Background As the randomized controlled trials excluded the patients with large vessel occlusion (LVO) strokes with low NIHSS <6, efficacy and safety of mechanical thrombectomy (MT) in this cohort is lacking. Several retrospective multicenter studies on this topic have demonstrated no difference in outcomes with medical therapy in comparison to MT. We sought to explore the safety and efficacy of MT in this subgroup of patients according to nature of deficits at presentation (disabling vs. nondisabling).

Methods Stroke patients with LVO and NIHSS <6 treated with MT were identified from 2 high volume endovascular stroke centers over an eight-year period (2013-2021). Two blinded stroke neurologists graded presenting deficits as disabling vs. nondisabling based on age of patient, baseline functional status, location of occlusion and nature of deficits. LVO patients with cortical signs (hemianopia, aphasia, neglect, or severe paresis) were labeled as disabling versus presenting symptoms of facial droop, dysarthria and mild hemiparesis (power of 4+ or greater) or drift were considered as non-disabling. Baseline demographic, clinical and procedural variables were obtained. Successful recanalization was defined as mTICI 2b, 2c and 3. Excellent outcomes were defined as modified Rankin Stroke (mRS) scale of 0-1 at 3 months.

Results 82 patients with low NIHSS LVO who underwent MT were included in the study. Of those, 54 patients (65.9%) were classified with disabling deficits and 28 patients (34.1%) with non-disabling deficits. Median NIHSS at presentation was 4, while the rate of successful recanalization was 86.3%. There was a non-significant trend towards higher NIHSS improvement (difference in NIHSS at admission and 24 hours) in LVO patients with disabling deficits [median (IQR): 2 (4) vs. 1(3), p>0.05]. LVO patients with disabling deficits had higher likelihood of excellent functional outcome after MT compared to those with non-disabling deficits (74% vs. 50%, p=0.048), however this difference did not retain significance in multivariable analyses after adjustment for various confounders. The 3-month mortality (9.4% vs. 3.4%, p=0.416) and SICH (3.7% vs. 3.4%, p=1.00) rates were not significantly different in patients with disabling vs. nondisabling deficits.

Conclusions Our retrospective study demonstrates a trend towards better functional outcomes in LVO patients with low NIHSS who were considered to have disabling deficits compared to those with non-disabling presenting symptoms. Future multicenter studies with a larger sample size and/or ongoing randomized trials for this subpopulation of LVO patients should examine this hypothesis further.

Disclosures N. Goyal: None. J. Sequeiros: None. B. Krishnaiah: None. C. Elangovan: None. S. Graham: None. D. Hoit: None. L. Elijovich: None. A. Arthur: None. V. Inoa: None.