In this study, the objective is to investigate inflammation in the arteries of the heart. A heart CT scan (CCTA) will be used to measure inflammation by assessing the fat tissue surrounding the arteries of the heart. Participants with and without type 2 diabetes who have no heart symptoms have been examined and had a CCTA scan performed.

This study aims to answer the following questions:

• Is inflammation in the surrounding fat tissue of the heart arteries associated with the following glycometabolic conditions: I) Obesity ii) Prediabetes iii) Type 2 diabetes

Background and significance:

Inflammation in the coronary arteries is a key driver of cardiovascular (CV) disease, particularly in individuals with glycometabolic conditions such as obesity and diabetes. However, traditional biomarkers have limited accuracy in detecting coronary inflammation.

Coronary CT angiography (CCTA) allows for the non-invasive measurement of pericoronary adipose tissue (PCAT) attenuation - the fat surrounding coronary arteries. PCAT and the underlying vessels engage in bidirectional communication, and inflammation alters the structure of PCAT, which can be detected by CCTA.

Glycometabolic diseases promote atherosclerosis through endothelial dysfunction and accumulation of inflammatory cells. Obesity and diabetes are both associated with enlarged adipocytes, which may influence PCAT attenuation by lowering its Hounsfield Unit values, potentially masking underlying inflammation. To date, no studies have thoroughly addressed the possibility that PCAT attenuation may be underestimated in this high-risk CV population.

The PCAT-GMD study is a post-hoc analysis of two trials - CARPE-DM (NCT03016910) and DANCAP (NCT04525508) - aiming to evaluate the relationship between PCAT attenuation and the following glycometabolic conditions:

• Obesity (BMI)
• Prediabetes (HbA1c)
• Type 2 diabetes mellitus

Setting and study population:

A single-center cross-sectional, observational study at Odense University Hospital, Svendborg, Denmark. The study enrollment began in March 2016 and ended in July 2019. The study population included 747 cardiovascularly asymptomatic men with and without diabetes.

Examinations:

All participants underwent CCTA.

Additional assessments included:

• Blood pressure and heart rate
• Anthropometrics: height, weight, waist-to-hip ratio
• Blood and urine sampling
• Medical history

Inclusion Criteria:

• Above 18 years
• Capable of giving written informed consent

Exclusion Criteria:

• History of CAD
• Symtoms of CAD (angina)
• Any tachyarrhythmias making CCTA impossible
• Estimated glomerular filtration rate (eGFR) under 45 ml/min
• Allergy to iodine contrast
• Critical illness with life expectancy less than 1 year
• Documented heart failure

Men

CARPE-DM:

Participants with type 2 diabetes who were cardiac asymptomatic and had no history of CAD. Participants were recruited from the Endocrinology Outpatient Clinic and the Retina Photographhy Clinic at Odense University Hospital, Svendborg, Denmark.

DANCAP:

Participants in the age range 65-75 years were recruitted from the large Danish Cardiovascular Screening (DANCAVAS) at Odense University Hospital (OUH), Svendborg Hospital, Denmark. Participants were cardiac asymptomatic and had no history of CAD.