Table 1.

Baseline Characteristics and Surgical Procedures of the Study Participants.^*

Characteristic	Red-Cell Storage ≤10 Days (N = 538)	Red-Cell Storage ≥21 Days (N = 560)
Demographic data
Age — yr
Median	73	72
Interquartile range	66–80	65–79
Male sex — no. (%)	228 (42)	247 (44)
White race — no./total no. (%)†	485/534 (91)	493/545 (90)
Clinical data
Weight — kg
Median	75	74
Interquartile range	65–89	66–86
Hemoglobin — g/liter‡
Median	11.7	12.0
Interquartile range	10.7–12.8	10.8–13.0
Creatinine — mg/dl§
Median	1.1	1.0
Interquartile range	0.8–1.4	0.8–1.4
Platelet count — per mm3¶
Median	207,000	209,000
Interquartile range	166,000–254,000	163,000–258,000
Bilirubin — mg/dl‖
Median	0.6	0.6
Interquartile range	0.4–0.9	0.4–0.8
ABO blood group — no. (%)
Group O	209 (39)	235 (42)
Group A	240 (45)	241 (43)
Group B	64 (12)	63 (11)
Group AB	25 (5)	21 (4)
Minimum TRUST score**
Median	4	4
Interquartile range	3–5	3–5
Baseline MODS	0.7±0.8	0.6±0.8
In ICU at randomization — no. (%)††	33 (6)	34 (6)
Surgical characteristics
Procedure — no. (%)
CABG plus valve repair or replacement plus other	69 (13)	76 (14)
CABG plus valve repair or replacement 110 (20) 119 (21)
CABG plus other	46 (9)	49 (9)
CABG	126 (23)	127 (23)
Valve repair or replacement plus other	91 (17)	95 (17)
Valve repair or replacement	91 (17)	81 (14)
Other	5 (1)	13 (2)
Type of surgical access — no. (%)
Primary sternotomy	384 (71)	410 (73)
Repeat sternotomy	150 (28)	143 (26)
Thoractomy	3 (1)	2 (<1)
Minimally invasive	1 (<1)	5 (1)
Cardiopulmonary bypass — no. (%)	516 (96)	535 (96)
Duration of cardiopulmonary bypass — min‡‡
Median	141	139
Interquartile range	99–187	105–194

^*Plus–minus values are means ±SD. P values for all comparisons were greater than 0.05 unless noted otherwise. To convert the values for bilirubin to micromoles per liter, multiply by 17.1; to convert the values for creatinine to micromoles per liter, multiply by 88.4. CABG denotes coronary-artery bypass grafting.

^†Race was self-reported.

^‡Data on hemoglobin level were not available for three participants in the group receiving red cells stored for 10 days or less.

^§Data on creatinine level were not available for five participants in the group receiving red cells stored for 10 days or less and for two participants in the group receiving red cells stored for 21 days or more.

^¶Data on platelet count level were not available for three participants in the group receiving red cells stored for 10 days or less.

^‖Data on bilirubin level were not available for 19 participants in the group receiving red cells stored for 10 days or less and for 10 participants in the group receiving red cells stored for 21 days or more.

^**If data on any components of the Transfusion Risk Understanding Scoring Tool (TRUST) score were not available, the score for that component was assumed to be 0. Data on the duration of cardiopulmonary bypass were not available for one participant in the group receiving red cells stored for 10 days or less. To be eligible for study participation, patients 18 years of age or older were required to have a TRUST score of 3 or higher, which corresponds to a likelihood of receiving a red-cell transfusion during surgery or on the first day after surgery of 60% or more. P = 0.01 by the Kruskal–Wallis test for the between-group comparison of the distribution of TRUST scores.

^††No P value was calculated for the variable of presence in the intensive care unit (ICU) because randomization was stratified according to this factor.

^‡‡Data on the duration of cardiopulmonary bypass applies to participants for whom the surgery was performed with the use of this technique.