Pathophysiology of extracranial cerebral arterial stenosis--a critical review.

Grady, Patricia A.

doi:10.1161/01.str.15.2.224

Cited by 24 publications

(11 citation statements)

References 142 publications

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“…3032 Local turbulent flow can be detected by Doppler testing when the arterial area reduction reaches 50% to 60%, 33 and distal hemodynamic impairment is usually associated with more than 70% reduction.…”

Section: Discussionmentioning

confidence: 99%

Clinical correlates of high-intensity transient signals detected on transcranial Doppler sonography in patients with cerebrovascular disease.

Babikian

Hyde

Pochay

et al. 1994

Stroke

100

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Background and Purpose High-intensity transient signals detected by transcranial Doppler sonography have been associated with particulate cerebral emboli. Their clinical correlates are poorly understood. This study was undertaken to assess their relation to cerebral ischemia and to determine whether the severity of cerebral arterial stenosis has an impact on their occurrence.Methods We studied 96 arteries in 75 consecutive patients with extracranial or intracranial arterial lesions or potential cardiac sources of cerebral embolism. Sixty patients had histories of cerebral or retinal transient ischemic attacks or infarcts, and 15 were asymptomatic. The diagnosis of ischemia was based on the clinical presentation and was supported by extensive laboratory testing. A transcranial Doppler sonography unit equipped with special software for emboli detection was used. Signals were selected based on criteria established a priori.

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Section: Discussionmentioning

confidence: 99%

Clinical correlates of high-intensity transient signals detected on transcranial Doppler sonography in patients with cerebrovascular disease.

Babikian

Hyde

Pochay

et al. 1994

Stroke

100

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show abstract

“…35,36 Hypertension seems to be the most important determinant in both intracerebral hemorrhage and cerebral infarction and is known to lead to atherosclerosis, with predilection for precerebral and large cerebral arteries. 37 On the other hand, the small intraparenchymal cerebral arteries develop hyaline degeneration and fibrinoid necroses associated with lacunar infarcts and hemorrhages; however, the body of evidence is much weaker for this explanation than for the association between hypertension and atherosclerosis. 38 The only risk factors examined in the present study that had opposite effects on the risks of intracerebral hemorrhage and cerebral infarction were serum total and HDL cholesterol levels.…”

Section: Leppälä Et Al Blood Pressure Cholesterol Antioxidants Andmentioning

confidence: 99%

Different Risk Factors for Different Stroke Subtypes

Leppälä

Virtamo

Fogelholm

et al. 1999

Stroke

223

105

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Background and Purpose-Blood pressure is an important risk factor for stroke, but the roles of serum total and HDL cholesterol, ␣-tocopherol, and ␤-carotene are poorly established. We studied these factors in relation to stroke subtypes. Methods-Male smokers (nϭ28 519) aged 50 to 69 years without a history of stroke participated in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, a controlled trial to test the effect of ␣-tocopherol and ␤-carotene supplementation on cancer. From 1985 to 1993, a total of 1057 men suffered from primary stroke: 85 had subarachnoid hemorrhage; 112, intracerebral hemorrhage; 807, cerebral infarction; and 53, unspecified stroke. Results-Systolic blood pressure Ն160 mm Hg increased the risk of all stroke subtypes 2.5 to 4-fold. Serum total cholesterol was inversely associated with the risk of intracerebral hemorrhage, whereas the risk of cerebral infarction was raised at concentrations Ն7.0 mmol/L. The risks of subarachnoid hemorrhage and cerebral infarction were lowered with serum HDL cholesterol levels Ն0.85 mmol/L. Pretrial high serum ␣-tocopherol decreased the risk of intracerebral hemorrhage by half and cerebral infarction by one third, whereas high serum ␤-carotene doubled the risk of subarachnoid hemorrhage and decreased that of cerebral infarction by one fifth. Conclusions-The risk factor profiles of stroke subtypes differ, reflecting different etiopathology. Because reducing atherosclerotic diseases, including ischemic stroke, by lowering high serum cholesterol is one of the main targets in public health care, further studies are needed to distinguish subjects with risk of hemorrhagic stroke.

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“…The normal flow patterns observed in the inferior bulb are associated with wall shear stress 3,9) and flow separation, 15) which are important factors in the pathogenesis of atherosclerotic plaques, which most often form at this site in the carotid artery. Laminar flow theory, an important concept in hemodynamics, 11,13) suggests that blood flow in the arterial vessels is faster in the inner layers of the lumen and slower in the outer layers of the lumen, because of the viscosity of the blood. In the carotid bulb, flow velocity decreases and intra-arterial pressure increases according to Bernoulli's law, because of the widening of the lumen.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Blood Flow in Carotid Artery Stenosis Using B-Flow Sonography

Mikami

Takahashi

Houkin

2003

Neurol. Med. Chir.(Tokyo)

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B-flow ultrasonography can directly visualize blood streams by reflecting the intravascular red blood cells, and so can detect turbulent flow in vessels. B-flow sonography was used to evaluate flow abnormalities in patients with cervical carotid artery stenosis, and to investigate the mechanism of large embolus formation that may cause distal arterial occlusion. Twenty-two patients with AE60% stenosis of the cervical carotid artery excluding cardiovascular embolism were examined by B-flow and color Doppler sonography. Two patients had distal embolism as revealed by digital subtraction angiography, 16 patients had lacunar infarction, and four patients had transient ischemic attacks. B-flow sonography demonstrated reverse flow at the poststenotic site in patients with AE70% stenosis. Increased echogenicity at the site of the stenosis was seen in patients with at least 80% stenosis. Prestenotic reverse flow was seen in nine patients with AE85% stenosis. The two patients with distal embolism had decreased echogenicity and flow velocity, and diastolic flow was absent. B-flow sonography could detect various turbulent flow patterns and changes in echogenicity associated with cervical carotid artery stenosis. Prestenotic reverse flow and decreased flow velocity may be potential causes of distal embolism. B-flow sonography is a useful method for the evaluation of flow abnormality in patients with carotid artery stenosis.

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Pathophysiology of extracranial cerebral arterial stenosis--a critical review.

Cited by 24 publications

References 142 publications

Clinical correlates of high-intensity transient signals detected on transcranial Doppler sonography in patients with cerebrovascular disease.

Clinical correlates of high-intensity transient signals detected on transcranial Doppler sonography in patients with cerebrovascular disease.

Different Risk Factors for Different Stroke Subtypes

Evaluation of Blood Flow in Carotid Artery Stenosis Using B-Flow Sonography

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