BackgroundWe sought to determine the rate of early neurologic decline (END) in patients with acute ischemic stroke (AIS) with large vessel occlusion (LVO) who presented with mild deficits and received intravenous tissue plasminogen activator (IVtPA).MethodsAmong 1022 patients with AIS who received IVtPA from 2014 to 2019, we identified 313 (30.6%) with LVO, of which 94 (30%) presented with National Institute of Health Stroke Scale (NIHSS) score ≤7. Thirteen patients were excluded, leaving 81 for analysis. END was defined as NIHSS worsening of ≥4 points within 24 hours.ResultsAmong 81 patients with LVO and low NIHSS score, the mean age was 65.8 years (range 25–93) and 41% were female. The mean time to IVtPA from last known well was 2.5 hours (range 0.8–7). LVO sites were as follows: 5 (6%) carotid, 23 (28%) M1, and 53 (65%) M2 occlusions. Among the 81 patients, 28 (34.6%) had END, and these patients were older (70.8 vs 63.2 years, p=0.036). The mean change in NIHSS score at 24 hours in those with END was 10.4 (range 4–22). Patients with END were less likely to be discharged home (25% vs 66%, p=0.004).ConclusionsAmong patients with LVO AIS who received IVtPA, 30% presented with initial mild deficits. END occurred in one-third of LVO patients with initial mild deficits despite receiving IVtPA. Clinicians should be aware that the natural history of LVO with initial mild deficits is not benign and these patients are eligible for rescue thrombectomy in the 24-hour window if they deteriorate.