Study Finds Earlier Blood Transfusions Reduce Heart Complications in High-Risk Surgical Patients

The timing of blood transfusions after major surgery may significantly impact heart failure and arrhythmia risks for patients with pre-existing heart disease, according to new research presented at the American Heart Association's Scientific Sessions 2025. The Transfusion Trigger after Operations in High Cardiac Risk Patients (TOP) trial investigated whether transfusing blood earlier, when hemoglobin levels drop below 10 g/dL after major surgery, might prevent complications better than waiting until hemoglobin levels fall below 7 g/dL.

In this study of more than 1,400 military veterans undergoing major general or vascular surgery, researchers found that while severe complication rates remained similar between the two approaches, the timing of transfusion made a substantial difference for certain heart-related outcomes. Severe complications including death, heart attack, kidney failure, need for a heart procedure or stroke occurred in 9.1% of patients in the early transfusion group compared to 10.1% in the later transfusion group, showing no significant difference.

However, the analysis revealed striking differences in heart failure and irregular heart rhythm outcomes. These complications occurred in only 5.9% of patients receiving earlier transfusions compared to 9.9% in the later transfusion group, representing a 41% lower risk among those transfused earlier. Lead author Panos Kougias, M.D., M.Sc., chair of the department of surgery at SUNY Downstate Health Sciences University, explained that these findings challenge conventional thinking about transfusion strategies for cardiac patients.

The traditional approach has been to wait until hemoglobin levels are quite low before transfusing blood, partly due to concerns that giving more blood might overload the heart and worsen failure. Kougias noted that their findings suggest the opposite may be true for high-risk heart patients. Persistent anemia might place greater strain on the heart than the volume from a transfusion, leading to complications such as heart failure and arrhythmia. The study was simultaneously published as a full manuscript in the peer-reviewed scientific journal JAMA and is available through the American Heart Association's Scientific Sessions 2025 Online Program Planner.

The TOP trial included 1,424 U.S. military veterans receiving care at 16 Veterans Affairs Medical Centers throughout the U.S., enrolled between February 2018 and March 2023. Participants averaged 70 years old, with 98% being men and 75% self-identifying as white adults. Researchers measured hemoglobin levels after surgery and after each transfusion, following participants for 90 days after their procedures. The study was funded by the Veterans Affairs Office of Research and Development, and additional information about the research can be found in the abstract.

These results suggest that a universal transfusion strategy may not be optimal for all patients. For individuals with serious underlying heart disease undergoing major surgery, earlier blood transfusion could help prevent serious heart complications other than heart attack. The study's limitations include that most participants were men, so the results may not apply to women, and health care professionals knew which patients received which transfusion strategy, which may have affected patient care. As this was a secondary outcome in the study, further research will be needed to confirm these findings about heart failure and arrhythmia risks.