Sequestration of Platelets Prior to Bypass Reduces Bleeding After Cardiac Surgery
Excessive bleeding is common after cardiac surgery. This may result in patients receiving a blood transfusion or suffering the life-threatening complication of cardiac tamponade. Tamponade is when excessive bleeding compresses the heart and prevents it from pumping properly. A major reason for the bleeding is the damage done to platelets by the cardiopulmonary bypass (CPB) machine. Often patients receive platelets and plasma from blood donors to try to reduce the bleeding post-operatively. The investigators plan to take platelets and plasma from patients before they are damaged. They would then return these 'undamaged' sequestered platelets to the patients after the bypass machine is no longer needed. Therefore, the investigators' primary question is whether platelet sequestration would reduce the bleeding problems that occur following cardiac surgery. They will evaluate bleeding problems using thromboelastography, which provides a comprehensive assessment of both how blood clots form and their strength. If sequestration reduces bleeding problems following cardiac surgery then it may reduce the chance of patients receiving blood products from donors. Although donated blood is thoroughly tested, its use does expose patients to the risk of transfusion errors, blood borne infections and reactions. Avoiding its use would be very desirable.
Cardiac Surgical Procedures
Blood Platelet Disorders
Blood Coagulation Disorders
Procedure: Platelet rich plasma sequestration
|Study Design:||Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Single Blind (Subject)
Primary Purpose: Treatment
|Official Title:||Post-operative Administration of Platelet Rich Plasma Sequestered Prior to Cardiopulmonary Bypass Reduces the Coagulopathy Associated With Complex Cardiac Surgery|
- Incidence of coagulation abnormalities as assessed by thromboelastography and platelet function analyser [ Time Frame: At end of surgery (usually <1 day) ] [ Designated as safety issue: No ]
- Volume of blood lost into chest drains during first 24 post-operative hours [ Time Frame: 24 hours ] [ Designated as safety issue: Yes ]
- Volume of blood product administered during first 24 post-operative hours [ Time Frame: 24 hours ] [ Designated as safety issue: Yes ]
- Length of stay in the intensive care unit (ICU) [ Time Frame: Usually < 30 days ] [ Designated as safety issue: Yes ]
- ICU mortality [ Time Frame: Usually < 30 days ] [ Designated as safety issue: Yes ]
- Incidence of surgical re-exploration [ Time Frame: Hospital admission (usually < 30 days) ] [ Designated as safety issue: Yes ]
|Study Start Date:||August 2006|
|Study Completion Date:||July 2009|
|Estimated Primary Completion Date:||July 2009 (Final data collection date for primary outcome measure)|
Experimental: Platelet sequestration
Sequestration of platelet rich plasma before cardiopulmonary bypass
Procedure: Platelet rich plasma sequestration
Venesection of blood (14 ml/kg) and separation to red cells and platelet rich plasma.
Other Name: Haemonetics cell salavage system
No Intervention: Standard care
No platelet rich plasma sequestration undertaken before cardiopulmonary bypass (usual practice)
Patients undergoing repeat median sternotomy or requiring prolonged cardiopulmonary bypass (CPB) often develop a coagulopathy at the end of surgery. We propose sequestering plasma and platelets from these patients prior to CPB and thus prior to the dilution and platelet damage that occurs with CPB. We hypothesise that if these plasma and platelets are stored properly during CPB, and administered at the end of the operation, they will reduce any coagulopathy and the associated bleeding.
Patients undergoing repeat median sternotomy, mitral valve repair, double valve operations, aortic surgery, or combined valve and coronary artery surgery.
Exclusion criteria will include those with anaemia, thrombocytopenia, unstable angina, anti-platelet therapy within the previous seven days, known or symptomatic cerebrovascular disease, known disorders of haemostasis, aprotinin sensitivity and pregnancy.
Patients will be randomised by a closed envelope technique to receive platelet/plasma sequestration or not. Patients randomised to undergo sequestration will have 14 mL/Kg blood taken. The blood will be separated into red cells and platelets/plasma. Anaemia would be prevented by returning the processed red blood cells to the patient. We will store platelets at 20-24°C/room temperature on a platelet rocker according to guidelines from the National Blood Service.
Assessment of coagulation:
Patients' coagulation status will be evaluated before and after surgery. Four methods will be employed to comprehensively assess the coagulation system: platelet counts and conventional clotting studies; heparin levels; thromboelastography; and platelet function analyser.
|Royal Brompton Hospital|
|London, United Kingdom, SW3 6LY|
|Principal Investigator:||Simon J Finney, MBChB, PhD||Royal Brompton & Harefield NHS Foundation Trust|
|Principal Investigator:||Andrea Kelleher, MBBS||Royal Brompton & Harefield NHS Foundation Trust|
|Principal Investigator:||Judith Hall||Royal Brompton & Harefield NHS Foundation Trust|
|Principal Investigator:||Simon Davidson, PhD||Royal Brompton & Harefield NHS Foundation Trust|