Cortical arterial pressure in occlusive cerebrovascular disease and results of bypass surgery

✓ The importance of hemodynamic factors in the pathogenesis and treatment of cerebrovascular disease remains uncertain. The extracranial-intracranial (EC-IC) bypass trial has been criticized for failing to identify and separately analyze those patients with chronic reduction in regional cerebral perfusion pressure (rCPP) who might be most likely to benefit from surgery. Positron emission tomography (PET) measurements of regional cerebral blood flow (rCBF) and blood volume (rCBV) were performed on 29 patients with symptomatic occlusion or intracranial stenosis of the carotid arterial system prior to undergoing EC-IC bypass surgery. Twenty-four patients had evidence of reduced rCPP (increased rCBV/rCBF ratio) distal to the arterial lesion. Of 21 patients who survived surgery without stroke, three suffered ipsilateral ischemic strokes during the 1st postoperative year. A nonrandomized control group of 23 nonsurgical patients with similar clinical, arterio-graphic, and PET characteristics experienced no ipsilateral ischemic strokes during the 1st year following PET. Based on these results in 44 patients, the probability that successful surgery reduces the occurrence of ipsilateral ischemic stroke 1 year later was calculated. This probability ranged from 0.045 for a 50% reduction to 0.168 for a 10% reduction. Thus, there was little evidence to suggest that measurements of cerebral hemodynamics can identify a group of patients who would benefit from EC-IC bypass surgery.

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Circulatory Reflexes in Cerebral Ischaemia Involving Different Vascular Territories

Clinical Science ◽

10.1042/cs0380491 ◽

1970 ◽

Vol 38 (4) ◽

pp. 491-502 ◽

Cited By ~ 17

Author(s):

M. Gross

Keyword(s):

Statistical Analysis ◽

Arterial Pressure ◽

Cerebrovascular Disease ◽

Internal Carotid ◽

Transient Ischaemic Attacks ◽

Vasoconstrictor Response ◽

Ischaemic Cerebrovascular Disease ◽

Significant Difference ◽

Valsalva's Manoeuvre ◽

Circulatory Reflexes

1. Circulatory reflex function was assessed in a series of subjects with chronic ischaemic cerebrovascular disease and compared with a group of subjects with no known cerebrovascular disease by intra-arterial pressure responses to Valsalva's manoeuvre. 2. Circulatory reflexes were impaired in the patients with cerebrovascular disease as compared with controls, but statistical analysis indicated that age was a more important factor than chronic cerebrovascular disease in producing the deterioration. 3. No significant difference was found in the circulatory reflex function of subjects with ischaemia in the internal carotid territory when compared with those having ischaemia in the vertebrobasilar territory. 4. Combined ischaemia in both carotid and vertebrobasilar territories significantly impaired the cardioaccelerator but not the vasoconstrictor response to Valsalva's manoeuvre. 5. No significant difference was found in circulatory reflex function in subjects who had suffered cerebral infarction as opposed to transient ischaemic attacks.

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Perfusion CT scanning and CT angiography in the evaluation of extracranial-intracranial bypass grafts

Journal of Neurosurgery ◽

10.3171/2010.6.jns10117 ◽

2011 ◽

Vol 114 (4) ◽

pp. 978-983 ◽

Cited By ~ 9

Author(s):

Soenke Langner ◽

Steffen Fleck ◽

Rebecca Seipel ◽

Henry W. S. Schroeder ◽

Norbert Hosten ◽

...

Keyword(s):

Computed Tomography ◽

Cerebrovascular Disease ◽

Bypass Surgery ◽

Superficial Temporal Artery ◽

Ct Scanning ◽

Temporal Artery ◽

Perfusion Ct ◽

Time To Peak ◽

Bypass Patency ◽

Before And After

Object Extracranial-intracranial (EC-IC) bypass surgery remains an important treatment alternative for patients with occlusive cerebrovascular disease. The aim of the present study was to use perfusion CT and CT angiography (CTA) to evaluate cerebral hemodynamics and bypass patency in patients with occlusive cerebrovascular disease before and after EC-IC bypass surgery. Methods Ten patients underwent perfusion CT and CTA before and after bypass surgery. Preoperative and postoperative digital subtraction angiography served as the diagnostic gold standard. An artery bypass was established from the superficial temporal artery to a cortical branch of the middle cerebral artery. Perfusion CT scanning was performed at the level of the basal ganglia. Color-coded perfusion maps of cerebral blood volume, cerebral blood flow, and time to peak were calculated. Results Preoperative perfusion CT showed significant prolonged time to peak and reduced cerebral blood flow of the affected hemisphere. Postoperative neurological deterioration did not develop in any patient. Computed tomography angiography provided adequate evaluation of the anastomoses as well as the course and caliber of the bypass and confirmed bypass patency in all patients. Postoperative perfusion CT showed improved cerebral hemodynamics with a return to nearly normal perfusion parameters. Conclusions Computed tomography angiography is a noninvasive and reliable tool for evaluating patients with EC-IC bypass. Perfusion CT allows monitoring of hemodynamic changes after bypass surgery. The combination of both modalities enables noninvasive anatomical and functional analysis of superficial temporal artery–middle cerebral artery anastomoses using a single CT protocol. Hemodynamic evaluation of patients with occlusive cerebrovascular disease before and after surgery may improve the prediction of outcome and may help identify patients in whom a bypass procedure can be performed.

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