Stroke secrets : If traffic is well regulated in circle of Willis . . . Chronic carotid occlusion simply doesn’t matter !

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Stroke secrets : If traffic is well regulated in circle of Willis . . . Chronic carotid occlusion simply doesn’t matter !

November 3, 2016 by dr s venkatesan

In early days of medical school we were taught there is an important vascular grade separator in the base of brain .God would not have created this circle (of Willis ) without any purpose , he must have designed it for a reason.

How good is the circle of Willis to prevent a stroke ?

Unfortunately , we have not answered this in detailed manner . Obviously it can’t prevent all strokes however , it is strongly believed it can abort many of them .My guess would be but for its presence many of episodes of TIA, syncope ,near syncope would end up in stroke with various degree of deficit.

The other factor that tests the efficiency of circle of Willis is the acuteness of the vascular insufficiency.Chronic carotid occlusion as expected are well tolerated . We failed to respect this natural hemodynamic sharing and indulged in so many unilateral carotid interventions with dubious results .

Here is a paper with fresh knowledge from Dr Seemant Chaturvedi , Miamai , Florida .Hats off to the authors.

Are the Current Risks of Asymptomatic Carotid Stenosis Exaggerated?Further Evidence Supporting the CREST 2 Trial Seemant Chaturvedi, Ralph L. Sacco,JAMA Neurol. Published online September 21, 2015.

Internal carotid artery (ICA) occlusion when occurring in a chronic fashion could be as benign as a small peripheral vessel occlusion .(Of course they can be symptomatic)

For all those patients with unilateral total carotid disease , let us thank the “circle of Hope” which if regulated by God whom should we fear ?

Secondary collaterals in stroke

There is one more collateral system that connects extra cranial branches of carotid to intra cranial circulation though Opthalmic artery and leptomeningeal collaterals .This could help prevent or mitigate cerebral Ischemia . A rare review about this important concept worth reading for both cardiologist and neurologists( David S. Liebeskind Collateral Circulation Stroke. 2003;34:2279–2284)

Further reading