Extract

Background and study aims Blood clots happen when platelets (cells in the blood) clump together at the site of an injury to stop bleeding. Diseased arteries, such as those affected by fatty deposits (atherosclerosis), are particularly susceptible to blood clots. Antiplatelet drugs prevent heart disease and stroke by preventing the formation of blood clots in the arteries. In people who have had a heart attack or have diseased arteries, low-dose aspirin is recommended indefinitely to prevent another heart attack or a stroke. People who have had a coronary stent put in one or more of their arteries or have had coronary artery bypass grafting (CABG) surgery following a heart attack are prescribed low-dose aspirin and an additional antiplatelet drug for up to 12 months following the event. Combined treatment with aspirin and another antiplatelet drug is called dual antiplatelet therapy (DAPT). Some patients (e.g. those with atrial fibrillation) are also prescribed an anticoagulant in addition to DAPT. After this period of combined treatment, antiplatelet treatment is continued with low-dose aspirin alone. Antiplatelet drugs increase the risk of bleeding. About 1 in 100 people on aspirin and 2 in 100 people on DAPT have a major bleeding event that requires hospitalisation. However, many more people (about 9 in 100) experience minor bleeding, such as bleeding in the stomach or bowel, and nuisance bleeding, such as nosebleeds, bleeding from gums, and excessive bruising. These minor bleeding events cause discomfort and anxiety, take up consultations with GPs and may cause patients to stop taking their tablets as prescribed. Few studies have assessed how often bleeding events happen in people taking DAPT. Hospital doctors (cardiologists and surgeons) are increasingly prescribing more potent antiplatelet drugs to people who have had a stent or CABG surgery, without taking into account the risk of minor bleeding. They are doing this mainly because they do not know the extent of minor bleeding and the effect that it has on patients. This information is not known because most minor bleeding events are treated by GPs and patients do not go to hospital. Currently, decision-makers such as the National Institute for Clinical Excellent (NICE) are uncertain about the risk of minor and nuisance bleeding in people who take DAPT. Therefore, they cannot take it into account when making recommendations about which antiplatelet drugs should be used in people with heart disease and how long these drugs should taken for. In this study we use a large GP database and a database of patients’ attendance and admissions to hospital, to determine how many people experience bleeding after being prescribed DAPT or both DAPT and an anticoagulant. Who can participate? Patients over 18 years of age who have been treated with a stent, CABG surgery or medication only for acute coronary syndrome. What does the study involve? We compare the patients who take aspirin only with the patients taking different combinations of DAPT (with or without an anticoagulant) in the different patient groups (treated with stent, CABG surgery or medication only) in order to calculate the rate of bleeding events in these groups. We also review other research to determine how bleeding affects patients’ quality of life. What are the possible benefits and risks of participating? Information from our study will help doctors to choose drugs that are more appropriate for individual patients’ specific needs, which will reduce the risk of bleeding and increase adherence to treatment. There are no risks to participants as only their data is used. Where is the study run from? Bristol Royal Infirmary (UK) When is the study starting and how long is it expected to run for? April 2016 to September 2018 Who is funding the study? National Institute for Health Research (UK) Who is the main contact? Dr Maria Pufulete [email protected]

Inclusion criteria

• Acute coronary syndrome

Links

• ictrp
• isrctn