The Direct Referral to Endovascular Center criteria: a proposal for pre-hospital evaluation of acute stroke in the Madrid Stroke Network

Background and purpose: For patients with acute ischaemic stroke due to large-vessel occlusion, it has recently been shown that mechanical thrombectomy (MT) with stent retrievers is better than medical treatment alone. However, few hospitals can provide MT 24 h/day 365 days/year, and it remains unclear whether selected patients with acute stroke should be directly transferred to the nearest MT-providing hospital to prevent treatment delays. Clinical scales such as Rapid Arterial Occlusion Evaluation (RACE) have been developed to predict large-vessel occlusion at a pre-hospital level, but their predictive value for MT is low. We propose new criteria to identify patients eligible for MT, with higher accuracy.

Methods: The Direct Referral to Endovascular Center criteria were defined based on a retrospective cohort of 317 patients admitted to a stroke center. The association of age, sex, RACE scale score and blood pressure with the likelihood of receiving MT were analyzed. Cut-off points with the highest association were thereafter evaluated in a prospective cohort of 153 patients from nine stroke units comprising the Madrid Stroke Network.

Results: Patients with a RACE scale score ≥ 5, systolic blood pressure <190 mmHg and age <81 years showed a significantly higher probability of undergoing MT (odds ratio, 33.38; 95% confidence interval, 12-92.9). This outcome was confirmed in the prospective cohort, with 68% sensitivity, 84% specificity, 42% positive and 94% negative predictive values for MT, ruling out 83% of hemorrhagic strokes.

Conclusions: The Direct Referral to Endovascular Center criteria could be useful for identifying patients suitable for MT.