Coronary artery disease

Coronary artery disease (CAD) is primarily due to narrowing of the coronary arteries due to atherosclerosis, which results in myocardial ischemia, and is the leading cause of mortality globally. 

Clinical presentation

Coronary artery disease is asymptomatic in most of the population. When severe enough it can cause angina or an acute coronary syndrome including myocardial infarction. CAD may also present with heart failure or sudden cardiac death. 

Pathology

Coronary artery disease is primarily due to atherosclerosis, an inflammatory process that leads to atheroma development and remodeling/stenosis of the coronary arteries. A stenosis of >50% of diameter or >75% cross-section diameter reduction can lead to angina. Thrombus formation after plaque disruption can lead to acute coronary syndrome ^1,2. 

Risk factors

• non-modifiable: family history, age, male sex ¹
• modifiable: hypercholesterolemia, left ventricular hypertrophy, obesity, hypertension, diabetes, sedentary lifestyle, smoking, alcohol ¹

Radiographic features

There are a variety of techniques to image coronary artery disease including both anatomical and functional modalities. Coronary angiography has been the mainstay for many years, but in certain patient groups is being replaced by non-invasive imaging such as coronary CT angiography (cCTA).

There are several appropriate clinical indications for the performance of coronary CTA ⁸: 

• acute chest pain in patients with a low-to-intermediate pretest probability of coronary artery disease
• evaluation of coronary artery anatomy and bypass grafts
• assessment of congenital heart disease
• coronary artery calcium scoring
• patients with technically limited images from echocardiography or MRI

Haemodynamically-significant stenoses are those >70% for all coronary arteries, except the left main coronary artery where >50% stenosis is considered significant ⁷.

In a post-hoc analysis of prospective acquired data, a cutoff value > -70 HU of the perivascular fat attenuation index (FAI) around the proximal right coronary artery was found to be predictive of increased all-cause mortality ¹⁰.

Severity assessment

The recently proposed SCCT grading scale for stenosis severity assesses the degree of luminal diameter stenosis ⁶:

• 0% = no visible stenosis
• 1-24% = minimal stenosis
• 25-49% = mild stenosis
• 50-69% = moderate stenosis
• 70-99% = severe stenosis
• 100% = occlusion

See also

• ACC/AHA classification of coronary lesions
• Coronary Artery Disease - Reporting and Data System (CAD-RADS)