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International Journal of Stroke 19(3)
Institutes of Health Stroke Scale (NIHSS) (median = 12.0 vs 15.0, p = 0.37), perfusion imaging characteristics (core:
median = 11.0 vs 9.0 mL, p = 0.86; mismatch volume: median = 106.0 vs 96.0, p = 0.44; mismatch ratio = 6.46 vs 7.24,
p = 0.91), and perfusion-to-groin time (median = 72.5 vs 76.0 min, p = 0.77). No significant differences were noted among
patients between the two groups in the primary endpoint functional independence analysis (50.0% vs 46.6%, p = 0.77)
and in the safety endpoint analysis: mortality (15.0% vs 11.0%, p = 0.71) or symptomatic hemorrhage (0% vs 3.42%,
p > 0.999). In PS-matched analyses, there were no significant differences among patients between the two groups in
functional independence (50.0% vs 54.8%, p = 0.74), mortality (16.7% vs 9.68%, p = 0.50), or symptomatic hemorrhage
(0% vs 6.45%, p = 0.53).
Conclusion: Endovascular treatment can be performed safely and effectively in LVO patients beyond 24 h from symptom
onset when selected by target mismatch profile. The clinical outcome of these patients was comparable to those
treated in the 6- to 24-h window. Larger studies are needed to confirm these findings.
Keywords
Stroke, >24-h time window, slow progression, endovascular treatment, advanced imaging
Received: 29 April 2023; accepted: 19 September 2023
Introduction
Ischemic stroke patients with anterior large vessel occlusion
(LVO) and onset-to-imaging time of less than 12 h can
be appropriately selected for endovascular treatment (EVT)
using the Alberta Stroke Program Early CT Score
(ASPECTS), collateral status, and the National Institutes of
Health Stroke Scale (NIHSS) score.1 Furthermore, the
DAWN (the DWI or CTP Assessment with Clinical
Mismatch in the Triage of Wake-Up and Late Presenting
Strokes Undergoing Neurointervention with Trevo) and
DEFUSE 3 (The Endovascular Therapy Following Imaging
Evaluation for Ischemic Stroke) clinical trials have
extended the treatment window for onset-to-imaging time
to 24 h by demonstrating the benefit of EVT in selected
patients using perfusion imaging.2,3 Patients in the early
window, with onset-to-imaging time of less than 6 h, and
the late window, with the onset-to-imaging time from 6 to
24 h, can also be classified into fast progressors and slow
progressors of their infarct growth based on the ischemic
core and onset-to-imaging time.4 The DAWN and DEFUSE
3 trials successfully selected slow progression of infarct
growth patients in the late window who could still benefit
from EVT. Most of those patients had favorable collaterals.2,3
Therefore, the current recommendation for stroke
treatment supports the use of the " tissue clock " instead of
the " time clock " for patient selection, which suggests the
possibility of extending EVT treatment beyond the 24-h
window for select stroke patients.5
Recent studies suggest that EVT could still be beneficial
in select patients in the very late window.6,7 The analysis of
the DEFUSE-3 trial showed that patients presenting more
than 24 h from onset can still have salvageable infarct volume,
with those showing a persistent penumbra index (the
quotient of Tmax > 6 s volume lesion and diffusionweighted
magnetic resonance imaging lesion at 24 h after
onset) being potential candidates for EVT.8,9 A study
International Journal of Stroke, 19(3)
conducted in Korea also showed the benefits of EVT in
patients presenting from more than 16 h up to 10 days after
their last-known well time.10
However, these pathways have not been investigated in
the clinical setting of a developing country. Therefore, we
aimed to compare the safety and effectiveness of EVT in
patients selected using the RAPID protocol and presenting
in the very late window (>24 h) versus those in the late
window (6-24 h) at the Department of Cerebrovascular
Diseases at the Tertiary Stroke Hospital in Ho Chi Minh
City, Vietnam.
Methods
Study design and patient enrollment
We conducted a retrospective analysis of EVT patients,
treated between from July 2019 to November 2020 at the
Department of Cerebrovascular Diseases at 115 People's
Hospital in Ho Chi Minh City. The following inclusion criteria
were applied, which are consistent with routine treatment
criteria for EVT: presentation to our Digital
Subtraction Angiography (DSA) lab more than 6 h after
last-known well time; age ⩾18 years; pre-stroke modified
Rankin Scale (mRS) score of 0-2; met DAWN or DEFUSE
3 criteria; had CTA (computed tomographic angiography)/
MRA (magnetic resonance angiography) evidence of an
LVO (internal carotid artery (ICA), M1 or proximal M2
segments of middle cerebral artery, or tandem occlusions).
The RAPID AI (iSchemaView, Menlo Park, CA, USA)
software was used to evaluate the core and penumbra of the
acute stroke patients. The decision for EVT was made by a
treating physician according to the hospital protocol. The
primary outcome was the 90-day functional independence
rate, defined as an mRS score of 0-2. Secondary outcome
included mRS shift analysis and rates of successful reperfusion
(thrombolysis in cerebral infarction (TICI 2b-3),
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