Pattakos and his fellow researchers say they don't know why the Jehovah's Witness patients fared as well or even better than their patient counterparts who received transfusions. It may be that erythropoietin and other blood-conserving strategies—believed to carry their own risks of higher morbidity such as stroke—were really less dangerous than receiving donated blood.
"There is a growing trend and increased awareness now of the negative side effects of blood transfusions that in prior decades was not realized," Pattakos says.
"It would be interesting to study whether the majority of cardiac surgery patients would benefit from erythropoietin (before surgery) because we do not know that yet," he adds.
Pattakos emphasizes that a major flaw in the study is that the Jehovah's Witness patients did not all receive the same blood conservation strategies prior to and during surgery, so it is hard to tell whether some pre-operative efforts worked better than others.