NICE publishes draft guidance on new tests for faster assessment of heart attacks

19 May 2014 12:27 PM

Draft diagnostics guidance from NICE recommends 2 new high-sensitivity troponin tests to help reduce the time it takes to diagnose heart attacks (acute myocardial infarction or “AMI”).

The tests - the Elecsys troponin T high-sensitive assay (Roche Diagnostics) and the ARCHITECT STAT high-sensitivity troponin I assay (Abbott Diagnostics) - measure the levels of cardiac troponin in the blood in people suspected of having a heart attack. Troponin is a protein that is released into the blood when heart muscle is damaged, often as the result of a heart attack.

Standard cardiac troponin tests are most accurate when carried out 10-12 hours after the symptoms of a heart attack start. Normally, 2 tests are performed so that a change in troponin levels can be detected. For many people, this means that they have to be admitted to hospital for observation while the testing is carried out.

In an attempt to overcome this limitation high-sensitivity troponin tests have been developed. These are able to detect lower levels of troponin in the blood than older cardiac troponin tests, and therefore enable a clinical decision to be made much sooner.

According to Professor Carole Longson, NICE Health Technology Evaluation Centre Director, use of these high-sensitivity tests enables the earlier detection of changes in troponin levels: “This in turn can allow doctors to rule out a diagnosis of a specific type of heart attack called a non-ST-segment elevation myocardial infarction (NSTEMI) within 4 hours, if test results are available within 3 hours of presentation to the emergency department. The increased sensitivity of these tests could mean a reduced length of stay for people without raised levels of troponin, and earlier treatment for those with a confirmed NSTEMI.”

As with the standard cardiac troponin tests, the new tests are used alongside clinical history taking and ECG monitoring to diagnose NSTEMI. This is because cardiac troponin levels can also be raised in people who do not have coronary heart disease. Conditions which may cause cardiac troponin levels to be raised include myocarditis, infections, and renal disease.

Because of a lack of evidence of its diagnostic accuracy, a further high-sensitivity cardiac troponin test - the AccuTnI+3 assay (Beckman Coulter) - is only recommended for use in research for the early rule out of NSTEMI in people presenting to an emergency department with a suspected acute coronary syndrome.

The draft diagnostics guidance for high-sensitivity troponin tests is available on the NICE website. The closing date for comments on the draft guidance is 10 June 2014.

Ends

For more information call the NICE press office on 0845 003 7782 or out of hours on 07775 583 813.

Notes to Editors

About acute myocardial infarction (AMI)

1. AMI is part of a group of conditions collectively known as acute coronary syndrome (ACS), which includes both ST-segment-elevation myocardial infarction (STEMI) and non-ST-segment-elevation myocardial infarction (NSTEMI), and unstable angina.

2. These conditions are associated with common symptoms but have different underlying pathologies; STEMI is usually associated with a relatively large amount of damage to the myocardium (heart muscle) caused by a major blockage in the coronary artery, and can be detected with ST-elevation on an ECG trace. By comparison, NSTEMI is associated with relatively less damage to myocardium caused by partial blockage of the coronary artery or blockage of a smaller artery, and does not produce ST-elevation on ECG.

3. Acute coronary syndromes arise from an obstruction in the coronary arteries, usually caused by atherosclerosis and build-up of plaque which ruptures. When blood flow to the heart is reduced or blocked for a significant length of time (around 30-60 minutes) damage to cardiomyocytes (heart muscle cells) occurs, a pathological change which distinguishes an AMI from unstable angina.

4. Patients with ACS generally present with chest pain, a symptom which is responsible for around 700,000 emergency department attendances per year in England and Wales and 253,765 emergency admissions per year.

5. During 2011/12, the Myocardial Ischaemia National Audit Project (MINAP) reported 79,433 admissions with AMI recorded in England and Wales, 32,439 (41%) of which were categorised as STEMI, and 46,994 (59%) were categorised as NSTEMI.

6. The incidence of acute myocardial infarction increases with age, with the average age of first STEMI being 65 years, and of first NSTEMI 70 years. The incidence is also greater amongst men, with men being twice as likely to have an AMI as women.

About the NICE Diagnostics Assessment Programme

1. For further information about the NICE diagnostics assessment programme see Developing NICE diagnostic technologies guidance

2. Topics to be considered by the Programme are routed through the related Medical Technologies Evaluation Programme. Further information about this can be found at Developing NICE medical technologies guidance

About NICE

The National Institute for Health and Care Excellence (NICE) is the independent body responsible for driving improvement and excellence in the health and social care system. We develop guidance, standards and information on high-quality health and social care. We also advise on ways to promote healthy living and prevent ill health.

Formerly the National Institute for Health and Clinical Excellence, our name changed on 1 April 2013 to reflect our new and additional responsibility to develop guidance and set quality standards for social care, as outlined in the Health and Social Care Act (2012).

Our aim is to help practitioners deliver the best possible care and give people the most effective treatments, which are based on the most up-to-date evidence and provide value for money, in order to reduce inequalities and variation.

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