3 Statistical analysis
Continuous variables are expressed as mean ± standard deviation. Categorical variables are presented as percentile value. Unpaired t-test was used to compare continuous variables. Categorical variables were compared using either the chi-square test or Fisher’s exact test, as appropriate. Multivariate logistic regression analysis was performed to evaluate the impact of different type of irrigation system on procedure-related ischemic complications. Covariates included in the multivariate model were chosen based on the baseline characteristics of each group and univariate logistic regression analysis. However, the known risk factors of ischemic stroke or TIA, such as individual components of the CHA2DS2-VASc score, were included in multivariate analysis regardless of the results of univariate analysis. Results were considered to be significant if the p-value was <0.05 on a two-tailed test. All statistical analyses were performed using SPSS version 24.0 (SPSS Inc., Armonk, NY, USA).