Patterns of Stroke Transfers and Identification of Predictors for Thrombectomy

Interhospital transfers for endovascular thrombectomy (EVT) evaluation have increased since the publication of landmark neuroendovascular stroke trials in 2015. The lack of guidelines to select potential EVT candidates prior to transfer can lead to instances where, despite considerable costs and transport risks, transferred patients do not ultimately undergo EVT. Our aim was to characterize the patterns and identify predictors for EVT on transfer.

In this observational cohort study, we retrospectively analyzed patients with acute ischemic stroke (AIS) transferred to our institution for EVT evaluation from January 2015 to March 2016. Clinical and radiographic predictors for EVT on transfer were determined with multivariable logistic regression analysis.

A total of 103 transfer patients with AIS were included in the study, and 52% were women. A higher collateral score (P < 0.01), a higher National Institutes of Health Stroke Scale (NIHSS) score (P < 0.01), computed tomography angiography (CTA) at referring hospital (P < 0.01), and large vessel occlusion on arrival CTA (P < 0.01) were significant in patients who underwent EVT on univariable analysis. More than half (61.1%) of transfers were futile and primarily related to absence of large vessel occlusion on arrival. A higher collateral score (P = 0.02), a higher NIHSS score (P = 0.006), and having undergone a CTA at the referring center (P = 0.002) remained the independent predictors of EVT. The C statistic for the model was 0.94.

A higher collateral score, the acquisition of CTA imaging at the referring centers, and a higher NIHSS score independently predicted EVT on transfer.