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Helmuth Steinmetz - One of the best experts on this subject based on the ideXlab platform.
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cerebral Microembolism and the risk of ischemia in asymptomatic high grade internal carotid artery stenosis
Stroke, 1995Co-Authors: M Siebler, Andreas Nachtmann, Matthias Sitzer, Georg Rose, Andreas Kleinschmidt, J Rademacher, Helmuth SteinmetzAbstract:Background and Purpose Previous work has shown that cerebral Microembolism detected with transcranial Doppler sonography distal to internal carotid artery stenosis occurs more frequently in recently symptomatic compared with asymptomatic patients. It has remained unclear whether cerebral Microembolism also indicates a higher risk of future cerebral or retinal ischemia. Summary of Report Sixty-four asymptomatic patients with unilateral 70% to 90% internal carotid artery stenosis were investigated prospectively (mean follow-up, 72 weeks). Five patients developed ischemic symptoms attributable to the stenosis (transient ischemic attack, 2 patients; stroke, 3 patients). A microembolic rate of ≥2 per hour in the ipsilateral middle cerebral artery was associated with a substantially increased risk of developing ischemia of the corresponding carotid territory (odds ratio, 31; 95% confidence interval, 3 to 302; P =.005). Conclusions This prospective pilot study suggests that cerebral Microembolism detected with transcranial Doppler sonography may define a high-risk subgroup among patients with asymptomatic high-grade internal carotid artery stenosis.
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cerebral Microembolism in patients with sneddon s syndrome
JAMA Neurology, 1995Co-Authors: M Sitzer, J Rademacher, D Sohngen, Mario Siebler, Christof Specker, Igor Janda, A Aulich, Helmuth SteinmetzAbstract:Background: The pathogenesis of Sneddon's syndrome is unclear. This study addresses the question whether cerebral thromboembolism may be involved in the pathogenesis of the neurologic complications of the disorder. The study consisted of 13 patients with Sneddon's syndrome defined by both generalized livedo reticularis and a history of one or more cerebrovascular ischemic events; none had clinical or Doppler ultrasonographic evidence of atherosclerosis. Methods: Transcranial Doppler microembolic monitoring of the middle cerebral artery; blood screening for antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibodies). Results: Five patients (38%) showed clinically silent Microembolism at transcranial Doppler monitoring, with individual microembolic event rates of the middle cerebral artery between 2 per hour and 33 per hour. In this group, the time since the last ischemic symptom was significantly shorter than in the eight patients without microemboli. Antiphospholipid antibodies were detected in three patients (23%), all of whom belonged to the microemboli-positive group. Conclusions: These data suggest that the detectability of both clinically silent cerebral Microembolism and antiphospholipid antibodies may provide paraclinical evidence of active disease in patients with Sneddon's syndrome. The results support the notion that an immune-mediated prothrombotic state facilitating the formation of arterial thrombi with subsequent cerebral embolization, and/or triggering in situ thrombosis of cerebral vessels, plays a pathogenetic role in the neurologic manifestations of this disorder.
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cerebral Microembolism in symptomatic and asymptomatic high grade internal carotid artery stenosis
Neurology, 1994Co-Authors: M Siebler, Matthias Sitzer, Andreas Kleinschmidt, Helmuth Steinmetz, H J FreundAbstract:Using transcranial Doppler (TCD) ultrasonography in patients with high-grade (> or = 70%) internal carotid artery (ICA) stenosis, we examined the relation between the rate of TCD-detected silent Microembolism of the ipsilateral middle cerebral artery and a history of recent ( or = 2/h had a positive predictive value of 0.88 for a history of recent symptoms. Our data suggest that TCD monitoring can provide reliable paraclinical evidence of "unstable ICA disease."
M Siebler - One of the best experts on this subject based on the ideXlab platform.
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cerebral Microembolism and the risk of ischemia in asymptomatic high grade internal carotid artery stenosis
Stroke, 1995Co-Authors: M Siebler, Andreas Nachtmann, Matthias Sitzer, Georg Rose, Andreas Kleinschmidt, J Rademacher, Helmuth SteinmetzAbstract:Background and Purpose Previous work has shown that cerebral Microembolism detected with transcranial Doppler sonography distal to internal carotid artery stenosis occurs more frequently in recently symptomatic compared with asymptomatic patients. It has remained unclear whether cerebral Microembolism also indicates a higher risk of future cerebral or retinal ischemia. Summary of Report Sixty-four asymptomatic patients with unilateral 70% to 90% internal carotid artery stenosis were investigated prospectively (mean follow-up, 72 weeks). Five patients developed ischemic symptoms attributable to the stenosis (transient ischemic attack, 2 patients; stroke, 3 patients). A microembolic rate of ≥2 per hour in the ipsilateral middle cerebral artery was associated with a substantially increased risk of developing ischemia of the corresponding carotid territory (odds ratio, 31; 95% confidence interval, 3 to 302; P =.005). Conclusions This prospective pilot study suggests that cerebral Microembolism detected with transcranial Doppler sonography may define a high-risk subgroup among patients with asymptomatic high-grade internal carotid artery stenosis.
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cerebral Microembolism in symptomatic and asymptomatic high grade internal carotid artery stenosis
Neurology, 1994Co-Authors: M Siebler, Matthias Sitzer, Andreas Kleinschmidt, Helmuth Steinmetz, H J FreundAbstract:Using transcranial Doppler (TCD) ultrasonography in patients with high-grade (> or = 70%) internal carotid artery (ICA) stenosis, we examined the relation between the rate of TCD-detected silent Microembolism of the ipsilateral middle cerebral artery and a history of recent ( or = 2/h had a positive predictive value of 0.88 for a history of recent symptoms. Our data suggest that TCD monitoring can provide reliable paraclinical evidence of "unstable ICA disease."
Viken L Babikian - One of the best experts on this subject based on the ideXlab platform.
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ophthalmic artery Microembolism in giant cell arteritis
Journal of Neuro-ophthalmology, 2001Co-Authors: Barbara Schauble, Christine A C Wijman, Behrooz Koleini, Viken L BabikianAbstract:A 70-year-old man presented with a history of headache and sudden loss of vision of the left eye. Funduscopic examination showed sector retinal edema and hemorrhage as well as optic disc swelling consistent with anterior ischemic optic neuropathy. The Westergren sedimentation rate was 66 mm/h. Temporal artery biopsy was consistent with giant cell arteritis. Routine transcranial Doppler testing performed on a Pioneer 2020 instrument (Nicolet Vascular, Inc., Golden, CO) equipped with special software for microembolus detection showed a microembolic signal in the left ophthalmic artery. During a subsequent monitoring study, microembolic signals were detected in the anterior and middle cerebral arteries, bilaterally. Microembolism can occur in giant cell arteritis. Ophthalmic artery Microembolism can be detected in vivo by transcranial Doppler ultrasonography. This new imaging capability can potentially be useful when evaluating patients with vascular disorders of the eye.
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distribution of cerebral Microembolism in the anterior and middle cerebral arteries
Acta Neurologica Scandinavica, 2000Co-Authors: Christine A C Wijman, Viken L Babikian, Michael Winter, Val E PochayAbstract:BACKGROUND AND PURPOSE Cerebral infarcts occur more frequently along the middle (MCA) than the anterior cerebral artery (ACA) territory. The reason(s) for this difference remains speculative. The objective of this study was to investigate the distribution of cerebral microemboli as detected by transcranial Doppler ultrasound (TCD) along the MCA and ACA territories. METHODS Records of consecutive patients examined for the presence of cerebral Microembolism during a 32-month period at the Neurovascular Laboratory were reviewed. Of the original 375 TCD studies in 268 patients, 28 studies in 24 patients demonstrated microembolic signals (MES) and monitored the MCA and ACA on the same side. TCD studies were performed on TC-2000 or TC-2020 instruments. MES positive studies were saved and off-line reviewed. MES satisfied previously established criteria. RESULTS MES were more frequent in the MCA than the ACA in 85.7% (24/28) of studies (P < 0.01). Of the total number of MES (n = 979), 29.6% (n = 290) were detected in the ACA and 70.4% (n=689) in the MCA (P<0.01). The mean (+/- SD) intensity of MCA MES of 12.2 (+/- 2.4) dB was significantly lower than that of ACA MES of 14.8 (+/-3.2) dB (P=0.05). The mean (+/-SD) duration of MCA MES of 38.1 (+/- 45.3) ms was longer than that of ACA MES of 30.7 (+/-34.0) ms (P=0.05). CONCLUSIONS Cerebral Microembolism occurs more frequently in the MCA than the ACA, which may explain the uneven distribution of cerebral infarcts along these arterial territories. Furthermore, there are significant differences in the characteristics of ACA and MCA MES.
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cerebral Microembolism in patients with retinal ischemia
Stroke, 1998Co-Authors: Christine A C Wijman, Viken L Babikian, Ippolit C A Matjucha, Behrooz Koleini, Charles K Hyde, Michael Winter, Val E PochayAbstract:Background and Purpose —We investigated the frequency of cerebral Microembolism detected by transcranial Doppler ultrasonography in patients with clinical evidence of retinal ischemia, including transient monocular blindness, central and branch retinal artery infarction, and ischemic oculopathy, and assessed its correlation with carotid artery stenosis. Methods —Records of 331 consecutive patients examined during a 47-month period at the Neurovascular Laboratory were reviewed. Of the original 453 intracranial arteries, 186 middle cerebral arteries (MCAs) satisfied qualifying criteria that excluded patients with cardiac embolic sources. Forty-five MCAs ipsilateral to the symptomatic eye constituted the study group. The control group consisted of 141 asymptomatic MCAs. Microembolus detection studies were performed on transcranial Doppler instruments equipped with special software, and the degree of carotid artery stenosis was measured by cerebral or MR angiography or by color duplex studies. Results —Microembolism was detected in 40.0% of study MCAs and 9.2% of controls ( P P P P =0.013). Conclusions —In patients without cardiac embolic sources, cerebral Microembolism is frequently present on the side of retinal ischemia, particularly during the week after onset of symptoms. It is often associated with severe stenosis or occlusion of the ipsilateral carotid artery.
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cerebral Microembolism and ischemic changes associated with carotid endarterectomy
Journal of Vascular Surgery, 1998Co-Authors: Nancy L Cantelmo, Viken L Babikian, Val E Pochay, R Samaraweera, Jonathan K Gordon, Michael WinterAbstract:Abstract Purpose: The purpose of this study is to characterize microembolic signals (MS) that occur during the various phases of carotid endarterectomy (CEA) and to consider their relationship to postoperative changes on magnetic resonance imaging (MRI). Methods: This was a retrospective study of 76 patients who underwent 78 carotid endarterectomies at a referral center. Perioperative transcranial Doppler monitoring and MRI were performed before and after CEA. The types of MS that occurred during phases of surgery were analyzed and compared with MRI changes. Results: We observed a clinical stroke in one patient (1.3%) and ipsilateral small areas of silent ischemic change on seven postoperative MRI studies (9.0%). In 95% of CEAs, MS were detected. Only those MS observed in the recovery room that occurred at a rate of more than five per 15 minutes were associated with postoperative MRI ischemic changes ( p Conclusions: Ischemic changes on MRI after CEA are related to postoperative MS. (J Vasc Surg 1998;27:1024-31.)
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cerebral Microembolism and early recurrent cerebral or retinal ischemic events
Stroke, 1997Co-Authors: Viken L Babikian, Christine A C Wijman, Charles K Hyde, Michael Winter, Nancy L Cantelmo, Errol Baker, Val E PochayAbstract:Background and Purpose We investigated whether cerebral Microembolism as detected by transcranial Doppler ultrasonography (TCD) identifies patients at an increased risk for early, recurrent cerebral or retinal ischemic events. Methods Records of consecutive patients examined during a 40-month period in the Neurovascular Laboratory were reviewed for the presence of cerebral Microembolism. Of the original 302 patients, 229 with 310 arteries met inclusionary criteria. Follow-up information was obtained from the laboratory’s database as well as the hospital records. Microembolus detection studies were performed on TC-2000 or TC-2020 instruments equipped with special software, and criteria established a priori were used for microembolus selection. TCD testing was performed a median interval of 9 days after the initial symptoms of cerebral ischemia. Severity of arterial stenosis was determined by cerebral angiography or noninvasive methods. Results Microembolic signals were detected more frequently in symptomat...
Andreas Kleinschmidt - One of the best experts on this subject based on the ideXlab platform.
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cerebral Microembolism and the risk of ischemia in asymptomatic high grade internal carotid artery stenosis
Stroke, 1995Co-Authors: M Siebler, Andreas Nachtmann, Matthias Sitzer, Georg Rose, Andreas Kleinschmidt, J Rademacher, Helmuth SteinmetzAbstract:Background and Purpose Previous work has shown that cerebral Microembolism detected with transcranial Doppler sonography distal to internal carotid artery stenosis occurs more frequently in recently symptomatic compared with asymptomatic patients. It has remained unclear whether cerebral Microembolism also indicates a higher risk of future cerebral or retinal ischemia. Summary of Report Sixty-four asymptomatic patients with unilateral 70% to 90% internal carotid artery stenosis were investigated prospectively (mean follow-up, 72 weeks). Five patients developed ischemic symptoms attributable to the stenosis (transient ischemic attack, 2 patients; stroke, 3 patients). A microembolic rate of ≥2 per hour in the ipsilateral middle cerebral artery was associated with a substantially increased risk of developing ischemia of the corresponding carotid territory (odds ratio, 31; 95% confidence interval, 3 to 302; P =.005). Conclusions This prospective pilot study suggests that cerebral Microembolism detected with transcranial Doppler sonography may define a high-risk subgroup among patients with asymptomatic high-grade internal carotid artery stenosis.
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cerebral Microembolism in symptomatic and asymptomatic high grade internal carotid artery stenosis
Neurology, 1994Co-Authors: M Siebler, Matthias Sitzer, Andreas Kleinschmidt, Helmuth Steinmetz, H J FreundAbstract:Using transcranial Doppler (TCD) ultrasonography in patients with high-grade (> or = 70%) internal carotid artery (ICA) stenosis, we examined the relation between the rate of TCD-detected silent Microembolism of the ipsilateral middle cerebral artery and a history of recent ( or = 2/h had a positive predictive value of 0.88 for a history of recent symptoms. Our data suggest that TCD monitoring can provide reliable paraclinical evidence of "unstable ICA disease."
Matthias Sitzer - One of the best experts on this subject based on the ideXlab platform.
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cerebral Microembolism and the risk of ischemia in asymptomatic high grade internal carotid artery stenosis
Stroke, 1995Co-Authors: M Siebler, Andreas Nachtmann, Matthias Sitzer, Georg Rose, Andreas Kleinschmidt, J Rademacher, Helmuth SteinmetzAbstract:Background and Purpose Previous work has shown that cerebral Microembolism detected with transcranial Doppler sonography distal to internal carotid artery stenosis occurs more frequently in recently symptomatic compared with asymptomatic patients. It has remained unclear whether cerebral Microembolism also indicates a higher risk of future cerebral or retinal ischemia. Summary of Report Sixty-four asymptomatic patients with unilateral 70% to 90% internal carotid artery stenosis were investigated prospectively (mean follow-up, 72 weeks). Five patients developed ischemic symptoms attributable to the stenosis (transient ischemic attack, 2 patients; stroke, 3 patients). A microembolic rate of ≥2 per hour in the ipsilateral middle cerebral artery was associated with a substantially increased risk of developing ischemia of the corresponding carotid territory (odds ratio, 31; 95% confidence interval, 3 to 302; P =.005). Conclusions This prospective pilot study suggests that cerebral Microembolism detected with transcranial Doppler sonography may define a high-risk subgroup among patients with asymptomatic high-grade internal carotid artery stenosis.
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cerebral Microembolism in symptomatic and asymptomatic high grade internal carotid artery stenosis
Neurology, 1994Co-Authors: M Siebler, Matthias Sitzer, Andreas Kleinschmidt, Helmuth Steinmetz, H J FreundAbstract:Using transcranial Doppler (TCD) ultrasonography in patients with high-grade (> or = 70%) internal carotid artery (ICA) stenosis, we examined the relation between the rate of TCD-detected silent Microembolism of the ipsilateral middle cerebral artery and a history of recent ( or = 2/h had a positive predictive value of 0.88 for a history of recent symptoms. Our data suggest that TCD monitoring can provide reliable paraclinical evidence of "unstable ICA disease."