Factors predicting warfarin sensitivity in patients after cardiac surgery 1.0
Research type
Research Study
Full title
Which factors predict warfarin sensitivity in patients undergoing cardiac surgery
IRAS ID
169899
Contact name
Greg Scutt
Contact email
Sponsor organisation
University of Brighton
Duration of Study in the UK
0 years, 6 months, 6 days
Research summary
Warfarin is a drug used to stop the blood clotting as quickly as normal. It is used to prevent blood clots after certain types of cardiac surgery, such as mechanical valve replacement, mitral valve repair, tissue mitral valve replacement and in atrial fibrillation, a condition where the heart beats irregularly. Patients’ who take warfarin need regular blood tests to see how quickly their blood clots called an International Normalised Ratio (INR). Dosing is then adjusted to keep the INR within a safe target range. The initial dose of warfarin is based on patient age, weight and risk factors for sensitivity. Patients who start warfarin after heart surgery appear to be more sensitive to warfarin than to those who have not had heart surgery. We do not know why this is. Despite using lower doses of warfarin and more frequent monitoring, the increase in INR is still very unpredictable in these patients.
The risk of major bleeding increases considerably when the INR exceeds 4.5 and discharge may be delayed if the INR is unstable. This study is looking to find out the reasons why this patient group are more sensitive to warfarin by examining the relationship between warfarin sensitivity and albumin levels, an inflammatory protein called C-Reactive Protein (CRP), heart function (ejection fraction and cumulative inotrope dose) and interacting drugs. This will help us to improve the way we use warfarin by highlighting those patients which may be more sensitive to the effects of warfarin.
REC name
East of England - Cambridgeshire and Hertfordshire Research Ethics Committee
REC reference
15/EE/0082
Date of REC Opinion
5 Mar 2015
REC opinion
Further Information Favourable Opinion