Impact of Hospital Volume on Long-Term Neurological Outcome in Patients Undergoing Carotid Artery Stenting: A Nationwide Propensity Score-Matched Study

Background: The impact of hospital volume on long-term outcome after carotid artery stenting (CAS) remains unknown. Objectives: We designed a nationwide cohort study to elucidate the impact of hospital volume on the incidence of stroke after CAS. Methods: The Taiwan National Health Insurance Research database was used to identify all patients admitted for CAS from 2008 to 2012. We defined high-volume hospitals as those performing more than 20 CAS per year. The primary outcome was new ischemic stroke after discharging from the index CAS. Propensity score-matching was performed to create two matched groups for comparison. Results: A total of 3,248 patients underwent 3,576 CAS procedures were enrolled. There were 56 hospitals performing CAS during the study period. Among these 3,248 patients, 2,226 (68.5%) were performed in high-volume hospitals. A propensity score-matching created two groups with 1,000 patients in each group. During a median of 2.06 years follow-up, 35 (3.5%) and 52 (5.2%) patients in high-volume hospitals and low-volume hospitals developed new ischemic stroke 30 days after discharging from the index CAS, respectively (for low-volume hospitals, HR 1.50, 95% CI 1.06-2.12, P = 0.023). The use of embolic protection device did not result in different periprocedural or postdischarge strokes. The periprocedural (within 30 days after CAS) ischemic stroke or all-cause mortality rates during follow-up period were similar between two groups. Conclusions: CAS performed in high-volume hospitals was associated with less new ischemic stroke after discharging from the index CAS, compared to those in low-volume hospitals. (C) 2017 Wiley Periodicals, Inc.