Tolga Daniel Dittrich, MD
Perfusion imaging currently represents a key selection tool for endovascular therapy (EVT) in stroke patients with large vessel occlusions in the extended time window. However, the extent to which imaging modality influences clinical outcome in EVTs remains unclear in this context.
Nogueira et al. tackled this question by comparing the functional outcome of patients with intracranial carotid, M1-, or M2-occlusions of the middle cerebral artery with modified Rankin Scale score from 0 to 2 and time to treatment between early (i.e., 0-6 hours) and extended time windows (i.e., 6-24 hours) depending on the imaging modality received. These were either non-contrast computed tomography (NCCT)±CT angiography (CTA) or NCCT±CTA with CT perfusion (CTP).
No significant differences were seen for 90-day functional independence in either the early (332 patients selected with NCCT±CTA, 373 with additional CTP) or late time window (67 NCCT±CTA, 180 with CTP) after adjustment for confounders (early time window: adjusted OR: 1.178 [95% CI, 0.833-1.666], p=.355) between the CTP and NCCT±CTA groups; late time window: aOR: 0.640 [95% CI, 0.318-1.289], p=.212).
Although the numbers of cases were comparatively small in the extended time window subgroup, the legitimate question is whether there is a benefit of CTP for patients with large-vessel occlusions or whether EVT remains beneficial in the absence of CTP data. Ongoing randomized controlled trials of EVTs in the extended time window — without requiring prior perfusion imaging — may further clarify this issue and optimize current selection approaches.
A rather milestone study which probably favor endovascular treatment in extended time window of course require further studies to come to conclusion.