Persistent hypoglossal artery: An anomaly leading to false-positive carotid duplex sonography

Endarterectomy of carotid artery bifurcation in the setting of a persistent hypoglossal artery and anomalous collateral vascular supply

Presented is a patient with carotid artery stenosis resulting in crescendo anterior and posterior circulation transient ischemic attacks. Treatment was complicated by a rare persistent hypoglossal artery (HGA) arising from the left internal carotid artery in addition to severe contralateral carotid disease, hypoplastic vertebral arteries, and incomplete circle of Willis. A carotid endarterectomy with shunting was performed, maintaining perfusion of both the proper left internal carotid artery and HGA. This is a rare case of carotid stenosis in the setting of a persistent HGA with contralateral carotid disease and highlights the importance of planning intracranial perfusion before carotid surgery.

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 Dependence on a Persistent Hypoglossal Artery Visualized at CT Angiography

The persistent hypoglossal artery is a rare perseverance of an embryonic vessel connecting the anterior and posterior circulations and is generally considered an incidental finding. This report describes a patient with a basilar dependence on a persistent hypoglossal artery visualized at CT angiography. The pertinent findings and clinical implications of this anomalous vessel are discussed.

Persistent primitive hypoglossal artery with retrograde flow from the vertebrobasilar system: a case report

The persistent primitive hypoglossal artery (PPHA) is one of the pairs of arterial connections that exist in the human embryo between the developing anterior and posterior circulation. Normally the PPHA arises from the cervical internal carotid artery (ICA) and passes through the hypoglossal canal to join the caudal basilar artery (BA). In most cases the vertebral arteries (VA) are either hypoplastic or aplastic and the posterior communicating arteries (PComA) are absent; thus, the main supply to the posterior circulation comes from the internal carotid via the PPHA in an antegrade fashion. Atherosclerotic plaques in the ICA and PPHA present with ischemic symptoms of both the carotid and vertebrobasilar systems. We report a case of a 53-year-old female who presented with a transient episode of left lower extremity numbness and weakness. Work-up with computed tomography (CT) and magnetic resonance imaging (MRI) showed a small watershed infarct in the right middle cerebral artery (MCA)/posterior cerebral artery (PCA) territory. Diagnostic angiography revealed severe proximal stenosis of the cervical ICA and presence of a PPHA just above the stenosis with retrograde filling from the vertebrobasilar junction to the distal cervical ICA. The patient underwent a carotid endarterectomy with intraoperative EEG monitoring. Intraoperative blood flow measurements were made before and after endarterectomy showing evidence of reversal of blood flow to a normal antegrade fashion. The postoperative angiogram showed resolution of the right ICA stenosis and persistence of the PHA. To our knowledge this is the first case report of a PPHA exhibiting reversal of blood flow from the posterior into the anterior circulation. Awareness of this embryological anomaly and its interaction with acquired atherosclerotic disease will minimize misinterpretation of vascular diagnostic studies.

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.

Carotid endarterectomy in the presence of a persistent hypoglossal artery: case report

OBJECTIVE AND IMPORTANCE

A persistent hypoglossal artery, one of the embryonic carotid-basilar anastomoses that can fail to regress in the embryo and can be observed past birth, is one of the only congenital anatomic variations of the internal carotid artery (ICA) that can complicate the performance of carotid endarterectomy. When associated with atherosclerotic carotid artery disease, the recognition and intraoperative management of a persistent hypoglossal artery is important.

CLINICAL PRESENTATION

A 72-year-old man presented with a symptom of transient right hemisphere ischemia, and although ultrasonography indicated a right ICA stenosis (and no other abnormality), angiography also demonstrated that the atherosclerotic plaque extended into the origin of a large right persistent hypoglossal artery arising 1.5 cm from the origin of the ICA. In this patient, the persistent hypoglossal artery was the only arterial supply to the basilar artery.

INTERVENTION

The patient underwent a right ICA endarterectomy, and intraoperative angiography was necessary to ensure that the persistent hypoglossal artery was the vessel shunted during the arterial repair.

CONCLUSION

Recognition of the primitive carotid-basilar anastomoses is important to surgeons who perform carotid endarterectomy and is not possible with ultrasonography alone. Intraoperative angiography enables the surgeon to accurately catheterize a persistent hypoglossal artery with a carotid shunt.

The persistent primitive hypoglossal artery: a rare anatomic variation with frequent clinical implications

The case of a persistent primitive hypoglossal artery (PHA) in a 72-year-old man dead from myocardial infarction is presented. The autopsy showed the presence of a semicircular marginal infarct on the surface of the left cerebral hemisphere. The PHA anastomized the basilar artery origin with the left internal carotid artery, running through the left hypoglossal canal together with the hypoglossal nerve. The vertebral and posterior communicating arteries were hypoplastic. The PHA represented the morphological base on which the cerebral vascular insufficiency acted, following the generalized circulatory insufficiency due to the myocardial infarct, causing the cerebral infarct. Based on the embryology of the cranial arteries and on the morphological findings we suggest that the persistence of the hypoglossal artery: 1) precedes the vertebral and posterior communicating arteries hypoplasia causing it by competition for the territory of distribution; 2) gives rise to an almost complete dependence of the cerebral circulation from the carotid system with predictable ischemic consequences in the case of a critical reduction of the carotid blood flow; 3) may be associated with an anomalous structure of the vessel wall and exposes the basilar trunk to an unusual haemodynamic stress, predisposing to the onset of aneurysms.

Persistent hypoglossal artery: diagnostic and therapeutic considerations concerning carotid thromboendarterectomy

Fetal anastomotic connections between the developing internal carotid and basilar arterial systems are via the three presegmental arteries: the otic artery, the hypoglossal artery, and the trigeminal artery. After formation of the posterior communicating artery from the caudal branch of the internal carotid artery, the presegmental arteries are generally obliterated. Rarely, however, these primitive carotid-basilar anastomoses will persist into adult life, and may be detected as incidental findings at the time of cerebral angiography during evaluation of the patient with suspected cerebrovascular disease. In addition, persistence of such anastomoses may result in the coexistence of anterior and posterior circulation symptoms, precipitating diagnostic confusion. Two patients with symptoms and persistent hypoglossal artery undergoing carotid thromboendarterectomy are discussed, with emphasis on clinical presentation, diagnostic criteria and intraoperative management.