Mechanical Thrombectomy of Distal Occlusions in the Anterior Cerebral Artery: Recanalization Rates,Periprocedural Complications,and Clinical Outcome

BACKGROUND AND PURPOSE:Patients with acute ischemic stroke in the anterior circulation are at risk for either primary or, following mechanical thrombectomy, secondary occlusion of the anterior cerebral artery. Because previous studies had only a limited informative value, we report our data concerning the frequency and location of distal anterior cerebral artery occlusions, recanalization rates, periprocedural complications, and clinical outcome.MATERIALS AND METHODS:We performed a retrospective analysis of prospectively collected data of patients with acute ischemic stroke undergoing mechanical thrombectomy in the anterior circulation between June 2010 and April 2015.RESULTS:Of 368 patients included in this analysis, we identified 30 (8.1%) with either primary (n = 17, 4.6%) or secondary (n = 13, 3.5%) embolic occlusion of the distal anterior cerebral artery. The recanalization rate after placement of a stent retriever was 88%. Periprocedural complications were rare and included vasospasms (n = 3, 10%) and dissection (n = 1, 3.3%). However, 16 (53.5%) patients sustained an (at least partial) infarction of the anterior cerebral artery territory. Ninety days after the ictus, clinical outcome according to the modified Rankin Scale score was the following: 0–2, n = 11 (36.6%); 3–4, n = 9 (30%); 5–6, n = 10 (33.3%).CONCLUSIONS:Occlusions of the distal anterior cerebral artery affect approximately 8% of patients with acute ischemic stroke in the anterior circulation receiving mechanical thrombectomy. Despite a high recanalization rate and a low complication rate, subsequent (partial) infarction in the anterior cerebral artery territory occurs in approximately half of patients. Fortunately, clinical outcome appears not to be predominately unfavorable.

Mechanical thrombectomy (MT) is an effective treatment in acute ischemic stroke secondary to a large-vessel occlusion.^1–4 Patients with acute ischemic stroke secondary to an occlusion of the internal carotid artery–T, middle cerebral artery trunk (M1), or MCA secondary division (M2) have relatively high rates of revascularization and favorable clinical outcomes after MT.^5,6 Unfortunately, for patients with ICA-T occlusions and MCA occlusions, there is a risk of approximately 8.6%–11.4% for secondary emboli into the anterior cerebral artery (ACA), especially the distal branches such as the pericallosal artery, during MT.^2,7,8 Although various technical possibilities, such as proximal flow control or combined aspiration, have been recommended to reduce the risk of secondary emboli^9–13, occlusions of the distal ACA occur.Regardless of the cause of the occlusion (primary occlusion or secondary emboli during MT), cerebral infarctions in the ACA territory may cause relevant clinical deficits by affecting the primary or supplementary motor areas.¹⁴ In a previous, relatively small patient cohort (n = 6), treatment of secondary ACA occlusions was technically successful in 80% of the cases and uneventful in all instances.⁷We present data on the frequency and location of distal ACA occlusions, recanalization rates, periprocedural complications, and clinical outcome.     

大脑中动脉狭窄或闭塞的形态学与血流动力学评价

目的　利用灌注磁共振和血管造影技术分析大脑中动脉狭窄或闭塞的形态学和血流动力学特点。方法　 2003 -03 ~2004-04我们收治了 41例单侧大脑中动脉狭窄或闭塞的患者,其中男 33例,女 8例;年龄 24~61岁,平均 (43. 30±4. 37)岁,借助灌注磁共振和血管造影技术对其形态学和血流动力学特点进行评价。结果　所有患者局部脑血流量没有显著性降低,但大脑中动脉分布区灌注明显延迟,且随着狭窄程度加重而明显,侧枝循环对分水岭区的灌注障碍有所代偿,而对大脑中动脉分布区影响不大。结论　单侧大脑中动脉狭窄时,灌注磁共振技术可以准确评价患者的血流动力学状况,而此时的血流动力学障碍与形态学特点有明显的关系。     

大脑中动脉闭塞后大脑后动脉侧支供血的MRA研究

目的:研究大脑中动脉闭塞后侧支供血的3DMRA表现。方法:回顾性分析大脑中动脉供血区脑梗死患者75例,均行MRI和3DTOFMRA,着重观察MRA中的侧支代偿供血情况。结果:75例患者3DTOFMRA均发现大脑中动脉起始段(M1)闭塞,同侧的大脑后动脉颞下后支及距状裂和顶枕动脉段出现增粗、延长、分支增多的表现,而多数患者同侧的大脑前动脉走行方向、管径粗细、分支情况则无明显变化。结论:大脑中动脉M1段闭塞后,MRA示同侧大脑后动脉主干及分支有显著改变,说明闭塞区的代偿血供是以大脑后动脉通过柔脑膜毛细血管网的侧支循环为主。     

CT灌注分析慢性进展性大脑中动脉主干闭塞性脑缺血

目的 探讨慢性进展性大脑中动脉主干闭塞性脑缺血的CT灌注血流动力学改变特点.资料与方法 搜集25例具有临床及影像资料的单侧大脑中动脉主干慢性进展性闭塞的病例,取双侧大脑中动脉支配镜像兴趣区各灌注参数值行配对t检验.结果 患侧与对侧之间局部脑血流量(rCBF)、平均通过时间(MTT)、达峰时间(TTP)的差异均有统计学意义(P<0.05),患侧与对侧之间局部脑血容量(rCBV)的差异无统计学意义(P>0.05).结论 慢性进展性大脑中动脉闭塞性脑缺血的CT灌注特征是:rCBF下降、MIT及TTP延长,rCBV无明显变化.     

Mechanical Thrombectomy for Early Treatment of Massive Pulmonary Embolism

We report our technique and results of percutaneous mechanical thrombectomy in a consecutive series of eight patients with massive PE. We also discuss the possible role of mechanical PE thrombectomy. Eight consecutive patients with acute massive PE, with or without hemodynamic impairment, were treated with mechanical thrombectomy. We used a modified 7-fr hydrolyzer catheter. The treatment was combined with systemic fibrinolysis. From the logistic and technical point we encountered no problems. All patients showed significant improvement while still in the angiography suite. There were no bleeding complications and no other events related to the procedure. Despite the clinical improvement, one patient died shortly after the procedure from cardiac failure. In all patients there was an acute increase in PO2 to normal values. Only a mean of about 50% of all local thrombus could be removed (range 30–80%). The mean PAP pre-intervention decreased only minimally from 42.5 mmHg to 36.3 mmHg post-intervention (not significant). In three patients, the PAP continues to remain high at follow-up. The most important feature of mechanical thrombectomy for massive PE is the immediate improvement of the cardiac output, PO2, and clinical situation, overcoming the first critical hours after massive PE. The amount of thrombus reduction seems not to be an important parameter.     

Acute Basilar Artery Occlusion: Outcome of Mechanical Thrombectomy with Solitaire Stent within 8 Hours of Stroke Onset

BACKGROUND AND PURPOSE:Mechanical thrombectomy with a stent retriever applied shortly after symptom onset could increase good functional outcomes and improve survival in patients with acute basilar artery occlusion, but this has not yet been studied. This study evaluated the efficacy and safety of mechanical thrombectomy with a Solitaire stent within 8 hours of stroke onset in patients with acute basilar artery occlusion.MATERIALS AND METHODS:We analyzed 25 consecutive patients with acute basilar artery occlusion who were treated with mechanical thrombectomy by use of the Solitaire stent within 8 hours of stroke symptom onset. Successful recanalization was defined as TICI grade 2b or 3. Good outcome was defined as mRS score of 0–2 at 3 months. Clinical and radiologic data in patients with good outcomes were compared with those with poor outcomes.RESULTS:Successful recanalization was achieved in 96% (24/25) of patients, and 48% (12/25) of patients had good outcomes. Eighty-eight percent (22/25) of patients survived to 3 months. The median NIHSS score on admission was significantly lower in patients with good outcomes than in those with poor outcomes (9.5 versus 14, P = .005). Procedure-related complications occurred in 2 patients (8%). No symptomatic intracerebral hemorrhages occurred.CONCLUSIONS:The current study suggests that mechanical thrombectomy by use of a Solitaire stent within 8 hours of stroke onset increases good outcomes and improves survival in patients with acute basilar artery occlusion.

Acute basilar artery occlusion (BAO) is associated with a very poor outcome and has the highest mortality rate among intracranial large-vessel occlusions.^1,2 In a prospective, observational study (BASICS [Basilar Artery International Cooperation Study]), 27 patients were treated conservatively because the patients were either comatose (n = 26) or tetraplegic (n = 1) at the time of presentation; 96.3% (26/27) of these patients died, and the 1 remaining patient had an mRS score of 5 at 1 month.²Clinical outcomes were unsatisfactory, even when patients with acute BAO were treated with intravenous or intra-arterial (IA) pharmacologic thrombolysis. A systematic analysis including 420 patients showed that the rates of death or dependency were 78% (59/76) in patients treated with IV thrombolysis and 76% (260/344) in those treated with IA thrombolysis.³In the past few years, the introduction of stent-type clot removal devices (stent retrievers) have initiated a new era in endovascular stroke therapy. Two randomized, controlled trials and many case series showed that stent retrievers can achieve a high rate of successful recanalization of up to 90%, thus improving the clinical outcome in patients with acute intracranial large-vessel occlusion.^4–11 Most studies were focused on anterior circulation stroke.The efficacy of stent retrievers for treating acute BAO was reported in several recent case series.^12–14 These previous studies used a longer time window of up to 24 hours for mechanical thrombectomy in patients with acute BAO. However, BASICS showed that early recanalization therapy in patients with acute BAO is associated with a more favorable outcome, and all patients with severe stroke treated >9 hours after symptom onset had poor functional outcome despite IV or IA thrombolysis.¹⁵ In this regard, the use of mechanical thrombectomy with a stent retriever within a shorter time period from symptom onset would increase the patient''s chances for a good functional outcome and decrease the mortality rate in patients with acute BAO, but this has not yet been studied. The aim of this study was to evaluate the efficacy and safety of mechanical thrombectomy with a stent retriever (Solitaire; Covidien, Irvine, California) as a first-line endovascular therapy within 8 hours of stroke onset in patients with acute BAO.     

Successful Recanalization of Acute Superior Mesenteric Artery Thromboembolic Occlusion by a Combination of Intraarterial Thrombolysis and Mechanical Thrombectomy with a Carotid Filter

Acute superior mesenteric artery (SMA) occlusion is a life-threatening disease, and acute intestinal ischemia develops from the sudden decrease in perfusion to the intestines. The key to saving the patient’s life is early diagnosis, and prompt revascularization of the SMA can prevent intestinal infarction and decrease the risk of bowel segment necrosis. Computed tomographic angiography may be useful for rapid diagnosis. We report recanalization of an SMA occlusion in an 80-year-old man with a combination of intraarterial thrombolysis and mechanical thrombectomy with a carotid filter.     

Negative Susceptibility Vessel Sign and Underlying Intracranial Atherosclerotic Stenosis in Acute Middle Cerebral Artery Occlusion

BACKGROUND AND PURPOSE:The role of MR imaging in predicting underlying intracranial atherosclerotic stenosis before endovascular stroke therapy has not been studied. Our aim was to determine the diagnostic value of the negative susceptibility vessel sign on T2*-weighted gradient-echo MR imaging for predicting underlying intracranial atherosclerotic stenosis in patients with acute MCA occlusion.MATERIALS AND METHODS:Ninety-one consecutive patients with acute stroke because of MCA occlusion underwent gradient-echo MR imaging and MRA before endovascular therapy. The negative susceptibility vessel sign was defined as an absence of a hypointense signal change within the occluded MCA on gradient-echo imaging. Underlying intracranial atherosclerotic stenosis was determined by conventional angiography. The sensitivity, specificity, predictive values, and accuracy of the negative susceptibility vessel sign for predicting the presence of underlying intracranial atherosclerotic stenosis were assessed.RESULTS:The negative susceptibility vessel sign was identified in 42 (46.1%) of 91 patients, and 18 (19.8%) patients had an underlying intracranial atherosclerotic stenosis responsible for acute ischemic symptoms. The negative susceptibility vessel sign was more frequently observed in patients with intracranial atherosclerotic stenosis than in those without it (100% versus 32.9%, P < .001). In the prediction of an underlying intracranial atherosclerotic stenosis, the negative susceptibility vessel sign had 100% sensitivity, 67.1% specificity, 42.9% positive predictive value, 100% negative predictive value, and an accuracy of 73.6%.CONCLUSIONS:The negative susceptibility vessel sign on gradient-echo MR imaging is a sensitive marker with a high negative predictive value for the presence of an underlying intracranial atherosclerotic stenosis in patients with acute ischemic stroke because of MCA occlusions. The susceptibility vessel sign can be used in decision-making when performing subsequent endovascular revascularization therapy in patients with acute MCA occlusions.

Intracranial atherosclerotic stenosis (ICAS) is one of the most common causes of ischemic stroke worldwide and is particularly prevalent in Asian, black, Hispanic, and Indian populations.^1,2 Underlying ICAS can be a hidden cause of refractory occlusions following modern mechanical thrombectomy procedures, such as stent-based thrombectomy (SBT) or manual aspiration thrombectomy in patients with acute ischemic stroke.³ Thus, preprocedural identification of underlying ICAS in patients with intracranial large-vessel occlusions is of particular importance when performing endovascular stroke therapy.On MR imaging, hypointense signal changes in the occluded MCA on gradient-echo (GRE) sequences have been described as a susceptibility vessel sign (SVS).^4,5 The pathophysiologic basis for this sign in patients with an acute MCA occlusion is a T2-shortening effect of the intracellular deoxyhemoglobin component in erythrocytes within the clot.⁴ Several researchers showed that the SVS was more commonly seen in red blood cell–dominant and mixed clots than in fibrin-dominant clots and could therefore reflect the composition of the clots.⁶ In addition, GRE SVS was observed more frequently in patients with cardiogenic embolic stroke than in those with other stroke subtypes.⁵ In contrast, the absence of the GRE SVS might be associated with a smaller clot burden or a fibrin-dominant clot that forms as a result of rupture of the underlying atherosclerotic plaque. Thus, we hypothesized that the absence of the GRE SVS despite the presence of intracranial large-vessel occlusions could indicate an underlying ICAS in patients with acute ischemic stroke within 6 hours of stroke onset, and we termed this finding the “negative SVS.” Despite the widespread use of MR imaging for the diagnosis of acute ischemic stroke, the role of MR imaging in predicting underlying ICAS before endovascular therapy has not been studied, to our knowledge. In this study, we evaluated the diagnostic value of the negative SVS on GRE imaging for the prediction of underlying ICAS in patients with acute MCA occlusion.     

自体血栓栓塞性兔大脑中动脉脑梗死影像学模型的建立

目的 探索建立兔自体血栓性脑梗死模型的方法 ,观察是否适合使用常规影像学设备研究.材料与方法 家兔40只,对照组10只,实验组30只.颈部正中切口,穿刺颈外动脉,实验组向颈内动脉内注射自体静脉血栓,对照组仅注射生理盐水,3h后行CT灌注(CTP)成像、MR常规及扩散加权、扩散张量成像、数字减影血管造影(DSA)检查.观察手术侧大脑中动脉(MCA)供血区的血流灌注、MR信号及血管是否异常.结果 实验组26只(86.67%)动物可见手术侧MCA区CT灌注异常、MRI异常信号及DSA上手术侧MCA闭塞,其中8只(30.77%,8/26)同时可见大脑前动脉供血区异常灌注及MR信号异常,病理学表现为Evans蓝(EB)异常染色,镜下可见急性脑梗死典型征象.对照组影像学及病理学均无异常.两组CTP灌注参数差异明显(P＜0.01或0.05).结论 自体血栓性兔大脑中动脉梗死模型制作较简单,成功率较高,各种临床型影像学设备均能显示其异常.     

MRI对线栓法制作大鼠脑缺血再灌注模型分组的价值

目的观察线栓法制作单侧大脑中动脉供血区脑缺血再灌注后的MRI表现,确定不同病变模式神经功能评分,评价MRI在模型制作中的价值。材料与方法清洁级健康雄性SD大鼠(200～250g)18只,随机分成两组:脑缺血1.5h再灌注组(MCAo/R)14只,假手术对照组4只。再灌注后24h行神经功能评分,并行MR扫描观察脑缺血范围,计算病变体积。结果4只假手术对照组大鼠MRI上皮质、皮质下结构等脑组织各部均未出现异常信号,神经功能无缺陷,评分为5分。1只MCAo/R组大鼠因出血而被排除。13只MCAo/R组大鼠MRT2WI有两种形态学改变模式:8只表现为病变范围累及皮质下区(尾状核壳核)和皮质,称为cp 组;5只病变范围限于尾状核壳核,称为cp组。测量计算校正后病变脑半球体积比(%HLV),cp组为(14.5±3.9)%,cp 组为(34.7±6.3)%。神经功能评分cp组为4.0±0.7,cp 组为2.4±0.5。两组间病变体积和神经功能评分差异有统计学意义。结论线栓法制作大鼠MCAo再灌注模型MRI显示两种病变模式,且神经功能损害程度存在差异。MRI和神经功能评分的联合使用有助于统一模型的纳入原则和亚型分组。     

Stent Retriever Thrombectomy in Different Thrombus Locations of Anterior Cerebral Circulation

Background

Mechanical thrombectomy (MT) is a safe and efficient treatment for acute ischemic stroke in patients with proximal anterior occlusion and large penumbra. We evaluated the technical and clinical success of MT in relation to the location of the occlusion (internal carotid artery, M1 and M2 segments of the middle cerebral artery).

Methods

We prospectively reviewed 130 patients of whom 105 met the inclusion criteria. Baseline clinical, procedural and imaging variables, technical outcome (TICI, thrombolysis in cerebral infarction), 24 h imaging outcome and three-month clinical outcome (mRS, modified Rankin Scale) were recorded. Differences between the groups were studied with statistical tests according to the type of the variable.

Results

There were 37, 46 and 22 patients in the internal carotid artery (ICA), M1 and M2 groups, respectively. TICI 2b or 3 was achieved in 92 cases (88 %) with a non-significant trend towards a better recanalization outcome in the ICA and M1 groups. Overall, 57 of the 105 patients (55 %) experienced favorable clinical outcome (mRS ≤ 2) with no significant differences between the groups. Excellent outcome (mRS ≤ 1) was seen in 40 patients (39 %) and there proportionally more patients with excellent outcome in the ICA and M1 groups (ICA: 44 %, M1: 41 %, M2: 23 % of patients, p = 0.22).

Conclusions

There were no statistically significant differences in the technical or clinical outcomes between the different sites of occlusion (ICA, M1 or M2). There was a non-significant trend towards achieving excellent clinical outcome (3-month mRS ≤ 1) more often and better recanalization results in the two more proximal locations.

     

3.0T磁共振PWI与DTI在单侧大脑中动脉闭塞中的应用

目的 探讨3.0T磁共振PWI及不同b值DTI在单侧大脑中动脉闭塞中的应用价值.方法 对36例脑常规MRI显示无明显缺血改变的单侧大脑中动脉重度狭窄或闭塞患者行PWI及不同b值(3100～400 s/mm2)DTI成像,以健侧脑组织为对照,分析患侧大脑中动脉供血区脑白质MTT、rCBV、rCBF、TTP及不同b值ADC、FA值变化.结果 患侧脑白质MTT、TTP值较健侧延长(P<0.05), rCBF较健侧减小(P<0.05),患侧rCBV与健侧无统计学差异;b值自3100～1000 s/mm2,患侧ADC值大于健侧(P＜0.05);b值等于700、400 s/mm2时,患、健侧ADC值无统计学差异;b值自3100～1300 s/mm2,患侧FA值小于健侧(P＜0.05),b值自1000～400 s/mm2,两侧FA值无统计学差异.结论 对于常规MRI显示无明显缺血改变的脑动脉闭塞患者,MTT、rCBF、TTP可敏感地检测其灌注异常,高b值较常规b值ADC、FA值能够更敏感地探测其弥散改变.     

银杏内酯B在中脑缺血／再灌后大鼠脑组织分布

目的研究脑缺血再灌损伤是否影响银杏内酯B在脑内处置。方法大鼠大脑中动脉阻断缺血2h,再灌10min后,静脉注射12mg·kg^-1银杏内酯B,于给药后不同时间处死动物,分取用LC／MS方法测定血浆、缺血侧和对照侧脑组织中银杏内酯B浓度。结果缺血侧脑组织中银杏内酯B浓度显著高于对照侧,其AUC约为对照侧的1．88倍。与正常动物比较,脑缺血鼠的血药浓度显著低于正常大鼠,其AUC仅为正常鼠的1／3。结论脑缺血损伤可改变银杏内酯B体内药代动力学行为,增加脑内浓度。     

经颅多普勒超声检测大脑中动脉主干严重狭窄或梗阻性病变的准确性

目的: 评价经颅多普勒超声(TCD)检测大脑中动脉(MCA)主干严重狭窄或梗阻性病变的准确性.材料和方法: 对47例患MCA区脑梗死的患者进行TCD及磁共振血管造影(MRA)检查,以MRA为金标准,以收缩峰值血流速度(PSV)作为动脉狭窄的诊断参数,利用四格表法,分析TCD检测上述病变的准确性.结果: TCD对MCA中度、重度狭窄及梗阻性病变检出的敏感性、特异性、准确性、阳性预期值及阴性预期值分别为85.3%、92.3%、87.2%、96.7%、70.6%;91.7%、91.3%、91.5%、91.7%、91.3%;62.5%、100%、93.6%、100%、92.9%.与MRA完全相符率为80.9%(38/47).结论: 在诊断MCA严重狭窄或梗阻性病变时,TCD与MRA有较好的一致性.     

质子磁共振波谱对大白鼠大脑中动脉线栓模型的连续观察

目的　用氢质子磁共振波谱 (1 HMRS)结合扩散加权成像连续观察大白鼠大脑中动脉线栓 (MCAO)模型2 4h内代谢物的变化规律 ,探讨1 HMRS对脑缺血性损伤和缺血再灌注后脑恢复程度的敏感性。材料与方法　共 2 9只Wistar成年鼠 ,4 .7T超导磁共振仪扫描。术前先取其中 8只作为正常组扫描 ;再将这 2 9只随机分为对照组 (只结扎左侧颈总动脉和颈外动脉 ) 7只 ,永久性大脑中动脉栓塞组 7只 ,缺血 30min再灌组 5只 ,缺血 1h再灌组 5只 ,缺血 2h再灌组 5只。检查完成后取栓塞组和再灌组的鼠脑四氮唑 (TTC)染色。结果　 (1 )在正常组 ,双侧代谢物分布对称 ,胆碱类复合物 (Cho) /肌酸和磷酸肌酸 (CrandPCr)、N 乙酰天门冬氨酸 (NAA) /Cr没有明显的差异 (P >0 .0 5 ) ;在对照组 ,双侧Cho/Cr、NAA/Cr也无显著性差异 (P >0 .0 5 ) ,没有检测到乳酸 (Lac)。 (2 )本实验最早观察到MCAO后 2 2min兴趣区内出现Lac ,DWI为高信号 ,ADC值下降。缺血 2 4h内Lac持续升高 ,以 0 .5hLac水平为基数 ,6h内升高最快 ,增加了 1 .2倍 ;1 2h内增加到 1 .6 2倍 ;2 4h后为 1 .4 7倍 ,稍显降低。相反 ,NAA呈持续下降 ,0 .5～ 1h内变化不明显 ,1 .5± 0 .2h观测到NAA下降 ;2h内下降 (2 3.6± 1 3.1 ) % ;1 2h内下降 (6 8.2± 2 1 .9) % ;2 4h内     

Treatment of an Acute Common Carotid Artery Occlusion Using a Large-Bore Aspiration Thrombectomy Device

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Selective left common carotid arteriography demonstrated complete occlusion by the lobulated appearing thrombus (arrow).