Symptomatic Haemodynamically Significant Carotid Occlusion Treated by Posterior Circulation Revascularization

Haemodynamic cerebral ischaemic symptoms secondary to occlusive atheromatous disease of the internal carotid artery may resolve with revascularization. We describe a case of symptomatic internal carotid artery occlusion and ipsilateral subclavian stenosis with duplex and angiographically demonstrated vertebrobasilar steal and a patent ipsilateral posterior communicating artery with flow towards the steal. The patient suffered frequent ipsilateral middle cerebral artery territory transient ischaemic attacks and one minor stroke. Transcranial Doppler demonstrated markedly impaired ipsilateral carbon dioxide reactivity (13.8%, lower-limit normal range >32.6%). Percutaneous angioplasty to the subclavian artery stenosis resulted in resolution of symptoms and an improvement in reactivity to near the lower limit of the normal range (33.5%). This case demonstrates that normalization of vertebral artery steal by subclavian artery revascularization may benefit anterior circulation haemodynamic symptoms in the presence of a functioning posterior communicating artery. The measurement of middle cerebral artery reactivity using transcranial Doppler can identify such cases of haemodynamic impairment and monitor the effect of therapy.