Abstract Body (Do not enter title and authors here): Introduction:
Perioperative anemia can cause a host of complications, such as renal injury, stroke, and mortality. However, the use of transfusions preoperatively also can cause various complications, such as an overload of fluids and the risk of infection. Learning if, and how much an effect transfusion has in cardiac surgery can lead to better decision-making to reduce postoperative complications.

Hypothesis:
The hypothesis tested was that there is a significant difference in postoperative outcomes between cardiac transplant patients who received a blood transfusion preoperatively and those who did not.

Methods:
The UNOS database was used to find adult patients who received a heart transplant between 2000 and 2023 (n = 51,325). The remaining individuals were split into groups that received preoperative blood products (n=10,873) or did not (n=40,452). Endpoints analyzed include mortality, length of stay, graft status, and acute rejection. Mortality was analyzed using a Kaplan-Meier curve and log-rank tests, and Cox proportional hazards were used to find risk factors. All analysis was done in JMP.

Results:
After analysis, it was found that there was a significant difference in length of stay (p<0.0001), graft status (p<0.0001), and acute rejection (p=0.0430), with transfusion patients having a longer LOS, and higher percentages of graft failure and acute rejection. The Kaplan-Meier curve shows a significant difference in mortality between the two groups (p<0.0001). Life support at registration also showed significant differences, with ECMO utilization (p<0.0001), ventilator utilization (p<0.0001), and IABP utilization (p<0.0001) having higher percentages with patients with preoperative transfusions. Cox regression results showed that there is an increased risk of mortality in patients who did not receive transfusions before transplant (p<0.0001).

Conclusion:
While there was an increase in postoperative complications with patients with preoperative transfusions, there also appears to be a correlation between the need for life support and the use of blood products preoperatively. This, along with the reduced risk of mortality from preoperative transfusion patients, shows the possibility that differences in outcomes relating to transfusions may be due to patient conditions before the surgery rather than transfusions alone.