Cerebrovascular diseases
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Cerebrovascular diseases · Jan 2004
Mechanisms of single and multiple borderzone infarct: transcranial Doppler ultrasound/magnetic resonance imaging correlates.
Hemodynamic patterns after borderzone (BZ) infarction are variable and dynamic. However, stroke mechanisms in different types of BZ infarctions have not been systematically studied by magnetic resonance angiography (MRA) and transcranial Doppler ultrasonography (TCD). ⋯ The association of severe ICA stenosis or occlusion with cardiopathies and left ventricular dysfunction may play a critical role in those with BZ infarcts having inadequate collateral supply, while a cardioembolism or acute ICA dissection may also cause BZ infarction due to the rapidity of the occlusive process and the inability of the cerebral vasculature to recruit collateral pathways quickly enough.
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The occurrence of stroke in patients with human immunodeficiency virus (HIV) infection has been traditionally associated with opportunistic infections and tumors, and advanced stages of immunosuppression. However, this reality is undergoing major changes. Effective antiretroviral regimens are now able to forestall the progression of HIV infection and avoid early mortality. ⋯ Cerebrovascular hemodynamic function is impaired in HIV-infected patients with evidence of abnormal vasoreactivity even in otherwise healthy individuals. The potential contribution from these novel mechanisms should be added to the high incidence of classic vascular risk factors in the HIV-infected population and the cardiac abnormalities frequently observed in these patients. Large-scale epidemiological studies should be carried out to define the true incidence of stroke in HIV-infected patients and the factors associated with its occurrence.
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Cerebrovascular diseases · Jan 2003
Cerebral magnetic resonance imaging within 6 hours of stroke onset: inter- and intra-observer reproducibility.
Magnetic resonance imaging (MRI) provides valuable pathophysiological information during the very first hours of cerebral ischemia. However, the reliability of prime-time MRI in the setting of emergency care remains unknown. ⋯ The visual assessment of T2* gradient echo, TOF, diffusion and perfusion sequences at the acute stage of stroke is reproducible between and within observers. The visual assessment is as good as the volumetric assessment to detect a mismatch of >20%.
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Cerebrovascular diseases · Jan 2003
Clinical TrialThe role of blood pressure in lacunar strokes preceded by TIAs.
Lacunar strokes (LS) are often preceded by repetitive transitory ischaemic attacks (TIAs) known as 'capsular warning syndrome'. The treatment of these symptoms remains controversial. Anticoagulants are often used in this situation, most of the time, however, with no or little benefit. ⋯ One patient received noradrenalin, which allowed stabilisation of the blood pressure values and complete resolution of the neurological symptoms. This observation suggests that in lacunar strokes preceded by TIAs monitoring and, if necessary, pharmacological increase of BP may prevent some patients from developing a definite stroke. Thus the 'capsular warning syndrome' could reflect a haemodynamic failure rather than repeated thrombo-embolism within the lumen of a single perforating arteriole.
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Cerebrovascular diseases · Jan 2003
Noninvasive assessment of spontaneous baroreflex sensitivity and heart rate variability in patients with carotid stenosis.
Previous limited observations have suggested that atherosclerosis may affect the distensibility of the carotid sinus and then impair the baroreflex sensitivity (BRS). No studies have been done to compare the BRS and heart rate variability (HRV) in patients with carotid stenosis and normal controls. ⋯ Our study linked significant carotid stenosis to two important autonomic markers (BRS and HRV) that may have prognostic value for patients with cardiovascular events. Further prospective studies are needed to explore whether or not the decreased BRS and HRV can be predictors for poor cardiovascular prognosis, or even for shortened life span in general, in patients with significant carotid stenosis.