Blood transfusions with stored blood may do more harm than good. Recent studies show that patients who receive blood transfusions have higher incidences of heart attack, heart failure, stroke and even death.
Researchers at Duke University Medical Center are now closer to understanding why, according to findings reported this week in the Proceedings of the National Academy of Sciences.
Duke medical professor Jonathan Stamler says his team found that within hours of donation, banked blood begins to lose nitric oxide, a gas that is crucial for the delivery of oxygen to tissues. "Whereas we have tended to think that how much oxygen you carry is key, we've learned that it is really how much your blood vessels are open. ... Patients that are having heart attacks have blood vessels that are closed."
Researchers sampled banked blood over regular intervals and measured whether nitric oxide was present. Stamler reports, "What we have found is that it is very quickly depleted in our blood banks." Nitric oxide decreased by as much as 80 percent after one day, and by the end of one week, was profoundly depleted. After 42 days, unused banked blood must be discarded.
However, further lab work by Stamler's team demonstrated that nitric oxide could be restored prior to transfusion. "And [banked blood] is revived. It is then able to dilate blood vessels and when infused into animals [it] improves blood flow, opens the blood vessels."
Stamler says there is little doubt that stored blood could be harmful and the problem must be corrected. He says the next step is to initiative large-scale clinical trials.