Off-hour effect is not significant in endovascular treatment for anterior circulation large vessel occlusion in a multicentre registry

Background and purpose Whether the off-hour effect has an impact on workflow and outcomes of endovascular treatment(EVT)for anterior circulation large vessel occlusion(AC-LVO)remains uncertain.This study aimed to compare the characteristics and outcomes of patients who presented or were treated during off-hour versus on-hour in a multi-center registry.Methods AC-LVO patients from 21 centres were categorised into the off-hour group and the on-hour group.Off-hour(weekends,holidays,and 18:00-7:59 on weekdays)and on-hour(8:00-17:59 on weekdays except for holidays)were defined according to arrival and groin-puncture time points,respectively.Subgroup comparisons between patients both arrived and treated during off-hour(true off-hour)and on-hour(true on-hour)were performed.The primary outcome was the 90-day modified Rankin Scale(mRS)score.Secondary outcomes included favourable outcome(mRS 0-2 at 90 days),EVT-related time metrics,and other clinical outcomes.Ordinary and binary logistic regression and linear regression were taken to adjust for confounding factors.Results Of all 698 patients enrolled,435(62.3%)and 456(65.3%)patients were categorised into the off-hour arrival and off-hour puncture group,respectively.Shorter onset to door time(adjustedßcoefficient:−21.56;95%CI−39.96 to−3.16;p=0.022)was noted in the off-hour arrival group.Ordinal and dichotomous mRS scores at 90 days were comparable between the off-hour group and the on-hour group regardless of off-hour definitions.Other time metrics and outcomes were comparable between the two groups.Of 595 patients both presented and were treated during off-hour or on-hour,394 patients were categorised into the true off-hour group and 201 into the true on-hour group.Time metrics and clinical outcomes were similar between the true off-hour and the true on-hour group.Conclusions The off-hour effect was not significant regarding clinical outcomes and in-hospital workflow in AC-LVO patients receiving EVT in this Chinese multicentre registry.