Involvement of Posterior Circulation Accounts for Higher Disability in Ischemic Strokes With NIHSS ≤3 But Not With NIHSS 4−5

OBJECTIVES: Minor strokes are defined as ischemic cerebrovascular accidents that present with mild symptoms scoring ≤5 on the National Institute of Health Stroke Scale (NIHSS). We aimed to investigate whether features related to stroke characteristics, location, severity, or symptoms could predict the risk of disability after minor strokes. METHODS: Minor strokes (105) were divided into 2 subgroups: those with baseline NIHSS ≤3 and those with baseline NIHSS 4-5. Comorbidities, occurrence of disability, stroke location, etiology, and outcomes were examined in the 2 subgroups and in those who developed a modified Rankin scale (mRs) of 0 to 1 or mRs >1. RESULTS: No-IVT minor strokes in the NIHSS 4-5 subgroup were associated with more disability compared with the NIHSS ≤3 subgroup ( P >0.05). Residual disability (mRS >1) was associated with a higher incidence of posterior circulation strokes (PCS) ( P =0.0015), large vessel stenosis ( P =0.01), and PCS-related symptoms (imbalance, gait ataxia, and eye movement disorders) not accounted for by NIHSS, in strokes with baseline NIHSS ≤3. Disability (mRS >1) was associated with baseline disabling symptoms, which NIHSS effectively and reliably captured in patients with stroke with NIHSS 4-5. CONCLUSIONS: Symptoms that might predict unfavorable outcomes are not well captured by the available clinical instruments that are usually used to evaluate and score acute ischemic stroke at onset. When deciding on the management of minor stroke, clinicians must consider and judge all potentially disabling deficits, in addition to the pure scores of the adopted evaluation scales.