Other variables
We collected basal and demographical variables for each patient by direct interview or reviewing medical records. The Charlson index was used to assess comorbidities (23). Clinical and surgical-related variables were also collected.
Operative risk was calculated using the European System for Cardiac Operative Risk Evaluation (EuroSCORE) I and II (24,25). Health-related quality of life (HRQoL) was assessed using the EuroQOL 5D5L questionnaire (26).