Collateral circulation pathways in patients with severe intra-and extra-cranial artery stenosis or occlusion

Objective To study the collateral circulation pathways in patients with severe intra-and fextra-cranial artery stenosis or occlusion.Methods Collateral circulation change was assessed by TCD in 100 patients with severe intra-and extra-cranial artery stenosis or occlusion.Results TCD showed piamatral anastomosis of the open collateral circulation pathways in 34(57.6%)out of the 59 patients with severe stenosis or occlusion of the main cerebral middle artery.Among the 30 patients with severe initial internal carotid artery portion stenosis or occlusion,open collateral circulation pathways were found in 24(80.0%) including anterior communicating artery collateral circulation pathway in 8,posterior communicating artery collateral circulation pathway in 2,simultaneous anterior and posterior communicating artery collateral circulation pathway in 4,ophthalmic artery collateral circulation pathway in 6,simultaneous anterior and posterior communicating artery and ophthalmic artery collateral circulation pathway in 4.In addition,TCD showed the steal waveform in 4(57.1%) of the 7 patients with severe subclavian artery stenosis,including proximal vertebral artery occlusion in 3,open external carotid collateral circulation pathway-vertebral artery circulation pathway in 2 with the initial vertebral artery portion occlusion,left common carotid artery occlusion accompanying moderate brachiocephalic trunk stenosis in 1.The sequence of collateral circulation pathways was open vertebral artery-external carotid artery-internal carotid artery collateral circulation pathways.Conclusion TCD contributes to the understanding of collateral circulation pathways in patients with severe intra-and extra-cranial artery stenosis or occlusion.