Endovascular Therapy for NIHSS =5 How Low Should We Go?

Since the efficacy of endovascular therapy (EVT) for ischemic stroke was established in 2015, its indications expanded considerably. The treatment time window has been extended from 6 to 24 hours from last seen well, and patients with large infarct cores and/or low Alberta Stroke Program Early CT Scores also demonstrated treatment benefit, contrary to initial expectations. In addition, patients with basilar artery occlusions - not included in the initial EVT trials - seemed to benefit from EVT as well. However, controversy persists regarding the treatment effect for patients with more distal or so-called medium vessel occlusions or with mild neurologic symptoms (defined as a National Institutes of Health Stroke Scale [NIHSS] score ≤5). For these patients, the smaller clinical improvements to be gained should be carefully weighed against the inherent potential risks of invasive treatments such as EVT. Although several randomized trials investigated treatment effects in patients with medium vessel occlusions, less attention has been paid to treatment of patients with low baseline NIHSS scores, particularly in the late window.