Abstract TP43: Trends in Interhospital Transfers and Mechanical Thrombectomy for Acute Ischemic Stroke

Introduction: Stroke care in the US is becoming increasingly regionalized. Many patients undergo interhospital transfer to obtain access to specialized, time-sensitive interventions such as mechanical thrombectomy. Methods: We used the stratified survey design of the US Nationwide Inpatient Sample, 2009-2014, to examine nationwide trends in interhospital transfers for ischemic stroke and the relationship between transfers and thrombectomy. International Classification of Disease—Ninth Revision diagnosis and procedure codes were used to identify acute stroke admissions and inpatient procedures (tissue plasminogen activator [tPA] administration and thrombectomy), respectively. The analysis was restricted to hospitals with the capabilities to perform thrombectomy. Trends were assessed using a Cochran-Armitage test. Results: From 2009 to 2014, an estimated 759,648 ischemic stroke admissions were identified within hospitals offering thrombectomy (102,674 in 2009; 154,280 in 2014). The proportion of stroke admissions to these hospitals that underwent interhospital transfer prior to arrival increased from 13.5% (n=13,811) in 2009 to 18.9% (n=19,175) in 2014 ( P trendP P P trend=0.016). Approximately 30% of patients receiving thrombectomy for ischemic stroke were transferred from another acute care facility (n=7,328). Among patients receiving tPA, transferred patients were slightly less likely to receive thrombectomy compared to those arriving by “front door” at thrombectomy performing centers (13.9% vs. 15.4%; P =0.004). Conclusions: From 2009 to 2014, interhospital stroke transfers to thrombectomy performing hospitals more than doubled. For every ~5 additional stroke transfers over the time period examined, one additional transferred patient received thrombectomy. As stroke systems of care continue to evolve across the US, the optimization of stroke transfers presents an opportunity to increase access to meaningful interventions such as thrombectomy.