Natural History of Acute Stroke due to Occlusion of the Middle Cerebral Artery and Intracranial Internal Carotid Artery

BACKGROUND AND PURPOSE The natural history of acute ischemic stroke (AIS) due to anterior circulation large artery occlusion is not well established. This information is essential for assessment of clinical benefit derived from recanalization therapies. METHODS Patients with AIS due to anterior circulation large artery occlusion not treated with reperfusion therapies admitted from January 2005 to September 2010 were consecutively selected. Site of occlusion was assessed with transcranial duplex according to Thrombolysis in Brain Infarction (TIBI) grades. Poor outcome was considered as a modified Rankin Scale>2 at 90 days. RESULTS A total of 120 patients were studied. Site of occlusion was terminal internal carotid artery (TICA) in 13 (10.8%), proximal middle cerebral artery (MCA) in 69 (57.5%), and distal MCA in 38 (31.7%) patients. Overall, 74.2% of patients had poor outcome. There were significant differences in poor outcome between patients with TICA, proximal MCA, and distal MCA occlusion (92%, 87%, 47%, P < .001) and mortality at 90 days (23%, 12%, 3%, P = .001). CONCLUSIONS Outcome of AIS patients with anterior circulation large artery occlusion not treated with reperfusion therapies is extremely poor in TICA and proximal MCA occlusions with better outcomes noted in distal MCA occlusions. These findings are relevant for estimation of treatment effect of reperfusion therapies according to occlusion location.