Photo by Elise Amendola
Patients undergoing cardiac surgery can safely receive transfusions with older red blood cells (RBCs), according to new research.
In many countries, RBCs can be stored for as long as 6 weeks before transfusion.
But a study published in 2008 suggested that transfusing RBCs stored for more than 2 weeks could increase the risk of serious complications.
Results of subsequent studies both supported and contradicted that finding.
The new study, published in JAMA, adds to the debate. The results suggest the duration of RBC storage does not affect the risk of death or serious complications after transfusion.
“There have literally been hundreds of studies conducted on this topic the past 5 or 6 years, none of which have been able to provide a definitive answer,” said Gustaf Edgren, MD, PhD, of Karolinska Institutet in Stockholm, Sweden.
In an attempt to change that, Dr Edgren and his colleagues conducted a large-scale study of transfusions among cardiac surgery patients in Sweden. National guidelines there require that the oldest available blood unit is allocated first.
The researchers analyzed registry data on patients who underwent coronary artery bypass graft surgery, heart valve surgery, or both between 1997 and 2012.
There were 47,071 patients who received transfusions at 9 different hospitals. Of these patients, 36.6% received RBCs stored for less than 14 days, 26.8%
received RBCs stored 14 to 27 days, 8.9% received RBCs stored 28 to 42
days, and 27.8% received RBCs of mixed age.
The researchers compared these patient groups, looking at the incidence of serious complications at 30 days and mortality at 30 days, 2 years, and 10 years.
They adjusted their analyses for potential confounding factors such as sex, age, blood group, and hospital. And they found no association between RBC storage duration and mortality or serious complications.
| RBC storage duration and adverse outcomes at 30 days | ||||||
| RBCs stored 1-13 days (n=17,224) | 14-27 days (n=12,602) | 28-42 days
(n=4173) |
||||
| Adverse outcome | No. of events | Adjusted
odds ratio (OR) |
No. of events | Adjusted OR | No. of events | Adjusted OR |
| Acute kidney injury | 202 | 1 (reference) | 121 | 0.94 | 38 | 0.97 |
| ARDS/respiratory
failure |
228 | 1 (ref) | 157 | 1.16 | 42 | 1.00 |
| Serious infection | 524 | 1 (ref) | 351 | 0.99 | 133 | 1.13 |
| Stroke | 403 | 1 (ref) | 295 | 1.04 | 106 | 1.13 |
| Thrombosis/embolism | 70 | 1 (ref) | 49 | 1.01 | 17 | 1.09 |
| Composite
adverse outcome (including death) |
1670 | 1 (ref) | 1151 | 1.02 | 371 | 1.03 |
| RBC storage duration and mortality | |||||||
| Storage age | Patient No. | Deaths at
30 days |
Adjusted
hazard ratio (HR) |
Deaths at
2 years |
2-year HR | Deaths at
10 years |
2-year HR |
| 1-13 days | 17,224 | 615 | 1 (ref) | 1593 | 1 (ref) | 5897 | 1 (ref) |
| 14-27 days | 12,602 | 410 | 1.06 | 1074 | 1.02 | 4358 | 1.02 |
| 28-42 days | 4173 | 103 | 0.90 | 325 | 0.98 | 1403 | 0.99 |
| mixed age | 13,072 | 911 | 0.86 | 1954 | 0.94 | 5655 | 0.99 |
“This study is by far the largest investigation focusing on the issue of blood storage in this very sensitive patient group, and we find absolutely no hint of negative health effects associated with stored blood,” said Ulrik Sartipy, MD, PhD, of Karolinska University Hospital.
“[W]e have been able to provide very firm reassurance that the current blood storage practices are safe,” Dr Edgren added.
