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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypertension is a major risk factor for atherosclerosis. Although antihypertensive drug treatment can reduce morbidity and mortality from stroke, there is no consistent benefit on ischemic heart disease. It may be that subtle adverse effects of the drugs used in these clinical trials may have blunted the beneficial effects of treatment. Isradipine, a new calcium antagonist of the dihydropyridine class, is a potent antihypertensive drug with pronounced antiatherogenic properties, at least in animal studies. Thus, isradipine may be a suitable drug for assessing the efficacy of antihypertensive treatment in retarding the progression of atherosclerosis. The Multicenter Isradipine/Diuretic Atherosclerosis Study (MIDAS) is a clinical trial to compare the efficacy of isradipine (2.5-5.0 mg b.i.d.) and hydrochlorothiazide (12.5-25 mg b.i.d.) in retarding atherosclerosis in carotid arteries. Carotid atherosclerosis will be monitored using B-mode ultrasonography. The sample size is 800 men and women aged 40 years and over. The power of the design is 90% to detect a 30% difference in the progression of plaque size between the isradipine- and hydrochlorothiazide-treated groups with a significance level of 5% (p = 0.05).
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PMID:Multicenter study with isradipine and diuretics against atherosclerosis. US MIDAS Research Group. 169 98

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

This report summarizes the study design and organization of a multicenter, randomized trial of carotid endarterectomy for the treatment of asymptomatic carotid stenosis. The Asymptomatic Carotid Atherosclerosis Study will determine whether the addition of carotid endarterectomy to aspirin plus risk factor modifications affects the incidence of ipsilateral transient ischemic attack, amaurosis fugax, and retinal and cerebral infarction in patients with asymptomatic hemodynamically significant carotid stenosis in at least one artery. Power calculations are based on assumptions of alpha = 0.05 (two-sided test) with annual event rate 3% transient ischemic attack and 1% cerebral infarction per year. The study has 90% power for detection of a 25% difference in events in a 5-year study. Two continuous validation programs are in use: a Doppler/angiogram correlation study for each Doppler instrument used in screening potential candidates and a transient ischemic attack/stroke questionnaire/validation study for verification of end points. Quality assurance is a major component in study design.
Stroke 1989 Jul
PMID:Study design for randomized prospective trial of carotid endarterectomy for asymptomatic atherosclerosis. The Asymptomatic Carotid Atherosclerosis Study Group. 266 5

Carotid atherosclerosis occurring secondary to cervical irradiation is known to produce stroke. Transient neurologic symptoms have necessitated surgical intervention to prevent stroke despite concern over technical problems, wound healing, operative risks, and uncertain therapeutic outcome. With this report, 26 surgical procedures in 20 patients are now documented in the literature (12 men--60%; eight women--40%). Mean age of these patients (56 years) was 10 years younger than carotid surgery patients with no prior radiation history. No relationship was noted between elevated serum cholesterol and the subsequent development of radiation-induced carotid atherosclerosis. Surgical procedures performed included carotid endarterectomy in 17 cases (65%) and arterial bypass in nine (35%). The combination of radiation therapy and previous neck surgery, including prior radical neck dissection, did not adversely influence operability. Surgical outcome was uniformly good with only one stroke (4%) documented in the perioperative period. Longer follow-up on our six cases (mean two years) disclosed neither new clinical symptoms nor the development of hemodynamically significant restenosis.
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PMID:Surgery for radiation-induced symptomatic carotid atherosclerosis. 271 27

The Asymptomatic Carotid Atherosclerosis Study (ACAS) results suggest that carotid endarterectomy combined with aspirin and risk factor reduction is superior to aspirin and risk factor reduction is superior to aspirin and risk factor reduction alone in preventing ipsilateral stroke in asymptomatic patients with diameter stenosis of the carotid artery of 60% or more. The absolute risk reduction over 5 years conferred by surgical therapy is modest (5.9%) compared with the risk reduction conferred by surgical therapy for symptomatic carotid disease but compares favorably with the degree of stroke prevention shown for antihypertensive therapy in the elderly. For prevention of stroke in women and for prevention of major stroke, the ACAS results favoring surgery did not reach statistical significance. The combined arteriographic and perioperative surgery-related mortality and stroke rates achieved by the carefully selected surgical teams was low (2.3%). Accordingly, carotid endarterectomy can be recommended for preventing stroke in the setting of hemodynamically significant stenosis when the arteriographic and surgical complication rates can be kept low.
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PMID:Medical compared with surgical treatment of asymptomatic carotid artery stenosis. 757 32

Several case series have suggested that endarterectomy is beneficial in asymptomatic carotid artery disease. Four randomized trials have been done in this area, the most recent of which is the Asymptomatic Carotid Atherosclerosis Study (ACAS). Results of the first three trials were negative, and ACAS produced a tantalizing, statistically significant finding that does not translate into clinical importance. Disabling strokes have not been reduced by surgical therapy, and the benefit for women has not been shown. It is unclear from this study whether persons with the greatest stenosis and the highest vascular risk profiles are appropriate candidates for endarterectomy. In patients in whom carotid artery disease is incidentally discovered, the benefits of the prophylactic addition of carotid endarterectomy to coronary bypass grafting or other major surgical procedure in patients are still unknown. Excellent surgical skill is of paramount importance for the future use of this procedure. Mass population screening to detect asymptomatic carotid disease will only be justified when and if future studies identify patients in whom the risk for disabling stroke after the procedure is clearly reduced.
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PMID:The dilemma of surgical treatment for patients with asymptomatic carotid disease. 877 74

On September 28, 1994, the investigators of the Asymptomatic Carotid Atherosclerosis Study (ACAS) reported the interim results of a randomized controlled clinical trial of carotid endarterectomy in patients who have asymptomatic carotid stenosis of greater than 60% reduction in diameter. In addition to aspirin and aggressive management of modifiable risk factors, one-half of the patients were randomly assigned to receive surgery after angiographic confirmation of the lesion. Carotid endarterectomy is beneficial with a statistically significant absolute reduction of 5.8% in the risk of the primary end point of stroke within 5 years and a relative risk reduction of 55%. As a consequence of the trial reaching statistical significance in favor of endarterectomy, and on the recommendation of the study's data monitoring committee, physicians participating in the study were immediately notified and advised to reevaluate patients who did not receive surgery. It is important to note that the success of the operation is dependent on medical centers and surgeons who have a documented perioperative morbidity and mortality of less than 3%, careful selection of patients, and postoperative management of modifiable risk factors.
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PMID:Carotid endarterectomy for patients with asymptomatic internal carotid artery stenosis. National Institute of Neurological Disorders and Stroke. 775 50

The investigators of the Asymptomatic Carotid Atherosclerosis Study (ACAS) are reporting the interim results of a randomized controlled clinical trial of carotid endarterectomy in patients who have asymptomatic carotid stenosis of greater than 60% reduction in diameter. In addition to aspirin and aggressive management of modifiable risk factors, one half of the patients were randomly assigned to receive surgery after angiographic confirmation of the lesion. Carotid endarterectomy is beneficial with a statistically significant absolute reduction of 5.8% in the risk of the primary end point of stroke within 5 years and a relative risk reduction of 55%. As a consequence of the trial reaching statistical significance in favor of endarterectomy, and on the recommendation of the study's data monitoring committee, physicians participating in the study were immediately notified and advised to reevaluate patients who did not receive surgery. It is important to note that the success of the operation is dependent on medical centers and surgeons who have a documented perioperative morbidity and mortality of less than 3%, careful selection of patients, and postoperative management of modifiable risk factors.
Stroke 1994 Dec
PMID:Clinical advisory: carotid endarterectomy for patients with asymptomatic internal carotid artery stenosis. 797 2

Cerebrovascular disease remains an important cause of disability and death in the geriatric population. This paper reviews the current state of knowledge with respect to the pathogenesis and medical and surgical treatment of carotid atherosclerosis. The majority of strokes are probably due to embolization from an ulcerated atherosclerotic plaque at the carotid bifurcation rather than from ischemia produced by global reduction in cerebral blood flow related to obstruction of the carotid arteries. Ultrasonography is an appropriate screening examination, but most vascular surgeons consider contrast angiography to be essential in the preoperative evaluation. Large clinical trials have evaluated the efficacy of stroke prevention by carotid endarterectomy in symptomatic patients. The North American Symptomatic Carotid Endarterectomy Trial clearly demonstrated a benefit of surgery in stroke prevention as compared with optimal medical therapy after only 18 months of follow-up. The European Carotid Surgery Trial and a VA Cooperative Study produced similar conclusions. Much less information is available concerning the patient with carotid atherosclerosis who has no cerebral symptoms. No convincing evidence that surgery is beneficial has yet been demonstrated, but a large multicenter clinical trial (Asymptomatic Carotid Atherosclerosis Study) remains in progress.
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PMID:Surgical management of carotid artery atherosclerotic disease. 821 52

Since its introduction 40 years ago, the value of carotid endarterectomy has been controversial. In the early 1980s, several clinical trials were initiated to determine the efficacy of this operation in patients with carotid stenoses who were either symptomatic or asymptomatic for retinal or hemispheric ischemia. In 1991, interim results were published for the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST), both reporting efficacy for surgery in patients with symptomatic carotid artery stenosis of greater than 70%. Subgroup analyses revealed variable risk groups. The Veterans Administration (VA) Symptomatic Trial (Cooperative Studies Program 309 of the Department of Veterans Affairs) terminated early because of these results and its findings were consistent with the results of the larger trials. NASCET and ECST continue for symptomatic patients with carotid stenoses between 30% and 69%. The results of three trials in asymptomatic patients, the Mayo asymptomatic trial, the Carotid Artery Stenosis with Asymptomatic Narrowing: Operation Versus Aspirin trial, and the VA Asymptomatic Trial (Cooperative Studies Protocol 167 of the Department of Veterans Affairs), have been reported. None showed a statistically significant benefit for surgery in the prevention of stroke or death. However, none was sufficiently large to exclude such a benefit. The large Asymptomatic Carotid Atherosclerosis Study is in progress. Differences in the results and design of these trials are discussed as are restrictions in the applicability of their results.
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PMID:Carotid endarterectomy: trials and tribulations. 828 92


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