Statistical analysis
The statistical analyses were performed with SPSS software, version 21.0 (SPSS Inc., Chicago, IL, USA). The summary statistics are presented as frequencies and percentages for categorical values, as the means and standard deviations for normally distributed continuous values and as medians with quartiles for nonnormally distributed continuous variables. Comparisons between the groups were performed with Student’s unpaired t test or the χ2 test. Probability values of less than 0.05 were considered to be statistically significant. The influence of different parameters on 30-day mortality was analyzed using multiple logistic regression analyses with backward elimination. The results of the logistic regressions are presented as odds ratio (OR) with confidence intervals. The possible risk factors (demographics, echocardiographic measurements, vessel involvement, laboratory results, procedure time and extracorporeal circulation time) included in the logistic regression analysis were analyzed using receiver-operating characteristic (ROC) curves to obtain diagnostic cutoff values, as well as specificity and sensitivity.