This is a multi-centre observational study. It will make use of the positron emission tomography (PET) tracer 18F-sodium fluoride (18F-NaF) as a marker of coronary plaque vulnerability to detect culprit and non-culprit unstable coronary plaques in patients with recent myocardial infarctions. The investigators will then perform long-term follow-up of these patients to determine the prognostic significance of coronary 18F-NaF uptake

The investigators intend to recruit 700 patients hospitalised with myocardial infarction and proven multivessel coronary artery disease. All patients will undergo a combined CT coronary angiogram (CTCA) and PET scan using 18F-NaF as a tracer. Patients will then have clinical follow-up before undergoing a repeat CTCA at 2 years to assess progression of coronary disease. Clinical review of all patients will continue until study completion (given 2 years of recruitment this is likely to last 4 years) and following this the investigators will continue to monitor for further cardiovascular events via review of patient electronic health records for a further 5 years.

Inclusion Criteria:

1. Patients aged ≥50 years with recent (<21 days) type 1 myocardial infarction and angiographically proven multi-vessel coronary artery disease defined as at least two major epicardial vessels with any combination of either (a) >50% luminal stenosis, or (b) previous revascularization (percutaneous coronary intervention or coronary artery bypass graft surgery).
2. Provision of informed consent prior to any study specific procedures

Exclusion Criteria:

1. Inability or unwilling to give informed consent
2. Women who are pregnant, breastfeeding or of child-bearing potential (women who have experienced menarche, are pre-menopausal and have not been sterilised) will not be enrolled into the trial
3. Major intercurrent illness with life expectancy <2 year
4. Renal dysfunction (estimated glomerular filtration rate ≤30 mL/min/1.73 m2)
5. Contraindication to iodinated contrast agent, positron emission tomography or computed tomography
6. Atrial fibrillation
7. Previous recruitment into the trial

Patients with recent (<21 days) type 1 myocardial infarction and multi-vessel coronary artery disease

Baseline characteristics split into low or high atherosclerotic plaque activity assessed after CT PET scan.

All-Cause Mortality was monitored for up to 2 years; serious and/or other adverse events were assessed up to 48 hours post PET CT scan

Adverse events were collected irrespective of plaque activity status and therefore cannot be separated. Adverse events were not assessed per group/arm.

We had a lower than anticipated event rate in the study population. This led us to change our primary end point to include unscheduled coronary revascularization. Our study was a longitudinal cohort study, we could only assess associations rather than causality. Low inclusion of women, reflects the lower proportion of women who present with ST-segment elevation MI.