WSO - April 2024 - 472

472
International Journal of Stroke 19(4)
Statistical analysis
Baseline demographic and clinical characteristics were
compared between Y-ESUS with CIL and without CIL,
between patients with cortical CIL and non-cortical CIL
and between Y-ESUS with PFO and without PFO using a
t-test for normally distributed continuous variables,
Wilcoxon `rank` sum test for continuous variables with
skewed distribution, and a chi-square test or Fishers' exact
test for categorical variables. The same statistical method
for categorical variables was used to compare the occurrence
of CIL and cortical CIL between Y-ESUS who had
PFO and those who did not have PFO and between patients
with unlikely, possible and probable PFO-related stroke.
To examine the association of recurrence of ischemic
stroke and the presence of CIL, an unadjusted and adjusted
Poisson regression models with robust error variance
were used,3 and relative risk (RR) and 95% confidence
intervals and p-values were reported. For the multivariable
model, covariates were history of stroke or transient
ischemic attack, diabetes, and cardiac arrest, which were
the predictors that were significantly associated with
recurrent stroke in the previous Y-ESUS publication.3 To
examine the association of presence of PFO with the presence
of CIL, an unadjusted and adjusted logistic regression
models were used and odds ratio (OR) and associated
95% confidence intervals and p-values were reported. The
adjusted model included body mass index (BMI), sex, history
of hypertension, history of diabetes and whether the
patient was current smoker as covariates reflecting the
factors of the RoPE Score. All analyses were conducted in
SAS, version 9.4
Ethics
Participants provided written informed consent and the
study was approved from institutional review boards at
each participating site.
Data availability
Data of this study will be shared if a reasonable request and
data analysis plan is sent to kanjana.perera@phri.ca and
ethics approval has been obtained.
Results
Overall, 535 Y-ESUS were enrolled (Supplemental Figure
S1). The mean age of registry participants was 40.4 (standard
deviation (SD) = 7.3) years, 238 (44%) were female,
and the median National Institutes of Health Stroke Scale
(NIHSS) was 2 (interquartile range = 1-6). Of the 535
patients, 238 (45%) had MRI performed, whereas the rest
had CIL assessed by CT imaging.
International Journal of Stroke, 19(4)
CIL presence
CILs were present in 76/534 (14.2%) patients. In one
patient, information on CIL was missing. The median number
of CILs was 1.0 (IQR = 1-2, see Table 1 for full details).
In patients with CIL, 42/76 (55%) had at least one cortical
CIL, 38/76 (50%) had at least one non-cortical CIL, and
3/76 (4%) had an uncertain phenotype.
Among 37 patients with a medical history of prior stroke
or transient ischemic attack, CIL was present in 25/37
(68%), whereas 51/76 (67%) Y-ESUS had CIL without a
medical history of prior stroke or transient ischemic attack
(TIA) (Table 2). There was no difference in the detection of
CIL according to the imaging modality (MRI vs CT), that
is, there was no difference in MRI obtained in those with
Table 1. Chronic ischemic lesions characteristics.
Parameter
Number of
patients
N enrolled
CIL on imaging, n (%)
Number of CILs, median
(IQR)
Anatomical location
Right hemisphere, n (%)
Right hemisphere,
cortical, n (%)
Right hemisphere,
subcortical, n (%)
Right hemisphere,
uncertain, n (%)
Left hemisphere, n (%)
Left hemisphere,
cortical, n (%)
Left hemisphere,
subcortical, n (%)
Left hemisphere,
uncertain, n (%)
Brainstem, n (%)
Cerebellar hemisphere,
n (%)
Phenotype
Cortical, n (%)
Non-cortical, n (%)
Uncertain, n (%)
535
534
72
Summary
76 (14.2%)
1.0 (1.0-2.0)
76
76
76
76
76
76
76
76
76
76
33 (43.4%)
14 (18.4%)
20 (26.3%)
2 (2.6%)
36 (47.4%)
18 (23.7%)
17 (22.4%)
2 (2.6%)
11 (14.5%)
18 (23.7%)
76
76
76
42 (55.3%)
38 (50.0%)
3 (3.9%)
CIL: chronic ischemic brain lesion; IQR: interquartile range.
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