You may have read about a recently published study of 321 patients who were given blood transfusions during operations for valve replacement or repeat coronary artery bypass.
Those who received transfusions of older stored blood had significantly greater in-hospital mortality, more acute kidney dysfunction, and stayed longer in intensive care units and in the hospital.
Particularly puzzling was the finding that recipients of older blood were slightly, but significantly, more likely to die in the three to eight years following their heart surgery.
The authors of the article were unable to explain these results, but they did point out that red blood cells tend to become more rigid, change their shape, and become more likely to trigger blood clot formation after longer periods of storage.
How worried should you be that you might get a transfusion with older blood? Not much, in my opinion. It won't help to ask whether you will receive older blood. Your surgeon won't be able to answer your question.
However, if you're having elective heart surgery, or any type of elective surgery, you may donate your own blood prior to the operation and have it saved for use at the time of your surgery.
This approach will ensure that you do not get transfused with the oldest blood and will protect you against the relatively rare transfusion reactions that can result from receiving blood from other people.