated analysis of intracranial 4D flow MRI. Internal consistency was shown through flow conservation along the tortuous ICA siphon, which is typically difficult to assess.

Smad2 and myocardin-related transcription factor B cooperatively regulate vascular smooth muscle differentiation from neural crest cells.

RATIONALE: Vascular smooth muscle cell (VSMC) differentiation from neural crest cells (NCCs) is critical for cardiovascular development, but the mechanisms remain largely unknown. OBJECTIVE: Transforming growth factor-ß (TGF-ß) function in VSMC differentiation from NCCs is controversial. Therefore, we determined the role and mechanism of a TGF-ß downstream signaling intermediate Smad2 in NCC differentiation to VSMCs. METHODS AND RESULTS: By using Cre/loxP system, we generated a NCC tissue-specific Smad2 knockout mouse model and found that Smad2 deletion resulted in defective NCC differentiation to VSMCs in aortic arch arteries during embryonic development and caused vessel wall abnormality in adult carotid arteries where the VSMCs are derived from NCCs. The abnormalities included 1 layer of VSMCs missing in the media of the arteries with distorted and thinner elastic lamina, leading to a thinner vessel wall compared with wild-type vessel. Mechanistically, Smad2 interacted with myocardin-related transcription factor B (MRTFB) to regulate VSMC marker gene expression. Smad2 was required for TGF-ß-induced MRTFB nuclear translocation, whereas MRTFB enhanced Smad2 binding to VSMC marker promoter. Furthermore, we found that Smad2, but not Smad3, was a progenitor-specific transcription factor mediating TGF-ß-induced VSMC differentiation from NCCs. Smad2 also seemed to be involved in determining the physiological differences between NCC-derived and mesoderm-derived VSMCs. CONCLUSIONS: Smad2 is an important factor in regulating progenitor-specific VSMC development and physiological differences between NCC-derived and mesoderm-derived VSMCs.