Table 2. Surgical and intraoperative characteristics.

Characteristic	Selenium (n=144)	Placebo (n=143)	P value†
Operative procedures on the thoracic aorta‡			0.03
Ascending-only operations	69 (47.9)	89 (62.2)
Root involvement	32 (22.2)	28 (19.6)
Arch/descending involvement	40 (27.8)	24 (16.8)
Intraoperative characteristics
Duration of surgical procedure (minutes)	261 [195–337]	260 [203–347]	0.46
Duration of CPB (minutes)	142 [105–192]	146 [108–209]	0.39
Duration of aortic clamping (minutes)	108 [79–146]	112 [81–153]	0.58
Intraoperative change in surgical procedure	28 (19.4)	41 (28.7)	0.07

Data are presented as n (%) or median [interquartile range]. ^†, P values were calculated using the Mann-Whitney U test for continuous variables and the Chi-squared test, or Fisher’s exact test when expected cell counts were <5; ^‡, each patient was classified into a single operative strategy (categories were mutually exclusive). Data were missing for 5 patients (3 in the selenium group and 2 in the placebo group). CPB, cardiopulmonary bypass.