Early neurologic deterioration with symptomatic isolated internal carotid artery occlusion: a cohort study, systematic review, and meta-analysis.

Background: Acute endovascular revascularization for isolated internal carotid occlusion without tandem intracranial occlusion has been proposed to prevent early neurologic deterioration (END) and improve outcome, but has not been shown to be more effective than medical therapy. We aimed to evaluate prognosis with initial medical therapy alone, and also performed a systematic review to put these results in a broader context. Methods: We performed a retrospective cohort study of patients admitted over a 2-year period with acute stroke/TIA due to isolated internal carotid artery occlusion. Subjects with tandem intracranial occlusion or ASPECTS≤5 were excluded. The primary outcome was END within 48 hours (NIHSS increase ≥4 persisting for ≥24 hours). Secondary outcomes included discharge NIHSS and disposition. We also performed a systematic review and meta-analysis of published studies along with the data from our cohort. Results: Twenty-three patients met our inclusion criteria. Median age was 69 years, initial ASPECTS 10, and NIHSS score 3. END attributed to recurrent ischemia occurred in 5/23 patients (22%, 95%CI: 7-44%). At discharge, 78% had a favorable outcome with a median NIHSS of 2 (IQR 1-3). END appeared more frequent in those with higher baseline NIHSS. In our systematic review, 7 prior studies met our inclusion criteria. END occurred in 17% (95%CI:12-23%) of patients, 18% with medical therapy versus 13% with endovascular therapy, with substantial heterogeneity among studies. Conclusions: In patients with acute stroke or TIA due to isolated internal carotid occlusion, END is relatively common (occurring in about 1 out of 6 patients). Further research is needed to evaluate the roles of maximal medical management or acute endovascular thrombectomy in these patients.