Qualifying Event and Recurrence of Ischemic Stroke in Symptomatic Artery Occlusion: A Post Hoc Analysis of CMOSS

Background The authors aimed to elucidate the relationship between latest ischemic event and the incidence of subsequent ischemic stroke in patients with symptomatic artery occlusion. Methods and Results We analyzed the association between qualifying event—the latest ischemic event (transient ischemic attack [TIA] or stroke)—and the incidence of ipsilateral ischemic stroke in patients with symptomatic artery occlusion treated with medical therapy alone in CMOSS (Carotid or Middle Cerebral Artery Occlusion Surgery Study). The incidence of CMOSS primary outcomes, including any stroke or death within 30 days after randomization or ipsilateral ischemic stroke between 30 days and 2 years, between the bypass surgical and medical groups, stratified by qualifying events, was also compared. Of the 165 patients treated with medical therapy alone, 75 had a TIA and 90 had a stroke as their qualifying event. The incidence of ipsilateral ischemic stroke did not significantly differ between patients with a TIA and those with a stroke as their qualifying event (13.3% versus 6.7%, P=0.17). In multivariate analysis, the qualifying event was not associated with the incidence of ipsilateral ischemic stroke. There were no significant differences in the CMOSS primary outcomes between the surgical and medical groups, regardless of the qualifying event being TIA (10.1% versus 12.2%, P=0.86) or stroke (6.7% versus 8.9%, P=0.55). Conclusions Among patients with symptomatic artery occlusion and hemodynamic insufficiency, the risk of subsequent ipsilateral ischemic stroke does not appear to be lower in patients presenting with a TIA compared with those with a stroke. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01758614.