2.5 | Statistical Analysis
Categorical variables were expressed as absolute numbers and percentages and continuous variables were expressed as mean (SD) or median (IQR) depending on the distribution. Kolmogorov-Smirnov test was used to access the normal distribution.
The pre-operative variables were selected a priori (not a stepwise method): age, gender, hypertension, Diabetes Mellitus (DM), dyslipidemia, New York Heart Association (NYHA) III/IV, Canadian Cardiovascular Society (CCS) scale III/IV, LVEF <50%, renal disease, carotid artery disease, respiratory disease, gastrointestinal disease, urgency surgery and history of stroke. Categorical variables were compared using χ2 test. Mann–Whitney U-test was used for independent samples not normally distributed.
Variables with a univariate p <0.05 were included in the Multivariable Cox Proportional Hazards Regression and Logistic Regression models to identify risk factors for MACCE and follow-up mortality. A probability value of p <0.05 was considered statistically significant. All analyses were performed using IBM SPSS Statistics for Windows, Version 22.0. (IBM Corp. Armonk, NY).