Persistent primitive proatlantal intersegmental artery (proatlantal artery I) results in 'top of the basilar' syndrome

Embryology of the vertebral artery and variants of the adult

The vertebral arteries represent in the adult the main blood supply of the posterior cranial fossa, even if they appear relatively late during the embryological life. We reviewed all the most important steps of the vertebral artery's embryological development and the most common variants that can occur in the adult. The aim of this review is to summarize the main events of the development of this artery and to give an embryological explication for the most common variants of this artery.

Intracranial Angioplasty via Type II Proatlantal Intersegmental Artery

A proatlantal intersegmental artery (PIA) is an exceedingly rare primitive anastomosis between the carotid and vertebrobasilar circulations. PIAs 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 VA angioplasty through a type II PIA in the setting of vertebrobasilar stroke. We present the case of vertebrobasilar stroke in which the right VA did not originate from the right subclavian artery but instead from the ECA. The patient was subsequently determined to have a type II PIA. We performed right VA angioplasty via the PIA, followed by partial restoration of vertebrobasilar blood flow. This is the first documented case of intracranial vertebral angioplasty through a type II PIA and serves as a reminder for neuroendovascular surgeons about persistent fetal circulation. In such instances, an angiogram of both the ICA and ECA should be performed to exclude right VA stenosis and visualize persistent fetal circulation. This case underscores the complexity of arterial thrombotic events, the beneficial role of endovascular intervention, and the necessity of future studies to identify the optimal treatment methods for vertebrobasilar stroke.

Mechanical Thrombectomy for Basilar Artery Occlusion with a Type 1 Persistent Proatlantal Artery: A Case Report and Literature Review

Objective

Persistent proatlantal artery (PPA) is a primitive carotid-vertebrobasilar anastomosis (CVA); acute ischemic stroke due to basilar artery (BA) occlusion via a PPA is extremely rare.

Case Presentation

An 84-year-old female developed disturbance of consciousness (Glasgow Coma Scale E2V1M5) and quadriparesis with a National Institutes of Health Stroke Scale score of 35. Head CT revealed early ischemic changes in the right temporal lobe, and a hyperdense vessel sign in the BA. Cerebral angiography showed that the left vertebral artery (VA) did not originate from the left subclavian artery or aortic arch. A left common carotid artery angiogram showed the presence of the left PPA originating from the left external carotid artery. Mechanical thrombectomy (MT) with contact aspiration using a Penumbra 5MAX ACE 60 aspiration catheter was performed, and successful recanalization was achieved after clot retrieval in the first attempt (thrombolysis in cerebral infarction scale 2b). MRI performed the following day, however, revealed a newly developed large hemorrhagic infarction in the pons, with no improvement in her symptoms (modified Rankin Scale score of 5 at 90 days).

Conclusion

Although MT achieved successful recanalization of the BA via the PPA, her clinical symptoms did not improve, probably because of poor collateral circulation or the long length of the occlusion. In patients with acute vertebro-BA occlusion, if the VA does not originate from the subclavian artery or aortic arch, the presence of a primitive CVA should be considered.

Case Report: Stent Retriever Thrombectomy of Acute Basilar Artery Occlusion via the Type 1 Proatlantal Intersegmental Artery

Stent retriever thrombectomy (SRT) is one of the most effective methods for the recanalization of acute basilar artery occlusion (ABAO). The proatlantal intersegmental artery (PIA) is a rare carotid-vertebrobasilar anastomosis. Recognition of this rare form of anastomosis is particularly important for the rapid establishment of positive blood flow in patients with ABAO. In this case, the patient had a rare, left type 1 PIA. The right vertebral artery (VA) was tenuous and did not enter the cranium. We performed a thrombectomy of the ABAO by inserting a catheter via the type 1 PIA. The complete recanalization of basilar artery (BA) flow was achieved following two stent retractions; however, the patient eventually died of brain stem hemorrhage.

Posterior fossa transient ischemic attack in the setting of bilateral persistent hypoglossal arteries: A case report and literature review

RATIONALE

Persistent hypoglossal artery (PHA) is the second rare abnormal anastomosis of the internal carotid and vertebrobasilar arteries, and bilateral persistent hypoglossal arteries in particular have rarely been reported. This is the first case of bilateral persistent hypoglossal arteries presenting with posterior fossa transient ischemic attack (TIA).

PATIENT CONCERNS

We reported a 54-year old female with posterior fossa TIA due to the coexisting bilateral persistent hypoglossal arteries and left internal carotid artery stenosis.

DIAGNOSIS

The patient was diagnosed with posterior fossa TIA, bilateral persistent hypoglossal arteries and left internal carotid artery stenosis.

INTERVENTIONS

The patient was given aspirin 100 mg/qd and advised to avoid excessive neck movement.

OUTCOMES

Symptoms of intermittent subjective dizziness accompanied by nausea were relieved.

LESSONS

Although requires no special treatment, PHA could be accompanied by hypoplasia of vertebral arteries and posterior communicating arteries and becomes the main blood supply pathway for the posterior circulation. Accurate identification and evaluation of PHA is important of ensuring the safety of carotid interventions and identifying specific types of stroke.

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

BACKGROUND

Proatlantal 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.

METHODS

Dual 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.

RESULTS

National Institute of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) got improved at discharge and ten months.

CONCLUSIONS

This case is the first report for ICAD management via PIA. A persistent type 2 PIA is essential for supplying posterior circulation.

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.

Isolation of right internal carotid artery, persistent proatlantal 1 artery and rete mirabile in a child with 22q11 deletion syndrome

We report a case of a 2-year-old girl with 22q11 deletion syndrome who underwent studies for cardiac murmur. Ultrasound, computed tomography angiography and digital subtraction angiography revealed an aberrant right subclavian artery and an isolated right internal carotid artery (ICA) originating from the right pulmonary artery. A right carotid rete mirabile (CRM) and a proatlantal (Pa) type 1 artery were also found. We hypothesize that Pa type 1 persistence and CRM development are secondary to the reversal of flow of the isolated ICA.

A Type 1 Persistent Proatlantal Artery Originating from the External Carotid Artery Detected by Computed Tomographic Angiography

A persistent proatlantal artery (PA) is rare. We report a type 1 persistent PA originating from the right external carotid artery (ECA). A 78-year-old woman presented with dizziness. Computed tomographic (CT) angiography showed a persistent PA originating from the right ECA. This persistent PA did not pass through the atlas transverse foramen. The extracranial segment of this artery in the atlas transverse process level had a more lateral position than a normal left vertebral artery. CT angiography well demonstrated the relationship with bony structures and the course of this persistent PA. This anomalous artery in our patient presented as an incidental finding. Surgeon should recognize a persistent PA when performing carotid endarterectomy or ligation of the ECA for avoidance of complication.

Unilateral Aplasia versus Bilateral Aplasia of the Vertebral Artery: A Review of Associated Abnormalities

Morphological characteristics of 108 cases of uni- and bilateral aplasia of the vertebral artery (VA) in reports or images of retrospective studies, including one recent case, published between 1967 and 2016 are analyzed. Incidence, gender, persistence of carotid-vertebrobasilar anastomosis (CVBA), associated with other vascular variants, and vascular pathology in each group of uni- and bilateral VA aplasia are mutually compared. Most of the cases of VA aplasia in ages 31 to 80 were discovered in USA, Japan, and India. The bilateral VA aplasia is more common in the male gender than in the female one. The side of the VA aplasia had a significant effect on the side of CVBA persistence. Associated aplasia of other arteries was more common in cases of unilateral VA aplasia. The left VA was more commonly hypoplastic in cases of single right VA aplasia than the right VA in cases of single left VA aplasia. Aneurysms of definitive arteries were more frequent in cases of single right VA aplasia than in cases of single left VA aplasia. We claim that the aplasia of the VA probably depends on genetic factors in some races, while diseases are expressed usually in persons over 30 years of age.

Left type I proatlantal artery with bilateral aberrant vertebral arteries and a ruptured aneurysm: a case report and review of the literature

Persistent proatlantal artery is one rare kind of persistent primitive anastomoses between carotid and basilar vascular system. This case firstly introduces a type I proatlantal artery with complex vascular anomalies of bilateral vertebral arteries and a ruptured aneurysm, which is extremely uncommon. A 43-year-old female was hospitalised for SAH and ventricular hematocele. The subsequent digital subtraction angiography and computed tomography angiography revealed a type I proatlantal artery which arises from left internal carotid artery, associating with a hypoplastic right vertebral artery, an aplastic left vertebral artery and a ruptured left posterior inferior cerebellar artery aneurysm. An interventional procedure was taken later. The present case raises awareness on the incidence of persistent primitive anastomoses which combined other complex vascular anomalies before surgical or interventional procedures, especially in view of unique blood supply to posterior circulation from the primitive vessel.

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.

Incidental finding of a proatlantal intersegmental artery. A case report

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.

Persistent fetal intracranial arteries: a comprehensive review of anatomical and clinical significance

As fetal intracranial vessels may persist into adulthood, knowledge of their anatomy and potential clinical and surgical complications should be borne in mind by the surgeon. A comprehensive review of these vessels, however, is not easily identified in the literature. Therefore, the present analysis was undertaken so that such information is available to the clinician and morphologist.

Persistent hypoglossal artery detected incidentally in a hypertensive patient with intracerebral hemorrhage: a case report and review of the literature

A 73-year-old woman with a history of chronic hypertension admitted to our clinic with complaint of acute paresis in her left arm. Computed tomography and magnetic resonance imaging were performed to the patient which displayed intracerebral hemorrhage in the right parieto-occipital lobe. Further review of the computed tomography and magnetic resonance imaging scan showed an enlarged left hypoglossal canal with a large vessel passing through it. The patient was thereafter examined with cerebral digital subtraction angiography to determine the cause of hemorrhage, but no vascular etiology was demonstrated, except from a persistent hypoglossal artery. We present a rare case of persistent hypoglossal artery, which we detected incidentally during angiographic evaluation, with a review of the literature.

Proatlantal intersegmental artery: a review of normal and pathological features

OBJECTS

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.

MATERIALS AND METHODS

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.

CONCLUSIONS

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.

Cerebral Arteriovenous Malformation Embolized through Persistent Primitive Hypoglossal Artery: A Case Report

SUMMARY

Carotid-vertebral anastomoses are commonly detected as incidental findings. But sometimes these channels are important for the clinical condition of the patient. Here a case of right thalamo- capsular arteriovenous malformation is described where a persistent primitive hypoglossal artery was the only route for embolization of the arteriovenous malformation.

Normal variants of the intracranial circulation demonstrated by MR angiography at 3T

Magnetic resonance angiography (MRA) at 3T offers increased signal to noise ratio with better background suppression, leading to exquisite depiction of the intracranial circulation. We present a pictorial review of the normal variations and anomalies of the intracranial circulation detected on MRA performed on a high field 3T clinical scanner using parallel imaging techniques. The salient imaging features of these anomalies and normal variations are discussed with relevance to clinical practice.

Persistent carotid-vertebrobasilar anastomoses

The persistent carotid-vertebrobasilar anastomoses (PCVBA) can be explained by an interruption of the vertebrobasilar system (VBS) embryogenesis. We present two very rare cases of persistent anastomoses: a hypoglossal artery and a type I proatlantal artery, insisting on the angiographic criteria allowing differentiation. After a brief review of the embryogenesis of the VBS, we describe the different types of persistent anastomoses (hypoglossal, type I and II proatlantal, trigeminal and otic arteries). We will insist on the potential risks, not well-known, but typical of each anastomosis. PCVBA usually are incidental findings but imaging follow-up may be required since aneurysms may develop.