Haemostatic markers in cardiopulmonary bypass (MIC-B study)
Research type
Research Study
Full title
Characterisation of the Haemostatic Changes in Patients Receiving Intravenous Heparin for Cardiopulmonary Bypass Surgery
IRAS ID
248558
Contact name
Deepa Jayakody Arachchillage
Contact email
Sponsor organisation
Imperial College London
Duration of Study in the UK
0 years, 6 months, 2 days
Research summary
This study is to understand the changes occurring in a blood clotting protein, von Willebrand factor (VWF), in patients undergoing cardiac surgery who receive the blood thinner called Heparin. These patients are given Heparin through their veins, to prevent blood clot formation as it passes through the heart bypass machine. At the end of the operation, the effect of Heparin is reversed by another drug, Protamine Sulphate.
Heparin prevents blood clots forming mainly by inactivating thrombin, a crucial protein needed for blood clotting. We can monitor this effect of Heparin through blood tests called the ‘Anti Factor-Xa’ and the ‘APTT’.
Heparin has another effect on clotting: it can block the attachment of special blood cell fragments called platelets to damaged blood vessels, but this effect is not usually measured.
Following blood vessel injury, the large VWF sticks to the damaged surface and captures platelets to form a ‘plug’ which stops bleeding. The platelet plug is then stabilised by other clotting proteins. This stops blood loss and allows vessel repair underneath.
Heparin blocks the ability of VWF to capture platelets at the site of blood vessel injury. The higher the dose of Heparin, the greater this blocking effect is. This secondary effect of Heparin cannot be readily monitored and may explain why bleeding complications occur in patients receiving Heparin despite the monitoring with blood tests we use.
This study will look at the blood levels of Heparin, VWF and platelets before, during and after surgery and how well VWF functions in the presence of heparin, including its ability to attach to platelets.
We will determine if all of the heparin related changes in blood clotting can be detected using a method that looks at all of the different steps in forming a blood clot.REC name
London - Harrow Research Ethics Committee
REC reference
18/LO/2158
Date of REC Opinion
19 Dec 2018
REC opinion
Further Information Favourable Opinion