New cardiac troponin assay improves diagnosis and outcomes of acute coronary syndrome

28th November 2023

Use of a high-sensitivity cardiac troponin I assay in emergency departments can improve diagnosis for one in five patients who have acute coronary syndrome, according to new research led by the University of Edinburgh.

The assay also helped doctors to better diagnose and treat these patients, reducing death and future myocardial infarction in this group by almost 10% after five years compared to those who received the older, less sensitive test.

The researchers also found that while the new cardiac troponin assay led to improvements for patients with myocardial infarction, those who benefitted most were patients with a heart muscle injury caused by conditions such as heart failure, heart valve conditions and heart arrhythmias.

Published in the BMJ and funded by the British Heart Foundation, the researchers conducted a secondary observational analysis of the High-Sensitivity Troponin in the Evaluation of patients with suspected Acute Coronary Syndrome (High-STEACS) trial.

High-STEACS used a high-sensitivity cardiac troponin assay to improve precision at very low concentrations and improve the diagnosis and risk stratification of patients with suspected acute coronary syndrome.

While these assays are increasingly being adopted worldwide, little is known about their impact on patient outcomes.

For the secondary observational analysis, researchers studied the results for nearly 50,000 people who arrived at 10 emergency departments across Scotland with a suspected acute coronary syndrome between 2013 and 2016. They used routinely collected health record data and the data service DataLoch to follow up all participants for five years.

The primary outcome was any myocardial infarction or all-cause death at five years.

Secondary outcomes were any myocardial infarction; coronary revascularisation; all-cause death; cardiovascular death; cardiac death; and hospital admission for heart failure, ischaemic stroke, and major haemorrhage.

Over 10,000 patients had high troponin levels indicating heart injury using the new cardiac troponin assay, with one in five of these patients only identified by this high-sensitivity assay.

The researchers also observed that improvements in outcomes at five years were greatest in those patients with an index diagnosis of non-ischaemic myocardial injury.

Dr Ken Lee, clinical lecturer in cardiology at the University of Edinburgh, and the lead author of the study, said: ‘In the past, clinicians could have been falsely reassured by the results of the less sensitive troponin test, discharging patients that appeared to not have heart disease.

‘This new high-sensitivity test is the tool they needed, prompting them to look deeper and helping them to identify and treat both heart attacks and less obvious heart problems. In our trial, introducing this test led to an impressive reduction in the number of future heart attacks and deaths seen in this at-risk group.’

Professor Sir Nilesh Samani, medical director at the British Heart Foundation, added: ‘Medical professionals in emergency departments need the most efficient and accurate tools to look after people. This particularly applies to those who arrive with a suspected heart attack. Such a time-sensitive and life-threatening condition requires the very best diagnostic tests.

‘It is very encouraging to see that the new test trialled here is better at predicting long-term outcomes for these patients, whether they had a heart attack or a different kind of heart injury. This can lead to improved care for such patients.’

The new high-sensitivity cardiac troponin assay has been rolled out to emergency departments across the UK, and the researchers hope that more people will receive the specialist heart care they need to avoid more serious events in the future.

ACS risk score tool fails to improve guideline use or adverse CV outcomes

15th June 2023

An acute coronary syndrome (ACS) risk stratification tool failed to improve either adherence to treatment guidelines or reduce the incidence of adverse cardiovascular outcomes compared to standard care, according to a recent cluster randomised controlled trial.

Non-ST segment elevation ACS (NSTEACS), which comprises non-ST elevation myocardial infarction (MI) and unstable angina, is a leading cause of disability, hospital admission and death. The Global Registry of Acute Coronary Events (GRACE) risk score (GRS) is designed to stratify risk in patients with ACS and provides an excellent ability to assess the risk for death.

In fact, optimal use of guideline-indicated care for non-ST-elevation myocardial infarction has previously been associated with greater survival gains. However, whether in practice using GRS leads to greater adherence to NSTEACS treatment guidelines and reduces the level of adverse cardiovascular sequalae was uncertain.

In the current study, published in the BMJ, researchers sought to determine if risk stratification using the GRS in patients presenting to hospital with suspected NSTEACS, enhanced the adoption of guideline-recommended therapy and reduced adverse cardiovascular outcomes.

Hospitals were randomised equally to patient management by either standard care or according to the GRS. The primary outcomes of interest were use of guideline recommended management and the time to a composite of cardiovascular death, non-fatal myocardial infarction, new onset heart failure hospital admission, and readmission for a cardiovascular event.

NSTEACS and the GRACE risk score

A total of 3,050 participants with a mean age of 65.7 years (69% female) were recruited and 1,440 were randomised to GRS care.

The uptake of guideline-recommended processes was not significantly different between the GRS and standard care groups (odds ratio, OR = 1.16, 95% CI 0.70 – 1.92, p = 0.56). In addition, the time to the first composite cardiac event was not significantly improved by the use of the GRS (hazard ratio, HR = 0.89, 95% CI 0.68 – 1.16, p = 0.37).

Secondary outcomes of interest included the EQ-5D-5L quality of life measure and the mean duration of the hospital admission for NSTEACS. As with the primary outcome, these metrics were not significantly different between the two groups.

The researchers concluded that use of the GRS score failed to improve guideline recommended management for NSTEACS or reduce a composite of adverse cardiovascular outcomes.

ACS presentations via emergency services at ED increased after warning signs campaign

8th November 2021

ACS presentations via emergency services at ED increased significantly after the introduction of a public health warning signs campaign.

Acute coronary syndrome (ACS) presentations using emergency medical services increased after the introduction of a public health ‘warning signs’ campaign. This was the finding of a retrospective study by researchers from the department of  Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.

Any delay in ACS presentations has a major impact on outcomes for patients, despite major advances in the care of such patients yet few fully understand the importance of early treatment. For example, a focus group study revealed a general ignorance of ACS symptoms and this has arisen in part, due to the perceptions derived from films and TV in which heart attack symptoms were displayed as sharp, crushing chest pain rather than the more common onset of initially ambiguous but gradually increasing discomfort. The study also highlighted a lack of awareness of the benefits of rapid action and using emergency service transport (EST) to hospital over alternative methods for reaching hospital. In fact, other work has shown that only 60% of patients used EST when experiencing ST-segment–elevation myocardial infarction.

The National Heart Foundation of Australia (NHFA) in recognising the importance of EST for patients with suspected ACS, launched a mass media campaign to improve Australian’s ACS symptom knowledge and address barriers to emergency transport use. Nevertheless, despite the media campaign, in a subsequent survey of 100 patients hospitalised with an acute myocardial infarction (AMI) only 26%  recognised that they were having an AMI and only 34% had called an ambulance. This led the researchers from Monash University to examine the impact of the NHFA warning signs campaign on ACS EST use and to explore any pre- and post-campaign changes on ED presentations via general practitioners for those with unspecified chest pain (U-CP). The team used the Victorian Department of Health and Human Services administrative database to collect information of ED admissions, patient characteristics, mode of arrival and referral sources. The primary outcomes of interest were ACS arrivals via ETS and ED presentations. Data were collected from 2003 to 2015, that included the period of the campaign which ran from 2009 to 2013. In their analysis, the researchers adjusted for factors such as age, gender, ethnicity, residential status (i.e., living alone etc) and location.

Findings

Between 2003 and 2015, there were 124,632 eligible ED presentations with ACS and 612,758 with U-CP. There was an 11% increase in ED presentations for ACS (incidence rate ratio, IRR = 1.11, 95% CI 1.07 – 1.15) during the campaign compared to the pre-campaign period. Similarly, there was an 8% increase (IRR = 1.08, 95% CI 1.05 – 1.12) for U-CP compared to the pre-campaign period.

For patients with ACS, 58% had arrived using emergency transport and compared with the pre-campaign period there was a slight increase in the adjusted odds of direct arrival via emergency transport (odds ratio, OR = 1.10, 95% CI 1.05 – 1.17) and a significant decrease in the adjusted odds of a GP referral (OR = 0.77, 95% CI 0.70 to 0.86). For U-CP, there was a modest increase during the campaign period of emergency transport arrivals (OR = 1.03, p = 0.019) but a more substantial reduction in GP referral compared to pre-campaign levels (OR = 0.79, 96% CI 0.75 – 0.82, p < 0.0001).

The authors concluded that the NHFA’s warning signs campaign was associated with an increase in ACS presentations and use of emergency transport and a reduction in GP referrals to ED.

Citation

Eastwood K et al. Impact of a mass media campaign on presentations and ambulance use for acute coronary syndrome. BMJ Open heart 2021

Early CTCA did not alter clinical outcomes in intermediate risk patients with suspected ACS

4th October 2021

The use of early CT coronary angiography in cases of suspected ACS had no overall effect on one-year cardiac outcomes in intermediate risk patients.

Acute chest pain is a common reason for attendance at an emergency department, accounting for approximately 10% of non-injury-related visits. While chest pain can arise from non-cardiac causes, all those presenting with chest pain will be assessed for acute coronary syndrome (ACS). Prompt treatment is required for patients with obvious clinical signs and symptoms of ACS whereas those deemed to be at either a low or intermediate risk initially undergo observation and further testing only if ACS is suspected. One strategic approach to the assessment of low risk ACS patients, is early computed tomography (CT) coronary angiography (CTCA). This technique has been increasingly used to assess patients with stable chest pain because it has high sensitivity and specificity for the detection of coronary heart disease. Within an emergency care department, CTCA therefore allows for a rapid evaluation of patients presenting with acute chest pain. In fact, one systematic review concluded that the use of CTCA is associated with a reduced length of hospital stay compared to usual care. Furthermore, a 2018 study examining the use of CTCA in patients with stable chest pain, found that over a 5-year period, there was a significantly lower rate of death from coronary heart disease or non-fatal myocardial infarction compared to standard care. However, while studies have focused on patients at low risk of ACS, whether early CTCA is of value in those patients deemed to be at an intermediate risk of ACS is less clear.

In trying to assess the value of early CTCA in patients presenting with acute chest pain and at an intermediate level of risk for acute coronary syndrome, researchers from Edinburgh University, established the RAPID CTCA study. The trial enrolled adult patients with suspected or a provisional diagnosis, of acute coronary syndrome and prior coronary heart disease. These individuals where then randomised 1:1 after admission to hospital to early CT coronary angiography with standard care or standard care alone. The primary outcome was the time to the first event of all-cause death or a subsequent non-fatal type 1 (spontaneous) or type 4b (related to stent thrombosis) myocardial infarction at one-year. Secondary outcomes included the cause of death and subsequent myocardial infarction.

Findings

The study recruited and randomised 1748 patients with a mean age of 61.6 years (64% men), of whom 877 received early CTCA. Overall, 89% of patients had chest pain as their primary complaint, 34% had existing coronary heart disease, 57% raised cardiac troponin levels and 61% an abnormal ECG. The primary outcome all cause death or non-fatal myocardial infarction (both types) occurred in 5.8% of those in the early CTCA group and 6.1% of those assigned to usual care (adjusted hazard ratio, aHR = 0.91, 95% CI 0.62 – 1.35, p = 0.65). Furthermore, there were no significant differences in any of the secondary outcomes. The need for invasive coronary angiography occurred in 54% of those in the CTCA group and 60.8% in the usual care group (aHR = 0.81, 95% CI 0.72 – 0.92, p = 0.001).

The authors concluded that early CTCA for patients with an intermediate risk of ACS did not alter overall coronary therapeutic interventions or one year clinical outcomes but did reduce the need for invasive angiography.

Citation

Gray AJ et al. Early computed tomography coronary angiography in patients with suspected acute coronary syndrome: randomised controlled trial. BMJ 2021