Published: 19 July 2023
A quick test to rule out heart attack
Chest pain is one of the most common symptoms seen by doctors in UK emergency departments and accounts for 6% of all visits and 20% of emergency admissions to hospital. It can be difficult for doctors to tell if a patient’s pain is caused by a heart attack, so most people need further assessment in hospital to decide how to treat them.
The usual approach is to take two blood tests a few hours apart, meaning that patients are admitted to hospital while they wait. Both blood samples are tested for troponin, which is a specific protein that is released during a heart attack. If troponin isn’t detected in the second blood test, the patient is unlikely to have had a heart attack and can be discharged.
As only 1 in 10 patients with chest pain have had a heart attack, this approach involves long waits in hospital for many patients with low-risk chest pain who could potentially be discharged sooner. With £340,000 funding from the NIHR Research for Patient Benefit Programme, a team from North Bristol NHS Trust carried out the LoDED trial (Limit of Detection of Troponin in the Emergency Department) to investigate a quicker way of assessing and discharging them.
The LoDED trial was designed to test whether results from a new, single high-sensitivity troponin blood test could be safely used alongside an electrocardiogram (ECG) to rule out a heart attack and discharge patients from the emergency department within 4 hours.
Professor Edward Carlton, Emergency Medicine Consultant at North Bristol NHS Trust and lead researcher for the project, commented: “Many patients are concerned about their chest pain, so ruling out heart attacks faster would reassure them earlier and potentially reduce their time spent in hospital.”
Identifying low-risk patients for early discharge
With support from the NIHR-funded Peninsula Clinical Trials Unit at the University of Plymouth, the team recruited more than 600 patients with chest pain from eight emergency departments in England and Wales. Half of the patients were randomly assigned to receive one high-sensitivity blood test and an ECG (the LoDED approach) and were discharged if no heart damage was found. The other half received one or two blood tests as usual, depending on the emergency departments’ usual procedures.
A comparison of the groups, published in the journal Heart, showed that over 40% of patients were discharged early and within 4 hours using the LoDED approach. None of these patients went on to experience a serious cardiac event, such as a heart attack or stroke, within 30 days of leaving hospital.
While the approach saw greater improvements in discharge times in some hospitals than others, this may have depended on how busy the emergency department was. The trial also confirmed that LoDED was a cost-effective way to manage patients’ testing, with no difference in healthcare costs between LoDED and the usual approaches.
Published in Emergency Medicine Journal, the team’s interviews and focus group discussions with doctors and patients revealed that patients with low-risk chest pain were happy to be discharged using the LoDED strategy. However, clinicians were more cautious about the approach in case some high-risk patients were mistakenly discharged.
With input from their patient advisory group, the researchers also designed a bespoke information leaflet for patients about heart attack symptoms, tests they had received and reassurance that they were unlikely to have a heart attack.
Supporting national changes in practice
Recognising the trial’s potential to significantly improve clinical practice and patient care, the LoDED approach was successfully put into practice in hospitals within the North Bristol NHS Trust.
LoDED was later identified by NICE’s Accelerated Access Collaborative (AAC) as a promising innovation and one of the new, evidence-based tests that could help patients access new treatments faster and improve their lives. In support of this, Professor Carlton helped develop a NICE adoption toolkit to assist the uptake of LoDED into everyday practice.
In 2020, the trial’s results were incorporated into the NHS Commissioning for Quality and Innovation (CQUIN) framework for emergency departments, further supporting its uptake and contribution to nationwide NHS service improvements. The results have also been acknowledged internationally, with their findings incorporated into the 2022 American Heart Association Guidelines.
"LoDED is an innovative strategy that could allow rapid discharge of a significant number of patients in a way that is safe and effective. However, it is just one part of the jigsaw and as we saw in this study, when emergency departments are very busy, treating patients in a timely manner is a huge challenge.”
Professor Edward Carlton
The study was funded by the NIHR Research for Patient Benefit Programme.
More information about the study is available on the NIHR’s Funding & Awards website.