Related Experiment Videos
Dynamics of collateral circulation in progressive asymptomatic carotid disease
Insights
Inadequate collateral blood flow, a risk for stroke, was studied in patients with asymptomatic carotid artery stenosis. Cerebral circulation adaptation through the circle of Willis remained stable, but collateral flow to the opposite hemisphere decreased.
Area of Science:
- Neurology
- Vascular Medicine
- Cerebrovascular Disease
Background:
- Inadequate collateral arterial flow is a primary risk factor for hemispheric infarction following spontaneous carotid artery occlusion.
- Understanding the compensatory mechanisms of collateral cerebral circulation is crucial for managing stroke risk.
Purpose of the Study:
- To prospectively measure the adaptation of collateral cerebral circulation via the circle of Willis.
- To assess collateral potential in patients with asymptomatic, hemodynamically significant unilateral carotid stenosis.
Main Methods:
- Ocular pneumoplethysmography (OPG) was used to assess collateral cerebral potential.
- Collateral ophthalmic artery pressure (COAP) was measured during proximal common carotid artery compression.
- Follow-up averaged nearly 3 years in 45 patients with asymptomatic carotid stenosis.
Main Results:
- The mean COAP/brachial artery pressure index did not change significantly on the side of stenosis progression (p > 0.05).
- Developing carotid stenosis led to reduced collateral circulation to the contralateral hemisphere.
- The risk of inadequate collateral cerebral circulation persisted with progressive extracranial arterial disease.
Conclusions:
- The circle of Willis demonstrates limited adaptation in maintaining collateral flow during progressive asymptomatic carotid stenosis.
- Contralateral collateral circulation is compromised, highlighting a persistent risk for stroke.
- Monitoring collateral flow is essential in managing patients with asymptomatic carotid artery disease.
Abstract:
Inadequacy of collateral arterial flow is the major risk factor for hemispheric infarction in association with spontaneous occlusion of the ipsilateral carotid artery. This prospective study was designed to measure the adaptation of collateral cerebral circulation through the circle of Willis in patients in whom a unilateral carotid stenosis of hemodynamic consequence develops asymptomatically. The collateral cerebral potential is assessed by ocular pneumoplethysmography (OPG) during proximal common carotid artery compression, measuring the collateral ophthalmic artery pressure (COAP). During an average follow-up of almost 3 years (maximum more than 7 years), 45 patients showed asymptomatic development of a unilateral hemodynamically significant carotid stenosis according to OPG evidence. In these patients the mean index COAP/brachial artery pressure did not change on the side of stenosis progression (p greater than 0.05). The developed carotid stenosis had only reduced collateral circulation to the contralateral hemisphere. The risk of inadequate collateral cerebral circulation remained during progression of asymptomatic extracranial arterial obstructive disease.