Primitive proatlantal intersegmental artery and carotid endarterectomy

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.

"Dual Internal Shunts Technique" for Carotid Endarterectomy with Carotid Vertebral Anastomosis: Technical Note

In revascularization of internal carotid stenosis with carotid vertebrobasilar anastomoses, attention should be paid not only to the anterior circulation but also to the posterior circulation cerebral infarction. A 74-year-old man was referred for treatment of carotid artery stenosis; NASCET 75% stenosis in the right internal carotid artery and acute cerebral infarction were confirmed. Occlusion of the left subclavian artery and vascular anastomosis between the right external carotid artery and the vertebral artery were indicated, such that the right external carotid artery may maintain blood flow to the vertebrobasilar artery. Therefore, dual shunts were used for the common and internal carotid arteries and the common and external carotid arteries to maintain blood flow during carotid endarterectomy. Management of the dual shunts is difficult due to the instable parallel placement of the common carotid artery shunt balloons. To solve this problem, the "dual internal shunts technique" was performed. The first shunt was inserted into the external and common carotid arteries, and the second into the internal and common carotid arteries. The shunt balloon on the common carotid artery side was placed distal to the first shunt balloon so that the dual balloons were placed in a tandem position. The proximal balloon was subsequently deflated gradually to improve flow in both shunts. The procedure is technically easy and safe.

Strategy of cerebral endovascular treatment for cervical internal carotid artery stenosis with a persistent primitive hypoglossal artery

Background

Persistent primitive hypoglossal artery (PPHA) is a rare residual arterial anastomosis. We placed a CASPER stent using Spider FX as an embolic protection device (EPD) in a patient with internal carotid artery (ICA) stenosis and PPHA. There are no reports of carotid artery stenting (CAS) using a CASPER stent for ICA stenosis with PPHA. We report the EPD strategy used in this case and the usefulness and precautions of CASPER stent insertion for cervical ICA stenosis in association with PPHA.

Methods

A 9Fr sheath was placed in the right femoral artery and a 9Fr Branchor balloon guide catheter was guided to the common carotid artery. A Spider FX was placed proximal to the bifurcation of the ICA and the PPHA. A 10 mm × 20 mm CASPER stent was deployed at the site of the stricture with no postoperative ischemic complications.

Results

There was no intra-stent occlusion, stenosis, or plaque protrusion immediately after surgery, and no postoperative ischemic complications were observed.

Conclusion

CASPER stent deployment with the Spider FX in the ICA and PPHA bifurcation can be considered to be an effective treatment method for ICA stenosis associated with PPHA. However, care should be taken in selecting the appropriate EPDs and stents depending on the location of the stenosis and bifurcation of the PPHA.

A case of carotid endarterectomy assisted with a three-way junction shunting tube for the internal carotid artery stenosis involving a persistent primitive hypoglossal artery

Only several cases of internal carotid artery (ICA) stenosis involving the persistent primitive hypoglossal artery (PPHA) have been treated with carotid endarterectomy (CEA) because of its extreme rarity. CEA was performed for an 87-year-old female with severe stenosis of the right ICA–PPHA bifurcation requiring shunting from CCA to both PPHA and ICA. We initially attempted to insert two intraluminal balloon shunts into the CCA, as previously reported. However, we found this procedure technically impossible to achieve. An improvised three-way junction tube was inserted distally into PPHA and ICA and proximally into CCA, securing blood flow during CEA. Unfortunately, the patient suffered post-operative ischemic brain lesions due to the prolonged ischemic time during our initial unsuccessful shunt attempt. A three-way junction shunting tube could be an effective shunt technique during an anatomically complicated CEA.

Persistent Hypoglossal Artery: Challenges Associated With Carotid Revascularization

Anomalous connections between the anterior and posterior cranial circulation are rare embryologic entities. A persistent hypoglossal artery has a reported incidence of 0.03% to 0.09% and has been linked to intracranial aneurysms, atherosclerosis, and posterior circulation ischemia. Identification of this anomaly is essential prior to carotid artery revascularization given the technical challenges and added risks with intervention. We report a case of an 80-year-old female with progression of carotid stenosis in the setting of a persistent hypoglossal artery. We provide a review of the literature and discuss the technical challenges of carotid revascularization in this patient.

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.

Basilar vascular system supplied by only right proatlantal intersegmentary artery type 1 with aneurysm and left internal carotid occlusion: a case report and review from the literature

Persistence of proatlantal artery (PA) is a rare condition. More than 40 cases were described in the literature. Aneurysm may involve the PA itself in approximately 2% of cases, most arising from the internal carotid artery (ICA) side of PA. This case was particular because the PA showed a saccular aneurysm on the posterior wall, probably due to atherosclerosis disease and other alterations: plaque ulcerative of ICA, occlusion of left ICA, and aberrant right VA.

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.

Internal carotid and ipsilateral type II proatlantal artery stenoses causing simultaneous hemispheric and vertebrobasilar transient ischemia

A case of persistent proatlantal artery (PA) is described in a 60-year-old woman who presented with cerebellar ataxia, homonymous hemianopia, and aphasia. Both Doppler scan and magnetic resonance angiography (MRA) showed agenesis of both vertebral arteries, 80% stenosis of the left internal carotid artery (ICA), and an anastomotic vessel between the left external carotid artery (ECA) and the left vertebral artery (LVA) with a tight stenosis at the origin. It was thought to be a type II PA. Both lesions were successfully treated by ICA endarterectomy and common carotid artery to PA bypass. This case demonstrates the clinical significance of persistent PA in the evolution of an ischemic cerebrovascular disease.

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.

Surgical revascularization in the presence of a preserved primitive carotid-basilar communication

Anomalous arteries that connect the anterior and posterior cranial arterial systems are unusual variants that can severely alter normal patterns of cerebral blood flow. Persistent trigeminal, hypoglossal, otic, and proatlantal arteries have been described. This report illustrates the technical aspects of carotid endarterectomy with an ipsilateral preserved primitive carotid-basilar communication. Identification of the internal carotid and hypoglossal arteries, maintenance of cerebral perfusion, arteriotomy closure, preoperative imaging, the use of shunts, and reconstruction strategy are discussed. Preoperative angiography and detailed, individualized surgical strategy should be used to ensure a successful endarterectomy in patients with preserved primitive carotid-basilar communications.