Diagnosis of heart attack (acute myocardial infarction) relies on troponin testing along with additional inpatient investigations. Researchers in the United Kingdom have developed a clinical decision rule (the MACS rule) for avoiding unnecessary hospitalisation for patients with chest pain. The MACS rule places individuals into four risk groups with suggested dispositions for each group, with the very low risk eligible for immediate discharge. Initial validation of the rule revealed that 31.5% of patients met the low risk criteria and so could be discharged from hospital with no further investigation. Of these patients, none had a heart attack within 30 days.
This study will conduct an external validation of the MACS rule using a sample of 1000 patients who presented to the Royal Brisbane and Women’s Hospital emergency department with chest pain. If the MACS rule accuracy identifies a group of patients who do not have a heart attack, it could be used in clinical care to rapidly rule out heart attack, decrease resource utilisation and ensure that patients are not subjected to unnecessary testing in hospital.
MACS and T-MACS rules provide for accurate risk stratification of very low risk patients. The T-MACS rule would allow for a slightly higher number of patients to be discharged early. The potential for missed MACE events means that further outpatient testing for coronary artery disease may be required for patients identified as very low risk.
Greenslade, J.H., Nayer, R., Parsonage, W., Doig, S., Young, J., Pickering, J.W., Than, M., Hammett, C. and Cullen, L., 2017. Validating the Manchester Acute Coronary Syndromes (MACS) and Troponin-only Manchester Acute Coronary Syndromes (T-MACS) rules for the prediction of acute myocardial infarction in patients presenting to the emergency department with chest pain. Emergency Medicine Journal, 34(8), pp.517-523.
Prof Louise Cullen
A/Prof Kevin Chu
A/Prof Jaimi Greenslade
Prof Anthony Brown