Heart attack diagnosis - High-STEACS

The clinical question

Every year, thousands of people in the UK are taken to A&E with a suspected heart attack. But the type and severity of symptoms that people experience from a heart attack can vary. This can mean that confirming a heart attack diagnosis is not always easy.

One of the diagnostic tests doctors use is to measure the amount of a molecule called troponin in the blood. Troponin is released from heart muscle when it is damaged. Tests to detect troponin have got increasingly more sensitive – that is, able to pick up tiny amounts of troponin in the blood. Using one of these ‘high-sensitivity’ troponin tests could potentially save lives by enabling doctors to diagnose and treat heart attacks that would previously have gone undiagnosed.

On the other hand, people can have small amounts of troponin in their blood for other reasons. There is a risk that a highly sensitive troponin test could misdiagnose these people as having a heart attack, leading to unnecessary, potentially harmful treatment. 

The BHF funded Professor Nick Mills and his team at the University of Edinburgh to conduct the ‘High-Sensitive Troponin in the Evaluation of patients with Acute Coronary Syndrome’ (High-STEACS) trial. The aim of this trial was to find out whether heart attack survival rates could be improved by using a new high-sensitivity troponin test to make the diagnosis.

What did the study involve?

Between 2013 and 2016, 48,282 people who had presented to the emergency department with a suspected heart attack were recruited into the trial. The trial took place across 10 hospitals in Scotland. All participants had cardiac troponin levels measured using both a standard and the new high-sensitivity test.

• Initially, in all hospitals taking part, the results from the high-sensitivity troponin tests were not released, and participants were treated according to the standard test results.
• Hospitals then entered the second stage of the trial, where participants were treated according to the high-sensitivity test results.  

All participants were followed up for 1 year. The investigators recorded whether participants had another heart attack, or died from a heart or circulatory disease.

What did the study show?

• Around a fifth of all participants (10,360 people) had raised troponin levels, signalling heart muscle injury. 
• The high-sensitivity test reclassified one in six patients as having heart muscle injury. But only a third of these patients were found to have had a typical heart attack.
• The rate of further heart attack or death from heart or circulatory disease did not differ when hospitals changed from using the standard test to the high-sensitivity test.
• The length of hospital stay was reduced when the high-sensitivity test was used. This was mainly because people who had a negative result using the new test were discharged more quickly compared with the standard test.
• There was no evidence of misdiagnosis or other harms following the introduction of the high-sensitivity test. 

Why is the study important?

Professor Mills commented on the results of High-STEACS at the 2018 European Society of Cardiology Conference in Munich: “We expected outcomes to improve, so we were surprised and disappointed. But reflecting on that and looking at the actual diagnosis of these patients, it is perhaps not so surprising.”

He explained that the patients reclassified as having using the high-sensitivity troponin test (who had not been detected by the standard troponin test) might have had small amounts of heart muscle injury. This could be caused by many different conditions for which we don’t as yet have effective treatments. For example microvascular disease, where the small blood vessels supplying the heart are abnormal.

In 2018, Professor Mills was awarded further funding from the BHF to use ‘artificial intelligence’ to create a tool to help doctors prescribe drugs safely for people who’ve had a heart attack. This tool may allow doctors to make personalised decisions about a person’s care after a heart attack.

Study details

"High-Sensitive Troponin in the Evaluation of patients with Acute Coronary Syndrome (High-STEACS)"
Award reference:  SP/12/10/29922
Principal Investigator: Professor Nicholas Mills, University of Edinburgh
Trial registration number: NCT01852123

Publication details

Shah ASV, Anand A, Strachan FE, et al. High-sensitivity troponin in the evaluation of patients with suspected acute coronary syndrome: a stepped-wedge, cluster-randomised controlled trial. Lancet. 2018;392(10151):919-928.