In acute ischemic stroke patients, internal carotid artery/middle cerebral artery (ICA/MCA) occlusion in tandem predicts a poor outcome after systemic thrombolysis. This study aimed to compare outcomes after mechanical thrombectomy for tandem and single occlusions of the anterior circulation.

This prospective study included consecutive patients with acute ischemic stroke of the anterior circulation who had undergone mechanical thrombectomy performed with a stent retriever under conscious sedation within 6h of symptom onset. Data on clinical, imaging and endovascular findings were collected. In cases of tandem occlusion, distal thrombectomy (retrograde approach) was performed first whenever possible. Tandem and single occlusions were compared in terms of functional outcome and mortality at 3 months.

From May 2010 to April 2012, 42 patients with acute ischemic stroke attributable to MCA and/or ICA occlusion were treated. Eleven patients (26.2%) presented with tandem occlusions and 31 patients (73.8%) had a single anterior circulation occlusion. Baseline characteristics were similar between the two groups. Recanalization status also did not differ significantly (P=0.76), but patients with tandem occlusions had poorer functional outcomes (18.2% vs. 67.7% for single occlusions; P=0.01), a higher mortality rate at 3 months (45.5% vs. 12.9%, respectively; P=0.03) and more symptomatic intracranial hemorrhages at 24h (9.7% vs. 0%, respectively; P=0.01). A high rate of early proximal re-occlusion or severe residual stenosis (66%) was also observed in the tandem group.

Tandem occlusions had poor clinical outcomes after mechanical thrombectomy compared with single occlusions. The retrograde approach (treatment of distal occlusion first) used in patients under conscious sedation may have contributed to these poor outcomes.