Transfusion of prion-filtered red cells does not increase the rate of alloimmunization or transfusion reactions in patients: results of the UK trial of prion-filtered versus standard red cells in surgical patients (PRISM A).

This study, conducted for the UK Blood Transfusion Services (UKBTS), evaluated the clinical safety of red cells filtered through a CE-marked prion removal filter (P-Capt™). Patients requiring blood transfusion for elective procedures in nine UK hospitals were entered into a non-randomized open trial to assess development of red cell antibodies to standard red cell (RCC) or prion-filtered red cell concentrates (PF-RCC) at eight weeks and six months post-transfusion. Patients who received at least 1 unit of PF-RCC were compared with a control cohort given RCC only. About 917 PF-RCC and 1336 RCC units were transfused into 299 and 291 patients respectively. Twenty-six new red cell antibodies were detected post-transfusion in 10 patients in each arm, an overall alloimmunization rate of 4.4%. Neither the treatment arm [odds ratio (OR) 0.93, 95% confidence interval (CI) 0.3, 2.5] nor number of units transfused (OR 0.95, 95% CI 0.8, 1.1) had a significant effect on the proportion of patients who developed new alloantibodies. No pan-reactive antibodies or antibodies specifically against PF-RCC were detected. There was no difference in transfusion reactions between arms, and no novel transfusion-related adverse events clearly attributable to PF-RCC were seen. These data suggest that prion filtration of red cells does not reduce overall transfusion safety. This finding requires confirmation in large populations of transfused patients.

The Transfusion Alternatives Preoperatively in Sickle Cell Disease (TAPS) study: a randomised, controlled, multicentre clinical trial.

BACKGROUND: No consensus exists on whether preoperative blood transfusions are beneficial in patients with sickle-cell disease. We assessed whether perioperative complication rates would be altered by preoperative transfusion. METHODS: We did a multicentre, randomised trial. Eligible patients were aged at least 1 year, had haemoglobin SS or Sß(0)thalassaemia sickle-cell-disease subtypes, and were scheduled for low-risk or medium-risk operations. Patients were randomly assigned no transfusion or transfusion no more than 10 days before surgery. The primary outcome was the proportion of clinically important complications between randomisation and 30 days after surgery. Analysis was by intention to treat. FINDINGS: 67 (96%) of 70 enrolled patients-33 no preoperative transfusion and 34 preoperative transfusion-were assessed. 65 (97%) of 67 patients had the haemoglobin SS subtype and 54 (81%) were scheduled to undergo medium-risk surgery. 13 (39%) of 33 patients in the no-preoperative-transfusion group had clinically important complications, compared with five (15%) in the preoperative-transfusion group (p=0.023). Of these, 10 (30%) and one (3%), respectively, had serious adverse events. The unadjusted odds ratio of clinically important complications was 3.8 (95% CI 1.2-12.2, p=0.027). 10 (91%) of 11 serious adverse events were acute chest syndrome (nine in the no-preoperative-transfusion group and one in the preoperative-transfusion group). Duration of hospital stay and readmission rates did not differ between study groups. INTERPRETATION: Preoperative transfusion was associated with decreased perioperative complications in patients with sickle-cell disease in this trial. This approach could, therefore, be beneficial for patients with the haemoglobin SS subtype who are scheduled to undergo low-risk and medium-risk surgeries. FUNDING: NHS Blood and Transplant.