Recurrent Hemispheric Stroke Syndromes in Symptomatic Atherosclerotic Internal Carotid Artery Occlusions: The Carotid Occlusion Surgery Study Randomized Trial

Background: There are limited data on outcomes of extracranial-intracranial (EC-IC) bypass in patients with recurrent hemispheric syndromes due to atherosclerotic internal carotid artery occlusion (AICAO).

Objective: To compare clinical outcomes and efficacy of EC-IC bypass surgery in patients with and without recurrent hemispheric syndromes associated with AICAO in the Carotid Occlusion Surgery Study (COSS).

Methods: In patients enrolled in the COSS trial, we compared baseline characteristics and clinical outcomes for participants with (rHEMI+) and without recurrent hemispheric ischemia (rHEMI-) prior to randomization into surgical vs medical groups. The primary outcome was all stroke and death from randomization through 30 d and ipsilateral ischemic stroke within 2 yr.

Results: Of 195 randomized participants, 100 were rHEMI+ (50 in each group). Baseline characteristics between rHEMI+ and rHEMI- participants were similar except rHEMI+ were more likely to have had previous stroke prior to randomization (61% vs 20%, P < .01) and to have TIA as the entry event (59% vs 21%, P < .01). All primary endpoints were ipsilateral ischemic strokes. There were no significant differences in occurrence of the primary endpoint between nonsurgical and surgical participants in rHEMI+ (26.3% vs 22.4%, P = .660) and rHEMI- (18.9% vs 19.5%, P = .943). For nonsurgical participants, there was no significant difference in the primary endpoint for rHEMI+ vs rHEMI- patients (P = .410).

Conclusion: Patients with recurrent hemispheric stroke syndromes enrolled in the COSS trial did not show benefit from EC-IC bypass compared to medical treatment. Early aggressive risk factor measures should be prioritized to reduce recurrent strokes in these patients.