Prognostic factors for acute large vessel occlusion with NIHSS 5 or lower

Background : Intravenous recombinant tissue plasminogen activator (IV rt-PA) and endovascular treatment have been performed for severe large vessel occlusion (LVO) and the results have been reported at high levels of evidence. However, acute treatment for LVO with mild symptom remains controversial. We retrospectively examined prognostic factors for LVO with mild symptoms. Method : We studied retrospectively the patients within 24 h of onset with large vessel occlusion with NIHSS score ≤ 5. Outcomes were evaluated by modified Rankin Scale (mRS) at 90 days, with 0–2 defined as a good outcome and 3–6 as a poor outcome. Clinical characteristics of each case were examined. Result : Participants comprised 76 patients. Of the 76 patients. ICA occlusion showed good outcome in 17 / 19 cases (90%), whereas MCA occlusion showed good outcome in 36 / 54 cases (67%). Among the 14 cases showing positive results for distal intraarterial signal (d-IAS), outcomes were good in 6 cases (43%). On the other hand, the 32 d-IAS-negative cases showed good outcome in 28 cases (88%). Outcomes were thus significantly poorer for d-IAS-positive cases. Conclusion : MCA occlusion is associated with poor prognosis, even with NIHSS score ≤ 5, and d-IAS may provide a predictor.