Inflammation drives atherosclerotic plaque rupture triggering most acute coronary syndromes. Despite advances in diagnosis and management of atherosclerosis, patients with myocardial infarction (MI) remain at increased risk of recurrent events. The RIPPLE study aims to examine the relationship between residual coronary inflammation detected by 68Ga-DOTATATE PET in patients treated for MI to long-term plaque progression measured by CT coronary angiography (CTCA). The association between infarct-related myocardial 68Ga-DOTATATE PET and myocardial function and viability will also be assessed.

While vascular inflammation can be detected using 18F-FDG PET, this method lacks inflammatory cell specificity and is unreliable for coronary imaging because of high background signals from the myocardium. Upregulation of somatostatin receptor subtype-2 (SST2) occurs in activated macrophages, offering a novel inflammation imaging target. 68Ga-DOTATATE, an SST2 PET tracer with low myocardial binding, shows promise for imaging coronary inflammation. Having previously demonstrated increased 68Ga-DOTATATE signals in coronary atherosclerotic lesions post-MI, we now aim to study the natural history of residual arterial inflammation in non-culprit arteries and better understand how 68Ga-DOTATATE signals relate to plaque morphology, progression and rupture. Residual infarct-related myocardial inflammation and its association with ischemic myocardial remodelling will also be examined.

Inclusion Criteria:

• Male or female participants >18 years old
• Able to give written, informed consent and to lie flat
• First-presentation of myocardial infarction within ~2 weeks
• At least mild non-culprit coronary artery disease on angiography, managed medically

Exclusion Criteria:

• Women of child bearing potential not using adequate contraception
• Contrast allergy or contrast-nephropathy
• Uncontrolled atrial fibrillation
• Chronic kidney disease (eGFR <30 mL/min/1.73 m2)
• Any medical condition, in the opinion of the investigator, that prevents the participant from lying flat during scanning, or from participating in the study
• Uncontrolled chronic inflammatory disorder
• History of recent malignancy deemed relevant to the study by the investigator
• Current use of systemic corticosteroids
• Previous coronary artery bypass grafting surgery (CABG) or percutaneous coronary intervention (PCI) before the index event
• Contraindication to coronary angiography
• Requires CABG or staged non-culprit artery PCI

Patients with recent myocardial infarction and medically managed non-culprit coronary artery disease