Proatlantal Intersegmental Artery Research Articles

Persistent Primitive Arteries

Primitive anastomotic arteries temporarily exist between the future internal carotid and vertebrobasilar arteries during the early embryonic period(between 28 and 32 days of life). The primitive trigeminal, otic, hypoglossal, and proatlantal intersegmental arteries serve as major blood channels to the developing vertebrobasilar circulation at this stage. These arteries are replaced by the posterior communicating and vertebral arteries, and the primitive anastomotic arteries rapidly regress following the development of the definitive vertebrobasilar circulation. Occasionally, these primitive anastomoses persist and are incidentally discovered after birth. Physicians who treat cerebrovascular diseases should be familiar with the anatomy and functions of these vessels. In this review, we discuss the embryonic basis of the carotid-vertebrobasilar anastomoses and the clinical significance of their persistent forms in adults.

Unusual vascular cause of syncope in an adult patient: type 2 proatlantal intersegmental artery.

A proatlantal intersegmental artery anomaly may present with symptoms such as dizziness and syncope. Because it has the risk of damage in surgical and interventional radiological procedures, to know the presence of this unusual vascular anomaly is very important.

Abstract Number ‐ 86: Intracranial Angioplasty via Type II Proatlantal Intersegmental Artery

Introduction A proatlantal intersegmental artery (PIA) is an exceedingly rare primitive anastomosis between the carotid and vertebrobasilar circulations. PIA’s may be accompanied by ipsilateral or bilateral vertebral artery (VA) agenesis and can originate from the cervical internal carotid artery (ICA, type I) or external carotid artery (ECA, type II) before eventually joining the vertebrobasilar system. Several authors have described this anomaly in different clinical scenarios, but to our knowledge, there are no studies documenting intracranial vertebral artery angioplasty through a type II PIA in the setting of a vertebrobasilar stroke. Methods Single case study Results A 62‐year‐old male presented to the ED with slurred speech that began one hour prior to arrival. Computer tomography (CT) of the head revealed a small right posterior acute parietal subdural hematoma, and CT perfusion scan revealed ischemia of the cerebellar hemispheres bilaterally with small areas of core infarction and a moderate‐to‐large surrounding penumbra. Magnetic resonance imaging (MRI) of the brain was positive for bilateral acute ischemic strokes of the cerebellar and pontine arteries. CT angiogram of the head and neck revealed high grade stenosis of the right intracranial VA and narrowing of the left V1, V2, and V3 segments. The proximal left V4 segment was occluded with distal reconstitution. Catheter angiogram of the ICAs and ECAs showed that the patient’s right VA did not originate from the right subclavian artery but instead from the right ECA. The patient was subsequently determined to have a type II PIA with critical stenosis. We proceeded with right VA submaximal angioplasty via the type II PIA. The procedure went without complications and resulted in restoration of vertebrobasilar blood flow, with only moderate stenosis following the submaximal angioplasty. On day 5 postoperatively, the patient reported resolution of his symptoms and was subsequently discharged. Conclusions We presented a case of vertebrobasilar stroke in which the right VA did not originate from the right subclavian artery but instead from the ECA, with a subsequent diagnosis of a type II PIA. The only option for management was to perform the right VA angioplasty via the PIA, which we believe to be the first documented case of intracranial vertebral angioplasty through a type II PIA. This case serves as a reminder of the very rare cases of persistent fetal circulation and the importance of performing a catheter angiogram of both the ICA and ECA. Evaluation of the ECA and subsequent observation of a PIA can completely change both the management and outcomes of the patient. This case underscores the complexity of the intracranial atherosclerotic disease, the beneficial role of endovascular intervention, and the necessity of future studies to identify the optimal treatment methods for vertebrobasilar stroke.

Management of intracranial vertebral artery stenosis with ipsilateral vertebral artery hypoplasia and contralateral vertebral artery occlusion via type 2 proatlantal intersegmental artery

BackgroundProatlantal intersegmental artery (PIA) is a rare primitive carotid-basilar anastomosis. PIA may accompany with ipsilateral or bilateral vertebral arteries (VAs) agenesis. Here, we presented the case with intracranial VA stenosis supplying via PIA and demonstrated how we evaluated and managed. MethodsDual antiplatelet therapy and adequate hydration were given for three weeks for intracranial atherosclerotic disease (ICAD). We arranged magnetic resonance (MR) vessel wall imaging to survey both intracranial VAs. Intracranial right VA stenosis supplying via PIA with ipsilateral VA hypoplasia and contralateral intracranial VA occlusion caused multiple posterior circulation infarcts. We performed angioplasty and intracranial stenting for ICAD at the right VA V4 segment via PIA. ResultsNational Institute of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) got improved at discharge and ten months. ConclusionsThis case is the first report for ICAD management via PIA. A persistent type 2 PIA is essential for supplying posterior circulation.

Abstract TP255: Assessment of Hemodynamic Changes in Persistent Carotid-Vertebrobasilar Anastomoses by Ultrasonography

Objectives: Persistent carotid-vertebrobasilar anastomoses (PCVBA) is a rare cerebral arterial variant between anterior and posterior circulation. This study aimed to evaluate the hemodynamic characteristics of PCVBA by the combination of color Doppler flow imaging (CDFI) and transcranial color-coded sonography (TCCS). Methods: Patients diagnosed with PCVBA were imaged by combination of CDFI and TCCS, then confirmed by digital subtraction angiography (DSA) or computed tomography angiography (CTA) from July 2015 to July 2017. The parameters, including peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI), were acquired in extracranial vertebral artery (VA), intracranial VA, basilar artery and posterior cerebral artery. The vessel diameter of the extracranial VA was measured as well. Results: A total of 14 patients were analyzed in this study. Posterior ischemic stroke associated with ipsilateral internal carotid artery (ICA) atherosclerosis were found in 3 patients (3/14, 21.4%), and posterior transient ischemic attack occurred in 8 patients (8/14, 57.1%). Persistent trigeminal artery (PTA) was confirmed in 6 cases, which the PSV decreased but RI increased in bilateral VA, meanwhile normal velocity was acquired in BA. After compressing the ipsilateral CCA, velocities of BA and bilateral PCA decreased significantly. There were 5 persistent hypoglossal artery (PHA) and 3 proatlantal intersegmental artery (PIA). Among these patients, CDFI displayed a tiny-lumen with reduced PSV and increased RI in bilateral VA. TCCS showed normal velocity in ipsilateral intracranial VA and BA, which were significantly reduced after compressing the ipsilateral CCA. Conclusions: PCVBA may cause the posterior circulation ischemia, especially in patients associated with ipsilateral ICA atherosclerotic lesions. The abnormal hemodynamic changes in different types of PCVBA could be evaluated by combination of CDFI and TCCS.

A rare case report of a mixed persistent proatlantal intersegmental artery

Adults with persistent proatlantal intersegmental artery (PPIA) are rarely seen. We present a case of a special type of PPIA that was in a 57-year-old man who presented with dizziness and episodic vertigo of 9 months duration. The diagnosis relied on computed tomography angiography and digital subtraction angiography, by which a left internal carotid artery stenosis and an ipsilateral PPIA originating from the external carotid artery (ECA) was found. This special type of PPIA can be described as a ‘‘mixed PPIA’’ that originated as Type II from the ECA and coursed as Type I. The patient underwent carotid artery stenting and had no relapse during 3 months follow-up. In addition, the literatures on PPIA were reviewed.

Diagnosis of variants of carotid-vertebasilar anastomoses on MR angiography

Objective To explore the feature of embryonic communication between the carotid and vertebro-basilar system using MRA of head and neck on MR. Methods The MRA images from 7 246 consecutive patients in Liaocheng People's hospital between June 2009 and December 2015 were retrospectively reviewed. The feature of embryonic communication between internal carotid, external carotid artery and vertebro-basilar system using MRA was analyzed by two doctors. Results Forty-four cases of embryonic communication between the carotid and vertebro-basilar system were found. Thirty-nine cases of primitive trigeminal artery (PTA) and primitive trigeminal artery variants (PTAV) were detected by MRA. The prevalence of both PTA and PTAV was 0.54% (PTA, 27 cases;PTAV, 12 cases). Twenty-three cases of PTA were lateral types;four cases were medial types. All PTA originated from C4 portion of internal carotid artery, of which 27 cases connected with the basilar artery and two cases connected with the superior cerebellar artery. The region of the BA proximal to the site of convergence with the PTA was hypoplastic in seven cases and completely absent in two cases. Three cases of primitive hypoglossal artery and 2 cases of primitive proatlantal artery were detected by MRA. The prevalence of primitive hypoglossal artery and primitive proatlantal artery was 0.04% and 0.03% respectively. Two cases of primitive hypoglossal artery were from the lateral internal carotid artery and one was from the external carotid artery. It's all on the right side. One case of primitive proatlantal artery was on the left which arises from the external carotid artery, one on the right which originated from the outer part of the internal carotid artery. Thirty-four cases were coexisted with other variants of head and neck vessels. All of the primitive hypoglossal arteries were coexisted with vertebral artery absence. One case of primitive proatlantal intersegmental artery was coexisted with vertebral artery dysplasia. Eighteen cases were associated with cerebral infarctions, and three cases with aneurysm. Conclusions MRA can accurately assess the variants of carotid-vertebasilar anastomoses and have diagnostic significance. Key words: Magnetic resonance imaging; Primitive trigeminal artery; Primitive hypoglossal artery; Primitive proatlantal intersegmental artery

Persistent Hypoglossal Artery and Proatlantal Intersegmental Artery, Case Report and Review

Persistent Hypoglossal Artery and Proatlantal Intersegmental Artery, Case Report and Review

Carotid-vertebrobasilar Anastomoses with Reference to Their Segmental Property.

The primitive carotid-vertebrobasilar anastomoses are primitive embryonic cerebral vessels that temporarily provide arterial supply from the internal carotid artery to the longitudinal neural artery, the future vertebrobasilar artery in the hindbrain. Four types known are the trigeminal, otic, hypoglossal, and proatlantal intersegmental arteries. The arteries are accompanied by their corresponding nerves and resemble an intersegmental pattern. These vessels exist in the very early period of cerebral arterial development and rapidly involute within a week. Occasionally, persistence of the carotid to vertebrobasilar anastomosis is discovered in the adult period, and is considered as the vestige of the corresponding primitive embryonic vessel. The embryonic development and the segmental property of the primitive carotid-vertebrobasilar anastomoses are discussed. This is followed by a brief description of the persisting anastomoses in adults.

Occurrence of a type 2 proatlantal intersegmental artery during carotid endarterectomy for symptomatic stenosis

Occurrence of a type 2 proatlantal intersegmental artery during carotid endarterectomy for symptomatic stenosis

Bilateral Type II Persistent Proatlantal Intersegmental Arteries

A 64-year-old man with treated hypertension presented with acute left arm and leg weakness. A brain magnetic resonance imaging (MRI) and neck magnetic resonance angiography (MRA) were performed. There was restricted diffusion in the right internal capsule posterior limb consistent with an acute lacunar infarct. The MRA demonstrated aplastic bilateral cervical vertebral arteries (V1 and V2 segments). bilaterally, a variant artery arose from the external carotid just above its origin, extended superiorly then medially, and forming the vertebral artery (V3 and V4 segments). bilaterally, the occipital artery arose from the variant artery at the juncture where it turned medially. The right variant artery terminated intracranially in the right posterior inferior cerebellar artery. The left variant artery continued intracranially to supply the basilar. The appearance was consistent with bilateral persistent proatlantal intersegmental arteries (PPIA) type II.

Monolateral type I proatlantal artery with bilateral absence of vertebral arteries: description of a case and review of the literature

We report a case of a patient with right type I proatlantal intersegmental artery associated with right fetal posterior cerebral artery and absence of both vertebral arteries and of the left posterior communicating artery. We also describe the clinical relevance of these findings for this patient. A 56-year-old woman with vertigo and tinnitus underwent contrast enhanced Magnetic Resonance Angiography (MRA) of the supra-aortic arteries using a 1.5 Tesla scanner. Maximum intensity projection and volume rendering reconstructions were obtained. MRA demonstrated the persistence of an anastomotic artery between the right internal carotid artery and basilar artery, passing through the foramen magnum, suggesting a type I proatlantal intersegmental artery. The examination also showed the absence of both vertebral arteries and the presence of a right fetal-type posterior cerebral artery. To our knowledge, this is the first report of a type I proatlantal intersegmental artery associated with an omolateral fetal-type posterior cerebral artery and the absence of both vertebral arteries and of the left posterior communicating artery. This condition requires a watchful monitoring of the patient and has to be considered in case of surgical procedures of the carotid arteries.

External Carotid Dissection and External Carotid Proatlantal Intersegmental Artery with Subclavian Steal Prompting External Carotid and Subclavian Artery Stenting

The authors describe a case of a proatlantal intersegmental artery seen in the setting of external carotid artery dissection and subclavian steal due to proximal subclavian artery stenosis. An 83-year-old woman presented with left homonymous hemianopsia and a right posterior cerebral artery distribution stroke. She was found to have severe left subclavian artery stenosis proximal to the vertebral artery (VA) and an occluded contralateral VA. Doppler ultrasonography and angiography both showed a dissection of the proximal left external carotid artery. Left common carotid artery angiography also demonstrated a connection between the external carotid and vertebral arteries at the C1 level with anterograde flow into the vertebrobasilar system and retrograde flow toward the vertebral origin, consistent with subclavian steal. The patient underwent successful stenting of the subclavian and external carotid arteries with resolution of anterograde flow in the left VA. This case represents an interesting presentation of both subclavian steal and an external carotid artery to VA anastomosis. Also, the presence of a dissection of the external carotid artery represents a rare finding.

Complex anomalies of type 1 proatlantal intersegmental artery and aortic arch variations

We report a case of type 1 proatlantal intersegmental artery (PIA) associated with multiple anomalies of the aortic arch, and discuss the possible embryonic mechanism and clinical importance of the multiple cerebrovascular variants in this patient. A 65-year-old woman with dizziness underwent cerebral magnetic resonance (MR) imaging and head and neck MR angiography using a 3-tesla scanner and computed tomography (CT) angiography using a 64-slice multidetector CT scanner. MR and CT angiography demonstrated an aneurysm of the distal end of the azygos anterior cerebral arteries and hypoplasia of the proximal right vertebral artery (VA) with an anastomotic artery, between the right internal carotid artery (ICA) and distal right VA that passed through the foramen magnum, indicating a type 1 PIA. She also demonstrated an aberrant right subclavian artery (ARSA) with hypoplasia of the right VA, and the left VA arose directly from the aortic arch. To our knowledge, this is the first report of a type 1 PIA associated with multiple vascular anomalies of the aortic arch, such as ARSA and origin of the left VA from the arch. In cases of persistent anastomoses between the carotid and vertebrobasilar arteries, such as PIAs, imaging examination should include the aortic arch to identify associated vascular variations.

Persistent primitive first cervical intersegmental artery (proatlantal artery II) associated with subarachnoid hemorrhage of unknown origin

Proatlantal intersegmental artery is a persistent arotid–vertebral embryonic anastomosis. This artery is very are, and 2 types have been described, proatlantal artery types and II. Persistent primitive proatlantal intersegmental artery proatlantal artery type I) arises from the internal carotid artery nd transverses rostrally to enter the foramen magnum where t joins the vertebral artery. Persistent primitive first cervical ntersegmental artery (proatlantal artery type II) arises from the xternal carotid artery, runs posteriorly to join the vertebral rtery and then passes through the transverse foramen of the C1 ertebra segment. The purpose of this paper is to present a case ith proatlantal artery type II without an ipsilateral vertebral rtery. This anomaly was an incidental finding in a patient with ubarachnoid hemorrhage (SAH) of unknown origin.

Incidental Finding of a Proatlantal Intersegmental Artery

We describe the case of a 70-year-old woman who had a left proatlantal intersegmental artery disclosed during carotid artery angiography with the findings of carotid-basilar anastomosis which originated from the petrous segment of the ICA and was filling the horizontal segment of the vertebral artery. Awareness of this vascular variation can prevent morbidity and mortality associated with carotid ligation or carotid endarterectomy, especially when an incomplete circle of Willis is present.

Type 2 proatlantal intersegmental artery associated with persistent trigeminal artery diagnosed by MR angiography

The type 2 proatlantal intersegmental artery (PIA) is a rare anastomosis between the external carotid artery (ECA) and vertebral artery (VA) that passes through the foramen magnum. The persistent trigeminal artery (TA) is the most common anastomosis between the internal carotid artery (ICA) and basilar artery. The purpose of this paper is to present the first case of a type 2 PIA associated with an ipsilateral persistent TA diagnosed using magnetic resonance (MR) angiography, and we briefly discuss the embryology of this rare anomaly. An 83-year-old man with cerebral infarctions underwent cerebral MR imaging, and head and neck MR angiography using a 1.5 T imager. MR angiography was obtained using the standard non-contrast three-dimensional time-of-flight technique. MR angiography showed aplasia of the proximal left VA and a large anastomotic artery between the left ECA and distal left VA that passed through the foramen magnum, indicative of a type 2 PIA. This patient also had an anastomosis between the precavernous segment of the left ICA and midbasilar artery via a lateral course, indicative of a lateral-type persistent TA. We present the first case of type 2 PIA associated with ipsilateral lateral-type persistent TA diagnosed by MR angiography. MR angiography should be performed including the carotid bifurcation to find more frequently extracranial arterial variations, including type 2 PIAs.

Proatlantal intersegmental artery with absence of the common carotid artery

Proatlantal intersegmental artery with absence of the common carotid artery

Brainstem disconnection associated with nodular heterotopia and proatlantal arteries

We report on a patient with brainstem disconnection associated with periventricular nodular heterotopia and bilateral proatlantal intersegmental arteries. The patient was a girl born after 37 weeks of gestation with birth weight of 1,938 g. Polyhydroamnios and lack of swallowing movement were noted on fetal ultrasonography. No spontaneous body movement or respiration was observed after birth, whereas facial movement was preserved. She had marked generalized weakness and absent deep tendon reflexes. She remains alive and hospitalized at 4 years of age but requires mechanical ventilation and feeding through a gastrostomy tube. MRI showed absence of the lower pons and the medulla oblongata associated with hypoplasia of the cerebellar vermis and hemispheres. In addition, ventriculomegaly and periventricular nodular heterotopia were observed in the cerebrum. MR angiography demonstrated the absence of vertebral arteries and presence of bilateral proatlantal intersegmental arteries arising from the external carotid arteries. Array-comparative genomic hybridization analysis did not show any genomic copy number aberrations. No mutation was found in the FLNA gene or the EN2 gene. The constellation of the malformations of our patient suggested that genes related to the development of the central nervous and vascular system may be involved in the pathogenesis of brainstem disconnection.

Proatlantal intersegmental artery: a review of normal and pathological features

Primitive carotid-vertebral and carotid-basilar anastomoses are formed early during human embryogenesis at approximately 24 days. From cephalic to caudal direction, these anastomoses are cranial extensions of the primitive internal carotid, trigeminal, otic, hypoglossal and proatlantal intersegmental arteries. Normal and/or abnormal morphofunctional aspects of prenatal and postnatal forms of the proatlantal intersegmental artery, from the 24th day of gestation to postnatal eight decades, are described according to personal and literature data. Many (ab) normal carotid-vertebral anastomoses are also marked in differential diagnosis of the proatlantal intersegmental artery. The proatlantal intersegmental artery maintains the posterior circulation until the vertebral arteries are fully developed between the seventh and eighth gestational weeks. When this artery fails to obliterate, it becomes persistent one. The proatlantal intersegmental artery, most commonly, is an incidental finding or it may be of clinical significance in some patients.