Re-engineering the clinical approach to suspected cardiac chest pain assessment; extending chest pain research evidence to the pre-hospital setting, enabled by novel point of care high-sensitivity cardiac troponin I (hs-cTnI) and artificial intelligence.

The intervention proposes a new model of care for initial chest pain assessment, which uses portable heart-related blood tests (high sensitivity troponin I level) and digital algorithms to support decision-making. The intervention will be administered by paramedics and general practitioners. Point of Care (POC) high sensitivity troponin I will be taken promptly, ideally within the first 10 minutes of the paramedic/GP encounter, however this will not be protocolized as part of the clinical trial. The POC high sensitivity troponin I level, as well as key clinical characteristics such as age, gender, prior coronary disease, nature and location of symptoms, the presences or absence of clinical finding, coronary risk factors (such as most recent cholesterol level, hypertension, diabetes, smoking status and family history) and baseline ECG will be gathered and assimilated into an algorithm. The timing of the ECG may occur immediately before or after POC high sensitivity troponin I testing, and ideally within the first 10 minutes of the paramedic/GP encounter, however this will not be protocolized as part of the clinical trial. The algorithm will produce a predicated likelihood of 48 hour death, myocardial infarction (MI), pulmonary embolism (PE) and aortic dissection. This will be displayed within the mobile clinical interface (i.e. digital application). Access to the clinical interface will either be via phone, tablet, or similar digital device. Data entry to receive an algorithm output is expected to take no more than 5 minutes at most. This predicted outcome rate information will be presented to the patient. From this, the health care worker and patient will decide whether the patient goes to ED or a Priority Care Centre for further assessment. The following dispositions will be offered: • If the algorithm-determined likelihood of adverse event is 1.0% and the high sensitivity troponin result is NOT elevated, and the ECG is NOT considered abnormal: 1. Patients will have the choice between being transported to and assessed further at a priority care centre OR the emergency department. 2. Rapid access cardiac clinic may be considered. Provision of the clinic appointment must occur within 72 hours. Rapid access cardiac clinic appointment bookings will be facilitated by the priority care centre at the end of the encounter. • If the algorithm-determined likelihood of adverse event is >1.0% OR there is an elevated high sensitivity troponin level, OR an abnormal ECG: 1. Patients will be transported to the emergency department for further assessment Rapid access cardiac clinic: These clinics will be staffed by dedicated nursing and medical experts with cardiac training and/or expertise. Subsequent testing will be determined by the treating clinicians, but application of the National Institute for Health and Care Excellence (NICE) guidelines recommended. These guidelines make recommendations regarding functional or invasive coronary testing based on characterisation of chest pain and cardiovascular risk factors. Priority Care Centres provide community-based health care for patients with urgent but non-life-threatening conditions, who would otherwise be seeking a service from an Emergency Department. Priority Care Centres are led by experienced General Practitioners with additional care from specially trained acute care nurses. They are health care facility that can provide prompt, risk-appropriate care for those not requiring emergency care. A cardiac clinic refers to outpatient clinic led by a cardiologist. Rapid access refers to the ability to obtain an appointment in a short timeframe (e.g. 72 hours). These rapid access cardiac clinical provide opportunity for timely cardiovascular assessment for risk-appropriate cohorts of patients such as those with new chest pain. Monitoring of uptake and adherence of the intervention during the study will occur via data review of the digital application and comparative investigation within the health system data if needed.