Editors' Note: Thrombectomy vs Medical Management in Low NIHSS Acute Anterior Circulation Stroke

Patients with a low NIH Stroke Scale (NIHSS) score have been historically excluded from randomized clinical trials evaluating mechanical thrombectomy (MT), and therefore, the efficacy of intervention in patients with milder symptoms is less well established. In their pooled analysis of 3 prospective registries (n = 236 patients), Dr. Volny et al. compared patients according to treatment with MT vs medical management if they fit the following criteria: NIHSS ≤6; prestroke modified Rankin Scale (mRS) 0–2; occlusion of the internal carotid, or M1 or M2 middle cerebral arteries; and arrival within 12 hours of last known well. The investigators found no difference in the rate of the primary outcome, mRS 0–1 at 90 days, between MT and medically managed groups (62% vs 64%, p = 0.79). With propensity matching, there remained no significant difference in the proportion of patients achieving the primary outcome (absolute difference of 8.6%, 95%CI –8.8% to 26.1%). Hypothetically, if the patients with missing 90-day outcomes all achieved excellent functional outcome (n = 13)—”best-case scenario”—MT would have been significantly associated with excellent functional outcome as compared to medical management (17.6%, 95%CI 0.01%–35.4%). Drs. Malhotra and Khunte address other potential important factors that could have contributed to functional outcome, such as less frequent use of thrombolysis in the MT arm (suggesting that these patients had more delay in MT and, therefore, more progressive ischemic injury) and a higher proportion of patients with internal carotid and M1 occlusions treated with MT (suggesting potentially greater volume of brain tissue at risk of infarction). Drs. Zerna and Volny respond that some of the patient-level data were missing from the consolidated registries. For example, there are no time-to-treatment data in any data source and no data regarding CT angiography or other imaging findings from 1 of the 3 registries.

Read article at journal's website

Related Articles

Responses

Your email address will not be published.