Mechanical thrombectomy improved clinical outcomes for patients with a larger ischemic penumbra (hypoperfusion to core ratio >1.2) in the setting of acute ischemic stroke with large vessel occlusion (LVO) and large ischemic core (>50 mL). Outcomes were also improved with mechanical thrombectomy in patients with ischemic core ≥70 mL plus a critical hypoperfusion to core volume ratio ≥1.8.
Why this matters
Traditionally, mechanical thrombectomy has not been recommended for patients with acute stroke with LVO and a large ischemic core (i.e., a large volume of irreversibly damaged brain tissue). These patients were underrepresented in pivotal trials due to the high likelihood of poor outcomes despite intervention.
Observational studies and subgroup analyses have suggested that penumbra size and persistence may influence functional benefits following mechanical thrombectomy in patients with large-core acute ischemic stroke.
Perfusion imaging may be used to calculate a critical hypoperfusion to core volume ratio that could help to stratify large-core ischemic stroke patients based on penumbra size. It is possible that patients with a large core, but substantial persistent penumbra may benefit from mechanical thrombectomy.