To investigate the early clinical outcomes of anterior circulation large vessel occlusion (LVO) with NIH Stroke Scale (NIHSS) ≤10 across different hyperacute treatments.   

15% of LVO ischemic strokes have NIHSS <9, and 20% deteriorate by NIHSS >4 during hospitalization. The DAWN and DEFUSE3 trials demonstrated improved outcome in LVO ischemic stroke after thrombectomy for NIHSS ≥10 and ≥6, respectively. However, retrospective analyses on medical management versus thrombectomy in low NIHSS LVO have yielded contradictory results.

This retrospective cohort study involved patient encounters at a single large academic medical center between 2017-2019 with key inclusion criteria: LVO of anterior circulation (intracranial ICA, MCA M1 or M2); management within 48 hours from symptom onset, and NIHSS ≤10. ANOVA type model compared change in NIHSS from admission to discharge across different treatments.

87 patients met inclusion criteria, and mean NIHSS at admission was 4.7. The mean change over time in NIHSS from admission to discharge across treatment groups were as follows: tPA only therapy (n=20) -3.2 ±0.7; thrombectomy without tPA (n=22) 0.4 ±1.8; thrombectomy after tPA (n=11) -3.2 ±0.6; no hyperacute treatment (n=34) -0.1 ±0.4. Early deterioration as marked by any increase in NIHSS was 17% in total, stratified as follows: tPA only therapy 5%; thrombectomy without tPA 23%; thrombectomy after tPA 0%; no hyperacute treatment 26%.  Both tPA alone and thrombectomy after tPA were significantly less likely to be associated with an increase in NIHSS compared with no therapy (p<0.001 and p=0.001 respectively), and no other comparisons between therapies reached significance. 

While there has been some mixed data in how to treat low NIHSS LVO, our study suggests that early treatment with IV thrombolysis may prevent early deterioration, and follow-up thrombectomy may further decrease the rate of deterioration.