Interfacility transfer for mechanical thrombectomy - Direct to neuroangiography or CT angiography first?

Faster time to mechanical thrombectomy (MT) improves outcome in stroke. In patients from other hospitals where a CT has ruled-out hemorrhage, transfer direct-to-angiography (DTA) may reduce door-to-groin time compared to transfer to CT angiography (CTA)+/-repeat CT first. However, this may result in unnecessary catheter angiography. We sought to determine how often CTA+/-CT changed the decision to proceed to MT.

Data on patients transferred to our comprehensive stroke center (CSC) from outside facilities for possible MT from 7/2016-5/2017 was extracted from a prospective database and supplemented with chart review.

Of 170 patients transferred for MT undergoing CT+/-CTA on CSC arrival, MT was aborted in 108 (64%). Of these, 87 (81%) were aborted directly based on imaging findings, with absence of large vessel occlusion or occlusion too distal to be amenable to MT the most common reasons (n = 76), followed by extensive early CT changes (n = 9) and ICH post-tPA (n = 2). Even with NIHSS ≥10 on CSC arrival, MT was aborted based on imaging findings in 35% patients. Time from symptom onset dichotomized as early/late based on median onset-to-CSC arrival (253 min) was an important modifier of proceeding to MT in this group, with 71% of early presenters going to MT compared to 33% of late presenters (p = .003).

Transfer DTA may result in many patients who would have been excluded based on CT+/-CTA findings undergoing unnecessary catheter angiography. However, a target population for a DTA approach might be identifiable based on severity of deficit and time from onset.