Mechanical Thrombectomy in Patients Presenting with NIHSS Score <6: A Safety and Efficacy Analysis

Introduction: Groundbreaking trials have shown the tremendous efficacy of mechanical thrombectomy for large vessel occlusions. Currently, mechanical thrombectomy is limited to patients with NIHSS scores 36. We investigated the feasibility and safety of MT in patients presenting with NIHSS scores < 6.

Methods: A retrospective review of patient who presented with acute ischemic stroke due to large vessel occlusion with an NIHSS score < 6 between 2015 – 2019. The patients were then divided into two groups: those who received MT and those who did not.

Results: Among 83 patients, 41 received a mechanical thrombectomy while 42 received medical treatment only. The mean age in the mechanical thrombectomy group was 66 years versus 60 years in the medical group (p = 0.06). Risk factors for stroke did not differ significantly between both groups. 14 patients (34.1%) in the mechanical thrombectomy group and 20 (47.6%) in the medical group received tissue plasminogen activator. No significant difference in clinical improvement (NIHSS) at discharge (p=0.85) or the mRS score at 90 days (p = 0.15) was noted. Mechanical thrombectomy was associated with smaller infarct size (p=0.04) and decreased mortality (p=0.03).

Conclusion : Mechanical thrombectomy is safe and effective for patients who present with large vessel occlusions and low initial NIHSS scores. Therefore, the decision to offer the patient MT or not should not be decided by NIHSS score alone. Rather, the decision should be multifactorial with the aim of maximizing the patients’ outcomes.