Stroke

Nguyên nhân học của đột quỵ thiếu máu não ảnh hưởng đến tiên lượng, kết quả và việc quản lý. Các thử nghiệm điều trị cho bệnh nhân đột quỵ cấp nên bao gồm đo lường các phản ứng bị ảnh hưởng bởi phân nhóm của đột quỵ thiếu máu não. Một hệ thống phân loại các phân nhóm đột quỵ thiếu máu não chủ yếu dựa trên nguyên nhân học đã được phát triển cho Thử nghiệm Org 10172 trong Việc Điều Trị Đột Quỵ Cấp (TOAST).

Một phân loại các phân nhóm đã được chuẩn bị dựa trên các đặc điểm lâm sàng và kết quả của các nghiên cứu chẩn đoán phụ trợ. "Có thể" và "khả năng lớn" chẩn đoán có thể được thực hiện dựa trên mức độ chắc chắn về chẩn đoán của bác sĩ. Tính hữu ích và sự đồng thuận giữa các nhà chẩn đoán của phân loại này đã được kiểm tra bởi hai bác sĩ thần kinh không tham gia vào việc viết tiêu chí. Các bác sĩ thần kinh đã độc lập sử dụng hệ thống phân loại TOAST trong việc đánh giá tại giường 20 bệnh nhân, đầu tiên chỉ dựa trên các đặc điểm lâm sàng, sau đó là sau khi xem xét kết quả của các xét nghiệm chẩn đoán.

Hệ thống phân loại TOAST chia đột quỵ thiếu máu não thành năm phân nhóm: 1) xơ vữa động mạch lớn, 2) huyết tắc từ tim, 3) tắc vi mạch, 4) đột quỵ do nguyên nhân khác đã xác định, và 5) đột quỵ do nguyên nhân chưa xác định. Sử dụng hệ thống này, sự đồng thuận giữa các bác sĩ rất cao. Hai bác sĩ chỉ không đồng ý ở một bệnh nhân. Cả hai đều có thể đưa ra chẩn đoán nguyên nhân cụ thể ở 11 bệnh nhân, trong khi nguyên nhân gây đột quỵ không được xác định ở chín bệnh nhân.

Hệ thống phân loại phân nhóm đột quỵ TOAST dễ sử dụng và có sự đồng thuận tốt giữa những người quan sát. Hệ thống này nên cho phép các nhà nghiên cứu báo cáo các phản ứng với điều trị trong các nhóm bệnh nhân quan trọng bị đột quỵ thiếu máu não. Các thử nghiệm lâm sàng kiểm tra các phương pháp điều trị cho đột quỵ thiếu máu não cấp nên bao gồm các phương pháp tương tự để chẩn đoán phân nhóm đột quỵ.

The impact of nonrheumatic atrial fibrillation, hypertension, coronary heart disease, and cardiac failure on stroke incidence was examined in 5,070 participants in the Framingham Study after 34 years of follow-up. Compared with subjects free of these conditions, the age-adjusted incidence of stroke was more than doubled in the presence of coronary heart disease (p less than 0.001) and more than trebled in the presence of hypertension (p less than 0.001). There was a more than fourfold excess of stroke in subjects with cardiac failure (p less than 0.001) and a near fivefold excess when atrial fibrillation was present (p less than 0.001). In persons with coronary heart disease or cardiac failure, atrial fibrillation doubled the stroke risk in men and trebled the risk in women. With increasing age the effects of hypertension, coronary heart disease, and cardiac failure on the risk of stroke became progressively weaker (p less than 0.05). Advancing age, however, did not reduce the significant impact of atrial fibrillation. For persons aged 80-89 years, atrial fibrillation was the sole cardiovascular condition to exert an independent effect on stroke incidence (p less than 0.001). The attributable risk of stroke for all cardiovascular contributors decreased with age except for atrial fibrillation, for which the attributable risk increased significantly (p less than 0.01), rising from 1.5% for those aged 50-59 years to 23.5% for those aged 80-89 years. While these findings highlight the impact of each cardiovascular condition on the risk of stroke, the data suggest that the elderly are particularly vulnerable to stroke when atrial fibrillation is present.(ABSTRACT TRUNCATED AT 250 WORDS)

To develop a simple, relatively noninvasive small-animal model of reversible regional cerebral ischemia, we tested various methods of inducing infarction in the territory of the right middle cerebral artery (MCA) by extracranial vascular occlusion in rats. In preliminary studies, 60 rats were anesthetized with ketamine and different combinations of vessels were occluded; blood pressure and arterial blood gases were monitored. Neurologic deficit, mortality rate, gross pathology, and in some instances, electroencephalogram and histochemical staining results were evaluated in all surviving rats. The principal procedure consisted of introducing a 4-0 nylon intraluminal suture into the cervical internal carotid artery (ICA) and advancing it intracranially to block blood flow into the MCA; collateral blood flow was reduced by interrupting all branches of the external carotid artery (ECA) and all extracranial branches of the ICA. In some groups of rats, bilateral vertebral or contralateral carotid artery occlusion was also performed. India ink perfusion studies in 20 rats documented blockage of MCA blood flow in 14 rats subjected to permanent occlusion and the restoration of blood flow to the MCA territory in six rats after withdrawal of the suture from the ICA. The best method of MCA occlusion was then selected for further confirmatory studies, including histologic examination, in five additional groups of rats anesthetized with halothane. Seven of eight rats that underwent permanent occlusion of the MCA had resolving moderately severe neurologic deficits (Grade 2 of 4) and unilateral infarcts averaging 37.6 +/- 5.5% of the coronal sectional area at 72 hours after the onset of occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Interobserver agreement for the assessment of handicap in stroke patients was investigated in a group of 10 senior neurologists and 24 residents from two centers. One hundred patients were separately interviewed by two physicians in different combinations. The degree of handicap was recorded by each observer on the modified Rankin scale, which has six grades (0-5). The agreement rates were corrected for chance (kappa statistics). Both physicians agreed on the degree of handicap in 65 patients; they differed by one grade in 32 patients and by two grades in 3 patients. Kappa for all pairwise observations was 0.56; the value for weighted kappa (with quadratic disagreement weights) was 0.91. Our results confirm the value of the modified Rankin scale in the assessment of handicap in stroke patients; nevertheless, further improvements are possible.

We designed a 15-item neurologic examination stroke scale for use in acute stroke therapy trials. In a study of 24 stroke patients, interrater reliability for the scale was found to be high (mean kappa = 0.69), and test-retest reliability was also high (mean kappa = 0.66-0.77). Test-retest reliability did not differ significantly among a neurologist, a neurology house officer, a neurology nurse, or an emergency department nurse. The stroke scale validity was assessed by comparing the scale scores obtained prospectively on 65 acute stroke patients to the patients' infarction size as measured by computed tomography scan at 1 week and to the patients' clinical outcome as determined at 3 months. These correlations (scale-lesion size r = 0.68, scale-outcome r = 0.79) suggested acceptable examination and scale validity. Of the 15 test items, the most interrater reliable item (pupillary response) had low validity. Less reliable items such as upper or lower extremity motor function were more valid. We discuss methods for improving the reliability and validity of brief examination scales to be used in stroke therapy trials.

The aim of this updated guideline is to provide comprehensive and timely evidence-based recommendations on the prevention of future stroke among survivors of ischemic stroke or transient ischemic attack. The guideline is addressed to all clinicians who manage secondary prevention for these patients. Evidence-based recommendations are provided for control of risk factors, intervention for vascular obstruction, antithrombotic therapy for cardioembolism, and antiplatelet therapy for noncardioembolic stroke. Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances, including aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. Special sections address use of antithrombotic and anticoagulation therapy after an intracranial hemorrhage and implementation of guidelines.