This article is conceptually quite strange – and that’s evident right in the title. Time from imaging, not time from onset, is the determining factor in outcomes from acute stroke? However, despite the overall oddity of their premise, there’s at least one pearl demonstrated here: patients with excellent collateral circulation are far more resilient.
This is a small, retrospective evaluation of patients undergoing endovascular intervention for large vessel occlusion within 18 hours, dichotomized between those with a “target” and a “malignant” mismatch profile on CT perfusion imaging. The “target” profile has a Tmax>10s volume ≤100 mL, while the “malignant” profile was ≥100 mL.
There were only 154 patients for analysis, only 48 of whom had “malignant” profile – and, in their tiny sample, they observed no association between time from CT to reperfusion and functional outcomes in those with “target” profile, while there was an apparent association between time delays and outcomes for the “malignant” profile. Whether this risk for poor outcomes can be truly assigned to these time delays or other features intrinsic to at-risk tissue, it does, again, demonstrate the marked heterogeneity in stroke patients with regard to their underlying tissue viability.
The value in endovascular intervention drops precipitously when, despite otherwise being eligible, the collateral circulation is insufficient. The “time is brain” absolutism continues to weaken, affecting both those traditionally considered appropriate and those in extended time windows.
“Time From Imaging to Endovascular Reperfusion Predicts Outcome in Acute Stroke”
http://stroke.ahajournals.org/content/early/2018/03/15/STROKEAHA.117.018858