Background/Aim: The no-reflow phenomenon, observed in 30% of ischemic stroke patients despite technically successful thrombectomy, is associated with poor outcomes. Its temporal evolution in humans remains uncharacterised. We examined the temporal dynamics of no-reflow through serial MRI perfusion imaging within 48-hours post-thrombectomy.
Methods: In a multicentre prospective study, 67 ischemic stroke patients with acute anterior large vessel occlusion underwent serial post-thrombectomy MRI within 3-hours post-procedure (timepoint 1, TP1) and at 24–48 hours (timepoint 2, TP2). No-reflow was defined as visually-detectable hypoperfusion within the infarct with >15% median relative cerebral blood volume (rCBV) or flow (rCBF) reduction compared to mirror homolog, after complete/near-complete angiographic reperfusion (eTICI 2c-3). No-reflow was assessed globally (entire DWI-positive lesion at TP2) and within two subregions (early infarction: DWI-positive at TP1 and TP2; infarct growth: DWI-positive at TP2 only).
Results: 29 patients achieving eTICI 2c-3 were included. At TP1, 4 patients (14%) exhibited global no-reflow and 2 patients showed no-reflow within a subregion (21% total). At TP2, 7 patients (24%) demonstrated global no-reflow, with no case of isolated regional no-reflow observed. By TP2, 2 patients showed resolution of no-reflow, 1 progressed from regional to global no-reflow, and 3 developed late-onset no-reflow. Global no-reflow at TP2 was associated with worse outcomes (mRS 0-1: OR 0.14, 95%CI 0.02–0.84, p=0.03) but not at TP1 (OR 0.16, 95%CI 0.02–1.33, p=0.09).
Conclusion: No-reflow manifests early after successful thrombectomy and frequently persists, contributing to worse patient outcomes. Cases of resolution and progression suggest a dynamic and reversible pathology potentially amenable to timely treatment.