Cardiac cycle-dependent alternating flow in vertebral arteries with subclavian artery stenoses

Continuous-wave Doppler sonography is a reliable method for detecting severe subclavian stenosis and occlusion as well as subclavian steal. Intermediate stages leading to subclavian steal can also be detected. These are characterized by a cardiac-phase-dependent alternating flow direction in the vertebral artery. Some cases of proximal subclavian or proximal vertebral artery stenosis produce a systolic deceleration of flow in the vertebral artery. Stenosis and occlusion of the subclavian artery as well as stenosis of the subclavian and vertebral arteries can be distinguished. The pulse curve changes described can be reversed by a vascular by-pass. Alternating flow direction or systolic deceleration of flow in the radial artery could also be observed or induced in a iatrogenic model using Cimino's a-v fistula in the arm in patients on dialysis. The results in beginning subclavian steal situations can be applied in principle to other collateral circulations, and in particular to the hemodynamics in the region of watersheds.     

Effect of subclavian syndrome on the basilar artery

Fifty-five patients with a permanent or intermittent subclavian steal syndrome demonstrated by continuous wave Doppler were included in a prospective study: 25 patients without vertebro-basilar symptoms, 8 symptomatic patients with defined vertebro-basilar symptoms and 22 with hemodynamic vertebro-basilar occurences. The basilar artery velocity was recorded by Transcranial Doppler Sonography in baseline conditions, and after a hyperaemia test to the upper limb. A spontaneous, incomplete basilar steal was diagnosed in seven patients, and a complete basilar steal in one patient, (14.5% of the cases). After hyperaemia test, 18 other incomplete basilar steal were observed. The occurence of a basilar steal was higher in the vertebro-basilar group (57% of the cases) especially in 7 of the 8 cases with defined vertebro-basilar symptoms; it was lower in the patients without vertebro-basilar occurences (36% of the cases). This basilar steal was also seen in five of the six symptomatic patients with opposite vertebral artery stenosis above a 50% diameter. Transcranial Doppler Sonography could help to define a subgroup of subclavian steal syndrome with a high risk of strokes.     

Stenosis and occlusion of the subclavian artery: ultrasonographic and clinical findings

Summary Continuous-wave (CW) Doppler sonography has proved to be a reliable tool both to detect subclavian stenosis or occulusion and to detect reversal of blood flow in the vertebral artery. This method is entirely atraumatic and in contrast to angiography allows investigation of asymptomatic patients and provides more representative data for epidemiological studies. The incidence of subclavian stenosis or occlusion was 1.15% among the 23,500 patients examined in our department between 1978 and 1985. Of the 272 patients with unilateral or bilateral subclavian stenosis or occlusion, 54% were asymptomatic with no subjective complaints and were normal upon neurological examination; 29% reported vertebrobasilar transient ischaemic attacks (TIAs), with or without concomitant TIAs or infarction in the vascular territory of the carotid arteries; and 17% complained of symptoms exclusively referring to the region of carotid blood supply. Reversal of blood flow in the ipsilateral vertebral artery was detected in 152 patients (56%). The incidence of neurological symptoms within this group was double that found in patients without steal. None of the patients suffered from permanent vertebrobasilar damage. In most cases, subclavian artery disease was due to atherosclerosis. For 13 patients an inflammatory, iatrogenic, traumatic, or congenital aetiology could be assumed. The marked preponderance of left-sided subclavian stenosis or occlusion, reported by others, could be confirmed among our patients, but was less pronounced for tight stenoses than for occlusions. Mild-to-moderate subclavian stenoses were about equally distributed on each side.     

重度锁骨下动脉盗血综合征的侧支代偿及临床特点

目的探讨重度锁骨下动脉盗血综合征(SSS)的侧支代偿及临床特点。方法回顾性分析12例经全脑数字减影血管造影(DSA)证实为重度SSS患者的临床资料。结果 12例SSS患者主要临床表现为发作性头晕、视物旋转、跌倒等,活动同侧上肢后症状加重;DSA示左侧锁骨下动脉重度狭窄或闭塞10例,双侧锁骨下动脉重度狭窄2例;侧支代偿途径椎动脉-椎动脉-锁骨下动脉10例,颈内动脉-后交通动脉-大脑后动脉/基底动脉8例,颈外动脉-枕动脉下支-椎动脉肌支动脉-椎动脉-锁骨下动脉9例。8例患者行锁骨下动脉支架成形术后临床症状完全消失;2例患者因锁骨下动脉闭塞及对侧椎动脉中度狭窄而接受对侧椎动脉支架成形术,术后症状减轻;随访3个月～2.5年,症状无复发。结论重度SSS临床表现主要为发作性头晕,侧支代偿途径主要为椎动脉-椎动脉-锁骨下动脉,支架成形术可纠正血流动脉动力学紊乱,缓解临床症状。     

Subclavian steal syndrome as the presenting feature of hypervascular thyroid nodule

Subclavian steal syndrome (SSS) is a clinical entity characterized by brachial and basilar insufficiency as a result of critical proximal subclavian artery stenosis or occlusion. We report a patient of giant hypervascular thyroid nodule presenting with features of SSS. The left hand ischemia and symptoms of vertebro-basilar artery in our patient were probably related to stealing of blood by the hypervascular thyroid nodule from the subclavian artery. The patient was relieved of the symptoms upon percutaneous subclavian stent placement.     

The posterior inferior cerebellar artery arising from the internal carotid artery directly: a variant of the persistent primitive hypoglossal artery]

We reported a rare case of the posterior inferior cerebellar artery arising from the internal carotid artery directly. A 33-year-old male was admitted to our hospital with the complaint of throbbing type headache. CT showed no abnormal findings. A saccular aneurysm at the bifurcation of the left middle cerebral artery was revealed by MR angiography and the left internal carotid angiography. The right internal carotid angiography demonstrated an anomalous branch originating at the level of the C1/2 in the cervical portion of the internal carotid artery. This branch terminated as the posterior inferior cerebellar artery without an interposed segment of the vertebro-basilar artery. The ipsilateral vertebral artery was aplasia. T2-weighted MR image showed a flow-void penetrating the right hypoglossal canal. This vessel was confirmed an artery passing through the hypoglossal canal with the source images of the three-dimensional time-of-flight MR angiography. We diagnosed it as a kind of variant of the persistent primitive hypoglossal artery. The persistent primitive hypoglossal artery is composed of the proximal segment derived from the primitive hypoglossal artery, and the distal segment consisting of portions of the lateral anastomotic channels (primitive lateral basillo-vertebral anastomosis) which give rise to the posterior inferior cerebellar artery. We speculated that this variant resulted from the persistence of the proximal segment, which communicated with the stem of the posterior inferior cerebellar artery via the distal segment, and next, the disconnection of the posterior inferior cerebellar artery origin with the vertebral artery due to the aplasia of right vertebral artery and the involution of the distal segment connected to the basilar artery.     

Atraumatic diagnosis and semi-invasive therapy of subclavian steal syndrome using percutaneous transluminal angioplasty. A current concept

Percutaneous transluminal angioplasty (PTA) is a semiinvasive, non-operative transvascular technique for dilatation of stenosed vessel segments by help of balloon catheters. This technique was applied to 30 out of 42 patients with a subclavian steal mechanism due to highgrade proximal subclavian artery (PSA) lesions. The transfemoral, transaxillary or both approaches were used. A staging of the severity of the subclavian steal mechanism on the basis of the pre-interventional Doppler ultrasound findings (Grade I-IV) was proposed for adequate selection of patients for angioplasty. During balloon dilatation of the subclavian artery permanent CW Doppler monitoring of the ipsilateral vertebral blood flow velocity was performed at the mastoid. Balloon dilatation failed to be effective in 4 patients with complete subclavian artery occlusions (Stage IV). In 26 patients with high-grade stenoses of the proximal subclavian artery (Stage II/III), angioplasty led to recanalisation of the vessel and abolishment of the steal mechanism. However, relief or improvement of the concomitant subclavian steal syndrome could not be achieved except in one-third or two-thirds of the patients, respectively. Long term follow-up with repeat Doppler sonography indicated a complete removal of the subclavian lesions in 50% of the cases, whereas the remaining patients produced some kind of re-stenosis. However, repeat angioplasty became necessary in only 5 cases and was permanently successful in two of them. If patients with complete subclavian artery occlusions were excluded, the complication rate due to angioplasty was very low. Embolism into the finger arteries could only be observed once. In another case, accidental dissection and complete occlusion of the distal subclavia artery occurred but underwent spontaneous recanalisation. Doppler monitoring of vertebral flow velocity was very useful for both control of the effectiveness of the dilatation procedure and deeper insight into the pathophysiology of the subclavian steal mechanism. An unexpected delay phenomenon concerning the re-establishment of cephalad vertebral flow direction was observed immediately after recanalisation of the subclavian artery and was thought to protect the posterior circulation against early embolism due to mobilisation of plaque debris within the proximal subclavian segment. From an angiological point of view, the outcome of percutaneous transluminal angioplasty does not yet meet the success rates of various modern extra-thoracic surgical procedures for operative treatment of subclavian steal mechanism. However, the rate of improvement of clinical signs and symptoms is equal with both methods.(ABSTRACT TRUNCATED AT 400 WORDS)     

Long term survival after basilar artery occlusion. 4 cases

Four cases of basilar artery occlusion with a follow-up from 7 to 12 years are reported. The first patient, a 60 year old woman, had a proximal occlusion which was revealed by an acute brain stem ischemia. The second case was a 63 year old man with an aortic aneurysm who had a single episode of vertebro-basilar insufficiency. Cerebral angiography demonstrated a lower basilar artery occlusion. The third patient, a 60 year-old woman, had been operated from right carotid artery and left vertebral artery stenosis; 8 years later, without clinical manifestations, a left carotid artery stenosis and an occlusion of the lower part of the basilar artery were discovered. The evolution was eventless after a left carotid endarterectomy. The last case was a 60 year old man who had a lower basilar artery occlusion associated with a left internal carotid occlusion. There was a full recovery after a hemiplegic stroke. From our personal cases and the review of the literature, long term survival after basilar artery occlusion may occur in occlusions restricted to the lower or middle part of the basilar artery and with a good collateral supply from carotid and cerebellar arteries.     

Subclavian Steal Syndrome with or without Arterial Stenosis: A Review

The subclavian‐vertebral artery steal syndrome (SSS) is the hemodynamic phenomenon of blood flow reversal in the vertebral artery due to significant stenosis or occlusion of the proximal subclavian artery or the innominate artery. Occasionally, SSS is diagnosed in patients not harboring arterial stenosis. With the exception of arterial congenital malformations, the limited case reports of SSS with intact subclavian artery are attributed to dialysis arteriovenous fistulas (AVFs). Interestingly, these cases are more frequently symptomatic than those with the classical atherosclerotic SSS forms. On the other hand, the disclosure of SSS due to subclavian/innominate artery atherosclerotic stenosis, even in the absence of accompanying symptoms, should prompt a thorough cardiovascular work‐up for the early detection of coexisting coronary, carotid, or peripheral artery disease. Herein, we review the incidence, clinical presentation, sonographic findings, and therapeutic interventions related to SSS with and without subclavian/innominate artery stenosis. We also review the currently available data in the literature regarding the association of SSS and dialysis AVF. In addition, we present a patient with bilateral symptomatic SSS as the result of an arteriovenous graft (AVG) that was introduced after the preexisting AVF in the contralateral arm became nonfunctional. SSS due to subclavian or innominate artery stenosis/occlusion is rarely symptomatic warranting interventional treatment. In contrast, when it is attributed to AVF, surgical correction is frequently necessary.     

Megadolichobasilar artery and acute cerebrovascular pathology

Sixteen patients with a megadolichobasilar artery and acute cerebrovascular symptoms are reported. All were explored by computerized tomography and vertebral angiography. Nine had transient ischaemic attacks or definitive ischaemic lesions, whereas 7 had subarachnoid or intracerebral haemorrhage. Among the patients with ischaemic troubles, vertebro-basilar insufficiency and pontine infarction were the most common clinico-radiological findings. Among the patients with intracranial haemorrhage, 4 had associated aneurysms or arteriovenous malformations, while 3 had subarachnoid or intracerebral haemorrhage with no vascular malformations on the angiograms. The possible relationships between the megadolichobasilar anomaly and the cerebral ischaemic or haemorrhagic pathologies are discussed also from a review of the pertinent literature.     

Megadolichobasilar artery and acute cerebrovascular pathology

Sixteen patients with a megadolichobasilar artery and acute cerebrovascular symptoms are reported. All were explored by computerized tomography and vertebral angiography. Nine had transient ischaemic attacks or definitive ischaemic lesions, whereas 7 had subarachnoid or intracerebral haemorrhage. Among the patients with ischaemic troubles, vertebro-basilar insufficiency and pontine infarction were the most common clinico-radiological findings. Among the patients with intracranial haemorrhage, 4 had associated aneurysms or arteriovenous malformations, while 3 had subarachnoid or intracerebral haemorrhage with no vascular malformations on the angiograms. The possible relationships between the megadolichobasilar anomaly and the cerebral ischaemic or haemorrhagic pathologies are discussed also from a review of the pertinent literature.     

Variant of Subclavian Steal in the Setting of Ipsilateral Common Carotid Artery Occlusion: Case Report

Subclavian steal is a well-described angiographic finding and clinical syndrome that rarely results in vertebrobasilar ischemic symptoms. In classic subclavian steal, left subclavian artery (SA) stenosis occurs proximal to the left vertebral artery (VA) origin. We report a symptomatic variant of this syndrome that occurred in the setting of left common carotid artery occlusion and anomalous origin of the left VA directly from the aortic arch. The steal and symptoms resolved after stenting of the left SA stenosis.     

Vertebro-basilar ischaemia with thrombosis of the vertebral artery: report of two cases with embolism.

Two cases with vertebro-basilar infarcts associated with severe stenosis of the vertebral artery in its cervical part is reported. Complete thrombosis of the vertebral artery was observed after a short delay in both cases. As the carotid arteries were normal and the controlateral vertebral artery was dominant, an embolic mechanism was suspected. No new event occurred in the following one and three years respectively after the stroke. These two cases demonstrate the possibility of embolism from severe stenosis of the cervical vertebral artery. This mechanism could explain some of the infarcts related to vertebral artery occlusion.     

Carotid Steal Syndrome: A Case Study

The progression of subclavian arterial stenosis and the subsequent formation of collateral pathways serve to alter the pressure gradients in subclavian steal syndrome, altering ipsilateral vertebral artery flow from its normal state to “latent,” “transient,” and “continuous” steals. A similar altered flow in the carotid arteries can be observed with stenosis of the proximal common or innominate artery. A 59-year-old man was seen in the vascular laboratory for evaluation of symptomatic peripheral arterial disease. An incidental asymptomatic stenosis of the right innominate and left proximal subclavian artery was found . Further cerebral vascular evaluation displayed a continuous right subclavian steal and a latent steal in the right internal carotid artery. Transcranial Doppler examination displayed “transient” steal in the terminal right internal carotid artery. Combining duplex and transcranial Doppler evaluation s allows sequential evaluation of the progression of arterial disease and its effect on the flow patterns in the cerebral vasculature.     

Emboligenic ulcerated plaque of the foramen of the vertebral artery

Atheromatous plaques of the vertebral artery ostium are usually smooth and cause hemodynamic ischemia in the vertebro-basilar territory only when stenosis is severe. A case of crescendo vertebro-basilar attacks is reported and related to an ulcerated plaque of the vertebral artery ostium. The patient underwent surgical endarterectomy after failure of an antiplatelet treatment. He has remained asymptomatic for six months. Diagnosis of vertebral artery ulceration is difficult by ultrasonics or digitalized arteriography because of the small diameter of the vessel and its posterior origin. The frequency of ulcerated plaques of the subclavio-vertebral intersection is probably underestimated in the literature Labauge et al. (1987) emphasized recently the risk of cerebellar infarction during the natural history of vertebral artery occlusion. Crescendo vertebro-basilar transient ischemic attacks can be caused by a plaque rupture of of the vertebral ostium which leads secondarily to vertebral artery occlusion. Therapeutic options for atheromatous lesions of the posterior circulation are not clearly defined by controlled studies. In the reported case and in series reported in the literature, surgery would appear to be an efficient procedure with low mortality and morbidity.     

锁骨下动脉闭塞支架植入术

锁骨下动脉闭塞引起有椎-基底动脉供血不足、患侧肢体缺血表现等,如共济失调、眩晕、运动时出现肢体疼痛、麻木、乏力、苍白等。目前主要采用血管内支架成形术,当病变完全闭塞或接近锁骨下动脉和椎动脉开口时可考虑选择外科手术治疗。本病例闭塞近心端过短、闭塞时间长,按目前的腔内治疗和外科手术方法,风险大,我们采用长鞘衬管技术、双向造影/双向导丝打通技术成功进行了腔内支架植入术。     

41例颈动脉蹼患者的影像学及临床特征

目的 探讨颈动脉蹼的影像学特点及其相关临床表现,提高对该病的认识及诊断能力。 方法 回顾性分析2016年1月-2018年12月于青岛大学附属医院行头颈部CTA检查的患者影像学资料, 对其中符合颈动脉蹼诊断标准的患者的影像及临床特点进行分析总结。 结果 行头颈部CTA检查的8653例患者中,检出颈动脉蹼患者有41例（0.47%）。41例中典型部位 的颈动脉蹼共38例（92.68%）,26例（63.41%）位于颈内动脉,12例（29.27%）位于颈总动脉近分叉 处;发生于颈动脉之外部位者共3例（7.32%）,其中2例（4.88%）位于锁骨下动脉,1例（2.44%）位 于椎动脉。41例患者共发现47个蹼结构,其中蹼附着于管腔后壁者33个（70.21%）,位于侧壁者10个 （21.28%）,位于前壁者4个（8.51%）。41例患者最终诊断脑梗死者20例（48.78%）,短暂性脑缺血发 作者14例（34.14%）,脑出血者3例（7.32%）,其他表现者4例（9.76%）。 结论 颈动脉蹼在CTA上有典型的影像学特点,除最好发于颈内动脉及颈总动脉外,亦可见于颈部 其他动脉如椎动脉及锁骨下动脉。蹼结构管腔内附着部位多见于后壁及侧壁,少数发生于前壁。颈动 脉蹼与卒中的发生关系密切。     

椎动脉起始位置与穿出颈椎横突孔高度关系的三维CT血管成像研究

目的通过三维CT血管成像(CTA)探讨椎动脉起始位置与穿出颈椎横突孔高度的关系。方法回顾性分析2017年3月至2019年3月河北医科大学第二医院神经外科行头颈上胸部CTA检查的480例患者的临床资料。将图像传输至图像后处理工作站进行骨质和血管重建,观察双侧椎动脉的起源、走行及穿出颈椎横突孔的高度。对于右侧椎动脉起源正常者,根据穿出颈椎横突孔的高度分为C₄、C₅、C₆组,每组随机选取10例分别测量右侧椎动脉起始位置至右侧颈总动脉起始的距离(L1)和右侧甲状颈干的距离(L₂),以L₁/(L₁+L₂)×100%计算椎动脉起始的相对位置。结果480例患者中,457例(95.2%)双侧椎动脉起源位置正常,均起源于锁骨下动脉,另23例(4.8%)起源异常,其中左侧椎动脉起源于主动脉弓19例、左侧颈外动脉1例;右侧椎动脉起源于右侧颈总动脉3例,且均合并迷走右锁骨下动脉。480例患者中,405例(84.4%)双侧椎动脉经C₆横突孔穿出;另75例(15.6%)穿出高度异常,其中左侧34例,经C₃、C₄、C₅、C₇横突孔穿出的分别有1、4、24、4例,直接入枕骨大孔1例;右侧41例,经C₃、C₄、C₅横突孔穿出的有1、14、26例。椎动脉起源异常的患者,左侧椎动脉起自主动脉弓的占比最高(19/20),且多数穿出颈椎横突孔的高度异常(18/19);右侧椎动脉均起自右侧颈总动脉合并迷走右锁骨下动脉(3/3),且穿出颈椎横突孔的高度均异常(3/3)。椎动脉起源正常的患者,96.7%(445/460)的左侧椎动脉穿出颈椎横突孔的高度正常,92.0%(439/477)的右侧椎动脉穿颈椎横突孔高度正常。3组右侧椎动脉起源正常的患者椎动脉起始的相对位置的差异有统计学意义[C₄组:(24.3±2.1)%、C₅组:(47.9±6.6)%、C₆组:(77.7±1.7)%,H=20.178,P<0.001]。结论椎动脉起始位置异常时,其穿出颈椎横突孔的高度多异常。右侧椎动脉的起始相对位置越靠近右侧颈总动脉时,穿出颈椎横突孔的高度越高;而越靠近右侧甲状颈干,穿出颈椎横突孔的高度越低。     

颈动脉狭窄闭塞性病变后交通支开放与椎动脉起始段狭窄的关系

目的探讨颈动脉狭窄闭塞性病变(≥70%)患者后交通支开放与否与椎动脉起始段狭窄的关系。方法对160例经血管造影证实颈动脉动脉狭窄(≥70%)并行外科治疗(内膜剥脱术、颈动脉支架术)的患者分为后交通支开放组与后交通支未开放组,术前及术后均采用彩色多普勒血流成像(CDFI)检测双侧颈动脉及椎动脉,分别比较两组患者双侧椎动脉起始段狭窄的发生率。结果后交通支开放组椎动脉起始段局部流速术前(后交通支开放)明显高于术后(后交通支关闭)。后交通支关闭前后椎动脉起始段峰值流速(PSV)与舒张末流速(EDV)分别为100.76±74.84cm/s、81.54±54.29 cm/s(P=0.000);后交通支开放患者占50%(80/160),其中椎动脉起始段存在狭窄支数占45.6%(73/160),后交通支未开放患者占50%(80/160),其中椎动脉起始段存在狭窄支数占28.1%(45/160),两者之间存在显著差异(P=0.002)。结论颈动脉狭窄闭塞性病变后交通支开放患者,椎动脉起始段狭窄的发生率显著升高。     

Treatment of posterior circulation ischemia with extracranial percutaneous balloon angioplasty and stent placement.

BACKGROUND AND PURPOSE: Vertebrobasilar territory ischemia (VBI) leads to disabling neurological symptoms and poses a risk for stroke by an embolic or flow-related mechanism. We present our clinical experience in the endovascular treatment of patients with symptomatic VBI from severe atherosclerosis or dissection of the vertebral and subclavian arteries that was unresponsive to medical therapy. METHODS: Twenty-one patients (9 female, 12 male) with a mean age of 65.7 years (range 47 to 81 years) underwent treatment with percutaneous endovascular balloon angioplasty and stent placement. Sixteen patients (76.2%) had evidence of contralateral involvement, and 9 (42.8%) demonstrated severe anterior-circulation atherosclerosis. Nine patients had a previous infarct in the occipital lobe, cerebellum, or pons before treatment. Follow-up was available for all patients. RESULTS: Balloon angioplasty with intravascular stent placement was performed in 13 vertebral artery lesions (10 at the origin, 3 in the cervical segment) and in 8 subclavian lesions. The prestenting stenosis was 75% (50% to 100%) and was reduced to 4.5% (0% to 20%) after stenting. Six of the patients with proximal subclavian stenosis demonstrated angiographic evidence of subclavian steal, which resolved in all cases after treatment. All patients showed improvement in symptoms after the procedure except for 1 who developed a hemispheric stroke after thrombotic occlusion of an untreated cavernous carotid artery stenosis (rate of major stroke and mortality=4.8%). One patient (4.8%) had a periprocedural transient ischemic attack (TIA), and none had minor stroke. At long-term follow-up (mean=20.7+/-3.6 months) of the surviving 20 patients, 12 (57.1%) remained symptom-free, 4 (19%) had at most 1 TIA over a 3-month period, 2 (9.5%) had at most 1 TIA per month, and 2 (9.5%) had persistent symptoms. There were no clinically evident infarcts during the follow-up period. CONCLUSIONS: Endovascular treatment using balloon angioplasty with intravascular stent placement for symptomatic stenotic lesions resulting in VBI that is unresponsive to medical therapy appears to be of benefit in this high-risk subset of patients with poor collateral flow.