Haemodynamics of the circle of Willis and the leptomeningeal anastomoses: an electromagnetic flowmeter study of intracranial arterial occlusion in the monkey

Predicting the Effect of Carotid Artery Occlusion During Carotid Endarterectomy

“…13 The response to clamp release involves all collateral pathways such as the leptomeningeal arteries. 12,18,26 It is unlikely that differences in MAP influenced our results since there were no differences during baseline in groups 1 to 3 or during occlusion in groups 1 and 2, and MAP was highest in group 3 during occlusion where FVm was lowest (Tables 2 and 3). If pressure autoregulation had been impaired during carotid artery cross-clamping, the effect of higher MAP would have minimized the differences between groups 1 and 2 compared with group 3.…”

Predicting the Effect of Carotid Artery Occlusion During Carotid Endarterectomy

“…13 The response to clamp release involves all collateral pathways such as the leptomeningeal arteries. 12,18,26 It is unlikely that differences in MAP influenced our results since there were no differences during baseline in groups 1 to 3 or during occlusion in groups 1 and 2, and MAP was highest in group 3 during occlusion where FVm was lowest (Tables 2 and 3). If pressure autoregulation had been impaired during carotid artery cross-clamping, the effect of higher MAP would have minimized the differences between groups 1 and 2 compared with group 3.…”

Experimental Studies on the Cerebral Circulation

“…It was found by that, following a severe ischwnmic episode to the whole brain, occasioned by the temporary obstruction of all four afferent vessels, a considerable transient hyperperfusion in the cerebral cortex could be demonstrated. This was subsequently confirmed by Ishikawa et al (1965) by electromagnetic flowmeter techniques, and it has been investigated in detail in a study of regional resistance changes in the cortical distribution of the middle cerebral artery. The method of production of reactive hyperemia in the cerebral circulation is far from fully established.…”

Effect of Collateral Flow Patterns on Outcome of Carotid Occlusion

“…Increased perfu sion in the vicinity of focal cerebral ischemia can reduce the penumbra through collateral circulation via leptomeningeal anastomoses [32], However, the neurological outcome of patients with watershed ischemia was not affected by the number of patent collateral vessels. Only 2 patients out of 13 with this type of ischemia had more than one patent collateral artery.…”

Predicting the Effect of Carotid Artery Occlusion During Carotid Endarterectomy

“…13 The response to clamp release involves all collateral pathways such as the leptomeningeal arteries. 12,18,26 It is unlikely that differences in MAP influenced our results since there were no differences during baseline in groups 1 to 3 or during occlusion in groups 1 and 2, and MAP was highest in group 3 during occlusion where FVm was lowest (Tables 2 and 3). If pressure autoregulation had been impaired during carotid artery cross-clamping, the effect of higher MAP would have minimized the differences between groups 1 and 2 compared with group 3.…”

Experimental Studies on the Cerebral Circulation

“…It was found by that, following a severe ischwnmic episode to the whole brain, occasioned by the temporary obstruction of all four afferent vessels, a considerable transient hyperperfusion in the cerebral cortex could be demonstrated. This was subsequently confirmed by Ishikawa et al (1965) by electromagnetic flowmeter techniques, and it has been investigated in detail in a study of regional resistance changes in the cortical distribution of the middle cerebral artery. The method of production of reactive hyperemia in the cerebral circulation is far from fully established.…”

Effect of Collateral Flow Patterns on Outcome of Carotid Occlusion

“…Increased perfu sion in the vicinity of focal cerebral ischemia can reduce the penumbra through collateral circulation via leptomeningeal anastomoses [32], However, the neurological outcome of patients with watershed ischemia was not affected by the number of patent collateral vessels. Only 2 patients out of 13 with this type of ischemia had more than one patent collateral artery.…”

Predicting the Effect of Carotid Artery Occlusion During Carotid Endarterectomy

“…13 The response to clamp release involves all collateral pathways such as the leptomeningeal arteries. 12,18,26 It is unlikely that differences in MAP influenced our results since there were no differences during baseline in groups 1 to 3 or during occlusion in groups 1 and 2, and MAP was highest in group 3 during occlusion where FVm was lowest (Tables 2 and 3). If pressure autoregulation had been impaired during carotid artery cross-clamping, the effect of higher MAP would have minimized the differences between groups 1 and 2 compared with group 3.…”

Experimental Studies on the Cerebral Circulation

“…It was found by that, following a severe ischwnmic episode to the whole brain, occasioned by the temporary obstruction of all four afferent vessels, a considerable transient hyperperfusion in the cerebral cortex could be demonstrated. This was subsequently confirmed by Ishikawa et al (1965) by electromagnetic flowmeter techniques, and it has been investigated in detail in a study of regional resistance changes in the cortical distribution of the middle cerebral artery. The method of production of reactive hyperemia in the cerebral circulation is far from fully established.…”

Effect of Collateral Flow Patterns on Outcome of Carotid Occlusion

“…Increased perfu sion in the vicinity of focal cerebral ischemia can reduce the penumbra through collateral circulation via leptomeningeal anastomoses [32], However, the neurological outcome of patients with watershed ischemia was not affected by the number of patent collateral vessels. Only 2 patients out of 13 with this type of ischemia had more than one patent collateral artery.…”