Transfusion with blood stored up to six weeks does not influence patient outcomes after heart surgery, according to a 16-year Swedish study published Tuesday that shed new light on the much debated issue of blood storage.
In most Western countries, blood units can be stored for as long as six weeks before being transfused. However, a 2008 study, which claimed that storage for a mere 14 days or more was unsafe for heart surgery, has caused confusion and anxiety at hospital clinics worldwide.
"There have literally been hundreds of studies conducted on this topic the past five or six years, none of which have been able to provide a definitive answer," senior author Gustaf Edgren, associate professor at Sweden's Karolinska Institutet said in a statement.
To tackle the problem at its roots, Edgren and his research team performed a large-scale study of almost 50,000 patients in Sweden who underwent coronary artery bypass graft surgery, heart valve surgery, or both between 1997 and 2012.
The study, published in the U.S. journal JAMA, was made possible by linking a number of high-quality health registries, which allowed researchers to include all heart surgery patients in Sweden during the study period, with complete information about all blood transfusions administered together with clinical details about the patients.
The cohort included patients receiving transfusions with blood that had been stored between 14 and 42 days.
The study, by far the largest investigation focusing on the issue of blood storage in this very sensitive patient group, found no hint of negative health effects associated with stored blood, the researchers said.
"Therefore, these results complement recent randomized trials in providing further reassurance of the safety of current blood storage practices," they wrote in the paper.
