The elderly group was more likely to have an American Society of Anesthesiologists score of @ or greater ( @ % vs @ % , P < @ ) , higher serum creatinine ( @ vs @ mol/L , P < @ ) , and more-severe ACC ( moderate ACC ( @ % vs @ % , P = @ ) , gangrenous cholecystitis ( @ % vs @ % , P = @ ) ) on preoperative imaging and confirmed intraoperatively .