Title: Randomised controlled trial of the LoDED (Limit of Detection of Troponin and ECG Discharge) strategy versus usual care in adult chest pain patients attending the Emergency Department.
Funder: Department of Health and Social Care

Abstract: Background The number of patients attending Emergency Departments (EDs) across England and Wales continues to rise, with over 22 million attendances in 2014 (11). Chest pain makes up nearly 10% of ED attendances and is the most common reason for emergency hospital admission (12). Due to limitations with current diagnostic technology, the majority of patients with chest pain have prolonged hospital stays during which they undergo serial blood tests to rule out acute myocardial infarction (AMI). Prolonged assessment leads to increased NHS costs (13), patient anxiety, and ED overcrowding. Recent observational data suggest a single blood test taken at presentation, called high-sensitivity troponin (hs-troponin), could be used to rule out AMI in 10-60% patients with chest pain with very high diagnostic accuracy (3-8). This is done using a novel &ldquo;undetectable&rdquo; cut-off (the Limit of Detection: LoD) for ruling out AMI. We have combined the LoD cut-off with ECG findings to create the LoDED strategy. Current data supporting the LoDED strategy are from observational studies and in patients who were not actually discharged (4,6,7). Further evidence is therefore needed to establish whether the LoDED strategy works under real-life conditions, when compared to existing strategies, in a way that is cost-effective and acceptable to patients. Study Question Does a novel diagnostic strategy for ruling out adverse events in emergency department patients with suspected cardiac chest pain increase rates of early discharge, reduce resource use and prove acceptable to patients, when compared to usual care? Objectives 1. Carry out a randomised controlled trial of the LoDED strategy compared to usual care to compare the proportion of patients successfully discharged within 4 hours of arrival, with no Major Adverse Cardiac Events (MACE) during the following 30 days. 2. Measure admission rates, hospital bed usage, length of stay, resource use and patient satisfaction, facilitating a health economic evaluation. 3. Determine whether the LoDED strategy is acceptable to patients. Plan of Investigation We will undertake a multi-centre parallel-group pragmatic randomised controlled trial across 5 EDs in the South-West. 594 Adults (&ge;18 years) presenting to ED with suspected cardiac chest pain and who trigger the chest pain investigation pathway, will be recruited and randomised 1:1. The intervention will be the LoDED strategy. This will allow discharge after a single hs-troponin test at presentation to ED if a participant has no new ischaemic ECG changes and the hs-troponin is 3mm or ST depression >1mm); admission indicated due to medical/social reasons; chest pain due to arrhythmia. The primary outcome is successful early discharge, defined as discharge from hospital within 4 hours of arrival, without MACE occurring within 30 days. MACE will be defined as cardiac death, AMI or emergency revascularisation occurring within 30 days of attendance (including the index presentation). Secondary outcomes are initial length of hospital stay; comparative costs; patient satisfaction (quantitative survey) and acceptability to patients (qualitative methodology). Potential Benefits to Patients and the NHS Given the pragmatic design and cost-effectiveness analysis, we anticipate that the study findings, whether they are positive or negative, will immediately inform clinical practice. If we demonstrate that the LoDED strategy avoids the need for prolonged assessment in an extra 9% of patients, in a way that is cost effective and acceptable to patients, we anticipate widespread uptake of the strategy, leading to earlier reassurance for patients and substantial cost savings for the NHS.

Lay abstract: Background and Aims When someone arrives in Accident and Emergency (A&E) with chest pain, it is often hard for doctors to tell if the pain is due to a heart attack. Most patients have to wait in hospital, having two blood tests taken a few hours apart, before a heart attack can be ruled out. Only 1 in 10 of these patients have actually had a heart attack - most have conditions like heartburn that aren t serious. Ruling-out heart attacks faster would reassure patients earlier and reduce time spent in hospital. Around 2 million people a year in Britain come to A&E with chest pain. Finding a way for them to be discharged earlier would mean hospitals would be under less pressure. A blood test, called high-sensitivity troponin, may be used to rule-out heart attacks using just one blood sample shortly after a patient arrives in A&E. This test measures low levels of heart muscle damage in the blood. We aim to find out whether this single test works in everyday practice. Design and Methods We will ask 600 patients with chest pain, arriving at one of five A&Es, to take part in the study. We will allocate them by chance to one of two groups. One group will be discharged after one blood test, if no heart damage is found. The other group will have two blood tests as usual. We will compare groups to see how many patients can be discharged within 4 hours. We will see if the new method saves hospital resources and if patients are reassured when discharged earlier. Patient and Public Involvement Patient volunteers have helped us design this research and will ensure the study is acceptable to patients. Dissemination Study results will be available to doctors and patients to allow improvements in care.

Research activity codes: 4.2 EVALUATION OF MARKERS AND TECHNOLOGIES
Health categories: CARDIOVASCULAR