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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cerebrovascular disease is the most important cause of mortality and morbility in some European Countries, but the prevalence of carotid occlusive disease has not been adequately assessed. From 1985 to 1987, 1,143 patients were consecutively evaluated in the Vascular Laboratory in order to determine the presence of extracranial carotid occlusive disease. 638 (55.8%) were males and 505 (44.2%) females and mean age was 58 years (16-87). 509 had previously focal brain ischemia, ocular and/or hemispheric (Group I), 78 had assymptomatic cervical bruit (Group II), 55 non-hemispheric neurologic dysfunction (Group III) and 501 had atypical symptoms for cerebrovascular disease (Group IV). Diagnostic criteria for carotid disease: were peak frequency greater than 4.0 KHz; spectral broadening greater than 40% and late sysstolic turbulence. Global prevalence of carotid disease was 31.8% and the results in each group were: Gr. I-37.2%; Gr. II-57.7%; Gr. III-43.6%; Gr. IV-21.2%. 49% of the patients had hypertension, 22.8% dyslipidemia, 22.4% evidence of coronary disease and 13.6% had diabetes. Hypertension, diabetes, coronary disease and the coexistence of two risk factors were significantly more prevalent in the group of patients with carotid disease. These results confirm a high prevalence of carotid disease in this population, which is comparable to the one is northern european populations.
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PMID:[Prevalence of extracranial carotid occlusive disease. Non-invasive study]. 157 Jul 56

Using the technology of his day, limited to direct observation and histological techniques, Fisher conclusively established the importance of the atherosclerotic carotid plaque in stroke. Recognizing the limits of his observations, he raised a number of questions as regards the degree of carotid disease necessary to adversely affect the brain and the effects of silent carotid occlusion. He also suggested the possible beneficial effects of revascularization. These questions have been addressed and in large part answered by PET. Thresholds of electrical activity and of cellular viability have been established both for cerebral blood flow and for oxygen metabolism. The effects of severe carotid stenosis have been found to be limited to the anterior border zone, where a decreased CBF and CBF to CBV ratio is seen in association with a trend towards rising OEF and declining CMRO2. The acute effects of a stroke and the passage of ischemia to infarction have been documented as they affect CBF, OEF, and CMRO2 in densely ischemic areas and in the penumbra region. An early pattern of elevated OEF in the face of diminished CBF is recognized and evolves into a later pattern of low OEF and CMRO2 characteristic of cell death. Silent carotid occlusion has been shown to produce widespread hypoperfusion and metabolic depression, the former improved by bypass, the latter not. Finally, the CBF to CBV ratio does not appear to be adequate in identifying patients who would benefit from EC-IC bypass, while an elevated preoperative OEF, an unusual event, does not clearly guarantee improved postoperative oxygen metabolism or the prevention of an ipsilateral stroke. Because the anterior border zone is selectively vulnerable to cerebral ischemia in patients with carotid stenosis, and since irreversible oxygen hypometabolism ensues once occlusion occurs, PET may be useful in identifying patients who may be at risk of further ischemic events should stenosis progress to occlusion. PET may also prove to be helpful in understanding the pathophysiology of ischemic complications associated with cerebral aneurysms and AVMs and may be a useful tool for deciding the timing of therapeutic intervention in these conditions.
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PMID:Physiologic studies of cerebral ischemia. 200 95

The evaluation and management of retinal ischemia from atherosclerotic carotid disease is in a state of flux reflected by the change from emphasizing surgical management in the '70s toward skepticism about the benefit of surgery in the '80s. In addition, reliable noninvasive diagnostic testing of the carotid artery has reduced the risk. The decision to consider surgical versus medical management must be made on an individual basis based on the patient's health, age, and the risk of angiography and surgery at each institution. In children and young adults, amaurosis fugax is a benign condition. In the older population amaurosis fugax is often the sentinel event of diffuse atherosclerotic disease and possible early death from myocardial infarction. A team including the neurologist, internist, ophthalmologist, and surgeon optimizes care of the whole disease and not just the symptom. It is hoped that information in the next decade will supply additional guidance in the care of this multifaceted malady.
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PMID:Atherosclerotic carotid disease and the eye. 201 Nov 6

The fear of cerebral complications after cardiopulmonary bypass in patients with heart disease and severe carotid artery disease has led many authors to suggest combined approaches in these patients. The pathogenetic mechanism for stroke is based partly on the stenotic narrowing of the carotid artery. A diameter reduction of 75% is frequently considered hemodynamically significant and indicative of an increased risk for neurological morbidity. We studied the cerebral blood flow in 7 patients undergoing coronary artery bypass grafting who also had severe bilateral carotid disease. The results were compared with the results in 17 patients without carotid disease who had bypass grafting. The cerebral blood flow was measured by xenon 133 washout technique before, during, and after cardiopulmonary bypass with moderate hypothermia. Acid-base regulation was according to the alpha-stat theory, and blood pressure was kept greater than 50 mm Hg. The cerebral blood flow levels (mL.100g-1.min-1) before, during, and after cardiopulmonary bypass in the study group (30 +/- 11, 31 +/- 8, 47 +/- 20) (mean +/- standard deviation) were almost identical to those in the control group (30 +/- 11, 28 +/- 8, 47 +/- 12). The cerebral blood flow levels for the left and right hemispheres in the group with carotid disease were comparable and within normal ranges. In 2 patients, slight differences were noted between hemispheres, and this finding may indicate an increased risk for ischemia. These patients, however, did not show any signs of postoperative deficit. The flow limitations of critical carotid stenoses do not seem to imply a risk for cerebral hypoperfusion if cardiopulmonary perfusion is performed in a controlled manner.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cardiopulmonary perfusion and cerebral blood flow in bilateral carotid artery disease. 201 11

We noninvasively evaluated the prevalence and severity of atherosclerotic lesions of the internal carotid artery in 146 nonobese, nondiabetic hypertensive patients who were free of cardiovascular symptoms. We found internal carotid artery disease in 63 patients (43%), 26 (18%) with unilateral disease and the other 37 (25%) with bilateral disease. Disease severity was correlated with age but not duration of hypertension, cholesterol level, or current smoking habit. We also followed disease progression and clinical outcome with respect to cardiovascular events for 3 years in a subgroup of 95 unselected patients. In 20 of the 93 survivors (21.5%) we noted progression of the atherosclerotic lesions that was predicted by neither risk factors nor initial status of the internal carotid artery. New neurologic symptoms developed in four survivors (4%) and symptoms of cardiac ischemia in six (6%). No survivor who developed new cerebrovascular symptoms showed progression of carotid disease. These data provide useful elements for a rational approach to prevention of the atherosclerotic complications of hypertension.
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PMID:Noninvasive study of arterial hypertension and carotid atherosclerosis. 230 66

Experience with 1035 carotid endarterectomies in a single community over a 2-year period was analyzed. Twenty-two surgeons working in six hospitals were involved. All surgeons had full-time or part-time appointments at the University of Rochester, 18 had special interest in vascular surgery, and eight had obtained a certificate of qualification in vascular surgery. Mortality rate was 1.4% (14 deaths), with additional permanent, nonfatal, neurologic morbidity of 3.4%. Mortality and morbidity were independent of surgeon, caseload, or hospital. Age and prior history of myocardial infarction influenced the incidence of postoperative myocardial infarction but not the incidence of death or neurologic morbidity. Factors that increased the risk of postoperative death or neurologic complication included hypertension; contralateral carotid disease as manifested by stroke, endarterectomy, or occlusion; whether the patient was a woman; and symptoms of crescendo ischemia. Lack of preoperative neurologic symptoms was correlated with decreased risk of myocardial infarction and neurologic complications. Overall mortality and neurologic morbidity associated with operation for "asymptomatic stenosis" was 3.1% (seven of 222 cases). However, the incidence of contralateral carotid disease was high in the patients in the asymptomatic group (60%), and all complications in this group occurred in patients with prior contralateral carotid endarterectomy or occlusion (p less than 0.05).
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PMID:Risk factors in a community experience with carotid endarterectomy. 276 Sep 95

To investigate the clinical significance of lucent defects in computed tomography (CT) scans of the cervical carotid artery plaque, we studied 95 patients with recent symptoms of hemispheric ischemia. Using multiple linear regression analysis, we estimated the strength of the association of symptoms with laterality of carotid artery lucent lesions, stenoses, and ulcerations observed in CT scans. Hemispheric symptoms correlated strongly with ipsilateral carotid lucent lesions (partial p less than 0.025) and with ipsilateral severe (greater than 75%) carotid stenosis (partial p less than 0.025). Carotid artery ulcerations had a weaker association (partial p less than 0.1), and stenoses of mild and moderate degrees showed none. The overall performance of all three plaque complications was highly significant (p less than 0.005). The lucent defect indicates a morphologic change in the carotid plaque that plays an important role in the development of symptoms of hemispheric ischemia. This is in agreement with the notion that the lucent defect is the image of intraplaque hemorrhage and/or necrosis, which are complications central to the development of symptomatic carotid disease.
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PMID:Computed tomography of the cervical carotid artery: significance of the lucent defect. 337 63

A consecutive series of 369 asymptomatic patients with a carotid bruit was prospectively followed with Ocular Pneumoplethysmography (OPG). The aim of the study was to identify those patients most prone to cerebrovascular ischemia and/or progression of obstructive carotid disease. During follow-up 13 patients developed a stroke of which six were fatal (two thrombo-embolic and four haemorrhagic strokes). TIA's occurred in 15 patients, including eight patients with amaurosis fugax. TIA's occurred more frequently on the side of a haemodynamically significant stenosis (9% = 9/95) than on the side of a normal, OPG (2% = 6/274). There was no difference in the strokelocated side. The occurrence of symptoms and/or signs of cerebrovascular disease was 4% at two years and 10% at five years. The left hemisphere was affected twice as often as the right. The development of a haemodynamically significant carotid stenosis, according to OPG, was equal for the right and the left carotid arteries, being 18% at two years and 56% after 5 years of follow-up. The major risk factors for progression of obstructive disease were systolic blood pressure above 160 mmHg independent of age, diabetes mellitus and the presence of ischaemic heart and peripheral arterial obstructive disease. This study supports the contention that in a group of patients with an asymptomatic carotid bruit, a group of patients at risk from cerebrovascular accidents can be filtered out by a simple non-invasive test in combination with a complete physical examination.
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PMID:Risk factors in asymptomatic patients with a carotid bruit. 350 60

Thirteen patients with transient vertebrobasilar insufficiency caused by emboli from a proximal subclavian artery lesion were treated over a 5-year period. This group was characterized by the absence of significant carotid disease (12 of 13 patients) and equal arm pressures bilaterally in most patients (8 of 13 patients). An isolated supraclavicular bruit (12 of 13 patients) and a history of ipsilateral digital ischemia (5 of 13 patients) were common. Arch angiography demonstrated proximal subclavian lesions in 12 patients, with obvious ulcerations in 10 cases and thrombus in an old carotid-subclavian bypass graft in one case. Surgery directed at removal or exclusion of the lesion was successful in all cases. Isolated lesions in the subclavian artery can be a source of emboli into the vertebrobasilar circulation. These lesions are effectively treated by exclusion and vascular reconstruction.
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PMID:Embolic lesions from the subclavian artery causing transient vertebrobasilar insufficiency. 376 81

A review of the UCSD experience with 456 consecutive carotid endarterectomy procedures confirms the acceptably low operative mortality and morbidity associated with this operation. Immediate complications were not different when routine or selective shunting was performed, but the patients with a low internal carotid artery back pressure had higher operative complication rates. The coexistence of atherosclerosis in other parts of the body severe-enough to warrant surgery for them was not associated with either higher early or late carotid surgery complication rates. Following both coronary bypass and carotid procedures, the late mortality was decreased, and the late incidence of stroke was particularly low in comparison to the remainder of the patient group. Late follow-up emphasized the high continuing attrition rate from all causes in these patients. Late strokes continued to occur, particularly in patients with prior strokes and severe preoperative bilateral carotid disease. The late course of patients with posterior circulation transient ischemic attacks treated by carotid endarterectomy was quite similar to that of patients treated for anterior circulation transient ischemia attacks (TIAs). Newer postoperative screening procedures may decrease the incidence of late postoperative stroke by identifying recurrent carotid stenosis while it is still in the asymptomatic stage.
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PMID:Life expectancy and late stroke following carotid endarterectomy. 660 97


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