WSO October 2023 – Issue 1 - 922

922
International Journal of Stroke 18(8)
Table 1. (Continued)
Subgroup analyses
Grading scales
PComA only
LMC only
Combined scales
Sample size
⩽100
>100
No. of
subjects
396
376
675
625
822
Definition of favorable/good functional
outcome
mRS 0-3
mRS 0-2
230
1217
5
11
1.88 (1.39, 2.56) <0.001
2.08 (1.55, 2.79) <0.001
0.0
55.8
pc-ASPECTS: posterior-circulation Alberta stroke program early computed tomography score; RR: risk ratio.
aDivided by LAA/CE ratio tertile of the primary studies.
outcome were more significant in studies with a more
extended time window in patient eligibility criteria for EVT
in BAO (p for between-subgroup heterogeneity = 0.028).
The rates of a favorable/good 90-day functional outcome in
patients with good versus poor collaterals in studies with a
12, 24, and 48 h's time window were, respectively, 60.0%
versus 38.9%, 49.5% versus 27.7%, and 78.9% versus
19.7%, and the RRs were, respectively, 1.54, 1.86, and
4.00 (Table 1). The median onset-to-groin puncture time
(Supplemental Table S3) was numerically shorter in studies
with a shorter time window for EVT (4.8, 6.2-7.0, 6.2 h,
respectively in these subgroups).
In the sensitivity analysis by omitting one study each
time, no individual study showed a significant influence on
estimates of the overall effect size (Supplemental Figure S4).
Associations between good collaterals and
secondary outcomes
By synthesizing 3 studies (317 participants),29-31 good collaterals
was associated with a slightly higher rate of successful
recanalization (RR = 1.23, 95% CI: 1.04-1.45, p = 0.015),
with moderate between-study heterogeneity (I2 = 36.7%;
Figure 2). In two studies (404 participants),30,32 good collaterals
was associated with lower mortality (RR = 0.59,
95% CI: 0.43-0.81, p = 0.001), without between-study heterogeneity
(I2 = 0; Figure 2). However, none of the primary
International Journal of Stroke, 18(8)
studies reported the associations of good collaterals with
sICH or final infarct volume after EVT.
NNT for the outcomes
The NNTs were, respectively, 4 and 6 to have one additional
favorable/good 90-day functional outcome and successful
recanalization, with good versus poor collaterals.
The NNT to prevent one additional death within 90 days
was 6, with good versus poor collaterals.
Publication bias
There was no significant publication bias by visual inspection
of the funnel plot for any outcome (Supplemental
Figure S5), or by the Harbord test for the primary outcome
(p = 0.307).
Discussion
We systematically reviewed and synthesized relevant evidence
published in the last decade, on the associations
between pretreatment collaterals and post-EVT outcomes
in patients with acute BAO. Although the proportions of
good pretreatment collaterals varied in individual studies
using various collateral assessment methods, good pretreatment
collaterals was associated with slightly increased rate
0.560
0.012
CE: cardioembolism; CI: confidence interval; EVT: endovascular treatment; IVT: intravenous thrombolysis; LAA: large artery atherosclerosis; LMC:
leptomeningeal collateral; mRS: modified Rankin Scale; NIHSS: National Institutes of Health Stroke Scale; PComA: posterior communicating artery;
No. of
studies
6
3
7
11
5
Between-study
heterogeneity
RR (95% CI)
p value
2.38 (1.74, 3.26) <0.001
1.86 (1.47, 2.34) <0.001
1.98 (1.24, 3.17)
0.004
2.08 (1.48, 2.94) <0.001
2.02 (1.61, 2.52) <0.001
I2, %
1.8
65.4
58.2
p value
0.405
0.459
0.008
0.871
0.008
0.778
0.861
p value for
between-subgroup
heterogeneity
0.459
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