Comparative Prognostic Value of Coronary Calcium Score and Perivascular Fat Attenuation Index in Coronary Artery Disease

Abstract

Coronary artery disease (CAD) is the leading global cause of mortality, accounting for approximately 30% of all deaths. It is primarily characterized by the accumulation of atherosclerotic plaques within the coronary arteries, leading to reduced blood flow to the heart muscle. Early detection of atherosclerotic plaques is crucial to prevent major adverse cardiac events. Notably, recent studies have shown that 15% of myocardial infarctions occur in patients with non-obstructive CAD, underscoring the importance of comprehensive plaque assessment beyond merely identifying obstructive lesions. Cardiac Computed Tomography Angiography (CCTA) has emerged as a cost-effective and efficient technique for excluding obstructive CAD, particularly in patients with a low-to-intermediate clinical likelihood of the disease. Recent advancements in CCTA technology, such as improved resolution and reduced scan times, have mitigated many technical challenges, allowing for precise quantification and characterization of both calcified and non-calcified atherosclerotic plaques. This review focuses on two critical physiological aspects of atherosclerotic plaques: the burden of calcifications, assessed via the coronary artery calcium score (CACs), and perivascular fat attenuation index (pFAI), an emerging marker of vascular inflammation. The CACs, obtained through non-contrast CT scans, quantifies calcified plaque burden and is widely used to stratify cardiovascular risk, particularly in asymptomatic patients. Despite its prognostic value, the CACs does not provide information on non-calcified plaques or inflammatory status. In contrast, the pFAI, derived from CCTA, serves as an indirect marker of coronary inflammation and has shown potential in predicting adverse cardiac events. Combining both CACs and pFAI assessment could offer a comprehensive risk stratification approach, integrating the established calcification burden with novel inflammatory markers to enhance CAD prevention and management strategies.

Keywords: cardiac computed tomography angiography; coronary artery calcium; coronary artery disease; perivascular fat attenuation index; primary prevention.

Figure 1

CAC score assessment. The provided image illustrates a calcium score evaluation of the coronary arteries. The yellow arrow highlights the calcium score measurement on the left anterior descending coronary artery. The red arrow indicates the calcium score measurement on the right coronary artery. Lastly, the blue arrow points to the calcium score measurement on the circumflex coronary artery.

Figure 2

The image depicts the evaluation of the pFAI around the proximal segment of the right coronary artery (RCA). The pFAI measurement was taken over a 40 mm segment (10–50 mm from the RCA origin) at a radial distance equal to the artery’s diameter, with the most proximal 10 mm segment excluded to avoid the effects of the aortic wall. The highlighted median value indicates an inflamed coronary artery.

Figure 3

This graphic summarizes the roles of the pFAI and CAC score in assessing coronary artery disease risk. By integrating both parameters, cardiovascular risk stratification is enhanced, enabling more personalized patient therapy.

Figure 4

A 45-year-old male with a history of hypertension and hyperlipidemia presents for emergency evaluation. The patient is symptomatic for chest pain. A coronary computed tomography angiography was performed. The right image shows a coronary artery calcium score = 0 for all coronary arteries, indicating no detectable calcified plaque. In the left panel, the Multiplanar Reformation and Volume Rendering show a clear soft plaque on left circumflex artery. The elevated perivascular fat attenuation index indicates a vulnerable plaque. These findings suggest the absence of calcified plaque but the presence of a soft, potentially vulnerable plaque that may predispose the patient to future cardiovascular events.