Association of endovascular thrombectomy volume and outcomes in acute ischemic stroke: A National Inpatient Sample Study

Background: Previous studies suggest a positive relationship between higher hospital endovascular thrombectomy (EVT) volume and improved outcomes. We investigated this association using the National Inpatient Sample (NIS) database from 2016 to 2020.

Methods: A cross-sectional analysis of the NIS examined the relationship between hospital EVT volume and outcomes. Data on clinical and demographic variables were collected. Outcomes included favorable functional outcome (discharge home without assistance), inpatient mortality, and intracerebral hemorrhage (ICH). Hospitals in the top quintile of annual EVT volume were classified as high-volume centers. We conducted univariate, multivariate, nearest neighbor matched analysis, and an exploratory analysis to identify annual EVT volume cutoffs.

Results: Among 114,640 patients with EVT, 24,415 (21.3%) were treated at high-volume centers. High-volume centers had higher rates of favorable functional outcomes in univariate (odds ratio (OR) 1.20, p < 0.001), multivariate (adjusted OR (aOR) 1.19, p = 0.003), and matched analysis (OR 1.14, p = 0.028). Before matching, inpatient mortality was lower in high-volume centers (OR 0.83, p < 0.001), but this difference was not significant in univariate and matched analyses. No differences in ICH were observed. Functional benefit was noted at ≥ 50 EVTs annually, with centers performing ≥ 175 EVTs showing significantly higher benefits (aOR 1.42, p = 0.002).

Conclusions: Increased hospital EVT volume is associated with modestly improved functional outcomes in patients with acute ischemic stroke. Functional improvements are evident at ≥ 50 EVTs annually and increase with higher case volumes, without associated increases in inpatient mortality or ICH.