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1.
IEEE Trans Neural Syst Rehabil Eng ; 27(2): 304-313, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30596581

RESUMO

High-definition transcranial direct current stimulation (HD-tDCS) is a potential neuromodulation apparatus for stroke rehabilitation. However, its modulatory effects in stroke subjects is still not well understood. In this paper, the offline modulatory effects of HD-tDCS on the ipsilesional primary motor cortex were investigated by performing wrist isometric contraction tasks before and after HD-tDCS in eleven unilateral chronic stroke subjects using a synchronized HD-tDCS and electroencephalogram/electromyography measurement system. This paper is a randomized, single blinded, and sham-controlled crossover study. Each subject randomly received three HD-tDCS (anode, cathode, and sham) with at least one-week washout period. Online feedback-guided medium-level wrist isometric contraction tasks were conducted for the affected upper limbs before stimulation and 10, 30, and 50 min after the end of 10-min 1-mA HD-tDCS. The characteristics of corticomuscular coherence (CMC), cortical oscillation power spectral density, and power spectral entropy were analyzed during tasks and compared across all sessions and stimulation conditions. Anode HD-tDCS induced significant CMC changes in stroke subjects, while cathode and sham stimulation did not induce significant CMC changes. The largest neuromodulation effects were observed at 10 min immediately after anodal HD-tDCS.

3.
Stroke ; 49(11): 2767-2769, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30355206

RESUMO

Background and Purpose- Intracranial artery calcification detected by computed tomography is associated with ischemic stroke as an indicator of intracranial atherosclerosis. However, little is known about its histopathology. This study aimed to explore the intracranial calcification patterns and their associations with atherosclerotic plaques. Methods- We recruited 32 adult autopsy cases to assess the calcification patterns and distributions in the middle cerebral artery, vertebral artery, and basilar artery. The relationships of calcification patterns with plaque phenotype and luminal stenosis were evaluated. The calcification patterns on computed tomography were correlated with that on histology. Results- Visible calcifications were detected within 37 (39%) segments, including 25 segments with intimal calcification, 6 segments with internal elastic lamina calcification, 3 segments with adventitial calcification, and 3 segments with concurrent calcification. Calcification occurred more often in the vertebral artery (51%), followed by the middle cerebral artery (35%) and basilar artery (14%; P<0.01 for vertebral artery versus basilar artery). Internal elastic lamina calcification was predominantly detected in the vertebral artery (7/8, 88%). All of the 27 (100%) intimal calcifications were present in the progressive atherosclerotic lesions ( P<0.001), whereas only 3/8 (38%) internal elastic lamina calcifications and 4/6 (67%) adventitial calcifications were associated with progressive plaques. Arteries with intimal calcification had more severe luminal stenosis than those without (46% versus 21%; P<0.001). Conclusions- Our histological findings indicate that the presence of intracranial artery calcification has 3 patterns, including intimal, internal elastic lamina, and adventitial calcifications. But only intimal calcification is related with progressive atherosclerotic lesions, indicative of a proxy for intracranial atherosclerosis.

4.
J Stroke ; 20(3): 342-349, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30309229

RESUMO

BACKGROUND AND PURPOSE: Vasa vasorum (VV) have been believed to be rare or non-existent in small-caliber intracranial arteries. In a series of human cerebral artery specimens, we identified and examined the distribution of VV in association with co-existing intracranial atherosclerosis. METHODS: We obtained cerebral artery specimens from 32 consecutive autopsies of subjects aged 45 years or above. We scrutinized middle cerebral artery (MCA), vertebral artery (VA), and basilar artery (BA) for the presence of adventitial VV. We described the distribution of VV, and the characteristics of co-existing atherosclerotic lesions. RESULTS: Among 157 intracranial arteries, adventitial VV were present in 74 of the 157 specimens (47%), involving MCA (n=13, 18%), BA (n=14, 19%), and VA (n=47, 64%). Although qualitatively these 74 adventitial VV distributed similarly in arteries with or without atherosclerotic lesions (disease-free arteries n=4/8; arteries of pre-atherosclerosis n=17/42; and arteries of progressive atherosclerosis n=53/107), the presence of adventitial VV in intracranial VA was associated with a heavier plaque load (1.72±1.66 mm2 vs. 0.40±0.32 mm2, P<0.001), severer luminal stenosis (25%±21% vs. 12%±9%, P=0.002), higher rate of concentric lesions (79% vs. 36%, P=0.002), and denser intraplaque calcification (44% vs. 0%, P=0.003). Histologically, intracranial VA with VV had a larger diameter (3.40±0.79 mm vs. 2.34±0.58 mm, P<0.001), thicker arterial wall (0.31±0.13 mm vs. 0.23±0.06 mm, P=0.002), and a larger intima-media (0.19±0.09 mm vs. 0.13± 0.04 mm, P=0.003) than VA without VV. CONCLUSION: s Our study demonstrated the distribution of adventitial VV within brain vasculature and association between vertebral VV and progressive atherosclerotic lesions with a heavier plaque load and denser intraplaque calcification.

6.
Neurosci Lett ; 2018 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-29476796

RESUMO

Transcranial non-invasive brain stimulation (NIBS) has been widely applied in basic research and clinical intervention in the past few decades. It modulates cortical excitability through varies combinations of current form, stimulation position, strength, frequency, duration and intervals. In this review, protocols of different types of NIBS and their aftereffect are introduced. Moreover, evidences in physiology, pharmacology and behavior response are provided to support the effects of NIBS are plasticity-like effects because of their common mechanisms of synaptic plasticity. This is further confirmed by experiments on small animals at the cellular level.

7.
J Stroke Cerebrovasc Dis ; 26(7): 1487-1492, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28396189

RESUMO

BACKGROUND AND PURPOSE: External counterpulsation (ECP) is a noninvasive method used to augment cerebral perfusion in ischemic stroke. However, the response of beat-to-beat heart rate variability (HRV) in patients with ischemic stroke during ECP remains unknown. METHODS: Forty-eight patients with unilateral ischemic stroke at the subacute stage and 14 healthy controls were recruited. Beat-to-beat heart rate before, during, and after ECP was monitored. The frequency components of HRV were calculated using power spectral analysis. Very low frequency (VLF; <.04 Hz), low frequency (LF; .04-.15 Hz), high frequency (HF; .15-.40 Hz), total power spectral density (TP; <.40 Hz), and LF/HF ratio were calculated. RESULTS: In stroke patients, although there were no statistical differences in all of the HRV components, the HRV at VLF showed a trend of increase during ECP compared with baseline in the left-sided stroke patients (P = .083). After ECP, the HRV at LF and TP remained higher than baseline in the right-sided stroke patients (LF, 209.4 versus 117.9, P = .050; TP, 1275.6 versus 390.2, P = .017, respectively). Besides, the HRV at TP also increased after ECP compared with baseline in the left-sided stroke patients (563.0 versus 298.3, P = .029). CONCLUSIONS: Irrespective of the side of the ischemia, patients showed an increased beat-to-beat HRV after ECP. Additionally, sympathetic and parasympathetic cardiac modulations were increased after ECP in patients after right-sided subacute stroke.


Assuntos
Isquemia Encefálica/terapia , Circulação Cerebrovascular , Contrapulsação , Frequência Cardíaca , Coração/inervação , Acidente Vascular Cerebral/terapia , Idoso , Isquemia Encefálica/diagnóstico , Isquemia Encefálica/fisiopatologia , Contrapulsação/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sistema Nervoso Parassimpático/fisiopatologia , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Fatores de Tempo , Resultado do Tratamento
8.
J Stroke Cerebrovasc Dis ; 26(2): 442-447, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27818028

RESUMO

BACKGROUND: Intracranial arterial calcification (ICAC) is frequently detected on head computed tomography and has been found to be associated with ischemic stroke by recent clinical studies. AIMS: Based on a hospital-based study, we aimed to compare the occurrence of cerebral microembolic signals (MES) among stroke patients with different degrees of ICAC, which may indicate the potential mechanisms linking ICAC and ischemic stroke in intracranial atherosclerosis patients. METHODS: This is a post-hoc analysis of our previous clinical study in 2005-2007, recruiting consecutive ischemic stroke patients with middle cerebral artery territory infarctions and good temporal window for MES monitoring. The degrees of ICAC in the Circle of Willis, especially calcification in the ipsilateral intracranial internal carotid artery (iICA), were evaluated both qualitatively and quantitatively on unenhanced head computed tomography. RESULTS: Among the 68 recruited patients, MES was detected in 26 patients (38.24%). The overall degree of ICAC in the Circle of Willis was similar between patients with and without MES. For calcification in ipsilateral iICA, the presence of MES was more frequent in the high extent group (widest arc of calcification ≥90°) than in the low extent group (54.2% versus 29.5%, P = .046). Logistic regression found that a high extent ipsilateral iICA calcification was an independent risk factor of MES (odds ratio: 3.134; 95% confidence interval, 1.029-9.543; P = .044). CONCLUSIONS: MES is frequently detected in patients with a high extent of ipsilateral iICA calcification, which suggests that a high extent of iICA calcification indicates artery vulnerability and accounts for the occurrence of microemboli in the corresponding artery.


Assuntos
Doenças das Artérias Carótidas/diagnóstico por imagem , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Arteriosclerose Intracraniana/diagnóstico por imagem , Embolia Intracraniana/diagnóstico por imagem , Calcificação Vascular/diagnóstico por imagem , Doenças das Artérias Carótidas/complicações , Feminino , Humanos , Infarto da Artéria Cerebral Média/complicações , Arteriosclerose Intracraniana/complicações , Embolia Intracraniana/etiologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X , Calcificação Vascular/complicações
9.
Med Hypotheses ; 93: 140-2, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27372874

RESUMO

Upper limb weakness and incoordination is a common disability following ischemic stroke. Previous studies have showed that the single application of external counterpulsation (ECP) and intermittent theta burst stimulation (iTBS) can effectively enhance the cortical motor excitability and facilitate recovery. However, it remains uncertain if sequential application of these therapies would further augment the recovery. We hypothesize a synergistic effect of ECP followed by iTBS to upper limb function may happen through improvements in both cerebral perfusion and neuron excitability.


Assuntos
Contrapulsação/métodos , Córtex Motor/fisiologia , Recuperação de Função Fisiológica/fisiologia , Reabilitação do Acidente Vascular Cerebral/métodos , Acidente Vascular Cerebral/fisiopatologia , Animais , Velocidade do Fluxo Sanguíneo , Circulação Cerebrovascular , Lateralidade Funcional/fisiologia , Hemodinâmica , Humanos , Isquemia/patologia , Destreza Motora , Neurônios/metabolismo , Ritmo Teta/fisiologia , Estimulação Magnética Transcraniana
10.
J Clin Neurol ; 12(3): 308-15, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27095525

RESUMO

BACKGROUND AND PURPOSE: External counterpulsation (ECP) is a noninvasive method used to enhance cerebral perfusion by elevating the blood pressure in ischemic stroke. However, the response of the beat-to-beat blood pressure variability (BPV) in ischemic stroke patients during ECP remains unknown. METHODS: We enrolled recent ischemic stroke patients and healthy controls. Changes in the blood flow velocities in bilateral middle cerebral arteries and the continuous beat-to-beat blood pressure before, during, and after ECP were monitored. Power spectral analysis revealed that the BPV included oscillations at very low frequency (VLF; <0.04 Hz), low frequency (LF; 0.04-0.15 Hz), and high frequency (HF; 0.15-0.40 Hz), and the total power spectral density (TP; <0.40 Hz) and LF/HF ratio were calculated. RESULTS: We found that ECP significantly increased the systolic and diastolic blood pressures in both stroke patients and controls. ECP decreased markedly the systolic and diastolic BPVs at VLF and LF and the TP, and the diastolic BPV at HF when compared with baseline. The decreases in diastolic and systolic BPV reached 37.56% and 23.20%, respectively, at VLF, 21.15% and 12.19% at LF, 8.76% and 16.59% at HF, and 31.92% and 23.62% for the total TP in stroke patients, which did not differ from those in healthy controls. The change in flow velocity on the contralateral side was positively correlated with the total TP systolic BPV change induced by ECP (r=0.312, p=0.035). CONCLUSIONS: ECP reduces the beat-to-beat BPV when increasing the blood pressure and cerebral blood flow velocity in ischemic stroke patients. ECP might be able to improve the clinical outcome by decreasing the beat-to-beat BPV in stroke patients, and this should be explored further in future studies.

11.
Oxf Med Case Reports ; 2015(10): 333-6, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26568838

RESUMO

Symptomatic vertebrobasilar artery (VBA) stenosis has a poor prognosis. Intravascular stents provide a new therapeutic approach, but the long-term outcome of stenting compared with medical outcome is controversial. External counterpulsation (ECP) is a noninvasive method to improve perfusion of vital organs. We report two cases of this combination with ECP treatment in addition to receiving endovascular stenting. Two patients experienced posterior ischemic stroke. Digital subtraction angiography revealed a severe basilar or vertebral artery stenosis. Computed tomographic perfusion revealed significantly decreased perfusion of posterior artery territories. Both of them underwent combined ECP treatment and endovascular stenting of the stenosed basilar or vertebral artery, without recurrent stroke within 30 days after stenting. The two patients were independent (modified Rankin scale ≤2) at the 12-month follow-up time. Combined ECP treatment and endovascular stent placement may be effective and safe for patients with symptomatic VBA stenosis who failed aggressive medical treatment.

12.
BMJ Open ; 5(9): e009233, 2015 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-26351195

RESUMO

OBJECTIVE: External counterpulsation (ECP) is a non-invasive method used to augment cerebral blood flow of patients with ischaemic stroke via induced hypertension. We aimed to explore the correlation between the cerebral blood flow augmentation effects induced by ECP and clinical outcome after acute ischaemic stroke. METHODS: We retrospectively analysed our ECP registry of patients with ischaemic stroke who were enrolled within 7 days after stroke onset. Bilateral middle cerebral arteries of patients were monitored using transcranial Doppler (TCD). Flow velocity changes before, during and after ECP were, respectively, recorded for 3 min. The cerebral augmentation index (CAI) was the increase in percentage of the middle cerebral artery mean flow velocity during ECP compared with baseline. TCD data were analysed based on the side ipsilateral or contralateral to the infarct. The modified Rankin Scale (mRS) (good outcome: mRS 0∼2; poor outcome: mRS 3∼6) was evaluated 6 months after the index stroke. RESULTS: 72 patients were included (mean age, 63.8±10.7 years; 87.5% males). At month 6 after stroke onset, univariate analysis showed that the National Institutes of Health Stroke Scale at recruitment was significantly higher and ECP therapy duration was longer in the poor outcome group, while the ipsilateral CAI was significantly lower in the good outcome group than that in the poor outcome group (3.71±4.94 vs 7.73±7.66, p=0.044). Multivariate logistic regression showed that ipsilateral CAI was independently correlated with an unfavourable functional outcome after adjusting for confounding factors. CONCLUSIONS: The higher degree of cerebral blood flow velocity augmentation on the side ipsilateral to the infarct induced by ECP is independently correlated with an unfavourable functional outcome after acute ischaemic stroke.


Assuntos
Isquemia Encefálica/terapia , Contrapulsação/métodos , Acidente Vascular Cerebral/terapia , Idoso , Velocidade do Fluxo Sanguíneo/fisiologia , Isquemia Encefálica/fisiopatologia , Circulação Cerebrovascular/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/fisiopatologia , Projetos Piloto , Estudos Retrospectivos , Acidente Vascular Cerebral/fisiopatologia , Estados Unidos
13.
J Neuroimaging ; 25(6): 922-6, 2015 Nov-Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25940508

RESUMO

BACKGROUND AND PURPOSE: Increased cerebral blood flow velocity of basilar artery (BA) is common but often neglected. By using digital subtraction angiography (DSA) to detect intracranial large artery stenosis, we performed transcranial Doppler (TCD) to evaluate cerebral hemodynamic changes of stroke patients. METHODS: Acute stroke patients with TCD-detected raised peak systolic velocity (PSV) in BA (≥100 cm/second) were recruited. RESULTS: Among 91 recruited patients, BA stenosis (>50%) was confirmed by using DSA in 29 patients (32%), among which 20 patients (70.0%) had coexistent internal carotid artery (ICA) and vertebral artery (VA) stenoses. Among patients without BA stenosis (n = 62, 68%), severe stenosis or occlusion of ICA was evaluated in 22 patients (22/62, 35.4%) and severe stenosis or occlusion of VA was detected in 22 patients (22/62, 35.4%). Among the values of PSV (120, 140, 160, and 180 cm/second) and the stenotic-to-prestenotic ratio (SPR) (1.5, 2.0, 2.5, and 3.0), 160 cm/second was found to show the highest predictive value (area under the receiver operator characteristic curve: .75, 95% CI: .65-.86), with a sensitivity of .70 and a specificity of .81. CONCLUSIONS: Apart from an intrinsic BA stenosis, high-grade steno-occlusion of ICA or VA may contribute a lot to induce an elevated flow velocity in BA. A higher value of cutoff point may increase the accuracy of diagnosing BA stenosis.


Assuntos
Angiografia Digital/métodos , Artéria Basilar/diagnóstico por imagem , Velocidade do Fluxo Sanguíneo/fisiologia , Isquemia Encefálica/diagnóstico por imagem , Acidente Vascular Cerebral/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana/métodos , Insuficiência Vertebrobasilar/diagnóstico por imagem , Idoso , Artéria Basilar/fisiopatologia , Isquemia Encefálica/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Acidente Vascular Cerebral/fisiopatologia , Insuficiência Vertebrobasilar/fisiopatologia
14.
J Neurointerv Surg ; 6(2): 96-102, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23512176

RESUMO

BACKGROUND: This study aimed to evaluate the 1-year clinical and angiographic outcome of angioplasty and stenting of intracranial atherosclerosis using Wingspan and Gateway system. METHODS: In this prospective study, patients with symptomatic lesions were treated and followed clinically and angiographically by digital subtraction angiography (DSA) for 1 year. The two primary endpoints were recurrent ipsilateral ischemic stroke and in-stent restenosis (ISR) at 1 year. Secondary endpoints included periprocedural death or stroke and all strokes at 1 year. Potential factors correlated with ISR were studied using univariate and multivariate analysis. RESULTS: Treatment was attempted in 65 patients and successfully completed in 61 (93.8%). Fifty-nine patients (44 men, 15 women) aged 62.86 ± 11.38 years with 66 stenoses (average degree of stenosis 71.78 ± 11.23%) underwent clinical and DSA follow-up at 1 year. There were 66 stenotic lesions. ISR occurred in 11 of the 66 lesions (16.7%). Luminal gain occurred in 32 of the lesions (48.5%), an unchanged lumen in 4 (6%) and luminal loss in 30 (45.4%). The periprocedural stroke or death rate was 6.1% (4/65), including three hemorrhagic and one ischemic stroke, all of which occurred at the corresponding site and resulted in death. There were no interval strokes between the periprocedural time and the 1-year follow-up. The occurrence of ISR was correlated with the degree of stenosis before treatment and was not correlated with patient age or sex, vessel diameter, location of stenosis or failure to control risk factors for atherosclerosis. CONCLUSIONS: One-year clinical and angiographic outcomes of angioplasty and stenting are promising for symptomatic intracranial atherosclerosis.


Assuntos
Angioplastia/métodos , Arteriosclerose Intracraniana/diagnóstico por imagem , Arteriosclerose Intracraniana/terapia , Stents , Idoso , Feminino , Seguimentos , Hong Kong/epidemiologia , Humanos , Arteriosclerose Intracraniana/epidemiologia , Masculino , Pessoa de Meia-Idade , Radiografia , Fatores de Tempo , Resultado do Tratamento
15.
J Neurointerv Surg ; 6(3): 212-8, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-23516268

RESUMO

BACKGROUND: Symptomatic brain hemorrhage was a significant cause of periprocedural stroke or death following stenting in the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis trial, which called into question the safety of Wingspan stenting for intracranial atherosclerosis. This study analyzed the role of a learning curve in the safety and outcome of Wingspan stenting from the experience of 95 consecutive patients at a single center. METHODS: In this prospective study the endpoints were major stroke or death (modified Rankin Scale score >3) within 30 days, other neurological complications, technical procedural problems, technical success in completion of angioplasty and stenting and recurrent ischemic stroke in the corresponding vascular territory after 30 days. Data splitting into quarters was used for learning curve analysis. RESULTS: The periprocedural major stroke or death rate was 4.2% (4/95), minor stroke rate was 5.3% (5/95), total 9.5% (9/95). The technical procedural problem rate was 11.6% (11/95) and the technical success rate was 93.7% (89/95). The 89 patients were followed for 38.9±22.7 months (median 40.8, range 0.2-72, 3463 patient-months) after stenting. The risk of recurrent ischemic stroke in the corresponding vascular territory was 0.7% per patient per year (2/3463 patient-months). Guidewire- or angioplasty-related hemorrhage was the major cause of periprocedural major stroke or death (3/4, 75%) and did not occur in the last quarter. Periprocedural intracerebral hemorrhage was uncommon and perforator stroke did not occur. CONCLUSIONS: There may be a learning curve for mastering the safety precautions of Wingspan stenting for intracranial atherosclerosis.


Assuntos
Angioplastia , Isquemia Encefálica/terapia , Arteriosclerose Intracraniana/terapia , Complicações Intraoperatórias , Complicações Pós-Operatórias , Stents , Acidente Vascular Cerebral/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Angioplastia/efeitos adversos , Angioplastia/instrumentação , Angioplastia/métodos , Angioplastia com Balão/efeitos adversos , Angioplastia com Balão/instrumentação , Angioplastia com Balão/métodos , Isquemia Encefálica/prevenção & controle , Hemorragia Cerebral , Constrição Patológica/terapia , Feminino , Humanos , Arteriosclerose Intracraniana/tratamento farmacológico , Ataque Isquêmico Transitório/prevenção & controle , Ataque Isquêmico Transitório/terapia , Curva de Aprendizado , Masculino , Pessoa de Meia-Idade , Inibidores da Agregação de Plaquetas/administração & dosagem , Estudos Prospectivos , Recidiva , Acidente Vascular Cerebral/prevenção & controle , Resultado do Tratamento
16.
Stroke ; 43(11): 3007-11, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22996956

RESUMO

BACKGROUND AND PURPOSE: External counterpulsation (ECP) is a novel noninvasive method used to improve the perfusion of vital organs, which may benefit ischemic stroke patients. We hypothesized that ECP may augment cerebral blood flow of ischemic stroke patients via induced hypertension. METHODS: We recruited ischemic stroke patients with cerebral intracranial large artery occlusive disease and healthy elderly controls into this study. Bilateral middle cerebral arteries of subjects were monitored using transcranial Doppler. Flow velocity changes before, during, and after ECP were, respectively, recorded for 3 minutes while continuous beat-to-beat blood pressure data were recorded. Cerebral augmentation index was the increase in percentage of middle cerebral artery mean flow velocity during ECP compared with baseline. Transcranial Doppler data were analyzed based on ipsilateral or contralateral to the infarct side. RESULTS: ECP significantly increased mean blood pressure of stroke patients and controls. During ECP, middle cerebral artery mean flow velocities of stroke patients increased on both ipsilateral and contralateral sides when compared with baseline (ipsilateral cerebral augmentation index, 9.64%; contralateral cerebral augmentation index, 9%; both P<0.001), but there was no increase in difference between the 2 sides when compared with each other. Mean flow velocities of controls did not change under ECP. After ECP, blood pressure and flow velocity of stroke patients returned to baseline level. CONCLUSIONS: ECP provides a new method of cerebral blood flow augmentation in ischemic stroke by elevation of blood pressure. Flow augmentation induced by ECP suggests the improvement of cerebral perfusion and collateral supply from infarct ipsilateral and contralateral sides.


Assuntos
Circulação Cerebrovascular/fisiologia , Transtornos Cerebrovasculares/terapia , Contrapulsação , Acidente Vascular Cerebral/fisiopatologia , Acidente Vascular Cerebral/terapia , Idoso , Pressão Sanguínea/fisiologia , Transtornos Cerebrovasculares/diagnóstico por imagem , Transtornos Cerebrovasculares/fisiopatologia , Feminino , Humanos , Masculino , Acidente Vascular Cerebral/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana
17.
Neurosurgery ; 70(1 Suppl Operative): 104-13, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21849921

RESUMO

BACKGROUND: Angioplasty and stenting using nitinol stents is a recognized treatment option for intracranial atherosclerosis. OBJECTIVE: To identify procedure-related factors that may affect patient safety and technical outcome. METHODS: In this prospective study of 57 consecutive patients, the primary end points were intraprocedural technical problems, periprocedure morbidity, and complications. Major periprocedure complication was defined as all stroke or death at 30 days. Technical failure was defined as the inability to complete the procedure because of technical or safety problems. Procedure failure was defined as a procedure outcome of technical failure or major periprocedure complication. Secondary end points were procedure-related factors that may affect patient safety and technical outcome. RESULTS: Procedure failure rate was 12.3% (7/57) (major periprocedure complication rate, 5.3% [3/57]; technical failure rate, 7% [4/57]). Initial failure in tracking of balloon or stent occurred in 20 patients, other technical problems occurred in 11 patients, including kinking or trapping of balloon catheter (2 cases), difficulty in unsheathing of stent (3 cases), forward migration of stent during deployment (4 cases), trapping of nose cone after stent deployment (1 case), fracture of delivery system (2 cases), and guidewire fracture (1 case). Unfavorable vascular morphology signified by the presence of 2 or more reverse curves along the access path was found to associate with initial failure in the tracking of instruments (OR = ∞), and occurrence of other technical problems (OR = 25). CONCLUSION: Procedure-related factors could be identified and lead to improvements in patient safety and technical outcome. Tortuous vascular morphology is a key factor to be overcome.


Assuntos
Ligas/uso terapêutico , Angioplastia/instrumentação , Angioplastia/métodos , Constrição Patológica/terapia , Arteriosclerose Intracraniana/terapia , Segurança do Paciente , Complicações Pós-Operatórias/epidemiologia , Stents/normas , Idoso , Angioplastia/mortalidade , Angioplastia com Balão/instrumentação , Angioplastia com Balão/métodos , Angioplastia com Balão/mortalidade , Artérias Cerebrais/anormalidades , Artérias Cerebrais/diagnóstico por imagem , Artérias Cerebrais/patologia , Constrição Patológica/diagnóstico por imagem , Constrição Patológica/patologia , Falha de Equipamento , Feminino , Humanos , Arteriosclerose Intracraniana/diagnóstico por imagem , Arteriosclerose Intracraniana/patologia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Avaliação de Processos (Cuidados de Saúde)/métodos , Estudos Prospectivos , Radiografia , Stents/efeitos adversos , Resultado do Tratamento
18.
J Neuroimaging ; 20(2): 122-9, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19187479

RESUMO

BACKGROUND AND PURPOSE: Current criteria for middle cerebral artery (MCA) stenosis by transcranial Doppler were mainly based on the flow velocity acceleration, ignoring other useful parameters. We tested the accuracy of new criteria using magnetic resonance angiography (MRA) as the confirmative method. METHODS: A compositive score for each MCA was calculated according to following parameters: Velocity Scale (score 0-6 for peak systolic velocity <140 to > or = 300 cm/second), Hemodynamic Scale (score 0-5 for diffuse or focal velocity increase; score 0-6 for differences between bilateral MCA; score 17 for damping velocity), and Spectrum Scale (score 0-2 for normal spectrum, turbulence, and musical murmurs). RESULTS: The median scores in normal-mild, moderate, and severe groups on MRA differed significantly (P < .001). The optimal cutoff score for <50% and > or = 50% stenosis was 3 with the PPV of 72.3% (95% confidence interval [CI]: 65.3% to 78.5%) and negative predictive value (NPV) of 89.5% (95% CI: 85.9% to 92.3%), for moderate and severe stenosis was 6 with the PPV of 85.9% (95% CI: 76.7% to 92.0%) and NPV of 61.9% (95% CI: 50.6% to 72.1%). Both scores performed better than peak systolic or mean velocity. CONCLUSIONS: This new method was feasible and reliable and showed some advantages over the velocity-only method. Further studies using digital subtraction angiography as the gold standard are needed to ameliorate the new criteria.


Assuntos
Algoritmos , Interpretação de Imagem Assistida por Computador/métodos , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana/métodos , Feminino , Humanos , Aumento da Imagem/métodos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
Radiology ; 251(1): 224-32, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19332854

RESUMO

PURPOSE: To evaluate the feasibility and preliminary results of using paclitaxel-eluting stents for angioplasty and to treat symptomatic atherosclerotic ostial vertebral artery (VA) stenosis. MATERIALS AND METHODS: Institutional review board approval and written informed consent were obtained for this prospective study. Nine men and one woman (average age, 65.9 years +/- 11.6 [standard deviation]) were included. Inclusion criteria were as follows: (a) Patients had angiographic evidence of VA ostial stenosis of 50% or more or stenosis of more than 45% if the contralateral VA was occluded. (b) Refractory vertebrobasilar ischemia, such as a stroke or transient ischemic attack, occurred while patients were taking one antiplatelet medication with optimal cardiovascular risk factor control. (c) Patients did not have another substantial vertebrobasilar stenotic lesion in the same territory. The primary end point was procedure safety, defined as mortality and permanent neurologic morbidity 30 days after stent placement. The secondary end point was clinical effectiveness, defined as recurrent vertebrobasilar ischemic symptoms within 12 months after stent placement and restenosis greater than or equal to 50% of the treated VA segment within 12 months after stent placement. RESULTS: The degree of stenosis ranged from 46% to 83% (mean, 67.3% +/- 11.9). The technical success rate was 100%. Procedure-related complication rate, mortality rate, and permanent neurologic morbidity rate at 30-day follow-up were 0%. At 12-month follow-up, no patient reported recurrent vertebrobasilar ischemic symptoms or had VA restenosis. CONCLUSION: This pilot study suggests that use of paclitaxel-eluting stents in angioplasty and to treat symptomatic atherosclerotic ostial VA stenosis are feasible and promising in terms of potential safety and effectiveness in prevention of recurrent ischemia and restenosis. These results could be helpful in the formulation of a larger prospective randomized controlled trial.


Assuntos
Angiografia , Stents Farmacológicos/efeitos adversos , Oclusão de Enxerto Vascular/etiologia , Oclusão de Enxerto Vascular/prevenção & controle , Paclitaxel/administração & dosagem , Insuficiência Vertebrobasilar/diagnóstico por imagem , Insuficiência Vertebrobasilar/cirurgia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Moduladores de Tubulina/administração & dosagem
20.
J Comput Assist Tomogr ; 28(5): 650-3, 2004 Sep-Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15480040

RESUMO

OBJECTIVE: To assess the prognostic value of computed tomography (CT) in hyperacute middle cerebral artery (MCA) infarcts. METHODS: The CT features, total CT score, and National Institutes of Health Stroke Scale (NIHSS) score were correlated with the 30-day mortality in 16 patients with a hyperacute MCA infarct. RESULTS: Admission NIHSS scores were significantly lower in the survival group (P = 0.016). The extent of infarct, attenuation of corticomedullary differentiation, and total CT score were associated with 30-day mortality (P < 0.05). In prediction of mortality, extent of an infarct > 67% gave sensitivity, specificity, positive predictive value, and negative predictive value rates of 86%, 100%, 100%, and 90%, respectively. Attenuation of corticomedullary differentiation gave sensitivity, specificity, positive predictive value, and negative predictive value rates of 86%, 89%, 86%, and 89%, respectively. An NIHSS score > 28 gave sensitivity, specificity, positive predictive value, and negative predictive value rates of 86%, 67%, 67%, and 86%, respectively. A CT score > 4 gave sensitivity, specificity, positive predictive value, and negative predictive value rates of 86%, 78%, 75%, and 88%, respectively. CONCLUSIONS: Computed tomography features and the admission NIHSS score are important predictors of survival in hyperacute extensive MCA infarcts.


Assuntos
Infarto da Artéria Cerebral Média/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Infarto da Artéria Cerebral Média/mortalidade , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Análise de Sobrevida
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