Study parameters
To investigate the influence of pre- and intraoperative variables on 30-day mortality, various parameters deemed relevant were tested in the statistical analysis (tables 1-2). Preoperative parameters covered demographics, echocardiographic measurements, vessel involvement and laboratory results, while operative parameters included procedure type and duration of procedure. The 30-day mortality included any death occurring from the intraoperative period through the 30th postoperative day. The study was approved by the institutional ethics board of Union Hospital Tongji Medical College, Huazhong University of Science and Technology.