Effects of endovascular therapy for mild stroke due to proximal or M2 occlusions: meta-analysis

To conduct a meta-analysis to evaluate the effect of endovascular therapy (EVT) in mild acute ischemic stroke (AIS) due to proximal versus distal occlusions.

We searched PubMed, Embase, the Cochrane Library, and clinicaltrials.gov from January 2000 to September 2021 to identify studies comparing EVT versus best medical management (BMM) in AIS with National Institutes of Health Stroke Scale (NIHSS) scores ≤5 due to proximal internal carotid artery (ICA) or M1 versus distal M2 occlusions. We included studies that reported the number of patients with proximal or distal occlusions separately and reported the number of patients with freedom of disability (modified Rankin Scale (mRS) score 0-1) or functional independence (mRS score 0-2) at 90 days in proximal or M2 occlusions, respectively. OR with 95% CI was used.

We identified six studies with 653 proximal ICA and M1 occlusion patients and 666 distal M2 occlusion patients. Pooled results showed EVT versus BMM was associated with a higher rate of being disability-free in patients with proximal occlusions (OR 1.58, 95% CI 1.09 to 2.30), but was associated with a lower rate of being disability-free in patients with M2 occlusions (OR 0.70, 95% CI 0.49 to 0.99). Effect of EVT in proximal versus distal occlusions was substantially different (P for interaction=0.002). A similar pattern was seen for functional independence (P for interaction=0.05).

For patients with mild AIS, observational data suggest that EVT may be beneficial for proximal ICA or M1 but not for distal M2 occlusions. Randomized trials are needed to confirm these findings.

CRD42021281034.