Stroke; a journal of cerebral circulation
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The objective of this study was to evaluate the yield of emergent transcranial Doppler (TCD) for the evaluation of acute cerebral ischemia. ⋯ A proximal occlusion on TCD was found in 69% of thrombolysis-eligible patients. In 26% of all patients, TCD provided further relevant information that, in addition to angiography, helped to refine the severity of a stenosis and determine stroke pathogenesis. Emergent TCD is both sensitive and specific in determining arterial occlusion and stenosis in acute cerebral ischemia.
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Dipyridamole increases the concentration of circulating adenosine, which is a potent vasodilator, by inhibition of uptake of adenosine into the erythrocytes, and hence produces coronary vasodilation. However, the effects of dipyridamole on cerebral circulation is not pronounced. This study investigates the effects of intravenous dipyridamole on cerebral blood flow (CBF) in humans with use of positron emission tomography (PET). ⋯ These results indicate that the observed decrease in CBF during dipyridamole stress was caused by a decrease in PaCO(2) rather than by any direct action of dipyridamole on CBF. The decrease in PaCO(2) during dipyridamole stress was most likely due to hyperventilation, which was a side effect of adenosine. These results support the hypothesis that circulating adenosine is largely prevented from binding to adenosine receptors of cerebral vessels by the blood-brain barrier.
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Comparative Study
Cost-effectiveness analysis of screening for asymptomatic, unruptured intracranial aneurysms. A mathematical model.
Subarachnoid hemorrhage (SAH) due to aneurysmal rupture is a major cause of cerebrovascular disease-related death. This problem could be eliminated by diagnosis and successful treatment of aneurysms before rupture. Recent developments in high-resolution imaging technology have made screening for unruptured aneurysms possible in the general population. Such screening has become widespread in Japan ("No Dokku, " or brain checkup). As a result, unruptured aneurysms are being identified with increasing frequency. However, the economic implications of treatment decisions for unruptured aneurysms have not been analyzed. Therefore, we performed such an analysis. ⋯ The cost-effectiveness of screening for an unruptured aneurysm is highly sensitive to the annual rate of subarachnoid hemorrhage due to unruptured aneurysms. The low annual rupture rate seen in the recent large international cooperative study implies that screening asymptomatic populations to identify and treat unruptured aneurysms would not be cost cost-effective.
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Comparative Study
Structural fragility and inflammatory response of ruptured cerebral aneurysms. A comparative study between ruptured and unruptured cerebral aneurysms.
Despite technical advances in endovascular and microsurgical treatment, patients with aneurysmal subarachnoid hemorrhage still have a high mortality and morbidity rate. To improve the treatment results in patients with aneurysms, we must better understand the pathophysiology of cerebral aneurysms and the mechanisms leading to their rupture. Therefore, we studied the pathological differences between unruptured and ruptured aneurysms. ⋯ We conclude that the pathophysiology of unruptured, asymptomatic and ruptured aneurysms is different. The wall of ruptured aneurysms was found to be fragile, possibly because macrophage infiltration into the aneurysmal wall resulted in loss of smooth muscle cells and in degradation of matrix proteins.
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The role of type of treatment on cerebral vasospasm occurrence after aneurysmal subarachnoid hemorrhage (SAH) has not been studied. Through multivariate analysis we determined the independent prognostic factors of the occurrence of symptomatic vasospasm following aneurysmal SAH in a study cohort of 244 patients undergoing either surgical or endovascular treatment. The prognostic factors of sequelae after aneurysmal SAH were studied as well. ⋯ Age <50 years, good neurological grade, and hyperglycemia were all associated with an increased risk of cerebral vasospasm whereas treatment was not. This provides a basis for future clinical prospective randomized trials comparing both treatments.