Distribution of artificial cerebral microemboli in stroke patients with patent foramen ovale

Abstract

Objectives: Patent foramen ovale (PFO) is considered as an important risk factor for cerebrovascular diseases. Nevertheless, the relationship between the distribution of highintensity transient signals (HITS), resulting from injection of air mixed with saline and detected by transcranial Doppler (TCD), and clinical cerebrovascular syndromes in these patients has not been investigated.

Methods: Using TCD, we screened 40 patients with stroke or transient ischemic attack (TIA), in whom PFO was proven by transesophageal echocariography (TEE). Of these, 30 patients (75%) with artificially produced HITS either in the middle cerebral artery (MCA) or the basilar artery (BA) were included in the analysis.

Results: Nineteen patients had a stroke or TIA in the carotid territory and 11 patients in the vertebro-basilar territory. HITS were found in the MCA in all 30 patients and in 21 of the 30 patients in the BA. Of the latter, ten patients were in the carotid group and 11 patients were in the veretebro-basilar group, p=0.011.

Conclusion: There is a significant association between the distribution of artificial HITS and the clinical cerebrovascular syndromes.     

Accuracy and Criteria for Localizing Arterial Occlusion With Transcranial Doppler

The authors determined transcranial Doppler (TCD) accuracy for the proximal internal carotid artery (ICA), distal ICA, proximal middle cerebral artery (MCA), distal MCA, anterior cerebral artery (ACA), posterior cerebral artery (PCA), terminal vertebral artery (tVA), and basilar artery (BA) occlusion in cerebral ischemia patients. Detailed diagnostic criteria were prospectively applied for TCD interpretation independent of angiographic findings. Of 320 consecutive patients referred to the neurosonology service with symptoms of cerebral ischemia, 190 (59%) patients also underwent angiography (MRA or DSA). 48 of those 190 patients had angiographic occlusion and 12 of those 48 patients had involvement of multiple vessels. Median time from TCD until angiography was performed was 1 hour (41 patients had angiography before TCD). TCD showed 40 true positive, 8 false negative, 8 false positive, and 134 true negative studies with sensitivity 83.0%, specificity 94.4%, positive predictive value 83.0%, negative predictive value 94.4%, and accuracy 91.6% to determine all sites of occlusion. Sensitivity for each individual occlusion site was: proximal ICA 94%, distaiiCA 81%, MCA 93%, tVA 56%, BA 60%. Specificity ranged from 96% to 98%. TCD is sensitive and specific in determining the site of the arterial occlusion using detailed diagnostic criteria, including proximal ICA and distal MCA lesions. TCD has the highest accuracy for ICA and MCA occlusions. If the results of TCD are normal, there is at least a 94% chance that angiographic studies will be negative. Key words: ultrasound, transcranial Doppler sonography, stroke, occlusion, angiography.     

短暂性脑缺血发作与颅内外血管狭窄的关系

目的 探讨短暂性脑缺血发作(TIA)与颅内外血管狭窄的关系.方法 对130例TIA患者的CT血管成像(CTA)进行分析,观察TIA患者颅内外段血管有无狭窄及TIA发作次数与狭窄数量关系.结果 130例TIA中有血管狭窄94例(占72.3%).颈内动脉系统TIA患者80例中有血管狭窄者55例(占68.75%),颈内动脉颅...     

The mechanism of ischemic stroke in patients with dolichoectatic basilar artery

Basilar artery dolichoectesia (BD) may cause brainstem ischemia by multiple mechanisms, including thrombosis, embolism, occlusion of deep penetrating arteries. The objective of this study was to determine and characterize clinical, imaging findings and hemodynamic mechanisms in patients with cerebrovascular event associated with BD and compare these data with those for patients with BD who did not have stroke. We studied 29 consecutive stroke, two transient ischemic attack (TIA) patients with BD who have been admitted to our stroke unit. We sought the diameter of ectasia, height of the bifurcation, lateral displacement, shape deformities, and blood flow velocity of the basilar artery (BA) by transcranial Doppler. Imaging and hemodynamic findings were compared with those found in a group of 18 patients without stroke or TIA. The main infarct localization was pons, eight (28%) with restricted single lesion, 10 (32%) with multiple lesions involving thalamus, midbrain, posterior cerebral artery (PCA) territory. Patients with BD were more probably to have had stroke fitting a clinical and imaging patterns of multiple infarcts than those with restricted infarct in territories supplied by branches of the BA (60% vs. 40%). Hypertension and atherosclerotic changes of the posterior circulation were more frequent in patients with stroke than those without (P = 0.004 and P = 0.028, respectively), whilst the incidence of other vascular risk factors were not significantly different in two groups. Patients with stroke/TIA had more often low blood flow velocity but not significant in the BA when compared with those for BD patients without cerebrovascular event (71% vs. 39%; P = 0.1). Reduced blood flow velocity in the BA was correlated significantly with distal lesions involving thalamus, midbrain and PCA territory rather than those located in the territory supplied by branches of the BA (P = 0.02). In conclusion, it seems probably that BD may cause vertebrobasilar system ischemia by multiple mechanisms, especially reduced blood flow in the BA and atheromatous changes in the vertebrobasilar system may precipitate thromboembolic stroke.     

Transcranial Doppler waveform blunting in severe extracranial carotid artery stenosis

OBJECTIVE: To investigate the frequency of transcranial Doppler (TCD) waveform blunting in patients with severe (80-99%) symptomatic or asymptomatic extracranial carotid artery stenosis. BACKGROUND: Severe carotid artery stenosis has been identified as a risk factor for ischemic stroke. Blunted Doppler flow waveforms (reduced systolic flow velocity and pulsatility) of the middle cerebral artery (MCA) are inferred to reflect hemodynamic impairment, possibly indicating an increased risk of stroke. METHODS: The 114 consecutive patients (mean age 72.4 years, SD 9.0 years; 37% women; 46 clinically symptomatic, 68 asymptomatic) with 80-99% stenosis of the extracranial internal carotid artery (ICA), as determined by duplex sonography, were examined with TCD. Flow velocities, pulsatility index, and spectral waveforms of the MCA distal to the ICA stenosis were assessed blinded to the clinical status of the ICA: Doppler waveform blunting was defined as loss of the characteristic systolic peak. Odds ratios with 95% confidence intervals and chi(2) statistics were used to describe the association between waveform blunting and the symptomatic status of the ICA stenosis. RESULTS: Among symptomatic patients, 23 (50%) had completed strokes, and a further 23 (50%) had transient neurologic deficits in the territory of the stenotic ICA. Blunted spectral waveform was found in 37 (80%, 95% CI 68-92%) of the symptomatic and 25 (37%; 95% CI 25-49%) of the asymptomatic patients. Symptomatic patients had significantly increased odds of having blunted TCD waveforms (OR 7.5, 95% CI 3.1-18.1, p < 0.001). CONCLUSIONS: Our findings suggest that TCD waveform blunting in the MCA as here described may be an additional risk factor in the setting of severe extracranial carotid artery stenosis. A prospectively designed study to confirm our results seems warranted.     

Size of PFO and amount of microembolic signals in patients with ischaemic stroke or TIA

Background and purpose:  The inter-relation between the size of patent foramen ovale (PFO) by transesophageal echocardiography (TEE) and the amount of microembolic signals (MES) on transcranial doppler (TCD) is still not determined.
Methods:  The study group comprised of 104 patients with first-ever ischaemic stroke or transient ischemic attack (TIA). Three groups were formed according to the amount of MES on TCD: a small amount of MES (0–10 MES); a moderate amount of MES (countable MES higher than 10); and multiple MES.
Results:  According to TEE, there were 52 patients (50%) with a small PFO, 37 patients (35.6%) with a moderate PFO, and 15 patients (14.4%) with a large PFO. There were 48 patients (46.1%) with a small amount of MES, 34 patients (32.7%) with a moderate amount of MES, and 22 patients (21.1%) with multiple MES on TCD. A strong relationship between the size of the PFO on TEE and the amount of MES on contrast transcranial Doppler was found ( P  < 0.0001), such that the larger the PFO on TEE, the greater the amount of MES on TCD.
Conclusions:  There is a high correlation between the size of the PFO on TEE and the amount of MES on TCD in stroke and TIA patients.     

Recurrent cerebrovascular ischaemic events in patients with interatrial septal abnormalities: a follow-up study

Abstract The aim of this study was to evaluate the risk of recurrent ischaemic cerebrovascular events (stroke or transient ischaemic attack (TIA)) in patients with patent foramen ovale (PFO) or atrial septal aneurysm (ASA) treated with different therapeutic regimens. We enrolled 86 patients aged 18–60 years with an unexplained ischaemic stroke or TIA referred to our inpatient department in the period May 1994–December 1999. Follow-up lasted until April 2003. Patients were excluded if the stroke or TIA was related to large-artery atherosclerosis, small artery occlusion, major cardiac sources of embolism or other uncommon causes. During a follow-up (mean±SD) of 64.1±28.8 months (range 8.1–105.6) a recurrent ischaemic cerebrovascular event occurred in 11/86 patients (12.8%) (5 TIA and 6 strokes). Eight events (4 TIA, 4 strokes) occurred in the 59 patients with PFO alone, three (1 TIA, 2 strokes) in the 21 with PFO plus ASA and none in the 6 patients with ASA alone. In the overall population the cumulative risk of recurrent stroke/TIA was 1.2% at 2 years, 5.5% at 4 years, 7.6% at 6 years and 23.6% at 8 years, and was similar in patients with PFO alone vs. patients with PFO plus ASA (9.0% vs. 6.1% at 6 years, 26.0% vs. 23.1% at 8 years; p>0.05). Nine cerebral ischaemic events (4 TIA, 5 strokes) occurred in the 48 patients treated with antiplatelet drugs (7 in patients with PFO, 2 in patients with PFO plus ASA), and two (1 TIA, 1 stroke) in the 17 patients treated with oral anticoagulants (1 with PFO, 1 with PFO plus ASA). No events occurred in patients submitted to transcatheteral closure.     

经颅多普勒超声对短暂性脑缺血发作的诊断价值

目的：评价经颅多普勒超声（TCD）对脑底动脉狭窄或闭塞所致短暂性脑缺血性发作（TIA）的诊断价值。方法：50例TIA患者进行常规TCD检查,发现39例为颅底单支或多支动脉狭窄或闭塞（78％）,11例正常（22％）,并对其进行了DSA或MRA证实。通过颅底动脉TCD检测,确定狭窄或闭塞血管的形态和血流动力学改变,并与血管造影对比。结果：血管造影显示单支大脑中动脉狭窄17支,双侧双支血管狭窄47支及虹吸部闭塞1支,;TCD综合分析后发现单支狭窄17支,多支血管狭窄64支及闭塞1支,符合率78．7％,结论：TCD检测对于诊断TIA有重要临床意义,尤其对中－重度狭窄或闭塞的诊断准确性较高,单支节段性狭窄准确性更高。     

Cryptogenic stroke and patent foramen ovale: clinical clues to paradoxical embolism

BACKGROUND: Patent foramen ovale (PFO) is an independent risk factor for cerebral infarction. Since ~25% of the population have a PFO, the simple association of PFO with stroke is not enough to establish the diagnosis of paradoxical embolism. We evaluated possible clinical clues to the diagnosis of paradoxical embolism. METHODS: Among patients with cryptogenic ischemic stroke (CS) who were investigated for a right-to-left shunt (RLS), we compared clinical, coagulation and biochemical parameters in patients with PFO versus without PFO. RESULTS: Among 1689 new patients referred for TIA/non-disabling stroke between 2001 and 2007, 175 with cryptogenic stroke (CS) were investigated for RLS by transcranial Doppler (TCD) bubble studies; 89 (5.5%) with positive TCD had a PFO confirmed by TEE. In multivariate logistic regression, a history of DVT or pulmonary embolism (OR, 4.39; 95% CI, 1.23-15.69; p=0.023), prolonged travel (OR, 8.77; 95% CI, 1.775-43.3; p=0.008) , migraine (OR, 2.30: 95% CI, 1.07-4.92; p=0.031), a Valsalva maneuver preceding the onset of focal neurological symptoms (OR, 3.33; 95% CI, 1.15-9.64; p=0.026) and waking up with stroke/TIA (OR, 4.53, 95% CI, 1.26-16.2; p=0.018) were independently associated with PFO-associated cerebrovascular events. Patients with PFO had higher plasma total homocysteine levels than patients without PFO (8.9+/-3 versus 7.9+/-2.6 micromol/L respectively; p=0.021). CONCLUSIONS: A history of DVT or pulmonary embolism, migraine, recent prolonged travel, sleep apnea, waking up with TIA or stroke or a Valsalva maneuver preceding the event are clinical clues to the diagnosis of paradoxical embolism among patients with CS.     

Atherosclerotic disease of the middle cerebral artery

Three hundred and fifty-two patients with atherosclerotic middle cerebral artery stenosis (MCAS, 53%) or occlusion (MCAO, 47%) have been systematically studied. The study involved all patients entered into the EC/IC Bypass Study with isolated MCA disease or a tandem lesion predominating in the MCA ipsilateral to the ischemic events (18 patients with a tandem lesion of greater magnitude in the internal carotid artery were not included). The Asian patients represented 58% of all Asians entered into the EC/IC Bypass Study, whereas the white patients represented 18% of all whites and the black patients 34% of all blacks. Isolated TIAs were less frequent in MCAO (12%) than in MCAS (34%). Warning TIAs before a stroke occurred in one third of the cases. Presentation with stroke or isolated TIA was not influenced by sex, age, level of MCA obstruction, collateral circulation nor associated carotid disease. In MCAS, no major difference in presentation was found between severe and moderate stenosis. Pure motor hemiparesis occurred in 15% and pure sensory stroke in 2% of the patients with stroke and 30% of the MCA territory infarcts were small and limited to the lenticulocapsular area, confirming that so-called lacunar infarcts may be due to large vessel disease. During follow-up (42 months) of 164 medically-treated patients, further cerebrovascular events (TIA and stroke) occurred in 11.7% of the patients per year. In MCAO the stroke rate was 10.1% per patient-year and the ipsilateral infarct rate was 7.1% per patient-year. In MCAS, the stroke rate was 9.5% per patient-year and the ipsilateral stroke rate was 7.8% per patient-year.(ABSTRACT TRUNCATED AT 250 WORDS)     

Microembolic signals and intraoperative stroke in carotid endarterectomy

Objectives – Microembolic signals (high-intensity transient signals, HITS) detected by means of transcranial Doppler sonography (TCD) may be relevant for intraoperative strokes in carotid endarterectomy (CEA). Material and methods – An intraoperative HITS detection study was performed on 77 patients (63 men, 14 women, mean age±SD, 64±8 years) with a total of 81 CEAs. Using the Scandinavian Stroke Scale the patients were clinically examined by a neurologist preoperatively and postoperatively within 6 h. A deterioration of the Scandinavian Stroke Scale was considered an intraoperative stroke if persisting longer than 24 h. Cranial computed tomography (CT scan) was performed preoperatively and 3 to 5 days postoperatively. By means of TCD total HITS count and mean blood velocity changes, for shunting, were recorded sufficiently in the middle cerebral artery in 79 CEAs. Results – HITS were significantly more frequent in symptomatic [ n =53; HITS: median, 15 (range 1–159)] than in asymptomatic stenoses [ n =26; HITS: 6.5 (0–41); P < 0.001]. An intraoperative stroke in the hemisphere ipsilateral to the operation occurred in eight of the 81 CEAs. On postoperative CT scans, five of the eight strokes showed new corresponding territorial infarctions. In the three strokes without new CT lesions, the mean blood velocity changes after clamping indicated normal cerebral perfusion. Total HITS count was significantly higher in procedures with intraoperative strokes [ n =8; HITS: 33 (11–159)] than in the uncomplicated [ n =71; HITS: 10 (0–62); P =0.002]. No stroke occurred in 37 CEAs with 10 or less HITS, but eight in 42 CEAs with 11 or more HITS [ P =0.006; relative risk 1.23 (95% confidence interval: 1.06 to 1.43)]. Conclusion – Microembolism seems clinically relevant in carotid endarterectomy. Asymptomatic patients may run a lower risk of intraoperative embolization.     

Outcome of patients with cryptogenic stroke and patent foramen ovale

OBJECTIVES: The aim was to estimate the recurrence rate and to define subgroups at increased risk for recurrent cerebral ischaemia in patients with patent foramen ovale (PFO) and so called cryptogenic stroke due to paradoxical embolism. METHODS: Patent foramen ovale was diagnosed in 318 patients with otherwise unexplained ischaemic stroke or transient ischaemic attack (TIA). One hundred and fifty nine were treated medically (oral anticoagulation 79, platelet inhibitors 80) and represent the study population. The remaining 159 patients underwent endovascular or surgical closure of the PFO and are not part of this study. RESULTS: Mean age was 50.7 (SD 13.5) years. The event leading to the diagnosis of PFO was a TIA in 38 patients (23.9%), an ischaemic stroke in 119 (74.8%), and an amaurosis fugax in two patients (1.3%). Forty four patients (27.7%) had experienced multiple cerebrovascular ischaemic events before the diagnosis of the PFO. During mean follow up of 29 (SD 23) months 21 patients (13.4%) had a recurrent cerebrovascular event (seven strokes and 14 TIAs). The average annual rate of recurrent strokes was 1.8% and that of recurrent strokes or TIAs was 5.5%. When patients with PFO with multiple cerebrovascular events before the diagnosis of the PFO were analyzed separately, the average annual rates of recurrent cerebral ischaemia were 3.6% for recurrent strokes and 9.9% for recurrent strokes or TIAs. These rates were significantly higher than in patients with first ever stroke or TIA (p=0.02). CONCLUSIONS: The study confirms a risk of stroke recurrence that is similar to the rates of previously published series of patients with PFO and cryptogenic strokes. Patients with more than one previous event were at increased risk of recurrent cerebral ischaemia.     

Arterial pulsatility as an index of cerebral microangiopathy in diabetes

BACKGROUND AND PURPOSE: This study was designed to evaluate cerebral hemodynamic changes related to diabetes mellitus (DM) with transcranial Doppler ultrasonography (TCD). METHODS: We measured the flow velocities and the Gosling pulsatility index (PI) of the middle cerebral artery (MCA), extracranial internal carotid artery (ICA), and basilar artery (BA) in 56 stroke-free, normotensive patients with type 2 DM and 70 age- and gender-matched healthy volunteers. Patients were divided into 2 groups according to the presence of microvascular complications such as retinopathy, nephropathy, and neuropathy. RESULTS: Patients showed slightly lower hematocrit and higher serum fibrinogen levels than control subjects, but other clinical profiles, including stroke risk factors except for diabetes, were comparable between patients and controls. The flow velocity of the ICA but not the MCA and BA in patients regardless of the complication was significantly higher than that in controls. The PIs of the MCA and ICA were significantly higher in patients with complication than those without complication, as well as in controls. The PI of the BA was also significantly higher, even in patients without complication, than in controls. The PIs of the MCA and ICA but not the BA were closely correlated with the duration of DM (r(2)=0.46 and 0.34, respectively). CONCLUSIONS: This study defines TCD findings of diabetes-related cerebral hemodynamic changes and suggests that the PI reflects microangiopathic changes of cerebral vessels.     

Specific transcranial Doppler flow findings related to the presence and site of arterial occlusion

BACKGROUND AND PURPOSE: Transcranial Doppler (TCD) can localize arterial occlusion in stroke patients. Our aim was to evaluate the frequency of specific TCD flow findings with different sites of arterial occlusion. METHODS: Using a standard insonation protocol, we prospectively evaluated the frequency of specific TCD findings in patients with or without proximal extracranial or intracranial occlusion determined by digital subtraction or MR angiography. RESULTS: Of 190 consecutive patients studied, angiography showed occlusion in 48 patients. With proximal internal carotid artery (ICA) occlusion, TCD showed abnormal middle cerebral artery (MCA) waveforms (AMCAW) in 66.7%, reversed ophthalmic artery (OA) in 70.6%, anterior cross-filling via anterior communicating artery (ACoA) in 78.6%, posterior communicating artery (PCoA) in 71.4%, and contralateral compensatory velocity increase (CVI) in 84.6% of patients. With distal ICA occlusion, TCD showed AMCAW in 88.9%, OA in 16.7%, ACoA in 50%, PCoA in 60%, and CVI in 88.9% of patients. With MCA occlusion, TCD showed AMCAW in 100%, OA in 23.5%, ACoA in 31.3%, PCoA in 23.1%, and CVI in 62.5%. With no anterior circulation occlusion at angiography, TCD showed these parameters in 1.8% to 17. 9%, chi(2) P相似文献   

Transcranial Doppler Markers of Diffusion-Perfusion Mismatch

BACKGROUND AND PURPOSE: During the evaluation of acute ischemic stroke with diffusion- and perfusion-weighted magnetic resonance imaging (DWI and PWI, respectively), the presence of salvageable brain tissue is suggested by the occurrence of a perfusion-diffusion "mismatch." DWI and PWI, however, are not universally available and have inherent inconveniences, which justify a search for practical diagnostic alternatives. The purpose of this study is to investigate whether there are transcranial Doppler (TCD) markers of mismatch. METHODS: Retrospective analysis of 22 patients with acute ischemic stroke affecting the middle cerebral artery (MCA) territory, who had a TCD performed within 24 hours of magnetic resonance imaging (MRI) with DWI and PWI. RESULTS: MRI and TCD were performed on average 10.8 +/- 9.2 hours apart. Time from symptom onset to MRI and TCD completion were 1.6 +/- 1.6 and 2 +/- 1.9 days, respectively. MCA and intracranial internal carotid artery (ICA) cerebral blood flow velocity (CBFV) asymmetry, together with a large ICA-to-MCA gradient, were associated with the presence of mismatch. The combined use of 2 TCD parameters (MCA CBFV asymmetry of > or = 30% and ICA-to-MCA gradient > or = 20 cm/sec) had a sensitivity of 75%, specificity of 80%, positive predictive value of 82%, and negative predictive value of 73% at detecting mismatch cases. CONCLUSIONS: Diffusion-perfusion mismatch appears to be associated with interhemispheric asymmetry between MCA and ICA CBFVs, and a large CBFV gradient between the ICA and MCA on the affected side. Prospective studies are required to verify these observations and to determine whether TCD can be used to follow patients with mismatch.     

Microembolic signals and clinical outcome in patients with acute stroke – a prospective study

The occurrence of microembolic signals (MES) in patients with transient ischemic attack (TIA) or stroke has already been described; the influence of the time interval between onset of symptoms and transcranial Doppler monitoring (TCD) on the MES rate or MES prevalence and the possible prognostic value of the early detected MES rate on the outcome of TIA or stroke symptoms in a 3 month interval are discussed. In a prospective study we evaluated 61 patients consecutively admitted to our stroke unit after their first ischemic neurological deficit involving the vascular territory of MCA and/or ACA. All of the patients underwent a 30-minute bilateral transcranial Doppler monitoring of their MCAs for the identification of MES. Monitoring was performed within 12.3 + -9.3 (average mean + -SD) hours of stroke onset for the first time, the second time 48 hours after first TCD monitoring. Prognosis for the recovery of neurological deficits was evaluated by using the Barthel index (BI) and Scandinavian Stroke Scale (SSS) at the time of admission of the patient to the stroke unit, and with Barthel indices after one month and after 3 months. As a result, 56% of all patients showed MES in at least one of the two registrations. MES were recorded not only on the symptomatic side. The MES prevalence between both TCD monitorings was significantly different (total MES prevalence: 1st TCD: 26 patients: 2nd TCD: 13 patients; p < 0.04; ipsilateral MES prevalence: 1st TCD: 19 patients; 2nd TCD: 9 patients; p < 0.01). The regression analysis showed a significant influence of the total MES rate on both neurological scores at admission (SSS: 0.03; Barthel index: 0.04), but not for the Barthel scores after one and three months. In conclusion, we found an influence of the time interval between onset of neurological symptoms of TIA or stroke on the MES rate and the prevalence of MES. The prevalence of MES or the MES rate, found after a short time interval to the onset of symptoms, did not have a prognostic value on the outcome of neurological deficits up to a three month follow-up.     

A transcranial Doppler study of basilar hemodynamics in progressive carotid artery disease

Abstract

In carotid artery disease (CAD) the basilar artery (BA) may act as an important intracranial collateral to supply hypoperfused middle cerebral artery (MCA) territories. Transcranial Doppler studies were performed to study the dependency between BA hemodynamics in relation to the MCA perfusion status. BA and MCA blood flow velocities (BFV), pulsatility indices (API) and cerebrovascular reactivity (CVR) were assessed in 40 patients with a progressive MCA hypoperfusion due to progressive CAD. All patients had patent cervical segments of their vertebral arteries with an antegrade vertebral flow profile. Duplex studies were performed to diagnose the severi~ of CAD. Hypoperfusion of the MCA was diagnosed by the degree of vasoparalysi assessed by a Diamox procedure. Analysis showed that the basilar BFV significantly increased in cases of progressive CAD; the basilar PI decreased but the basilar CVR remained unchanged. However, in cases of bilateral hemodynamic significant CAD and bilateral exhausted CVR in the MCA territory, the basilar artery did not exhibit an increase of BFVs or a decrease of the basilar PI, but the basilar CVR showed a significant decrease. Basilar artery CVR is not impaired if this artery has a function as intracranial collateral in CAD. However in cases of bilateral hypoperfused MeA territories the basilar artery does not function as a collateral pathway. The basilar CVR declines under these circumstances which merely reflects the exhausted hemodynamics in the anterior/posterior borderzones. This situation might lead to an increased stroke risk in the distal basilar supply zones. [Neural Res 1998; 20: 493-498]     

Centrum ovale infarcts: subcortical infarction in the superficial territory of the middle cerebral artery.

The centrum ovale, which contains the core of the hemispheric white matter, receives its blood supply from the superficial (pial) middle cerebral artery (MCA) system through perforating medullary branches (MBs), which course toward the lateral ventricles. Though vascular changes in the centrum ovale have been emphasized in dementia, stroke from acute infarction in the centrum ovale is less well documented. We studied 36 patients with infarct limited to MB territory, without involvement of the lenticulostriate territory. Ten patients had a large infarct, associated with severe disease of the ipsilateral carotid artery and with neurologic-neuropsychological impairment not different from that of large MCA infarcts. In 26 patients, the infarct was small and round or ovoid, and was associated with hypertension or diabetes and with "lacunar syndromes," usually of progressive onset. These findings show that two forms of centrum ovale infarcts can be delineated according to infarct size and shape, clinical picture, risk factors, and associated vascular disease. We propose to classify subcortical infarcts in the carotid system into four main territory groups: (1) deep perforator territory (from the MCA trunk, carotid siphon, anterior choroidal artery, anterior cerebral artery trunk, Heubner's artery, and posterior communicating artery); (2) perforating MB territory (from the superficial MCA branches); (3) junctional (territory between 1 and 2); and (4) combined territories.     

Basilar and distal vertebral artery stenosis: long-term follow-up

Forty-four patients with greater than or equal to 50% stenosis of a distal vertebral artery (VA) and/or basilar artery (BA) were followed up for an average of 6.1 years. Angiography was performed for definite vertebrobasilar (VB) transient ischemic attacks (TIA) in 19 (43%), for VB infarcts in 13 (30%) and for non localizing symptoms in 12 (27%). Stenosis in the BA with or without VA involvement was present in 28 patients (64%), while 16 patients (36%) had occlusive disease in one or both distal VA sparing the BA. In follow up, 7 patients (16%) had definite VB TIA and 3 patients had possible VB TIA. Eight patients (18%) sustained a stroke, 5 of which were in the VB territory. The observed stroke rate was 17 times the expected rate for a matched normal population. Eight patients died during follow up, three patients due to stroke (2 brainstem infarctions, one intraventricular hemorrhage). The observed 5 year survival rate was 78% compared to 90% in a matched normal population. In comparing this data with our previous study of 93 patients with proximal VA occlusive disease, distal VB occlusive disease appears to carry a higher risk for brainstem ischemia.     

短暂性脑缺血发作急性期进展成脑梗死的临床因素分析

目的探讨颈内动脉系统短暂性脑缺血发作(TIA)急性期(7d内)进展成脑梗死的危险因素方法对急性期(7d内)的颈内动脉系统TIA患者及有颈内动脉系统TIA发作7d内进展成脑梗死的患者共143例的临床资料进行回顾性分析。结果TIA发作时间延长>30min,TIA发作间期测量收缩压偏高≥160mmHg与TIA急性期(7d内)进展成脑梗死显著相关(P<0.05)。结论发作持续时间>30min,TIA发作间期测量收缩压偏高(≥160mmHg)是急性期(7d内)TIA进展成脑梗死的危险因素。