Statistical analysis
Categorical variables were expressed as the mean ± standard deviation
(SD) or median with interquartile range (IQR). Student’s t-test was used
to compare characteristics of the segments with acute PVR and those
without. Receiver-operating characteristics (ROC) curve analysis was
utilized to identify the most optimal cut-off value (with a Youden
index) to predict acute PVR among various indices, and to determine the
cut-off value with the specificity of 90%. Logistic regression analysis
was performed to evaluate predictors of acute PVR in univariate and
multivariate model for all segments, and region-specific analysis. The
log-rank test was carried out for Kaplan-Meier curve analysis to assess
cumulative rate of ATA-free survival in all subjects. All tests were
considered statistically significant at P -value <0.05.
All statistical analyses were performed with JMP® 13
(SAS Institute Inc., Cary, NC, USA).