Abstract WP024: Impact of Time on Thrombectomy Utilization in Patients with Acute Stroke Due To Large Vessel Occlusion

Introduction: Randomized controlled trials have established the benefit of thrombectomy within 24 hours of time last known normal (LKN). Studies supporting the role of thrombectomy in the 6– to 24–hour window selected patients based on favorable penumbral imaging, and it is unclear how thrombectomy eligibility and utilization change over time. We aimed to characterize changes in thrombectomy utilization within the 24-hour time window. Methods: Using data from the American Heart Association/American Stroke Association Get With The Guidelines-Stroke registry, we identified patients with a proximal large vessel occlusion (LVO) of the intracranial internal carotid artery, M1, or M2 segments of the middle cerebral artery, and NIHSS ≥ 6 who presented directly to a Comprehensive or Thrombectomy-Capable Stroke Center between January 1, 2018, and June 30, 2024. Patients were stratified by time from LKN to vascular imaging. The odds of thrombectomy over time were modeled using generalized estimating equations adjusted for patient-level characteristics (demographics, medical history, and thrombolytic administration) and hospital-level factors (stroke center certification, geographic region, and annual thrombectomy volume). Results: Of 356,250 ischemic stroke patients presenting within 0–5.5 hours of LKN, 45,502 (12.8%) ultimately underwent thrombectomy, compared to 11,083 of 94,720 (11.7%) at 5.5–11.5 hours, 7,279 of 75,410 (9.7%) at 11.5–17.5 hours, and 2,452 of 39,035 (6.3%) at 17.5–23.5 hours. Among the 49,191 patients with NIHSS ≥6 and proximal LVO identified on vascular imaging, thrombectomy use decreased with each successive stratum of time from LKN to imaging (Figure 1). Compared to those within 0–5.5 hours, patients with LVO imaged at 5.5–11.5 hours had 32.8% (95% CI, 28.1–37.1%) lower adjusted odds of thrombectomy; those at 11.5–17.5 hours had 46.0% (95% CI, 41.7–50.0%) lower odds, and those at 17.5–23.5 hours had 66.8% (95% CI, 63.5–69.9%) lower odds (p<0.001 for all comparisons). Each hour of delay was associated with a 6.0% (95% CI, 5.5–6.4%; p<0.001) reduction in the odds of thrombectomy. The rate of decay in thrombectomy utilization did not change between 0–6 and 6–24 hours. Conclusions: Thrombectomy utilization declines linearly over the 24-hour window, which may reflect a corresponding reduction in salvageable penumbra. All efforts should be made to identify and assess stroke patients as quickly as possible to increase the likelihood of receiving treatment.