Storage time of red blood cells for transfusion does not affect risk of postoperative AF
Compared with the usual intraoperative allogeneic transfusion of red blood cells, longer storage times of the red blood cells for allogeneic transfusion is not associated with increased postoperative atrial fibrillation (AF) following cardiac surgery, a new study has shown.
The study included 2,978 patients (mean age 66.4 years) receiving coronary artery bypass grafting or valve surgery. For inclusion, patients had to be above the age of 15 years. Those with a history of AF or flutter prior to the surgery were excluded.
The association between the risk of postoperative AF and transfusion of red blood cells on the day of the surgery was determined. Similarly, the association between length of time of storage of the red blood cells before transfusion and postoperative AF was also investigated.
Of the patients, 21 percent underwent transfusion of red blood cells on the day of the surgery. Furthermore, 25 percent developed postoperative AF.
Compared with patients who did not undergo transfusion, those who did were at a greater risk of postoperative AF (adjusted odds ratio [OR], 1.37; 95 percent CI, 1.11 to 1.69; p=0.004).
This risk showed dependence to dose. Those who received four to six units of red blood cells had an OR of 1.62 (1.02 to 2.42) compared with those who received only one to thee units.
Patients were then stratified according to whether they received red blood cells stored for <14 days (adjusted OR, 1.59; 1.23 to 2.06) or at least 14 days (adjusted OR, 1.24; 0.94 to 1.64). Comparisons with those who did not receive transfusion showed no significant difference.
Results thus show that using stored red blood cells, taking into account storage time, does not influence the development of postoperative AF after cardiac surgery.