Endovascular therapy after stroke increases with transport policy in emergency services

A transport policy for emergency medical services resulted in a substantial and swift increase in rates of endovascular therapy after acute ischemic stroke, according to findings from a single-center study published in JAMA Neurology.

This increase occurred “without deleterious associations with thrombolysis rates or times,” according to the study results.

“Time to reperfusion by endovascular therapy (EVT) is a major determinant of outcomes in acute large vessel occlusion (LVO) stroke, with delays in reperfusion leading to worse outcomes. However, [one in three] patients becomes ineligible for EVT because of unfavorable imaging characteristics caused in part by delays resulting from potentially eligible patients with LVO presenting at hospitals without EVT capability,” the researchers wrote. “Limited data exist on the implementation of [comprehensive stroke center] triage protocols and their association with EVT rates.”

Tareq Kass-Hout, MD, assistant professor of neurology, medical director of inpatient services in the department of neurology and director of the neuro-endovascular service at the University of Chicago, and colleagues aimed to determine the impact of a regional pre-hospital transport policy, in which patients with suspected LVO stroke were directly triaged to the closest comprehensive stroke center, on rates of EVT. The researchers conducted a retrospective, multicenter pre- and post-implementation study using an interrupted time series analysis to examine treatment rates before and after implementation among patients with acute ischemic stroke. The study included patients arriving at 15 primary stroke centers and eight comprehensive stroke centers in Chicago via emergency medical services transport between Dec. 1, 2017, and May 31, 2019, 9 months before and after the implementation of the policy in September 2018.

Researchers used a three-item stroke scale to examine the transport intervention. Rates of EVT before and after implementation of the policy among those transported via emergency medical services within 6 hours of stroke onset served as the main outcome.

The study included 7,709 patients with stroke. Among these patients, 663 (mean age, 68.5 years; 51.6% women; 52.5% Black) arrived within 6 hours of stroke onset via emergency medical services, including 11.9% in the period before the policy and 13.4% in the period after implementation of the policy.

Rates of EVT increased among all patients with acute ischemic stroke before (4.9%; 95% CI, 4.1% to 5.8%) and after (7.4%; 95% CI, 7.5% to 8.5%) implementation of the policy (P < .001) and among those transported via emergency medical services within 6 hours of stroke onset before (4.8%; 95% CI, 3% to 7.8%) and after (13.6%; 95% CI, 10.4% to 17.6%) implementation of the policy (P < .001).

An interrupted time series analysis among patients transported via emergency medical services demonstrated that the level change within 1 month of implementation was 7.15% (P = .04), with no slope change before (0.16%) or after (0.08%), “which indicates a step rather than gradual change,” according to the study results. Researchers reported no change in time to thrombolysis or rate of thrombolysis (step change, 1.42%). They also reported no differences in EVT rates among patients who did not arrive via emergency medical services within the window of 6 to 24 hours after symptom onset or by interhospital transfer or walk-in, regardless of time window.

The researchers acknowledged several limitations of their study, including the inability to generalize their findings in non-urban settings or areas with fewer, or geographically distant, stroke centers. They also described potential selection bias and issues with retrospective data collection, but noted that regional and external requirements for data reporting without sampling could address those issues.

“In this pre-implementation [and] post-implementation study, we observed that the implementation of a regional prehospital protocol directing patients with suspected [acute ischemic stroke] and LVO to [comprehensive stroke centers] that included [emergency medical services] training on LVO screening was associated with an increase in the rate of EVT for eligible patients with [acute ischemic stroke],” Kass-Hout and colleagues wrote. “Our results provide further evidence to support the development of regional strategies to direct patients with suspected LVO to [comprehensive stroke centers] and thrombectomy-capable centers when feasible.”