Imaging selection for endovascular thrombectomy: the SELECT trial
Imaging for patient selection for mechanical thrombectomy (MT) was the focus of the Stryker sponsored symposium led by Dr Amrou Sarraj, Associate Professor in the Department of Neurology, UTHealth, Houston, TX, USA. Dr Sarraj presented a review of the SELECT trial, the TREVO registry and the upcoming SELECT 2 trial.
The SELECT trial is a prospective study comparing CT and CT perfusion imaging in correlation with clinical outcomes. It looked, as well, at the relationship between imaging selection and time (0-6 hours vs. >6 hours). Out of 4,722 screened patients, 361 were finally included of whom 284 received EVT and 77 medical management comprising IVT.
The study did not show any significant differences in clinical outcome among patients selected by ordinary CT and perfusion imaging, with an overall 53% mRS 0-2 in the CT selected group and 54% mRS 0-2 in the perfusion imaging selected group. In addition, no difference was seen either when considering the good CT and CTP profiles alone or when stratifying by imaging time between >6 hours and 6 – 24 hours delay after onset.
A retrospective analysis of the TREVO registry dataset was performed looking at initial patient imaging for those patients included in the 6 – 24 hour time window. This analysis identified 67 patients who were included on CT only and 394 with CT and CTP or MRI perfusion imaging – once again, clinical outcomes in both groups were similar. Of interest, among patients of the second group who had discordant CT and CTP profiles and successful mechanical thrombectomy – 33.3% were mRS 0-2 when the rCBF defined infarct core was small with a low ASPECTS score, and 46% when the ASPECTS score was >5 with a large rCBF defect.
When analysing the SELECT trial, in patients meeting criteria for a large infarct core (either ASPECTS ≤5 or rCBF defect >50 ml) mechanical thrombectomy was associated with good functional outcomes and a favourable shift on the outcome scale in relation to medical treatment alone.
Moreover, the effect of time is more pronounced as core size increases.
Based on these considerations, Dr Sarraj ended his presentation by introducing the initial stages of the SELECT 2 trial, which will focus on the safety and efficacy of thrombectomy in patients with large core strokes based on different imaging modality selection.
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