Impact of the Penumbral Pattern on Clinical Outcome in Patients with Successful Endovascular Revascularization

Abstract

Background: In patients with acute ischemic stroke, the impact of penumbral patterns on clinical outcomes after endovascular treatment (EVT) remains controversial. We aimed to establish whether penumbral patterns are associated with clinical outcome after successful recanalization with EVT while adjusting for onset to revascularization time. Materials and Methods: Using a web-based, multicenter, prospective stroke registry database, we identified patients with acute ischemic stroke who underwent perfusion and diffusion magnetic resonance imaging (MRI) before EVT, had anterior circulation stroke, received EVT within 12 hours of symptom onset, and had successful revascularization confirmed during EVT. Based on pretreatment MRI, patients were stratified as having a favorable or nonfavorable penumbral pattern. Onset to revascularization time was dichotomized by median value. Primary outcome was functional independence (modified Rankin Scale score = 2) at 90 days. Findings: Among 121 eligible patients from three university hospitals, 104 (86.0%) had a favorable penumbral pattern, and the median time to revascularization was 271 minutes (interquartile range, 196-371). The functionally independent patient proportion was higher in those with a favorable penumbral pattern than in those without (53.8% versus 5.9%; P <.001), but was not different between early and late revascularization groups (49.2% versus 45.0%; P =.65). The favorable penumbral pattern was associated with functional independence after adjusting confounders (odds ratio, 23.25; 95% confidence interval: 1.58-341.99; P =.02). Time to revascularization did not modify the association (P for interaction,.53). Conclusion: A favorable penumbral pattern is associated with improved functional independence in patients with endovascular revascularization, and the association was not time-dependent.