Perioperative red blood cell transfusion and outcome in stable patients after elective major vascular surgery.

Objectives: Definitive evidence that red blood cell transfusion improves outcome after vascular surgery is lacking. The aims of the study were to determine, among stable consecutive patients who underwent elective major vascular surgery, (1) the association between postoperative transfusion and 30-day death, myocardial infarction, and both, and (2) and if this association differs according to the presence of postoperative anaemia (haemoglobin value less than 9.0 g/dL within 7 days after surgery).

Methods: A retrospective observational study was conducted on 359 patients prospectively screened according to the ACC/AHA guidelines for preoperative risk in non-cardiac surgery. Main outcome was 30-day death; secondary outcomes 30-day myocardial infarction, and composite of 30-day myocardial infarction or death.

Results: Of the patients included, 95 (26.5%) received at least one unit of red blood cells. Patients who received transfusion had a significantly increased hazard of 30-day death (hazard ratio [HR] 11.72, 95% confidence interval [CI] 3.92-35.10; p<0.0001), myocardial infarction (HR 3.3, 95% CI 1.7-6.1; p=0.0003), and both (HR 4.0 95% CI 2.2-7.3; p<0.0001). Such associations held even after adjusting for baseline characteristics, surgical risk, bleeding, and propensity to receive transfusion. There was a significant interaction between transfusion and postoperative anaemia (p=0.012). In patients without anaemia, transfusion was associated with higher risk of 30-day death (HR 19.20, 95% CI 3.99-92.45; p=0.007), myocardial infarction (HR 5.05, 95% CI 2.23-11.44; p=0.0001), and both. Conversely, in patients with anaemia this association was not significant.

Conclusions: In patients who underwent elective major vascular surgery, perioperative transfusion was associated with a significantly increased risk of 30-day events which was more attributable to patients with lesser degree of anaemia. Our data caution against the use of liberal transfusion in stable vascular surgery patients.