Peter Alan Barber

Background Endovascular thrombectomy (EVT) is limited to comprehensive stroke centers (CSCs), with patients who first present to primary stroke centers (PSCs) transferred for treatment by road ambulance or helicopter emergency medical services (HEMS). We aimed to determine if there were outcome differences in patients transferred for EVT via HEMS. Methods A retrospective observational study was performed in the setting of a large regional network with 1 CSC receiving patients directly, or via road ambulance from 3 metropolitan PSCs or HEMS from 13 more distant PSCs. Consecutive patients were identified from a mandatory national EVT registry. HEMS transfers were compared with 2 metropolitan patient groups: direct‐to‐CSC and metro PSC‐to‐CSC patients. The primary outcome was day 90 functional independence (modified Rankin scale score, 0–2). Secondary outcomes included day 90 death rate. Results A total of 1183 EVT‐treated patients were identified (45% women; median age, 69 years; 88% anterior circulation strokes; median baseline National Institutes of Health Stroke Scale score, 16). A total of 332 (28%) patients were HEMS transfers, 428 (36%) were direct‐to‐CSC, and 423 (36%) were metro PSC‐to‐CSC transfers. The median transfer distances to the CSC were 11 (8–11) miles for road ambulance and 81 (70–121) miles for HEMS. HEMS patients were matched at baseline with the 2 metropolitan groups, except for a lower prevalence of congestive heart failure ( P <0.001) and a higher thrombolysis rate (54% versus 42% and 45%; P =0.004). HEMS patients had longer onset‐to‐EVT‐groin time (median minutes 370 versus 195 direct‐to‐CSC patients and 255 metro PSC‐to‐CSC; P <0.001). Direct‐to‐CSC patients were more likely to be independent at day 90 ( P =0.026), but there was no difference between the 2 transfer groups ( P =0.911). There were no differences among the 3 cohorts in day 90 mortality rate for all stroke types ( P =0.321) or independence in anterior circulation strokes ( P =0.124). Conclusion In this large regional stroke network, patients transferred via HEMS for EVT had similar day 90 outcomes to their metropolitan counterparts despite longer transfer times. CSCs should not be discouraged from considering patients from more distant PSCs who require HEMS.