To compare the outcomes of acute ischemic stroke (AIS) patients with low admission NIHSS score who underwent mechanical thrombectomy versus those treated with IV tPA alone.

Stroke-related disability is relatively common even in patients with mild stroke. Per American Stroke Association guidelines, there is Level IIb evidence supporting endovascular management of patients with large vessel occlusion (LVO) in ICA or proximal M1 and NIHSS < 6. 

We performed a retrospective chart review from January 2013 to June 2017 of all patients with confirmed AIS, NIHSS ≤ 6, and 3-month follow-up modified Rankin Scale (mRS) who underwent mechanical thrombectomy (with or without IV tPA) or received IV tPA alone.  We used Fisher’s exact test to compare outcomes (favorable: mRS 0-2, unfavorable: mRS 3-6) between patients who underwent thrombectomy and those who did not.

We identified 56 patients with NIHSS ≤ 6.  Of the 42 patients with 3-month follow-up mRS scores, 17 (40.5%) had no change in mRS from preadmission to 3-month follow-up.  Unfavorable outcomes (mRS 3-6 at follow-up) occurred in 4 of 5 patients (80%) who underwent mechanical thrombectomy compared to 9 of 37 patients (24.3%) who received IV tPA alone (Fisher’s exact p-value = 0.0259). Fifteen of the 42 patients had LVO and, among these patients, there was no significant difference in follow-up mRS scores between those that underwent thrombectomy and those that did not (Fisher’s exact p-value = 0.5804).

In our study, patients with AIS and admission NIHSS < 6 who received IV tPA alone had better 3-month outcomes than those who received mechanical thrombectomy.  Among patients with low NIHSS and LVO, there was no significant difference in outcome between who those who underwent thrombectomy versus those who did not.  Larger studies with CT or MR perfusion are required for validation.