Statistical Analysis
Continuous data are presented as means±SD or median and interquartile ranges, according to normality of distribution assessed by the Shapiro-Wilks test. Comparisons of continuous variables between groups were performed using the Student’s t test (when Gaussian distribution) or Mann-Whitney test (when non-Gaussian distribution) for independent samples. For categorical variables, the Chi-square test (χ2) or Fisher’s exact test, when indicated, were used. The within-group comparison of means was performed using the paired Student’s t test. Finally, comparison of the “delta” (Δ) of values ​​obtained from the follow-up of each group was done by the unpaired Student’s t test.
Bivariate linear regression was performed to assess correlation between main variables of the CPX and data obtained from the echocardiogram-STE.
All tests were 2-tailed and a P value <0.05 was considered statistically significant. Statistical analyses were done using the SPSS 25.0 software for Macintosh (SPSS Inc, Chicago, IL).