Objective
We aimed to assess the impact of time to endovascular
thrombectomy (EVT) on clinical outcomes in the DAWN trial, while also
exploring the potential effect modification of mode of stroke onset on
this relationship.
Methods
The association between every 1-h treatment delay with
90-day functional independence (modified Rankin Scale [mRS] score 0–2),
symptomatic intracranial hemorrhage, and 90-day mortality was explored
in the overall population and in three modes of onset subgroups (wake-up
vs. witnessed vs. unwitnessed).
(Well since 1.9 million neurons die from each untreated minute you should be able to graph out a linear relationship of time to treat vs. disability. And if you do nothing about stopping the
Results
Out of the 205 patients, 98 (47.8%) and 107 (52.2%)
presented in the 6 to 12 hours and 12 to 24 hours time window,
respectively. Considering all three modes of onset together, there was
no statistically significant association between time last seen well to
randomization with either functional independence or mortality at
90 days in either the endovascular thrombectomy (mRS 0–2 1-hour delay OR
1.07; 95% CI 0.93–1.24; mRS 6 OR 0.84; 95% CI 0.65–1.03) or medical
management (mRS 0–2 1-hour delay OR 0.98; 95% CI 0.80–1.14; mRS 6 1-hour
delay OR 0.94; 95% CI 0.79–1.09) groups. Moreover, there was no
significant interaction between treatment effect and time (p = 0.439 and p = 0.421
for mRS 0–2 and 6, respectively). However, within the thrombectomy
group, the models that tested the association between time last seen
well to successful reperfusion (modified Treatment in Cerebral
Infarction ≥2b) and 90-day functional independence showed a significant
interaction with mode of presentation (p = 0.013). This appeared
to be driven by a nominally positive slope for both witnessed and
unwitnessed strokes versus a significantly (p = 0.018) negative
slope in wake-up patients. There was no association between treatment
times and symptomatic intracranial hemorrhage.
Interpretation
Mode of onset modifies the effect of time to reperfusion
on thrombectomy outcomes, and should be considered when exploring
different treatment paradigms in the extended window. ANN NEUROL 2024
