Yasmin Aziz, MD
Patients with acute large vessel occlusions (LVOs) have better outcomes if they are sent to the endovascular suite expeditiously. Yet, many times these patients are taken to the nearest primary stroke center under the “drip and ship” model.
In this study, the authors used geographic information, census data, and stroke center accreditor information to build an origin to destination matrix analyses of patient location to nearest primary stroke center and to nearest intervention center. To do so, four different triage strategies were compared: (1) always going directly to the nearest primary stroke center, (2) always going directly to an endovascular center; (3) using the current AHA algorithm suggesting direct transfer to endovascular center if driving time is less than 30 minutes when LVO is suspected and won’t preclude tPA administration; (4) using a modified algorithm that would allow for additional driving time if an LVO is suspected if thrombolysis isn’t precluded (adding <30 minutes of driving time, <60 minutes of driving time, or not restricting by driving time at all).
Good primary outcome was defined as an modified Rankin Scale (mRS) of 2 or less, with the aim to keep number needed to treat <100 to prevent severe disability or death by transferring to an intervention center. The authors ran the above algorithms on a county by county level for all 48 states of the continental U.S. The prehospital triage intervention with the best outcome in most states (32 states) was the algorithm that did not have a time restriction on transport if an LVO was suspected and tPA administration would not be excluded, increasing the number of good outcomes per year by 1369, or an increase by 2.4%. Of note, this is in contrast to the current AHA guidelines, which elicited an increase in 594 cases per year, or an increase by 1%. Locations that benefitted from transfer to primary stroke center first included less densely populated states of the Midwest.
Importantly, the study is limited by ground transport times only in their algorithms. Secondly, as the authors mention, regional expertise with either tPA or thrombectomy may affect outcomes. Overall, the findings of the study support a tailored, more regional specific approach to prehospital stroke triage. Given the clearly disparate geographical density of endovascular-capable centers across the U.S., and the low number needed to treat for thrombectomy, more studies are needed to evaluate prehospital triage in order to assure appropriate stroke care for Americans regardless of their zip code.
