2.5. Statistical Analysis
Stata version 16.0 was used for statistical analyses. Continuous
variables are displayed as means ± SD, and categorical variables are
presented as frequencies and percentages. For observational studies with
two arms, we calculated the relative risk (RR) and corresponding 95%
confidence intervals (CI) for each outcome, whereas for single-arm
analysis, we calculated the incidence of events (number of events
divided by number of patients) and 95% confidence intervals. P< 0.05 was considered statistically significant.
Meanwhile, chi-square tests and I-squared (I2) are
used to quantify and assess statistical heterogeneity among studies. If
the I2 value was more than 50% and/or P< 0.05 for the chi-squared test, we considered the
between-study heterogeneity to be significant, and we would adopt a
random-effect model. Otherwise, we would adopt fixed-effect model.
Sensitivity analysis was performed by sequentially omitting one study at
a time to assess the effect of a single study on the overall risk, and
potential publication bias was also evaluated via Egger’s test.
In addition, subgroup analysis was conducted to screen potential
determinants of LAAO outcomes between ICE and TEE groups. According to
the characteristics of eligible studies, a total of eight subgroup
factors were identified, including study design, elderly age cutoff, ICE
group sample size, AF type, male proportion, hypertension proportion,
device types and duration of follow up. If the study design included
more than one center, it was defined as a multicenter subgroup;
otherwise, it was defined as a single-center subgroup. According to age
cut-off values of 75, it was divided into ≥ 75 years subgroup and
<75 years subgroups. If more than 50% of patients have
paroxysmal AF, they are classified as ≥50% PAF group, otherwise they
are classified as <50% PAF group. According to the proportion
of the male, they were divided into subgroups with ≥ 70% and subgroups
with < 70%. Similarly, the proportion of hypertension with
“≥ 90%” and “< 90%” subgroup also was defined. According
to the sealing position, the existing sealers can be roughly divided
into plug type and disc type. Plug type sealers, also known as single
sealers, including Watchman, Plaato, and Lefort. Disc sealer is also
called dual sealer, including ACP, Lambre, Lacbes, and Leftear. If the
LAAO devices included only dual-seal mechanism devices, it was assigned
to dual-seal mechanism subgroup, and if the LAAO devices included only
single-seal mechanism devices, it was assigned to the single-seal
mechanism subgroup. In addition, studies using both dual-seal mechanism
devices and single-seal mechanism devices are divided into muti-seal
mechanism subgroup. Follow-up time was divided into two subgroups (≥12
months and <12 months).