Statistical analysis:
Statistical analysis were performed with SPSS StatisticsĀ® software (IBM Corporation, New York, USA). Categorial variables were expressed as numbers and percentages. Continuous variables were reported as mean +/- standard deviation (SD) and median with interquartile range (IR) when appropriated. Event-free survival curves were calculated using the Kaplan-Meier method. Univariate analysis was performed by comparing the Kaplan-Meier survival curves using the Log-Rank test to identify risk factors of late re-operation of the PH. Multivariate analysis was performed to identify independent risk factors of late re-operation of the PH, using a Cox regression model. P value <0.05 was retained for statistical significance.