Interhospital Transfer Before Thrombectomy Is Associated With Delayed Treatment and Worse Outcome in the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke)
Authors: Froehler Michael T. , Saver Jeffrey L. , Zaidat Osama O. , Jahan Reza , Aziz-Sultan Mohammad Ali , Klucznik Richard P. , Haussen Diogo C. , Hellinger Frank R. , Yavagal Dileep R. , Yao Tom L. , Liebeskind David S. , Jadhav Ashutosh P. , Gupta Rishi , Hassan Ameer E. , Martin Coleman O. , Bozorgchami Hormozd , Kaushal Ritesh , Nogueira Raul G. , Gandhi Ravi H. , Peterson Eric C. , Dashti Shervin R. , Given Curtis A. , Mehta Brijesh P. , Deshmukh Vivek , Starkman Sidney , Linfante Italo , McPherson Scott H. , Kvamme Peter , Grobelny Thomas J. , Hussain Muhammad S. , Thacker Ike , Vora Nirav , Chen Peng Roc , Monteith Stephen J. , Ecker Robert D. , Schirmer Clemens M. , Sauvageau Eric , Abou-Chebl Alex , Derdeyn Colin P. , Maidan Lucian , Badruddin Aamir , Siddiqui Adnan H. , Dumont Travis M. , Alhajeri Abdulnasser , Taqi M. Asif , Asi Khaled , Carpenter Jeffrey , Boulos Alan , Jindal Gaurav , Puri Ajit S. , Chitale Rohan , Deshaies Eric M. , Robinson David H. , Kallmes David F. , Baxter Blaise W. , Jumaa Mouhammad A. , Sunenshine Peter , Majjhoo Aniel , English Joey D. , Suzuki Shuichi , Fessler Richard D. , Delgado Almandoz Josser E. , Martin Jerry C. , Mueller-Kronast Nils H. 
Published: September 2017

Background:
Endovascular treatment with mechanical thrombectomy (MT) is beneficial for patients with acute stroke suffering a large-vessel occlusion, although treatment efficacy is highly time-dependent. We hypothesized that interhospital transfer to endovascular-capable centers would result in treatment delays and worse clinical outcomes compared with direct presentation.

Methods:
STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter, observational, single-arm study of real-world MT for acute stroke because of anterior-circulation large-vessel occlusion performed at 55 sites over 2 years, including 1000 patients with severe stroke and treated within 8 hours. Patients underwent MT with or without intravenous tissue plasminogen activator and were admitted to endovascular-capable centers via either interhospital transfer or direct presentation. The primary clinical outcome was functional independence (modified Rankin Score 0–2) at 90 days. We assessed (1) real-world time metrics of stroke care delivery, (2) outcome differences between direct and transfer patients undergoing MT, and (3) the potential impact of local hospital bypass.

Results:

A total of 984 patients were analyzed. Median onset-to-revascularization time was 202.0 minutes for direct versus 311.5 minutes for transfer patients (
P
<0.001). Clinical outcomes were better in the direct group, with 60.0% (299/498) achieving functional independence compared with 52.2% (213/408) in the transfer group (odds ratio, 1.38; 95% confidence interval, 1.06–1.79;
P
=0.02). Likewise, excellent outcome (modified Rankin Score 0–1) was achieved in 47.4% (236/498) of direct patients versus 38.0% (155/408) of transfer patients (odds ratio, 1.47; 95% confidence interval, 1.13–1.92;
P
=0.005). Mortality did not differ between the 2 groups (15.1% for direct, 13.7% for transfer;
P
=0.55). Intravenous tissue plasminogen activator did not impact outcomes. Hypothetical bypass modeling for all transferred patients suggested that intravenous tissue plasminogen activator would be delayed by 12 minutes, but MT would be performed 91 minutes sooner if patients were routed directly to endovascular-capable centers. If bypass is limited to a 20-mile radius from onset, then intravenous tissue plasminogen activator would be delayed by 7 minutes and MT performed 94 minutes earlier.

Conclusions:
In this large, real-world study, interhospital transfer was associated with significant treatment delays and lower chance of good outcome. Strategies to facilitate more rapid identification of large-vessel occlusion and direct routing to endovascular-capable centers for patients with severe stroke may improve outcomes.

Clinical Trial Registration:

URL:
https://www.clinicaltrials.gov
. Unique identifier: NCT02239640.