Pre-Operative Transfusion Reduces Serious Adverse Events in Patients with Sickle Cell Disease (SCD): Results From the Transfusion Alternatives Preoperatively in Sickle Cell Disease (TAPS) Randomised Controlled Multicentre Clinical Trial
Authors: Howard Jo , Malfroy Moira , Charlotte Llewelyn , Choo Louise , Rees David , Walker Isabeau , Johnson Tony , Tillyer Louise , Fijnvandraat Karin , Kirby-Allen Melanie , Hodge Renate , Purohit Shilpi , Davies Sally C. , Williamson Lorna M 
Published: October 2019

Abstract
Abstract 9

Introduction:
The rate of complications after surgery is increased in patients with Sickle Cell Disease (SCD) and pre-operative blood transfusion has historically been used to decrease this risk. Observational studies and one limited Randomised Controlled Trial (RCT) have suggested that in some patients, transfusion can safely be omitted. Since transfusion is associated with complications including alloimmunisation and increased post-operative infections, we performed a RCT to address whether overall peri-operative complications in SCD are reduced by pre-operative transfusion.

Methods:
TAPS was a Phase III multicentre, pragmatic, randomised controlled trial with a parallel group sequential superiority design, carried out between November 2007 and March 2011 at 22 sites in the UK, Netherlands and Canada. Eligible patients had HbSS or HbSβ°thal, were aged one year or more and were having low risk (eg adenoidectomy, dental surgery) or medium risk (eg joint replacement, cholecystectomy, tonsillectomy) elective surgery. Patients were excluded if they had a haemoglobin (Hb) <6.5g/dl, had received a blood transfusion within the last 3 months or had severe SCD. Patients were randomly assigned to Arm A, which received no pre-operative transfusion, or Arm B, which received a top-up transfusion if Hb<9g/dl or a partial exchange if Hb≥9g/dl. Sites followed their own standards for all other aspects of peri-operative care, although guidance was provided. The primary outcome was all significant complications between randomisation and 30 days post surgery as defined in the protocol. These were sent blinded to the End-Point Review Panel for final classification. Complications which were life-threatening, or resulted in death or persistent or significant incapacity/disability and other important medical events were also recorded as Serious Adverse Events (SAEs) and were reviewed by an Independent Data Monitoring Committee (IDMC). Due to a major imbalance in the number of SAEs between treatment groups, the trial was terminated early following an IDMC recommendation.

Results:
333 patients were screened for the trial and 70 patients were randomised at the time the trial was terminated. Thirty three completed 30 day follow up in Arm A and 34 in Arm B. Both groups were comparable with respect to age, gender, severity of SCD, type of surgery and baseline Hb. Only 13 patients had low risk surgery. The pre-operative (post-transfusion) Hb was higher in Arm B (9.7g/dl vs 7.7g/dl) and 5 patients in Arm B received partial exchange transfusion with a mean pre-operative HbS% of 47.2%. There were no differences in peri-operative management, including fluid support and oxygen therapy, between the two groups.
There were 11 SAEs (33%) in patients who did not receive a pre-operative transfusion, compared to only 1 SAE (3%) in patients who did receive a top-up transfusion or partial exchange. Eleven of the SAEs were Acute Chest Syndrome (ACS). Patients in the no pre-operative transfusion group also had more significant complications (13/33, 39%), which included SAEs, as compared to patients in the top-up/exchange group (5/34, 15%).
Type of surgery: 58% of patients underwent abdominal or ENT surgery. Four out of 13 patients (31%) who had Abdominal surgery in Arm A had ACS events compared to none out of 10 patients in Arm B. Out of the 9 patients who had Tonsillectomy in Arm A, 3 patients had ACS events (33%) compared to none in 7 patients in Arm B.

Discussion:
This RCT has shown a large increase in SAEs in un-transfused patients with HbSS and HbSβ°thal having low and moderate risk surgery. In particular there was a striking increase in ACS, a potentially life-threatening complication. We therefore recommend that pre-operative transfusion should be strongly considered for patients with HbSS and HbSβ°thal undergoing moderate risk surgery, in particular abdominal surgery and tonsillectomy. There was no evidence of increased benefit of exchange transfusion over top-up, although numbers were small, and exchange transfusions should be reserved for patients with a Hb>9g/dl. There is insufficient evidence to reach a conclusion on the role of pre-operative transfusion in other types of surgery or in patients with other sickle genotypes. Pre-operative transfusion in these patients should be decided on a case by case basis.

Acknowledgment:
submitted on behalf of the TAPS Trial Investigators.

Disclosures:
No relevant conflicts of interest to declare.