Table 2.

Schedule of Enrollment, Interventions, and Assessments

	Study period
Timepoint	Enrollment	Allocation	Post-allocation
			Surgery	Acute transfusion period	Adverse event monitoring	End of monitoring period	Status	Close-out
	Day -30 to day 0 pre-surgery	Day -7 to day 0 pre-surgery	Day 0 surgery	Day 0 post-surgery–day 7	Day 8–28	Day 28	Day 30	Day 75
Enrolment
Informed consent	X
Demographics & medical history	X
Baseline lab studies	X
S-303 antibody screening panel	X
Baseline serum creatinine	X
Sample for HLA antibodies	X
Pre-transfusion testing	X
Randomization		X
Intervention
Cardiac or thoracic aorta surgery			X
Study RBC transfusions			X	X
Assessments
Serum creatinine			X	X (48 h)
Document daily labs			X	X
DAT						X
Document AEs, SAEs and TRs			X	X	X	X
S-303 antibody screening panel				(as needed)		X		X
Sample for HLA antibodies						X
Vitals status and RRT status							X	X
Investigate S-303 antibodies				X	X	X	X	X
Document non-study blood components			X	X	X	X