Embolism from vertebral artery origin occlusive disease.

We report 10 patients with severe occlusive disease of the vertebral artery (VA) origin in the neck with intra-arterial embolism to the posterior circulation. The VA lesions in seven patients were complete occlusions, and three patients had severe atherostenosis. All patients had strokes in the vertebrobasilar territory. The most frequent recipient sites of intra-arterial embolism were the intracranial VA-posterior inferior cerebellar artery region (8), and the distal basilar artery (BA) and its superior cerebellar and posterior cerebral artery branches (7). Two patients had pontine infarction due to BA embolism. The most common clinical signs were due to cerebellar infarction. Atherosclerotic disease of the VA origin has features in common with disease of the internal carotid artery origin. Both have similar risk factors and demography, and each can cause strokes by intracranial intra-arterial embolism.     

Vertebrobasilar infarcts in patients with dolichoectatic basilar artery

We reported 18 patients who had stroke in the posterior circulation with dolichoectatic basilar artery. TIAs preceded posterior circulation infarct in 5 patients. Strokes involved medulla oblongata (3), pons (4), cerebellum (4), mesencephalon (4), thalamus or occipital lobe (3). Dolichoectatic basilar artery also produced hydrocephalus in one patient. The mechanism of stroke may be due to penetrating artery occlusion, basilar artery thrombosis or an embolism from the abnormal basilar artery. Short-term prognosis was poor seeing that 4 patients died within 12 days of stroke.     

New England Medical Center Posterior Circulation registry

Among 407 New England Medical Center Posterior Circulation registry patients, 59% had strokes without transient ischemic attacks (TIAs), 24% had TIAs then strokes, and 16% had only TIAs. Embolism was the commonest stroke mechanism (40% of patients including 24% cardiac origin, 14% intraarterial, 2% cardiac and arterial sources). In 32% large artery occlusive lesions caused hemodynamic brain ischemia. Infarcts most often included the distal posterior circulation territory (rostral brainstem, superior cerebellum and occipital and temporal lobes); the proximal (medulla and posterior inferior cerebellum) and middle (pons and anterior inferior cerebellum) territories were equally involved. Severe occlusive lesions (>50% stenosis) involved more than one large artery in 148 patients; 134 had one artery site involved unilaterally or bilaterally. The commonest occlusive sites were: extracranial vertebral artery (52 patients, 15 bilateral) intracranial vertebral artery (40 patients, 12 bilateral), basilar artery (46 patients). Intraarterial embolism was the commonest mechanism of brain infarction in patients with vertebral artery occlusive disease. Thirty-day mortality was 3.6%. Embolic mechanism, distal territory location, and basilar artery occlusive disease carried the poorest prognosis. The best outcome was in patients who had multiple arterial occlusive sites; they had position-sensitive TIAs during months to years.     

Local embolism from vertebral artery occlusion

Basilar artery territory stroke may result from embolism arising from the site of vertebral artery occlusion. This stroke mechanism (local embolism) has been well documented in the middle cerebral artery territory from extracranial internal carotid artery disease but not fully appreciated in the vertebral basilar circulation. We report two patients whose clinical presentation indicated major basilar artery territory infarction documented by angiography to be the result of vertebral artery occlusion and artery-to-artery embolism. Vertebral artery occlusion has often been associated with a benign course, but under certain circumstances embolism to the basilar artery may complicate the outcome.     

Multiple acute infarcts in the posterior circulation.

OBJECTIVE--to evaluate clinical, radiological, and prognostic features of patients with multiple acute infarcts in remote arterial territories of the posterior circulation. DESIGN--Data analysis from a prospective acute stroke registry in a community based primary care centre using a standard protocol including MRI and MRA. RESULTS--In three and a half years, 27 of the 236 patients (11%) with posterior circulation stroke had multiple acute infarcts in the posterior circulation as shown by gadolinium enhancement on MRI. Eighteen patients had multiple infratentorial and supratentorial infarcts including the cerebellum and posterior cerebral artery territory, with coexisting brainstem involvement in seven patients. Fourteen patients had a rostral basilar artery syndrome and cerebellar signs; four patients had a visual field defect with cerebellar signs. Causes were vertebral (six) or basilar (four) artery atheromatosis, and cardioembolism (four). Seven patients had multiple acute infarcts in the posterior circulation of the cerebellum and lower brainstem. Brainstem and cerebellar signs were found in most patients (five); aetiologies were small vessel disease (four), cardioembolism (one), and vertebral artery dissection (one). Two patients with large artery atheromatosis had multiple acute infarcts in the posterior circulation in the brainstem and posterior cerebral artery territory. One month after stroke more than 25% of the patients were dependent or had died. There was no difference in the outcome between the three groups, and recovery was linked to the size of infarcts rather than to a high number of infarcts. CONCLUSIONS--multiple acute infarcts in the posterior circulation usually involve the cerebellum. Simultaneous brainstem and posterior cerebral artery territory infarcts sparing the cerebellum are uncommon. They can be suspected clinically before neuroimaging, mainly when supratentorial and infratentorial infarcts coexist. This may be important, because different patterns of infarction are associated with different causes of stroke.     

后循环大血管闭塞患者血管内治疗后早期神经功能恶化的危险因素分析

目的 探究后循环大血管闭塞患者血管内治疗(Endovascular treatment,EVT)后早期神经功能恶化(Early neurological deterioration,END)的危险因素。方法 选择2018年6月-2020年6月本院收治的164例行EVT治疗的后循环大血管闭塞患者作为研究对象,根据治疗后END的发生情况将患者分为END组(29例)和非END组(135例),比较2组患者的一般资料、病灶部位和后循环血管情况; 单因素及多因素Logistic回归分析影响患者EVT后END的因素; 构建列线图预测模型并评价其预测效能。结果 2组患者的性别、高血压病、糖尿病、基线美国国立卫生研究院卒中量表(National institutes of health stroke scale,NIHSS)评分、脑桥梗死、椎动脉V4段狭窄、基底动脉狭窄、大脑后动脉P1段狭窄均有明显差异(P<0.05); 高龄女性、高血压病、糖尿病、基线NIHSS评分≥22分、脑桥梗死、椎动脉V4段狭窄、基底动脉狭窄、大脑后动脉P1段狭窄均是导致患者EVT后END的危险因素; 列线图预测模型预测的区分度和校准度较好,有较高的预测价值。结论 分析影响后循环大血管闭塞患者EVT后END的因素并构建列线图预测模型,为临床上风险因素的识别和治疗提供参考价值,对提高患者预后有重要意义。     

Ischemia in the territory of a hypoplastic vertebrobasilar system

BACKGROUND: Congenital variations in the configuration and size of the cerebral vessels may predispose to ischemic stroke. OBJECTIVES/METHODS: To illustrate that a hypoplastic basilar artery may lead to posterior circulation ischemia in adults, eight cases are reported from two university medical centers. RESULTS: Five men and three women with a mean age of 49.8 years are reported. Four of the patients had other conventional stroke risk factors. Two patients had brainstem strokes, and six had TIA. All patients had hypoplastic basilar arteries. Seven patients had at least one hypoplastic vertebral artery (bilateral in five cases), and six patients had both posterior cerebral arteries originating from the internal carotid arteries. CONCLUSIONS: A hypoplastic basilar artery is frequently accompanied by vertebral artery hypoplasia, and this can predispose adults to posterior circulation ischemia. This entity can be suspected on the basis of MR angiogram, but conventional angiography will provide definitive diagnosis. Optimal medical and surgical treatment of this condition is unresolved.     

Basilar artery occlusive disease in the New England Medical Center Posterior Circulation Registry

BACKGROUND: Most reports on basilar artery (BA) occlusive disease have retrospectively described single cases or small patient series. OBJECTIVE: To assess clinical and vascular features, stroke mechanisms, etiologies, and outcome of moderate to severe BA occlusive disease among 407 patients in the New England Medical Center Posterior Circulation Registry, the largest prospective series of consecutively collected patients with posterior circulation ischemia to date. RESULTS: We studied 87 patients and identified 3 patient groups with distinct vascular, clinical, etiological, and prognostic characteristics: isolated BA disease (39 patients [44.8%]), BA involvement as part of widespread posterior circulation atherosclerosis (36 patients [41.4%]), and embolism to the BA (12 patients [13.8%]). Vascular risk factors were common and often multiple. Most patients (54 [62.1%]) had involvement of the midportion of the BA. Fifty-eight patients (66%) initially had transient ischemic attacks, of whom 34 (58.6%) progressed to stroke. Transient ischemic attacks were usually multiple, lasted for several months, and increased in frequency as the stroke approached. When an infarct was present, the middle posterior intracranial territory was most often involved (66 patients [75.9%]). Outcome was much better than previously assumed. The mortality rate was 2.3%, and 62 patients (almost 75%) had minor or no deficits at follow-up. Outcome was best among patients with widespread atherosclerotic disease and worst in 7; (58.3%, with major disability) of 12 patients with embolism to the BA. Distal territory involvement, embolism, BA occlusion, decreased level of consciousness, tetraparesis, and abnormal pupils were significant predictors of poor outcome. CONCLUSION: Inclusion of patients into 1 of the BA groups and early identification of predictive outcome factors guide diagnostic evaluation and treatment.     

后循环动脉瘤显微外科手术治疗

目的 探讨后循环动脉瘤手术适应证和治疗效果.方法 纳入42例共44个后循环动脉瘤,包括基底动脉动脉瘤26例(27个)、椎动脉动脉瘤16例(17个).其中15例分别行颈外动脉-大脑后动脉P2段(4例)、颈内动脉-大脑后动脉P2段(2例)、颌内动脉-大脑后动脉P2段(2例)、椎动脉颅内外段(2例)、枕动脉.小脑后下小动脉(5例)搭桥联合动脉瘤孤立术;余27例行单纯动脉瘤夹闭术.结果 经随访共37例(基底动脉顶端动脉瘤14例、基底动脉主干动脉瘤3例、椎动脉动脉瘤9例、小脑后下动脉动脉瘤5例、大脑后动脉P1～P2段交界处动脉瘤4例、小脑上动脉动脉瘤l例和小脑前下动脉动脉瘤1例)患者恢复正常生活活动能力,无一例发生手术相关性神经功能障碍,恢复良好率达88.09%.其余5例患者,1例(基底动脉顶端动脉瘤)术后出现严重神经功能缺损症状与体征,生活不能自理;2例(1例基底动脉顶端动脉瘤、1例基底动脉主干动脉瘤)因术后发生脑干缺血,围手术期死亡;2例(椎动脉动脉瘤)复发患者经再次治疗康复.结论 对于不宜直接行手术夹闭的后循环动脉瘤,为了避免因夹闭动脉瘤和延长临时阻断载瘤动脉时间而发生术后脑缺血事件.可选择颅内外血管搭桥联合动脉瘤孤立术,以避免动脉瘤夹闭术带来的危险.     

Bilateral intracranial vertebral artery disease in the New England Medical Center, Posterior Circulation Registry.

BACKGROUND: Previous studies of patients with bilateral intracranial vertebral artery (ICVA) disease were selective and retrospective. METHODS: We studied risk factors, vascular lesions, symptoms, signs, and outcomes in patients with bilateral ICVA disease among 430 patients in the New England Medical Center Posterior Circulation Registry. RESULTS: Forty-two patients had bilateral ICVA occlusive disease (18 had bilateral stenosis; 16, unilateral occlusion and contralateral stenosis; and 8, bilateral occlusion). The most common risk factors were hypertension (32/42 [76%]) and hyperlipidemia (22/42 [52%]). Sixteen patients (38%) had transient ischemic attacks (TIAs) only; 18 (43%), TIAs before stroke. Occlusive vascular disease also involved the basilar artery in 29 patients (69%), the extracranial vertebral arteries in 18 (43%), and the internal carotid arteries in 11 (26%). Only 6 patients had no other major vascular lesion. Cerebellar symptoms were common. Among 30 patients with infarction, 21 (70%) had proximal intracranial territory involvement, and 15 (50%) had distal territory involvement. The location of occlusive lesions in relation to posterior inferior cerebellar artery origins did not significantly influence prognosis. During follow-up, 31 patients had no symptoms or slight disability, 2 had progression, and 7 died. Among 7 patients with poor outcome, 6 also had basilar artery stenosis or occlusion and 5 had proximal and distal intracranial territory infarcts. CONCLUSIONS: Most patients with bilateral ICVA occlusive disease have hypertension, other major occlusive lesions, and TIAs before stroke. Short- and long-term outcomes are usually favorable, but patients with bilateral ICVA and basilar artery-occlusive lesions often have poor outcomes.     

大脑后动脉区梗死与后循环血管状态及危险因素关系

目的探讨大脑后动脉区梗死与后循环血管状态及危险因素的关系。方法回顾性收集2010年1月-2014年6月在首都医科大学宣武医院神经内科住院的经头部MRI证实的首次新发大脑后动脉区梗死的患者192例,其中171例行CT血管成像,21例行DSA,排除有可疑心源性栓子来源的患者。根据头部MRI将梗死部位分为A(中脑组)、B(丘脑组)、C(颞叶内侧组)、D(胼胝体压部组)、E(枕叶组)、F(多部位梗死组)6组。比较PCA区梗死与后循环血管状态及危险因素的关系。结果 (1)PCA区梗死病变分布:192例患者中A、B、C、D、E、F组分别为12例(6.3%)、74例(38.5%)、15例(7.8%)、11例(5.7%)、28例(14.6%)、52例(27.1%)。(2)椎-基底动脉系统血管状态:椎动脉病变66例(34.4%)合并大脑后动脉狭窄13例,基底动脉病变27例(14.1%)合并大脑后动脉狭窄2例,大脑后动脉病变45例(23.4%),未发现血管病变69例(35.9%)。(3)对PCA区梗死病变分布与后循环血管病变行单因素卡方检验:B组与基底动脉病变相关(χ~2=5.318,P=0.021);E组与PCA P4段病变相关(χ~2=18.556,P0.001);F组与椎动脉、基底动脉病变相关(χ~2=4.386,7.059;P=0.036,0.008)。(4)血管病变组与无血管病变组比较:合并高血压病差异有统计学意义(11.126,P=0.001)。结论大脑后动脉区梗死与后循环血管病变关系密切,尤其合并导致血管病变的危险因素时,更应重视血管检查,减少卒中再发。     

急性后循环梗死患者血管病变特点和危险因素分析

目的 探讨急性后循环梗死患者血管病变特点及与危险因素的相关性.方法 收集南京卒中注册系统中自2007年1月至2010年6月首发急性后循环梗死患者337例的临床资料,患者均行CT血管造影、MR血管造影、数字减影全脑血管造影等相关检查,明确血管病变的部位和机制,并对其与危险因素的关系进行分析.结果 本组337例急性后循环梗死患者中有血管病变者195例(57.9％),共394处,其中以椎动脉起始部病变最为常见,其次为椎动脉V4段、基底动脉、大脑后动脉等.后循环梗死患者最常见的危险因素是高血压(64.9％),其次为吸烟、糖尿病、饮酒、高同型半胱氨酸血症等.有血管病变患者中高血压患病率明显高于无血管病变患者,心脏疾病发生率明显低于无血管病变患者,差异均有统计学意义(P＜0.05).结论 我国后循环梗死患者中发生血管病变的比例较高,尤其是有高血压、糖尿病等危险因素的患者更有可能出现血管病变.     

双侧椎动脉/基底动脉重度狭窄或闭塞的急性后循环梗死患者临床特点及预后分析

目的总结分析双侧椎动脉/基底动脉重度狭窄或闭塞的急性后循环梗死患者的临床特点和预后。方法收集急性后循环梗死且伴有双侧椎动脉/基底动脉重度狭窄或闭塞的住院患者资料,分析其血管危险因素、起始症状、治疗及病情演变情况,并随访90 d预后,以mRS2分定义为预后不良。结果共纳入28例患者,最常见的起始症状为孤立性头晕或眩晕(57.1%)。53.6%的患者出现病情加重,加重≥2次9例(32.1%),预后不良15例(53.6%)。预后不良组高血压3级、病情加重、加重≥2次比例明显高于预后良好组(P0.05)。病情加重≥2次组高血压3级、高脂血症、孤立性头晕或眩晕起病、预后不良和死亡比例明显高于加重2次组(P0.05)。基底动脉不显影组死亡率(75%)明显高于显影组(4.2%)(P0.05)。结论双侧椎动脉/基底动脉重度狭窄或闭塞的急性后循环梗死患者多以孤立性头晕或眩晕起病;孤立性头晕或眩晕起病和高血压3级患者病情容易加重;病情反复加重患者预后不良比例高,死亡率高;基底动脉不显影患者死亡率高。     

Stroke in patients with fusiform vertebrobasilar aneurysms

We studied seven patients with brainstem infarction and large fusiform vertebrobasilar (VB) aneurysms to clarify the clinical, radiologic, and pathologic features. All presented with pontine infarcts; one also had a cerebellar infarct. VB TIAs preceded brainstem infarction in four patients. Angiography and CT documented VB fusiform aneurysmal dilatation. Four had intraluminal thrombi and one had severe basilar artery stenosis. Two distinct clinical pictures emerged: unilateral pontine infarcts with favorable outcome, presumably related to obstruction of a pontine penetrating artery at its origin from the posterior wall of the aneurysmal basilar artery, and major fatal bilateral pontine infarcts from basilar artery occlusion. Two patients came to autopsy. One had thrombus in the dilated basilar artery and a posterior cerebral artery branch embolus with hemorrhagic occipital infarction; the other had basilar artery thrombus with aneurysmal rupture and subarachnoid hemorrhage. Fusiform VB aneurysms caused brainstem stroke by intraluminal thrombus, local embolism, atherostenosis, and obstruction of paramedian penetrating arteries. Subarachnoid hemorrhage is an uncommon complication.     

Warfarin vs aspirin for symptomatic intracranial stenosis: subgroup analyses from WASID

The WASID trial showed no advantage of warfarin over aspirin for preventing the primary endpoint of ischemic stroke, brain hemorrhage, or vascular death. In analyses of selected subgroups, there was no definite benefit from warfarin. Warfarin reduced the risk of the primary endpoint among patients with basilar artery stenosis, but there was no reduction in stroke in the basilar artery territory or benefit for vertebral artery stenosis or posterior circulation disease in general.     

Clinical findings of intracranial vertebral artery disease using magnetic resonance angiography

The vertebral artery lesion has a variety of clinical characteristics. We sought to clarify the clinical patterns and the location of the intracranial vertebral artery (ICVA) diseases according to analyses of images obtained using magnetic resonance angiography (MRA). We studied vascular lesions, risk factors, symptoms, signs, and outcomes in 35 patients with ICVA disease (3 had bilateral occlusion; 9, unilateral occlusion; 6, bilateral stenosis; and 17, unilateral stenosis). The most common site of unilateral and bilateral lesions was the distal ICVA after the origin of posterior inferior cerebellar artery (PICA). We found accompanying basilar artery disease in 28.6% of patients with unilateral and bilateral ICVA disease. The majority of the ICVA lesions were associated with internal carotid arteries disease (48.8%). The common vascular risk factors were hypertension (71%), diabetes mellitus (34%), hyperlipidemia (31%), smoking (29%), and coronary artery disease (23%). Eighteen patients (51.4%) had transient ischemic attacks (TIAs) only, 10 patients (28.6%) had TIAs before stroke, and 5 patients (14.3%) had strokes without TIAs. Most patients (80%) with TIAs, with or without stroke, had multiple episodes. Vertigo or dizziness, ataxia, limbs weakness and abnormal gait were the common symptoms and signs. At 6 months follow-up, 66.7% patients had no symptoms or only slight symptoms that caused no disability. Our data showed (1) the usual location of ICVA disease (occlusion or severe stenosis) was distal to PICA, especially near the vertebrobasilar junction; (2) the risk factors were hypertension, diabetes mellitus, hyperlipidemia, smoking, and coronary artery disease; (3) patients with ICVA disease had a high frequency of accompanying internal carotid, middle cerebral, or basilar artery disease; (4) vertigo or dizziness, and ataxia were the common symptoms and signs; (5) TIA was the most common clinical pattern; (6) the outcome was favorable, except in cases with bilateral ICVA occlusion.     

多灶性后循环缺血患者的病灶分布与血管形态异常及近期预后分析

目的 观察多灶性后循环缺血患者的病灶分布和血管形态异常的特点,评估患者出院时的近期预后及其与病灶分布和血管形态的关系.方法 对34例经过MR/所证实的多灶性后循环缺血患者行主动脉弓及全脑血管DSA,全面分析病灶分布及血管形态异常的特点;同时对患者出院时的近期预后用改良Rankin分级(MRS)评分表进行评估,分析病灶分布及血管形态异常与近期预后的关系.结果 多灶性后循环缺血患者最常被累及的部位是脑桥(22例),最常被累及的区段是中段+远段(12例);34例患者中有26例(76.5%)DSA显示出血管形态异常,最常被累及的动脉是椎动脉起始段(14例)和颅内段(13例)及基底动脉(7例);出院时7例患者(20.6%)存在预后不良,其中6例(17.6%)为重度残疾,1例(2.9%)死亡.近中远段同时受累和基底动脉受累的患者表现出预后不良.结论 血管形态异常是多灶性后循环缺血的重要病理基础和致病因素,病灶区段的分布和数目及血管受累部位是决定预后的关键因素.     

Comparison of spontaneous intracranial vertebral artery dissection with large artery disease

OBJECTIVE: To compare clinical and angiographic characteristics and stroke patterns between spontaneous intracranial vertebral artery dissection (VAD) and vertebral large artery disease (LAD) (atherosclerosis). DESIGN: Retrospective study. SETTING: Tertiary referral center for cerebrovascular diseases. Patients Twenty-two patients with spontaneous VAD and 25 with LAD in the intracranial portion of the vertebral artery. MAIN OUTCOME MEASURES: We compared (1) clinical characteristics, including epidemiologic data, vascular risk factors including inflammatory markers, the presence of headache, and stroke syndromes and severity; (2) stroke pattern on diffusion-weighted imaging, which was classified as vertebral perforator infarct, basilar perforator infarct, small scattered infarct, large scattered infarct, and territorial infarct; and (3) angiographic findings, ie, the distribution of involved arteries, degree of stenosis, and the involvement on the anterior circulation and calcification of vertebral artery. RESULTS: Although patients with VAD were younger, and more often had headaches and fewer vascular risk factors than those with LAD (P<.01 in all cases), these clinical features were also observed in some LAD patients. Diffusion-weighted imaging data showed that vertebral perforator infarct and small scattered infarct were most common in the VAD group, while territorial infarct and large scattered infarct were most common in the LAD group (P = .02). On angiography, LAD more frequently had anterior circulation arterial involvement (P = .002), higher degree of stenosis (P = .002), and calcifications (P = .008). CONCLUSION: Our findings indicate that results of diffusion-weighted imaging and noninvasive vascular studies might provide clues to the clinical characteristics in differential diagnosis between VAD and LAD.     

Characteristics of vascular lesions in patients with posterior circulation infarction according to age and region of infarct

Patients with posterior circulation infarction underwent CT angiography and magnetic resonance angiography. Intracranial and extracranial vasculopathy was evaluated according to age group and location of stroke. Patients aged > 60 years and < 60 years had similar rates of vertebral artery dominance and vertebrobasilar artery developmental or origin anomalies. Vertebrobasilar artery stenosis or occlusion and tortuosity occurred more frequently in patients aged > 60 years than < 60 years. The rates of vertebrobasilar artery anomalies and tortuosity were high in patients with posterior circulation infarction. Vertebrobasilar artery tortuosity occurred more frequently in patients aged > 60 years, whereas vertebrobasilar artery developmental anomalies occurred with similar frequency in patients aged < 60 years and > 60 years. Patients with infarction of the brainstem or cerebellum were more likely to have vertebral artery stenosis or occlusion, basilar artery stenosis or occlusion, vertebral artery dominance or tortuosity, and basilar artery tortuosity, and patients with infarction of the thalamus, medial temporal, or occipital lobes were more likely to have stenosis or occlusion of the vertebral or basilar arteries. Vertebrobasilar artery tortuosity, vertebral artery dominance (hypoplasia), and congenital variations of the vertebrobasilar system may lead to posterior circulation infarction at different locations in different age groups.     

Hypoplastic vertebral artery: frequency and associations with ischaemic stroke territory

Background

In patients with posterior inferior cerebellar artery infarction (PICAI) or lateral medullary infarction (LMI), the ipsilateral vertebral artery is often hypoplastic and therefore at an increased risk of ischaemic stroke.

Objective

To investigate the frequency and clinical relevance of hypoplastic vertebral artery (HVA) in patients with ischaemic stroke with or without vertebral artery territory and in normal healthy people.

Methods

529 patients with ischaemic stroke, including vertebral artery territory infarction (LMI or PICAI), were classified according to their stroke location (303 anterior circulation strokes (ACS) and 226 posterior circulation strokes (PCS)) by MRI. The frequency of HVA, defined as a diameter of ⩽2 mm by magnetic resonance angiography, was measured in comparison with 306 normal healthy people.

Results

185 patients (35.2%) from the cohort had HVA (3.4%, bilaterally). Patients with PCS showed a higher rate of HVA than those with ACS (45.6% vs 27.1%, p<0.001). The HVA frequency of those with ACS was similar to that of the normal group (26.5%). Of the 112 patients with vertebral artery territory stroke, 58 (51.8%) had HVA (bilateral HVA in 10), and all of 48 showed ipsilateral HVA territory stroke. In 102 patients with vertebral artery territory stroke, classification of the ipsilateral vertebral artery as hypoplastic (vs dominant or symmetric) tended to predict the involvement of multiple and extensive lesions, and a higher incidence of steno‐occlusion (p<0.001).

Conclusion

HVA is not rare in the normal population, and is frequent in patients with PCS. People with HVA may have a high probability of PCS, with atherosclerotic susceptibility and ipsilateral lesions in the vertebral artery territory.Congenital variations in the arrangement and size of the vertebral arteries are frequently recognised, ranging from asymmetry of both vertebral arteries to severe hypoplasia of one vertebral artery on cerebral angiography. In a pathoanatomical study, hypoplastic vertebral artery (HVA) was defined as a lumen diameter of ⩽2 mm,¹ but there is no consensus on this value.The absence of vertebrobasilar insufficiency symptoms among people with HVA indicates that even marked vertebral artery asymmetry is a normal variation,^2,3,4 and has led to an underestimation of the incidence and clinical relevance of HVA. However, ipsilateral HVA is common in patients with posterior inferior cerebellar artery infarction (PICAI) or lateral medullary infarction (LMI), suggesting that HVA confers an increased probability of ischaemic stroke. Although the relationship between hypoplasia of the vertebral artery or the basilar artery and the risk of posterior circulation ischaemia has been examined,⁵ there have been few reports on the relationship between HVA and territorial ischaemic stroke, to our knowledge.The objectives of this study were to determine the frequency of HVA in normal healthy people and in patients with stroke, and the clinical relevance of HVA in patients with ischaemic stroke with vertebral artery territory.