A liberal strategy of red blood cell transfusion reduces cardiovascular complications in older patients undergoing cardiac surgery

Introduction

Owing to their high risk in cardiac surgery, it is essential to define which transfusion strategy results in a lower rate of cardiovascular complications in older patients [1]. The aim of this study was to compare clinical outcomes after the implementation of either a restrictive or a liberal transfusion strategy in patients aged 60 years and above.

Methods

This study was a substudy of the Transfusion Requirements After Cardiac Surgery study. In this subgroup analysis we included all patients aged 60 years and above randomized to a restrictive or a liberal strategy of RBC transfusion. A composite endpoint for cardiovascular complications was used and defined as a combination of 30-day allcause mortality and severe cardiovascular morbidity.

Results

The primary composite endpoint - all-cause 30-day mortality, cardiogenic shock, or myocardial infarction - occurred in 9.6% of patients in the liberal strategy group and in 18.4% in the restrictive strategy group (P = 0.041). The incidence of cardiogenic shock was 5.2% in the liberal group and 12.8% in the restrictive group (P = 0.031) and of myocardial infarction was 2.2% in the liberal group and 5.6% in the restrictive group (P = 0.203). There was no significant difference between transfusion strategies in 30-day mortality rates (4.4% vs. 8%, respectively; P = 0.23).

Conclusion

In this prospective, randomized clinical trial, older patients submitted to a restrictive strategy of RBC transfusion had a rate of cardiovascular complications in 30 days after cardiac surgery twice as high than a liberal strategy. In this group of patients, probably untreated anemia would be more harmful than in a younger or healthier population undergoing cardiac surgery.