Gurmeen Kaur, MBBS

Froehler MT, Saver JL, Zaidat OO, Jahan R, Aziz-Sultan MA, Klucznick RP, et al. Interhospital Transfer Prior to Thrombectomy is Associated with Delayed Treatment and Worse Outcome in the STRATIS Registry. Circulation. 2017

Since “Time is Brain” when it comes to ischemic strokes and large vessel occlusions (LVO), the authors designed the STRATIS trial, which is a multicenter, observational, single-world perspective on real-life issues faced during transfers of patients for tPA and mechanical thrombectomy.

1000 patients with anterior circulation LVOs were included over a 22-month period. About half of the patients were transferred to a comprehensive stroke center which is capable of mechanical thrombectomy, and the remaining half was transferred from an outside hospital to an endovascular-capable center. IV-tPA was administered to 628 patients; 329/539 (61.0%) of direct patients and 299/445 (67.2%) of transferred patients (p=0.044).

Interestingly, time to achieve revascularization, onset of symptoms to recanalization was 202 minutes in the direct group and 311 in the transferred group, with a difference between the mean times of 100 minutes. There was a statistically higher NIHSS of patients who were transferred versus direct presentations, probably because the higher NIHSSs needed mechanical thrombectomy more because of the higher chance of them being an LVO.

To reduce the delays in recanalization or mechanical thrombectomy, a direct EMS-routing to endovascular-capable center has been proposed in the past. To answer that debate, the authors of STRATIS used hypothetical bypass modelling for patients who had been brought by EMS first to a non-endovascular hospital and then transferred by ground ambulance to the endovascular-capable center. A projected time to transfer to the thrombectomy-capable site was hence calculated. Using this model, the prediction made was that if patients with potential LVOs were directly transferred to an endovascular-capable center, comparing mean times, tPA would be administered 12.0 minutes later, but endovascular treatment would be delivered 91.0 minutes sooner.

The authors conclude that inter-hospital transfer was associated with mean treatment delays of 116 minutes compared to direct presentation to the endovascular-capable center. The above stated hypothetical model also showed that if the thrombectomy-capable center was within 20 miles, then the delay in IV tPA was 6.9 min but thrombectomy could be performed 94 minutes sooner. Data from the HERMES group and SWIFT-PRIME have previously demonstrated that functional independence and outcomes are much better with early thrombectomy. Despite the limitations of the observational study, there is a clear need for better systems of care and transfers to avoid delay in revascularization in patients with LVOs.