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What is Atherosclerosis?
Coronary atherosclerosis is defined as a disease of the arteries characterized by the deposition of plaques of fatty material on the inner walls.
The plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, the plaque hardens and eventually narrows the arteries in a phenomenon referred to as arterial stenosis. This limits the flow of oxygen-rich blood to the organs and other parts of the body.
Eventually, the hardened plaque can rupture which results in lesion formation. This can lead to blood clots, further limiting blood supply, which can increase the risk of stroke.
Risk Factors
Unhealthy Cholesterol Levels
Including both high LDL ("bad" cholesterol) and low HDL ("good cholesterol)
High Blood Pressure
High blood pressure is considered to be at or above 140/90 mmHg. This value changes to 130/90 mmHg if you have chronic kidney disease.
Smoking
Smoking can tighten and damage blood vessels and raise cholesterol levels and blood pressure. It also doesn't allow for enough oxygen to reach tissues.
Type 1 Diabetes
Having an insulin resistance results in the body being unable to move blood sugar into cells where it's used as an energy source, which further leads to diabetes.
Obesity
Obesity accelerates atherosclerosis by increasing blood pressure, glucose levels, abnormal lipid profiles, and systemic inflammation
Genetics
If a family member has been diagnosed with atherosclerosis the risk increases for yourself.
Diet
A diet composed of high saturated fats, trans fats, cholesterol, sodium, and sugar can worsen atherosclerotic risk factors
How Patients are Diagnosed
How to Treat Atherosclerosis
Blood tests - To check blood sugar and cholesterol levels.
Electrocardiogram (ECG/EKG) - A noninvasive technique to measure the electrical signals in the heart
Physical Stress Test - Performed while doing cardiovascular exercise while connected to an ECG. If you are experiencing symptoms during exercise your doctor might suggest this method.
Echocardiogram - Determines how the blood moves in the arteries through sounds waves.
Ankle-Brachial Index (ABI) - Can determine whether or not atherosclerotic lesions exist in the arteries of the legs and/or feet.
Coronary Calcium Scan - Used to image and create detailed photos of the heart. It can show the presence of calcium, and the results are given a rating. The higher concentration of calcium leads to a higher score, and a higher risk of heart disease.
Invasive Coronary Angiogram (ICA) - The most common diagnostic technique for atherosclerosis, the ICA is an X-ray imaging technique that captures features internal to the blood vessel. During this procedure, a catheter is inserted in the arm or groin and navigated to the coronary artery or heart, allowing doctors to manually unclog blocked arteries while imaging cardiac disease.
Life style changes - Changing exercise and eating habits
Medication - Statins, blood thinners, and blood pressure medication can all be used to slow or even reverse effects of atherosclerosis.
Surgery
Angioplasty and stent placement help to open clogged or blocked arteries. A catheter is inserted into the desired artery in order to place a mesh tube (stent) inside the artery to help open it.
Endarterectomy is a surgical procedure that removes the plaque buildup form the walls of the narrowed artery.
Fibrinolytic therapy utilizes a clot-dissolving drug to break apart the blood clot.
Coronary artery bypass surgery is a very invasive procedure that takes a healthy blood vessel from another part of the body to create a bypass around the diseased artery in order to redirect blood flow.
Coronary angioplasty for the treatment of atherosclerosis
Advantages of Using CTA Images in Atherosclerosis Diagnosis and Research
Advantages of Using CTA Images in Atherosclerosis Diagnosis and Research
CTAs have a high spatial resolution that is comparable to the resolution of ICAs
The current gold standard angiogram for imaging cardiac diseases and behavior is invasive. CTAs offer a non-invasive approach to analyzing atherosclerosis
Ability to examine physical features external to the blood vessel including tissue disposition and measurements of adipose volume
CTAs are much less expensive than magnetic resonance angiograms (MRAs) and therefore more suitable for clinical research.
Invasive Coronary Angiography
Magnetic Resonance Angiography
An Outside Perspective: A New Method of Studying the Pathophysiology of Atherosclerosis
Looking Toward the Adventitia
Research on the etiology of atherosclerosis often focuses on factors inside the arteries that could contribute to the formation of plaque, and eventually lesions. Notably, one of the most accepted hypotheses for the cause of plaque build-up is that bifurcations in the vessel disturb the laminar flow of blood resulting in the build-up of LDL deposits that further lead to atherosclerotic lesions. However, this hypothesis does not explain the existence of lesions that don't occur at bifurcations. Additionally, it also doesn't explain why only certain bifurcations develop atherosclerosis.
By comparison, there is less research on how the adventitia (the outermost layer of the blood vessel) and the tissues directly adjacent to the adventitia could possibly play a role in lesion formation.
A fair amount of research has been done on how inflammation in the perivascular adipose tissue caused by the accumulation of IL-6 can be a biomarker or "companion diagnostic" of atherosclerosis. This research does indicate the importance of examining factors external to the artery and the correlation between the accumulation of adipose tissue and plaque formation.
Because of this, we have focused on creating an image analysis program that can analyze CTA scans to determine the composition of the tissue surrounding a segmented artery that's either healthy or contains a lesion. This program will help us to better understand if there is in fact a potential relationship between epicardial adipose accumulation and the presence of an atherosclerotic lesion.
UC San Diego 2021
Page Leader: Katherine Young
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