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 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The last decade has seen several major technological advances in vascular neuroradiology, the most clinically significant of which have been the facility to image the brain and the extracranial carotid bifurcation noninvasively with accuracy and safety. Another major advance has been unequivocal evidence from formal statistical overviews that antiplatelet therapy, particularly aspirin, reduces the risk of serious vascular events by about 25%. These advances have changed clinical practice such that most patients presenting with symptoms suggestive of cerebral ischaemia should now have cranial CT to exclude intracerebral hemorrhage, not only because the causes and prognosis of cerebral ischaemia differ from those of intracerebral hemorrhage, but because many patients with cerebral ischaemia should be considered for antiplatelet therapy. Besides the use of long term antiplatelet therapy and control of vascular risk factors, other acute treatment options are limited with the possible exception of anticoagulation, thrombolysis, cytoprotective agents and carotid endarterectomy. If, as seems likely, the current clinical trials show that carotid endarterectomy plus medical therapy improve upon the stroke-free survival of patients treated medically, at least in symptomatic patients with severe stenosis, the number of carotid endarterectomies performed will increase considerably because carotid bifurcation disease is the most common cause of cerebral and ocular ischemic events. It will then be even more important to be able to obtain accurate anatomical and physiological information about the extracranial and intracranial circulations with utmost safety. Duplex ultrasound is currently the noninvasive screening method of choice for carotid bifurcation disease because it is available, relatively cheap, and reasonably accurate. It not only images the vessel lumen and degree of stenosis, but also the morphology of the vessel wall and associated plaque, the relevance of which is still uncertain in the pathogenesis of cerebral and ocular ischaemia. A major limitation of duplex sonography is that it cannot reliably distinguish tight stenosis from occlusion and it does not image the proximal or distal carotid circulation. The aim of newer techniques will be to distinguish tight extracranial carotid stenosis from occlusion and to provide anatomical, physiological and pathological information about the intracranial circulation and ischemic lesions (in view of potential for thrombolytic therapy of major intracranial vessel occlusion) with safety and reproducible accuracy.
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PMID:The role of imaging in the management of cerebral and ocular ischaemia. 174 65

Thrombus formation in the left atrium and left ventricle is primarily due to stasis of blood which causes activation of the coagulation system. Migration of thrombotic material into the circulation depends on the dynamic forces of the circulation. Atrial fibrillation is the commonest underlying cardiac disorder predisposing to thromboembolism. Rheumatic mitral stenosis, left atrial enlargement, prior myocardial infarction, hypertension, and echocardiographic left ventricular hypertrophy are risk factors for thromboembolic stroke in elderly patients with chronic atrial fibrillation. Non-valvular atrial fibrillation accounts for 45% of cardiac sources of thromboembolic stroke and includes patients with ischemic heart disease, hypertension, thyrotoxic heart disease, hypertrophic cardiomyopathy, chronic sinoatrial disorder, and idiopathic atrial fibrillation. 15% of cardiac sources of thromboembolic stroke are associated with acute myocardial infarction, 10% with left ventricular aneurysm and mural thrombi remote from an acute myocardial infarction, 10% with rheumatic valvular heart disease, and 10% with prosthetic cardiac valves. Mitral valve prolapse, mitral annular calcium, nonischemic cardiomyopathies, infective endocarditis, nonbacterial thrombotic endocarditis, left atrial myxoma, paradoxical embolism associated with congenital heart disease, calcific aortic stenosis, and complex atherosclerotic plaque within the proximal aorta also contribute to thromboembolism.
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PMID:Etiology and pathogenesis of thromboembolism. 176 43

The authors report their experience from 1985 to 1988 with 75 consecutive patients affected by bilateral carotid artery stenosis in whom only one side was surgically treated and the other had a minor (15-45%) asymptomatic carotid stenosis. These patients have been followed for a period ranging from 10 to 50 months (mean follow-up 21 months) by clinical examinations and non-invasive investigations (Doppler CW, Duplex scanner). The non-invasive evaluation included assessment of haemodynamic data and characterisation of plaque morphology (regular vs. irregular or ulcerated surface, homogeneous vs. heterogeneous plaque). During follow-up eight patients died: two (2.6%) from acute myocardial infarction, four from stroke (5.3%), and two (2.6%) from other causes. Twenty-five patients (33.3%) had neurological symptoms related to the unoperated side: and four suffered stroke (5.3%). Twenty-one patients had TIAs (28%) related to the observed side. During follow-up five out of 29 (17.2%) homogeneous and 20 out of 46 (43.4%) heterogeneous plaques progressed (p less than 0.01). With regard to the surface characteristics, nine out of 25 regular plaques progressed and only three patients (12%) had neurological events; 19 out of 34 (55.9%) irregular plaques showed a progression and 14 caused neurological symptoms. Fourteen ulcerated plaques (87.5%) progressed (p less than 0.01). Our experience suggests that the basic trend in the follow-up of patients with bilateral carotid artery disease, is that the contralateral unoperated lesion may evolve and become symptomatic. These symptoms are generally TIAs but five patients (4.3%) suffered from strokes related to the unoperated side, all without warning TIAs.
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PMID:Minor asymptomatic carotid stenosis contralateral to carotid endarterectomy (CEA): our experience. 186 89

We investigated the clinical outcomes and the progression of the internal carotid arterial lesions of a group of patients presenting with hemispheric TIAs. The cumulative frequency of TIAs during a mean follow-up period of 40 +/- 14 months was 14%, and no relationship was found between new TIAs and the presence of known cardiovascular risk factors or plaque characteristics as determined by duplex scanning. With the exception of one patient who died of stroke, none of the patients developed a permanent neurologic deficit. The cumulative death rate was 6.5%; myocardial infarction was the most common cause (3 out of 7). Anatomic progression of plaques was determined by duplex scanning in 22% of the internal carotid arteries. No relationship between progression of these plaques and the development of new TIAs was evident. We conclude that, in this group of patients, TIAs do not inevitably lead to stroke and that TIAs are not predictable based on risk factors or plaques characteristics.
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PMID:Clinical follow-up and progression of carotid atherosclerosis determined by duplex scanning in patients suffering from TIA. 186 67

Although carotid endarterectomy is the standard procedure, the purpose of this paper is to describe a new surgical technique and indicate its role in the surgery of cervical cerebrovascular disease. The technique consists of resection of the pathologic carotid artery bifurcation followed by its total replacement with a bifurcated thin-wall polytetrafluoroethylene (PTFE) graft constructed by the surgeon. Prosthetic graft reconstruction of the carotid bifurcation (PGRCB) was performed in 21 patients (25 procedures) from November 1984 to May 1987. Many patients were over 70 years old. The indications for surgery were transient ischemic attacks (TIA)'s in 10 patients (high-grade stenosis), established stroke with mild deficit in 3 patients (high-grade stenosis). Eight patients (high-grade stenosis) were asymptomatic and 4 had vertebro-basilar symptoms. In 11 procedures the indications were the same as for standard carotid endarterectomy (significant stenosis and/or ulcerated plaque). In 14 cases, the procedure was justified by extensive lesions involving a long segment of the internal carotid artery (2 restenoses, 12 calcified lesions). In the perioperative period, there were no deaths and no TIA's. The 25 procedures were assessed one month postoperatively by ultrasonic imaging and venous substraction angiography. All the grafts were patent with perfect restoration of the carotid bifurcation anatomy. Systematic follow-up study was carried out in 1987. Three patients had died of non-neurologic causes and one was lost to study. The remaining 19 procedures were evaluated with an average follow-up of 19 months (range 7 to 32 months). The patients were asymptomatic and all the grafts remained patent including one stenosis (greater than 50%) at the common carotid artery anastomosis. Because recent studies have documented a much higher rate of technical defects or recurrent stenosis after carotid endarterectomy, we believe that PGRCB merits consideration, particularly in difficult endarterectomies, and in recurrent carotid stenosis. Furthermore it seems acceptable to advocate PGRCB in aneurysms of the internal carotid artery and in post-irradiation arteritis.
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PMID:Resection and reconstruction of the carotid bifurcation with polytetrafluoroethylene grafts; operative technique. Preliminary results in 25 procedures and indications. 186 68

We performed serial prospective ultrasound examinations of four flat and 17 soft carotid plaques during an average of 17 months in seven patients with heterozygous hypercholesterolemia during heparin-induced extracorporeal low density lipoprotein elimination on precipitation from plasma. By means of a specially designed quantitative three-dimensional ultrasound analysis, significant plaque volume reduction could be evaluated in all subjects, along with a marked reduction of total and low density lipoprotein cholesterol and fibrinogen serum levels.
Stroke 1991 Aug
PMID:Regression of carotid plaques during low density lipoprotein cholesterol elimination. 186 66

Carotid atherosclerosis is commonly detected in the asymptomatic elderly and in patients with known vascular disease in other distributions. Although there has been considerable interest in carotid bruits, they are not a reliable indicator of asymptomatic stenosis. In patients with asymptomatic stenosis detected by carotid ultrasound or angiography, the annual risk of ipsilateral infarction is approximately 1% to 2%. If ischemic events occur, they are usually transient ischemic attacks. Stroke risk is higher when there is progressive stenosis, stenosis exceeding 75% to 80%, and, possibly, complicated plaque-morphologic characteristics. The treatment of asymptomatic carotid stenosis remains controversial. Antiplatelet agents are of unproven value in asymptomatic patients. The role of surgical management is disputed because of uncertainties regarding the natural history of asymptomatic stenosis and the efficacy and complication rates of endarterectomy. Pending results of several ongoing randomized clinical trials, it may be advisable to withhold endarterectomy from those asymptomatic patients with stenosis of less than 75% to 80%. Prophylactic carotid endarterectomy is not necessary in the patient with asymptomatic stenosis who will undergo another operative procedure such as coronary artery bypass.
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PMID:Asymptomatic carotid artery disease in the elderly. Diagnosis and management strategies. 186 1

The sensitivity and specificity of Hachinski's Ischaemic Score (IS) in the diagnosis of the vascular aetiology of dementia was studied in a series of 32 demented patients, dementia of the Alzheimer type (16), multi-infarct dementia (7), mixed dementia (6), Pick's disease (3), with neuropathological diagnosis as the point of reference. The IS distinguished between primary degenerative dementia and multi-infarct or mixed dementia. As single features of the IS "a positive history of stroke" and "a fluctuating course" showed differing prevalences in the latter two diagnostic categories. The IS labelled 21% of patients with primary degenerative dementia as having a vascular aetiology. The uncritical application of the IS to large samples in epidemiological studies may cause incorrect labelling of a significant proportion of patients with primary degenerative dementia as vascular dementia. These results are based on observations of long-term inpatients and depend on neuropathological criteria. While the definite diagnosis of DAT by threshold criteria concerning plaque and tangle counts is well established, neither clinical nor pathological evidence of stroke necessarily means that cerebrovascular disease has anything to do with a patient's dementia.
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PMID:Prospective neuropathological validation of Hachinski's Ischaemic Score in dementias. 189 20

To show relationship between degree of carotid arterial stenosis and cerebral blood flow reactivity (RES%) to induced hypercapnia, fluorine-18-fluoromethane and positron emission tomography (PET) was used to study 18 patients with carotid distribution transient ischaemic attacks (TIA), all free of stroke, who had angiographic-proven unilateral arterial disease. Non-involved carotid arteries were either normal or had non-stenotic plaque. Either normal arteries or nonstenotic ulcerations in the symptomatic carotid arteries were present in five of 18 (28%), ipsilateral carotid stenosis from 50-99% was present in eight of 18 (44%), and ipsilateral internal carotid occlusion was present in five of 18 (28%) patients. In comparison with 14 normal controls, all patients with symptomatic middle cerebral artery (MCA) flow territories had significantly lower mean (SEM) RES% [5.0' (0.2) vs 4.0 (0.9), p less than 0.04]. Symptomatic anterior borderzone (ABZ) RES% was also significantly lower [4.6 (0.4) vs 3.3 (0.9), p less than 0.04], than controls. In patient subgroup comparisons, the 50-99% stenosis subgroup clearly had the lowest MCA RES% [3.4 (0.2)] as well as the lowest ABZ RES% [2.8 (0.4)] on their symptomatic sides. Age, expired pCO2, mean arterial blood pressure, serum glucose, serum haematocrit and number, type and estimated duration of TIAs were not significantly different between subgroups. Linear regression showed a significant relationship between RES% and both measured percentage-stenosis (p = 0.04) and residual luminal diameter (p = 0.05) in symptomatic MCA territories. This approached significance in symptomatic ABZ regions. This preliminary data set suggests that unilateral carotid stenosis can and does result in impaired CO2 reactivity following hypercapnia. The relative normality of CO2 reactivity in those with carotid occlusion is discussed.
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PMID:Blood flow reactivity to hypercapnia in strictly unilateral carotid disease: preliminary results. 190 47

Dislodgement of atheromatous plaque from the ascending aorta following manipulation is one of the principal causes of stroke following cardiac surgery. To define clinical correlates that predict the presence of severe atherosclerosis, we performed ultrasonographic evaluation of the ascending aorta at the time of cardiac surgery in 100 consecutive patients. The ascending aorta was divided into three equal segments for analysis, and the severity of atherosclerosis was determined as mild when intimal thickening (less than 3 mm) was localized to one segment, moderate when intimal thickening (greater than 3 mm) was present in one or two segments, and severe when intimal thickening (greater than 3 mm) was present throughout the entire circumference in all three segments. Thirty-eight percent of the studies were normal, mild atherosclerosis was present in 33%, moderate atherosclerosis in 19%, and severe atherosclerosis in 10% of the patients. Palpation of the ascending aorta to detect atherosclerosis significantly underestimated the presence (p less than 0.001) and severity (p less than 0.001) of atherosclerosis when compared with ultrasonography. Age, carotid artery disease, diabetes, gender, smoking, and hypertension were evaluated for their ability to discriminate between normal and severely atherosclerotic aortas. Stepwise logistic regression analysis showed age (p less than 0.02) and diabetes (p less than 0.04) to be significant independent predictors of the presence of severe atherosclerosis in the ascending aorta. Based on the ultrasonographic findings, the operative procedure was altered to reduce the risk of embolization in 17% of the patients. We conclude that high-resolution images of the ascending aorta for identification of atherosclerosis can be obtained by ultrasonography.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intraoperative ultrasonographic evaluation of the ascending aorta in 100 consecutive patients undergoing cardiac surgery. 193 41


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