Impaired thrombotic status is associated with adverse cardiovascular events. Patients with acute coronary syndrome (ACS) are at increased cardiovascular risk. The aim of the study is to determine the usefulness of thrombotic status assessment in a large cohort of ACS patients, managed with contemporary treatments, to identify patients at risk of thrombosis and those at risk of bleeding complications.

Patients presenting with acute coronary syndrome (ACS) are at increased risk of future cardiovascular events, despite optimal medical treatment and coronary intervention. Such events are usually caused by increased stickiness of the blood causing a blood clot (thrombus) to block arterial blood vessels in the heart. Much of the medication to prevent recurrent thrombotic events increases the risk of bleeding complications. Identification of patients at recurrent thrombotic risk could allow targeted treatment with potent antithrombotic medications, with less potent agents in others to reduce bleeding. The investigators will assess the stickiness of the blood (i.e. thrombotic status) in patients who are admitted to hospital with ACS; at baseline, at discharge from hospital and at 30 days post hospitalisation. Blood stickiness will be tested using a number of tests of thrombotic status including thrombin generation assays, Thromboelastography (TEG) and the near-patient, point-of-care Global Thrombosis Test (GTT). The results will be evaluated to assess the effect of disease process and clinical state on blood stickiness to gain further understanding of the condition and form the basis for future studies aimed at identifying patients who are at high risk of future cardiovascular events.

Inclusion Criteria:

1. Male and female patients aged 18 years or over.
2. Patients diagnosed with ACS and free of exclusion criteria below.
3. The patient is willing and able to understand the Patient Information Sheet and provide written informed consent.
4. The patient must agree to comply with the drawing of blood samples for the assessments.

Exclusion Criteria:

1. The patient has, in the opinion of the investigator, significant neurological, hepatic, renal, endocrine, cardiovascular, gastrointestinal, pulmonary, haemorrhagic, metabolic or other disease likely to confound the study requirements or analyses.
2. The patient has a history of substance abuse or demonstrates signs or clinical features of active substance abuse or psychiatric disease.
3. Alcohol consumption above recommended safe levels (i.e. more than 21 units per week for males, or more than 14 units per week for females) due to the potential effects of high alcohol levels on platelet reactivity.
4. Any illness deemed significant by the investigator during the four (4) weeks preceding the screening period of the study.
5. Any major bleeding diathesis or blood dyscrasia (platelets < 70 x 109/l, Hb < 8 g/dl, INR > 1.4, APTT > x 2 UNL, leucocyte count < 3.5 x 109/l, neutrophil count < 1 x 109/l).
6. Currently enrolled in an investigational device or drug trial.

Acute Coronary Syndrome (ACS) Patients. ACS patients will comprise of patients admitted to hospital with suspected cardiac chest pain and at least 2 of the following 3 criteria of (1) chest pain, (2) ischaemic ECG changes (3) a cardiac troponin measurement exceeding the 99th percentile of a normal reference population (upper reference limit).