Pre-intervention triage incorporating perfusion imaging improves outcomes in patients undergoing endovascular stroke therapy: a comparison with the device trials.

OBJECTIVES: Endovascular therapy of acute ischemic stroke is evolving towards thrombectomy devices for vessel recanalization. High rates of revascularization have been reported in stroke device trials. However, the discrepancy between recanalization and outcomes raises the question whether patients with irreversible ischemic injury are being exposed to these interventions. This study evaluated a triage methodology that incorporates perfusion imaging against previous device trials that treated all patients within a certain time frame.
METHODS: 99 consecutive patients were identified with anterior circulation strokes who had undergone endovascular therapy. All patients had a baseline NIHSS score ≥8 and had undergone pre-intervention CT perfusion. Rates of recanalization and functional outcomes were compared with the MERCI, Multi-MERCI and Penumbra trials.
RESULTS: This study's recanalization rate of 55.6% is not significantly different from the 46% for MERCI (p=0.15) and 68% for Multi-MERCI (p=0.08) but was significantly lower than the 82% for the Penumbra trial (p<0.0001). Successfully recanalized patients had a significantly higher good outcome of 67% in this cohort versus 46% in MERCI, 49% in Multi-MERCI and 29% in Penumbra. The rate of futile recanalization was 33% compared with 54% for MERCI, 51% for Multi-MERCI and 71% for Penumbra. A small cerebral blood volume (CBV) abnormality (p<0.0001) and large mean transit time-CBV mismatch (p<0.0001) were strong predictors of a good outcome.
CONCLUSION: Despite similar or lower recanalization rates, there was a significantly higher rate of good outcomes in the recanalized population and thus a significantly lower rate of futile recanalization in this study versus the device trials, suggesting a role for pre-intervention perfusion imaging for patient selection.