Groups @ and @ were similar in preoperative characteristics including age ( @ @ vs @ @ , P = @ ) New York Heart Association class ( @ @ vs @ @ , P = @ ) , EuroSCORE ( @ @ vs @ @ , P = @ ) , the degree of carotid stenosis ( @ @ vs @ @ % , P = @ ) and average left ventricular ejection fraction ( @ @ vs @ @ % , P = @ ) .