Fat Around Heart Arteries as a Measure of Inflammation in Patients With Diabetes

Prospective Associations of Pericoronary Adipose Tissue Computed Tomography Attenuation With Coronary Plaque Features and Major Adverse Cardiovascular Events in a Population With Diabetes Mellitus

In this prospective 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 type 2 diabetes who have no heart symptoms have been examined, using a CCTA at the start of the study and again after 12 months.

This study aims to answer the following questions:

• Can inflammation in the surrounding fat tissue at the baseline CCTA predict the amount and type of plaque, and the presence of harmful plaque characteristics present after 12 months? (paper 1)
• Do changes in inflammation in the surrounding fat tissue from baseline to the 12 months CCTA correlate with the amount and type of plaque and the presence of harmful plaque characteristics at the 12 months CCTA? (paper 1)
• Is inflammation in the surrounding fat tissue a predictor for the development of cardiovascular events after a follow-up period of 7 years? (paper 2)
• Do changes in inflammation in the surrounding fat tissue after 12 months predict the later development of cardiovascular events after a follow-up period of 7 years? (paper 2)

Background and significance:

Inflammation in the coronary arteries plays a significant role in the development of heart disease, particularly in individuals with type 2 diabetes (T2D), who are at an increased risk. However, this inflammation has been difficult to detect because the currently used biomarkers have limited accuracy in identifying inflammation in the coronary arteries.

Exiting advancements have been made in the field of coronary CT angiography (CCTA). CCTA enables the measurement of the pericoronary adipose tissue (PCAT) attenuation, which refers to the fat tissue surrounding the coronary arteries. PCAT and the coronary arteries have a bidirectional communication, and when PCAT is exposed to high inflammation it causes the fat-structure to change. These structural changes in PCAT can be detected with a CCTA scan. Additionally, a CCTA scan can assess plaque characteristics, such as the amount of plaque (burden), the type of plaque (composition), and the presence of high-risk plaque features, all of which, are linked to major adverse cardiovascular events (MACE). Furthermore, recent studies have shown that PCAT attenuation can predict cardiac events and mortality.

The PCAT-DM study is a post-hoc analysis from the CARPE-DM study (NCT03016910). The goal of this prospective study is to investigate whether PCAT attenuation and/or PCAT changes are associated with high-risk plaque features, plaque composition and burden. Additionally, the study aims to investigate whether PCAT attenuation and/or PCAT changes can predict development of MACE over a follow-up period of 7 years.

Setting and study population:

A single-center prospective observational study at Odense University Hospital, Svendborg, Denmark. The study enrollment began in March 2016 and ended in September 2017. The study population consists of cardiovascularly asymptomatic participants with type 2 diabetes mellitus.

Examinations:

A total of 314 patients were examined with a CCTA scan at baseline and again after 12 months. The following examinations were conducted at baseline:

• CCTA scan
• CAC-score
• Blood pressure and pulse frequency
• Height, weight, waist to hip-ratio
• Blood samples and urin samples
• Medical history After 12 months, all of the above examinations were repeated.

Journal audits will be performed in the period from September 2024 to January 2025 to examine the number of clinical events according to the primary and secondary outcomes.

Inclusion Criteria:

• Above 18 years
• Capable of giving written informed consent
• Type 2 diabetes mellitus

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