While invasive coronary angiography (ICA) remains one of the most commonly performed procedures in Australia, currently exceeding >100,000 admissions per annum, we have demonstrated >7-fold geographic variation in its use, and only ~27% of these procedures are performed in the context of its core indication of type 1 myocardial infarction (T1MI). Compared with other similar OECD countries, ICA use in Australia is high despite comparable rates of ACS, suggesting that the “appropriateness” of ICA use is sub-optimal in Australian clinical practice.

Appropriateness of care depends on three “sufficient” conditions: 1. The patient needs to be at sufficient risk of specific clinical events to warrant the treatment; 2. The treatment must be of sufficient efficacy in reducing relevant events; and 3. The treatment strategy must be of sufficient value to the patient (i.e. absolute benefits versus side-effects, complications and economic costs)

Anatomical investigation of the coronary arteries is of proven benefit in directing care and improving outcome in T1MI, but the appropriateness of such investigations in type 2 myocardial infarction (T2MI) and myocardial injury, where there is high risk of cardiac mortality and high competing risk of death from other causes, is unknown. As such, clinical equipoise remains.

To date, few studies formally integrating risk assessment into the strategy of coronary investigation and management have been undertaken. A randomised trial of routine early angiography versus conservative management that carefully evaluates baseline patient risks and competing risks, is critical to the development of robust recommendations for these common high morbidity and mortality patients. This study will comprehensively evaluate the clinical impact, and economic value of early anatomic coronary investigation in T2MI and myocardial injury within a pragmatic multi-centre randomised clinical trial.