Statistical analysis
Quantitative data are expressed as mean ± standard deviation and were compared using the two-tailed t test. Categorical data are expressed as percentages and were compared using the chi-square test. Comparisons of events by groups were made by Kaplan–Meier analysis and the log-rank test. Predictors of delayed PE/PT were analysed by univariate and subsequent multivariate Cox regression analyses. The results were expressed as hazard ratios (HRs) with 95% confidence intervals (CIs). P<0.05 was considered statistically significant. All statistical analyses were performed using SPSS version 23.0.