Prehospital selection of thrombectomy candidates beyond large vessel occlusion: M-DIRECT scale.

Objective: Current prehospital scales used to detect large vessel occlusion reveal very low endovascular thrombectomy (EVT) rates among selected patients. We developed a novel prehospital scale, the Madrid-Direct Referral to Endovascular Center (M-DIRECT), to identify EVT candidates for direct transfer to EVT-capable centers (EVT-Cs). The scale evaluated clinical examination, systolic blood pressure, and age. Since March 2017, patients closer to a stroke unit without EVT capabilities and an M-DIRECT positive score have been transferred to the nearest EVT-C. To test the performance of the scale-based routing protocol, we compared its outcomes with those of a simultaneous cohort of patients directly transferred to an EVT-C.

Methods: In this prospective observational study of consecutive patients with stroke code seen by emergency medical services, we compared diagnoses, treatments, and outcomes of patients who were closer to an EVT-C (mothership cohort) with those transferred according to the M-DIRECT score (M-DIRECT cohort).

Results: The M-DIRECT cohort included 327 patients and the mothership cohort 214 patients. In the M-DIRECT cohort, 227 patients were negative and 100 were positive. Twenty-four (10.6%) patients required secondary transfer, leaving 124 (38%) patients from the M-DIRECT cohort admitted to an EVT-C. EVT rates were similar for patients with ischemic stroke in both cohorts (30.9% vs 31.5%). The M-DIRECT scale had 79% sensitivity, 82% specificity, and 53% positive predictive value for EVT. Recanalization and independence rates at 3 months did not differ between the cohorts.

Conclusions: The M-DIRECT scale was highly accurate for EVT, with treatment rates and outcomes similar to those of a mothership paradigm, thereby avoiding EVT-C overload with a low rate of secondary transfers.