What Do We Know About Intracranial Atherosclerosis?
What Do We Know About Intracranial Atherosclerosis?
A comprehensive review compactly conveys current knowledge.
This clinical update is a review of information about intracranial atherosclerosis discussed at a consensus meeting. Concise sections review the prevalence, risk factors, and natural courses of symptomatic and asymptomatic intracranial atherosclerosis, its diagnosis, and its treatment. The most extensive sections consider interventional treatment.
The authors mention recommendations, when available, concerning treatment. For example, for patients with symptomatic intracranial atherosclerosis, the American Heart Association/American Stroke Association recommends aspirin plus extended-release dipyridamole, or possibly clopidogrel alone, over aspirin alone. The review also touches on newer and experimental approaches.
Comment: The strength of this review is its very broad and up-to-date coverage of many aspects of intracranial atherosclerosis. The reference list is extensive. The short paragraphs cannot adequately convey many aspects of current knowledge. Although prevalence data are mentioned, the particularly high prevalence in Asian countries is not emphasized; in fact, the major intracranial arteries are the most frequent site of narrowing in individuals of Asian origin (J Clin Neurosci 2003; 10:30 and Gorelick P et al. Epidemiology. In: Kim JS et al. Intracranial Atherosclerosis. Wiley-Blackwell; 2008). Nor is the higher prevalence in women compared with men mentioned. Moreover, in some countries (e.g., Korea), the relative preponderance of intracranial over extracranial disease is changing, perhaps related to lifestyle changes. Japanese individuals have different frequencies and locations of atherosclerosis in Japan than they do in Hawaii and California (Stroke 1975; 6:539).
The review covers medical treatments, especially antithrombotic agents, only cursorily. It includes the main conclusion of the WASID trial regarding antithrombotics — that aspirin effectiveness was comparable to warfarin and that warfarin anticoagulation was associated with more hemorrhages and deaths. Omitted is the finding that patients whose anticoagulation was accomplished within the target international normalized ratio (INR) range had fewer strokes than the aspirin-treated group (N Engl J Med 2005; 352:1368). Hemorrhages occurred mainly when the INR was higher than targeted. Warfarin has proven difficult to use. Newer direct thrombin inhibitors (e.g., dabigatran) will undoubtedly be much easier to control and prescribe. Also not mentioned is a major conclusion of WASID: that risk-factor control and thorough management of lifestyle factors proved very effective and important in reducing unwanted outcomes of intracranial atherosclerosis.
— Louis R. Caplan, MD
Dr. Caplan is Professor of Neurology, Harvard Medical School, and Senior Neurologist, Stroke Service, Beth Israel Deaconess Medical Center, Boston.
Published in Journal Watch Neurology June 22, 2010
https://docs.google.com/fileview?id=0B278nGJMQBk7YWQzOTRjOWEtMjA3Yi00NDMyLWEwMzgtMmM2MjMzYTdlZWVi&hl=zh_TW
A comprehensive review compactly conveys current knowledge.
This clinical update is a review of information about intracranial atherosclerosis discussed at a consensus meeting. Concise sections review the prevalence, risk factors, and natural courses of symptomatic and asymptomatic intracranial atherosclerosis, its diagnosis, and its treatment. The most extensive sections consider interventional treatment.
The authors mention recommendations, when available, concerning treatment. For example, for patients with symptomatic intracranial atherosclerosis, the American Heart Association/American Stroke Association recommends aspirin plus extended-release dipyridamole, or possibly clopidogrel alone, over aspirin alone. The review also touches on newer and experimental approaches.
Comment: The strength of this review is its very broad and up-to-date coverage of many aspects of intracranial atherosclerosis. The reference list is extensive. The short paragraphs cannot adequately convey many aspects of current knowledge. Although prevalence data are mentioned, the particularly high prevalence in Asian countries is not emphasized; in fact, the major intracranial arteries are the most frequent site of narrowing in individuals of Asian origin (J Clin Neurosci 2003; 10:30 and Gorelick P et al. Epidemiology. In: Kim JS et al. Intracranial Atherosclerosis. Wiley-Blackwell; 2008). Nor is the higher prevalence in women compared with men mentioned. Moreover, in some countries (e.g., Korea), the relative preponderance of intracranial over extracranial disease is changing, perhaps related to lifestyle changes. Japanese individuals have different frequencies and locations of atherosclerosis in Japan than they do in Hawaii and California (Stroke 1975; 6:539).
The review covers medical treatments, especially antithrombotic agents, only cursorily. It includes the main conclusion of the WASID trial regarding antithrombotics — that aspirin effectiveness was comparable to warfarin and that warfarin anticoagulation was associated with more hemorrhages and deaths. Omitted is the finding that patients whose anticoagulation was accomplished within the target international normalized ratio (INR) range had fewer strokes than the aspirin-treated group (N Engl J Med 2005; 352:1368). Hemorrhages occurred mainly when the INR was higher than targeted. Warfarin has proven difficult to use. Newer direct thrombin inhibitors (e.g., dabigatran) will undoubtedly be much easier to control and prescribe. Also not mentioned is a major conclusion of WASID: that risk-factor control and thorough management of lifestyle factors proved very effective and important in reducing unwanted outcomes of intracranial atherosclerosis.
— Louis R. Caplan, MD
Dr. Caplan is Professor of Neurology, Harvard Medical School, and Senior Neurologist, Stroke Service, Beth Israel Deaconess Medical Center, Boston.
Published in Journal Watch Neurology June 22, 2010
https://docs.google.com/fileview?id=0B278nGJMQBk7YWQzOTRjOWEtMjA3Yi00NDMyLWEwMzgtMmM2MjMzYTdlZWVi&hl=zh_TW
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