Death occurred in 1.5 % of patients , and 10.8 % were readmitted within the first 30 postoperative days.On multivariate analysis , AAE and SAE were both significantly associated with American Society of Anesthesiologists class 4 ( AAE : odds ratio [ OR ] = 2.7 , P = 0.013 ; SAE : OR = 2.5 , P = 0.040 ) and inpatient status before procedure ( AAE : OR = 2.7 , P < 0.001 , SAE : OR = 2.4 , P = 0.003 ) .