Heart attack or Heartburn

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Improved assessment of cardiac patients diverts resources to acute cases.
Chest pain is the most common complaint seen in adult emergency departments, with more than half a million patients presenting each year to hospitals across the country. Despite this large figure, only one in five of these patients actually suffers from an Acute Coronary Syndrome (ACS), a condition that includes heart attack and angina. The majority are diagnosed with indigestion, reflux and other less serious illnesses.

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A novel approach to assessing major cardiac emergencies within the hospital emergency department is seeing significant benefits for patients and medical staff. Queensland-based researcher and emergency medicine physician Associate Professor Louise Cullen and cardiologist Professor Will Parsonage are leading research in Accelerated Diagnostic Protocols (ADPs) that has the potential to change the way emergency patients are assessed not just in Australia but internationally.
A missed diagnosis of ACS can lead to further complications and even death, so patients with suggestive symptoms are often required to undergo lengthy assessment. Diagnosing ACS can be challenging due to its diversity in clinical presentation and the lack of one single diagnostic test. Current international guidelines for diagnosing ACS suggesting delayed serial blood testing, adds to the length of stay required for assessment.
Although the vast majority of these patients will be found not to be suffering ACS, the rigorous testing required to exclude it as a differential diagnosis often results in the patient being admitted to hospital for more than 24 hours. The challenge is to diagnose these patients in a safe, timely and cost-effective manner, so that emergency resources can be diverted to acutely ill patients.
A/Prof Louise Cullen was awarded two research grants totalling more than $1 million overall from the Queensland Emergency Medicine Research Medicine Foundation (part of the Emergency Medicine Foundation). This was part of the funding required to support her hypothesis that this assessment time could be reduced and in collaboration with New Zealand researchers two different strategies have been identified.

• A TIMI score is used to assess a patient’s risk of death from a cardiac emergency.


• An ECG measures the electrical activity of the heart. In patients experiencing ACS there will usually be abnormalities in this exam.


• Troponin is a protein released by the myocardium when the heart is under stress and its measurable presence in blood can indicate a serious cardiac event.

ADAPT
The first strategy trialled was the ADAPT protocol (2-Hour Accelerated Diagnostic Protocol to Assess Patients With Chest Pain Symptoms Using Contemporary Troponins as the Only Biomarker).
Proposed algorithm for assessment of possible cardiac chest pain incorporating an accelerated diagnostic protocol based upon the ADAPT study.
To qualify for rapid assessment, patients were required to have a Thrombolysis in Myocardial Infarction (TIMI) score of 0 (reference range 0-7), a normal electrocardiogram (ECG) and a normal troponin. A second troponin reading was taken 2 hours after the initial result. Patients who met these criteria were considered suitable for rapid discharge from the emergency department with follow-up no later than 30 days.
Importantly, patients who were not low-risk according to the rapid assessment were managed in-line with current clinical care practices involving extended observation and/or admission.
Results

• A significant reduction in the length of stay for low-risk patients from 24.5 hours to 4.3 hours.


• Reduction in patient admission rates by 15-20% for ED patients with chest pain.


• Individual diagnostic parameters were not as effective as the combination used in the ADP.

Figure: Analysis of hospital length of stay for ADAPT ADP vs non ADP in the first hospital that was trialled.
NEAT – National Emergency Access Target for assessing emergency department patients.
A pilot intervention project funded by Queensland Health assessing the translation of the ADAPT ADP in clinical practice commenced at a medium-sized hospital in 2012. On admission patients were assessed and received a TIMI score, an ECG and a blood test to analyse their cardiac troponin levels. The findings of this were in keeping with the original trial in that both safety was maintained and efficiency of assessment practices improved.
Implications for patients and the health system
The Queensland Government has since funded the implementation of the ADAPT ADP to 22 hospitals across the state. Known as the Accelerated Chest pain Risk Evaluation (ACRE) Project, early results to December 2015 are that 18/22 sites have implemented the strategy and 8,724 patients (23% of 37,418 cardiac chest pain patients) have been assessed using the ADP. If this protocol is adopted across the whole state of Queensland it could:

• Improve the assessment of more than 61,000 Queensland patients per year.


• Potentially release more than 1 million hours of patient admitted time or 42,468 bed days per year, allowing resources to be diverted to more acute cases.


• Potentially re-divert an estimated $68 million per year to other areas within Queensland Health.

Figure: Interim analysis of the hospital length of stay for chest pain patients pre- and post-implementation of the ADAPT ADP in Queensland
Importantly, patients also benefit by either being discharged or admitted to hospital as quickly as possible, with minimal time in the emergency department.
If emergency departments are to meet the demands of a growing and aging population, new methods for reducing admissions, assessment time and outpatient care need to be investigated. The findings of this study are being closely monitored by the medical community with A/Prof Cullen’s research being published in The Medical Journal of Australia, The Lancet and the Journal of the American College of Cardiology..
After the success of the pilot program A/Professor Cullen was awarded a second grant from the Queensland Emergency Medicine Research Foundation to review assessment times for other ACS patients that were not low risk. Although unpublished at this stage, she believes that the assessment process can be shortened for up to 70% of all ED chest pain patients. It is hoped these new results will be published in 2016.
Dr Louise Cullen
Dr Louise Cullen is an emergency physician and acute cardiac disease researcher at a large Brisbane hospital. She is now recognised as an international leader in chest pain research and is frequently invited to present her research at national and international conferences. She is aiming to make Queensland a world leader in cardiac research through testing new cardiac biomarkers, investigating novel strategies for risk assessment in the emergency department and translational research.

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“Although the vast majority of these patients will be found not to be suffering ACS, the rigorous testing required to exclude it as a differential diagnosis often results in the patient being admitted to hospital for more than 24 hours.”

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