Restrictive versus liberal red blood cell transfusion strategies in surgical patients with high cardiovascular risk: a meta-analysis of randomised trials
R Silva, S M H Mehdi, S R Fatima, M F Machado, V A Gomez, G C Moraes, B S F Jorge, G Lisanti, L Gioli-PereiraAbstract
Background
It remains uncertain whether a restrictive or a liberal red blood cell transfusion strategy leads to better clinical outcomes in surgical patients with high cardiovascular risk, as randomised controlled trials (RCTs) have reported mixed results.
Purpose
To compare restrictive and liberal haemoglobin-guided red blood cell transfusion strategies applied during the perioperative or critical care period among surgical patients with high cardiovascular risk.
Methods
We conducted a systematic review and meta-analysis of RCTs. We searched PubMed, Embase, and the Cochrane Library for trials comparing restrictive and liberal haemoglobin-guided transfusion strategies in surgical patients with high cardiovascular risk. Trials in any surgical setting were eligible if they reported outcomes in this population. Restrictive strategies targeted haemoglobin ≤8 g/dL and liberal strategies targeted haemoglobin ≥9 g/dL. Outcomes were all-cause mortality at 30 days or during hospitalisation, major adverse cardiovascular events (MACE), and ischaemic events defined as stroke or myocardial infarction. We calculated risk ratios (RR) with 95% confidence intervals (CI) using random-effects models with Hartung–Knapp adjustment and assessed heterogeneity using the I² statistic.
Results
Six RCTs including 8,371 participants were analysed. Four trials were conducted in cardiac surgery, one in hip fracture surgery, and one in vascular or general surgery. Restrictive and liberal strategies showed similar risks of all-cause mortality (RR 0.87, 95% CI 0.77–1.00; I² = 0%) and MACE (RR 0.99, 95% CI 0.81–1.21; I² = 0%). Liberal transfusion was associated with a lower risk of ischaemic events (RR 0.93, 95% CI 0.90–0.97; I² = 0%).
Conclusion
In surgical patients with high cardiovascular risk, restrictive and liberal transfusion strategies showed no clear difference in mortality or MACE. Liberal transfusion was associated with a lower risk of ischaemic events.