Blood Transfusions Aid High Risk Surgery Patients

Researchers evaluated whether a liberal transfusion strategy improves outcomes for patients with high cardiac risk who develop postoperative anemia after major surgery.

Trial design and patient population

The TOP trial was a parallel, single‑blind, randomized clinical study conducted at 16 Veterans Affairs medical centers across the United States. From February 2018 to March 2023, investigators enrolled 1,428 veterans with a history of ischemic heart disease, peripheral artery disease, or cerebrovascular disease. Participants were randomized after their hemoglobin fell below 10 g/dL following major vascular or general surgery.

Patients assigned to the liberal arm received red‑cell transfusions to keep hemoglobin above 10 g/dL, while those in the restrictive arm were transfused only when hemoglobin dropped under 7 g/dL. By postoperative day five, the two groups differed by an average of 2.0 g/dL in hemoglobin levels.

Primary outcomes

The study’s primary composite endpoint combined 90‑day all‑cause mortality, myocardial infarction, coronary revascularization, acute kidney failure, or stroke. Results showed 9.1 % of patients in the liberal group experienced the composite outcome, compared with 10.1 % in the restrictive group (relative risk 0.90; 95 % CI 0.65 to 1.24). One‑year mortality rates were also comparable between the strategies.

These findings suggest that a more aggressive transfusion approach does not confer a clear advantage in reducing death or major ischemic events within three months after surgery for this high‑risk cohort.

Secondary findings and analysis

Among prespecified secondary outcomes, the liberal strategy was associated with fewer non‑myocardial‑infarction cardiac complications, such as new arrhythmias and heart‑failure episodes (5.9 % vs. 9.9 %; relative risk 0.59; 99 % CI 0.36 to 0.98). When myocardial infarction was added to this analysis in a post‑hoc fashion, the difference lost statistical significance (8.2 % vs. 12.5 %; relative risk 0.66; 99 % CI 0.43 to 1.01).

The trial was underpowered because overall event rates were lower than expected and funding ended early. Consequently, the confidence intervals around the primary outcome are wide, leaving some uncertainty about a modest benefit or harm.

From a broader perspective, these results echo earlier studies that found restrictive transfusion thresholds generally safe for most hospitalized patients, but they also reveal subtle benefits—like fewer arrhythmias—might emerge in subgroups with compromised cardiac reserve.

Implications for practice

Current guidelines favor a restrictive transfusion threshold for most patients, typically around 7 g/dL. The TOP trial’s data support continuing this approach even for patients with established cardiac disease undergoing major surgery, given the lack of a significant difference in the primary composite outcome.

Nevertheless, the observed reduction in non‑infarction cardiac events with liberal transfusion raises a question for clinicians managing patients at the edge of hemodynamic stability. Further research could clarify whether targeted liberal transfusion in selected individuals might improve cardiac outcomes without increasing other risks.

Investigators noted that the trial’s early termination and lower event rates limit definitive conclusions, and they recommend larger, adequately powered studies to confirm these secondary observations.