Danny R. Rose, Jr., MD 

Sanossian N, Liebeskind DS, Eckstein M, Starkman S, Stratton S, Pratt FD, et al. Routing Ambulances to Designated Centers Increases Access to Stroke Center Care and Enrollment in Prehospital Research. Stroke. 2015

Patients with acute stroke have better outcomes when treated at organized stroke centers. Emergency Medical Services (EMS) providers play a critical role in the stroke care system by identifying patients with suspected stroke and then providing rapid transport to a facility providing an appropriate level of specialty care. Since 2007, this notion has been reflected in the American Stroke Association guidelines, which recommend Emergency Medical Services (EMS) systems preferentially route acute stroke patients to certified stroke centers that have proven their capability to deliver stroke care. Although this was supported by legislation or regulations in states and counties covering 53% of the US population by 2010, few studies have investigated whether these policies increase access to stroke center care. The impact on research associated with having a greater proportion of acute stroke patients treated at stroke centers, many of which actively enroll patients in clinical trials, is unknown.

Although the FAST-MAG study, a phase 3 clinical trial for prehospital initiation of magnesium vs. placebo for suspected acute stroke patients, failed to show a statistically significant benefit, it proved the feasibility of conducting a trial utilizing prehospital EMS protocols in a large metropolitan area spanning multiple provider agencies. What makes this study unique was that it was carried out in Los Angeles County over a period that in which there was a substantial change in the way EMS routed patients due to the implementation of a regional system of stroke care. Sanossian et al. performed an analysis using data from this study to investigate how the implementation of preferential routing for acute stroke patients impacted Emergency Department arrival times, the percentage of patients treated at an acute stroke center, and the numbers of patients enrolled in this prehospital stroke study. 

A total of 1627 subjects were enrolled in Los Angeles County over the course of the study, with 863 (53%) prior to and 764 (47%) after adoption of the countywide EMS routing protocol. In the nearly 5 years prior to EMS routing, only 90/863 (10%) of patients were transported to a designated Primary Stroke Center (PSC). EMS routing increased this proportion dramatically, with 698/764 (91%) of patients enrolled after the protocol implementation (P<0.001). Interestingly, the time from EMS arrival on scene to ED arrival actually decreased slightly after the routing change (34.5 min. vs 33.5, p=0.045). An analysis focused on the years immediately before and after the stroke center diversion policy was implemented showed an equally impressive improvement in the percentage of patients transported to PSCs (17% vs. 88%, P<0.0001), shorter scene to door times (33.6 min. vs 34.5, p=0.221), and a greater mean monthly enrollment into the FAST-MAG study (21.2 vs 17.9 subjects per month)

The analysis illustrates the dramatic effect that a properly implemented policy can have on improving the proportion of suspected acute stroke patients treated at stroke centers without detrimentally affecting transport times, one of the most common concerns regarding these types of changes. As these and similar changes designed to ensure acute stroke patients are preferentially treated at Joint Commission-certified stroke centers are implemented, there will likely be benefits beyond the more efficient conduct of clinical trials.

There, however, are significant limitations to the study that affect its generalizability. As in most major metropolitan areas in the US, Los Angeles County has a large amount of adult ED receiving facilities in a relatively small geographic area, with a total of 69 facilities participating in this study. The proportion of these facilities that obtained PSC certification increased steadily throughout the course of the trial, from 9 at the initiation of the routing policy in 2009 to a total of 29 by the trial end in December 2012. Although this can serve as a useful model for other major metropolitan areas in the US, access to primary stroke centers is more limited in large portions of the country. In these areas, routing suspected stroke patients exclusively to stroke centers could result in important delays in evaluation and treatment. This should not discourage policymakers in rural areas from adopting protocols to ensure acute stroke patients are triaged and transported efficiently. In these relatively underserved areas, collaboration and cooperation between stroke centers and critical access hospitals will likely remain a crucial component of stroke systems of care as medical infrastructure continues to evolve and mature.