Elsevier

The Lancet

Volume 377, Issue 9771, 26 March–1 April 2011, Pages 1077-1084
The Lancet

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A 2-h diagnostic protocol to assess patients with chest pain symptoms in the Asia-Pacific region (ASPECT): a prospective observational validation study

https://doi.org/10.1016/S0140-6736(11)60310-3Get rights and content

Summary

Background

Patients with chest pain contribute substantially to emergency department attendances, lengthy hospital stay, and inpatient admissions. A reliable, reproducible, and fast process to identify patients presenting with chest pain who have a low short-term risk of a major adverse cardiac event is needed to facilitate early discharge. We aimed to prospectively validate the safety of a predefined 2-h accelerated diagnostic protocol (ADP) to assess patients presenting to the emergency department with chest pain symptoms suggestive of acute coronary syndrome.

Methods

This observational study was undertaken in 14 emergency departments in nine countries in the Asia-Pacific region, in patients aged 18 years and older with at least 5 min of chest pain. The ADP included use of a structured pre-test probability scoring method (Thrombolysis in Myocardial Infarction [TIMI] score), electrocardiograph, and point-of-care biomarker panel of troponin, creatine kinase MB, and myoglobin. The primary endpoint was major adverse cardiac events within 30 days after initial presentation (including initial hospital attendance). This trial is registered with the Australia-New Zealand Clinical Trials Registry, number ACTRN12609000283279.

Findings

3582 consecutive patients were recruited and completed 30-day follow-up. 421 (11·8%) patients had a major adverse cardiac event. The ADP classified 352 (9·8%) patients as low risk and potentially suitable for early discharge. A major adverse cardiac event occurred in three (0·9%) of these patients, giving the ADP a sensitivity of 99·3% (95% CI 97·9–99·8), a negative predictive value of 99·1% (97·3–99·8), and a specificity of 11·0% (10·0–12·2).

Interpretation

This novel ADP identifies patients at very low risk of a short-term major adverse cardiac event who might be suitable for early discharge. Such an approach could be used to decrease the overall observation periods and admissions for chest pain. The components needed for the implementation of this strategy are widely available. The ADP has the potential to affect health-service delivery worldwide.

Funding

Alere Medical (all countries), Queensland Emergency Medicine Research Foundation and National Health and Medical Research Council (Australia), Christchurch Cardio-Endocrine Research Group (New Zealand), Medquest Jaya Global (Indonesia), Science International (Hong Kong), Bio Laboratories Pte (Singapore), National Heart Foundation of New Zealand, and Progressive Group (Taiwan).

Introduction

Every year, an estimated 5–10% of presentations to emergency departments, and up to a quarter of hospital admissions are attributable to symptoms suggestive of acute coronary syndromes.1 Patients with a missed diagnosis of acute myocardial infarction are at increased risk of a major adverse cardiac event. The need for safe discharge without a substantial risk of a major adverse cardiac event is a priority and a driver of clinician behaviour. Consequently, most patients with symptoms suggestive of acute coronary syndromes undergo lengthy assessment, either in the emergency department or as hospital inpatients, even though 75–85% of these patients ultimately do not have a final diagnosis of acute coronary syndromes.2, 3, 4 The assessment processes vary between institutions, with no one process being ideal. Present recommendations are for serial sampling of cardiac troponin over at least 6 h from the onset of symptoms.5, 6, 7 Concerns about accuracy of patients' recall of events has led many centres to time troponin sampling from the moment of presentation to the emergency department.8 Prolonged assessment contributes to overcrowding in the hospital or department, physician duplication of effort, and clinical risk as patients are treated by different clinical staff.1 Emergency department overcrowding is associated with increased costs and adverse patient outcomes, including increased mortality.9

A reliable, reproducible, and more timely process for the identification of chest pain presentations that have a low short-term risk of a major adverse cardiac event is needed to facilitate earlier discharge.4 Accelerated diagnostic protocols (ADPs), clinical decision rules, and prediction rules are terms for processes or methods intended to help clinicians to make bedside diagnostic and therapeutic decisions. They involve variables from the patient's history and examination, and often incorporate the results of diagnostic tests.6 ADPs for chest pain are well established but emphasise the need to assess the patient for at least 6 h after the onset of symptoms.6, 10 Some studies have safely investigated patients with serial biomarkers during 1·5–3 h in a low-risk patient group, but have not defined a reproducible method to identify this low-risk group.11

For an assessment of possible acute coronary syndromes, a maximum of 60 min is recommended for the availability of troponin results.12 Many central laboratories have difficulty in meeting this standard. Point-of-care biomarkers represent a possible solution to meeting this target. The Thrombolysis In Myocardial Infarction (TIMI) score for unstable angina or non-ST elevation myocardial infarction is an externally validated and widely used structured risk assessment method.3, 13, 14 Its use in conjunction with serial 0–2 h biomarker testing (either via central laboratory or point-of-care systems) and electrocardiograph (ECG) has not been prospectively tested. Importantly, there has been little validation of ADPs based in emergency departments outside North America, or in diverse population groups such as the Asia-Pacific population, in whom a mix of ethnic backgrounds and variations in service delivery introduce important differences.15

The ASia-Pacific Evaluation of Chest pain Trial (ASPECT) was a prospective observational validation study designed to assess whether a predefined ADP would identify patients presenting to the emergency department with chest pain, who would be at low risk of harm if they were to be discharged early.

Section snippets

Participants

Enrolment occurred at 14 urban emergency departments in nine countries in the Asia-Pacific region (Australia, China [including Hong Kong], India, Indonesia, New Zealand, Singapore, South Korea, Taiwan, and Thailand). Patients were included if they were at least 18 years old and had at least 5 min of chest pain (or discomfort) suggestive of acute coronary syndromes for whom the attending physician planned to investigate for these syndromes with serial biomarker tests. In accordance with American

Results

3651 consenting eligible patients were enrolled, of whom 3582 completed 30-day follow-up (figure 1). Webappendix p 3 shows the countries and hospitals that recruited patients. Study participants were mostly older men, either white or Chinese, and commonly had cardiovascular risk factors and background cardiovascular past medical history (table 1). A major adverse cardiac event occurred within 30 days in 421 (11·8%) patients. Non-ST-segment acute myocardial infarction (NSTEMI) was the most

Discussion

Findings from this large, multinational study have prospectively validated that a 2-h accelerated diagnostic protocol, with use of point-of-care biomarkers, ECG, and TIMI score, can safely identify patients at very low short-term risk of a major adverse cardiac event (panel 2). These patients could potentially be discharged several hours earlier to outpatient follow-up and further investigations than with present practices.

The near 10% possible reduction in patients needing prolonged assessment

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