Statistical Analysis
All statistical analyses except inter- and intra-rater reliability analyses were carried out in SAS 9.4 (SAS Institute, Cary, N.C.). To assess inter- and intra-rater reliability, Pearson correlation coefficients were calculated for edited autostrain GLS measurements within and between raters. Demographics were summarized by pre/post group using means and standard deviations for numeric variables and frequencies and percentages for categorical variables. Mean pre-post changes in LVEDV, LVESV, LVEF, LAVI, and RVSP were calculated and were tested for significance using paired t-tests. The effect of pre-procedural GLS (Pre-GLS) on the odds of a 10% change in EDV was modeled using logistic regression. This was done for the entire sample and for several sub-groups. Finally, the effect of GLS on the numeric change in EDV was modeled using linear regression, as were the effects of LVEDV, LVESV, LVEF, LAVI, and RVSP on numeric change in EDV. For this final set of linear regression models, crude (single-predictor) models were fit for each predictor first. Linear and quadratic models were fit to assess the best functional form. GLS and any other predictors that were significant in their respective crude models were included as predictors in a final multivariable model.