Background: Mechanical thrombectomy is the standard of care for patients presenting with acute ischemic stroke (AIS) due to large vessel occlusion (LVO). Recent studies have shown that door to reperfusion time is longer during nighttime and weekends. In this study we examine the long term functional outcome of stroke patient treated with mechanical thrombectomy performed during work hours (on-hours) versus after hours (off-hours).
Methods: Data on all patients receiving mechanical thrombectomy at a comprehensive stroke center between Dec/2014 and Dec/2016 was collected. Our primary outcome was the 90-day Modified Rankin Scale (mRS). Independent variables included receiving thrombectomy during on-hours (7am and 4pm) or off-hours 4pm-7am, weekends, and official holidays), admission NIH stroke scale, age, race, and sex. Multivariable logistic regression was used to examine the relationship between off-hours thrombectomy and mRS, controlling for patient baseline characteristics. Chi-square and t-tests were used to compare differences among categorical and continuous variables.
Results: During the study period, 92 (41%) patients underwent thrombectomy during on-hours and 133 (59%) during off-hours. On average, the on-hours patients were older (P=0.02), and had a higher percentage of males (P=0.04) compared to the off-hours. Differences in median admission NIHSS, rate of tPA administration, location of occlusion, mean time from last known well to thrombectomy, revascularization rates, and hemorrhagic transformation rates were not statistically significant between the two groups. Median door to groin time was 53 minutes versus 78 minutes for the on-hours and off-hours groups respectively (P= < 0.00). Logistic regression showed that the odds of a favorable mRS ≤2 are 47% lower for off-hours patients compared to patients seen during on hours (OR 0.53, P=0.044, [95%CI 0.28-0.98]). Additional significant predictors included, age (OR 0.97 [CI.95-.99]) and admission NIHSS (OR 0.9 [CI.87-.94]).
Conclusion: Our study shows that there is higher likelihood of good functional outcome following mechanical thrombectomy when performed during work hours. This could be due to a prolonged door to groin time.