A retrospective analysis of stent retriever size in M2 occlusion outcomes

Abstract

Background

Mechanical thrombectomy (MT) is the standard of care in acute ischemic stroke, but the efficacy of differently sized stent retrievers (SRs) for MT in M2 segment middle cerebral artery (MCA) occlusions has not been extensively evaluated. We conducted a retrospective study comparing outcomes of 3, 4, and 6 mm SRs in MT at the M2 segment.

Methods

Data collected from M2 MCA strokes in a comprehensive stroke center were retrospectively analyzed. Patient outcomes were quantified using National Institutes of Health Stroke Scale (NIHSS) 24 h post-procedure and modified Rankin Scale (mRS) scores at discharge and after 90 days. Successful outcomes were defined as an NIHSS score of <10 and an mRS score of <3. First pass success rate and thrombolysis in cerebral infarction (TICI) scores of 2b or greater were also compared. Analysis was performed using chi-square and Kruskal–Wallis tests.

Results

A total of 139 patients with similar baseline demographics underwent MT with SRs sized 3 mm (n = 23), 4 mm (n = 56), and 6 mm (n = 60). No significant difference between groups was noted in 24-h NIHSS (p = 0.83), mRS at discharge (p = 0.597), mRS score at 90 days (p = 0.251), time from groin to recanalization (p = 0.12), or first pass success (p = 0.058). All three sizes had similar complication rates. However, the rate of successful recanalization (final TICI ≥2b) differed significantly between groups (91.3% for 3 mm, 80.4% for 4 mm, and 95.0% for 6 mm; p = 0.043).

Conclusion

This retrospective study showed successful recanalization of isolated M2 occlusions was greatest with 6 mm SR.