An Overview of Coronary Artery Disease

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Coronary artery disease (CAD) is characterized by disease within the arteries that supply the heart muscle. The disease typically develops due to atherosclerosis (hardening) and plaques (sections of calcified material) within the blood vessels. As a result, the coronary arteries often cannot carry blood as efficiently as they should and may even become completely obstructed (blocked off). Because the heart muscle requires a continuous supply of oxygen and nutrients to survive, obstruction of a coronary artery rapidly leads to significant problems, such as heart attacks and strokes.

CAD is caused by lifestyle factors such as smoking and lack of exercise, as well as medical conditions such as high blood pressure and diabetes. Treatment includes managing risk factors with lifestyle adjustments and prescription medications, and sometimes directly repairing or replacing the arteries with surgical or specialized procedures.

Symptoms

CAD does not usually cause symptoms, and when it does, this is often a sign that the disease is progressing. The symptoms of CAD generally appear suddenly, but in some instances, they may come and go and are expected to worsen over time.

Eventually, a heart attack or a stroke can occur as the result of a severe case of CAD, so it is important to discuss any signs or symptoms with your doctor so that you can get appropriate treatment before a more serious health issue arises.

Symptoms of CAD include:

  • Fatigue and lack of energy
  • Shortness of breath with physical exertion
  • Chest discomfort with physical exertion or with stress
  • Angina (chest pain that is usually worse with physical exertion or stress, though this can also occur at rest in some)

Women may have subtler symptoms of CAD, such as chest or arm discomfort, not necessarily severe crushing chest pain, and this can lead to some women ignoring the early symptoms of CAD.

If CAD is not treated, a heart attack or a stroke can occur. A heart attack can cause severe chest pain or chest pressure and shortness of breath that does not improve after a few seconds the way angina does. If you experience angina, it is not possible to predict if an episode will resolve in a few seconds, or whether it will persist, resulting in a heart attack. A stroke causes weakness, numbness, visual changes, or trouble speaking.

Causes

CAD takes years to develop. Typically, CAD is caused by atherosclerosis, a chronic, progressive disorder of the arteries in which plaques, which are deposits of cholesterol, calcium, and inflammatory cells, build upon the inner lining of the arteries (the tunica intima is the innermost layer of an artery and the tunica media is the inner coat). This results in a narrowing of the arteries and an inability of the arteries to relax and dilate (widen) as they should.

These plaques can also gradually obstruct the artery or suddenly rupture (break off), causing an obstruction in a smaller blood vessel in the heart or the brain. 

A plaque can be thick, extending into the lumen (opening) of the artery to cause a major obstruction, or flatter, extending throughout a longer section of an artery. Usually, someone with CAD has several plaques throughout the coronary arteries.

Generally, these issues develop as a result of long-term damage to the inner lining of the arteries. Causes include:

  • Smoking
  • Hypertension
  • High cholesterol and fat levels
  • Diabetes
  • Obesity
  • Stress
  • Genetics

Diagnosis

Because CAD does not usually cause symptoms, diagnosis relies on screening for risk factors and specialized diagnostic testing. Risk factors include hypertension, high cholesterol, diabetes, and smoking, all of which are normally screened for at a routine yearly physical examination.

This means that the first step in making sure that you are evaluated for "silent" CAD is maintaining regular health check-ups.

Diagnosis of CAD also includes cardiac tests that can evaluate heart function and identify disease within the coronary arteries. 

  • Electrocardiogram (EKG): This is a non-invasive test that examines heart rhythm and function using small disks that detect the electrical activity of a heart and display its pattern on a monitor. This is a preliminary test of cardiac function and does not specifically detect CAD, but rather evidence of damage from the disease. 
  • Stress test: In this test, you are asked to perform physical tasks that place additional demands on your heart muscle while you are monitored with tests such as EKG or echo. A stress test can detect evidence of CAD if you have symptoms or if your heart function changes when the demands increase. 
  • Echocardiography: Often referred to as an echo, this ultrasound test allows your doctor to observe your heart muscle function and can reveal evidence of heart muscle damage or alterations in blood flow. 
  • Angiogram: An interventional test in which a catheter (tube) is placed in the coronary vessels, an angiogram can identify regions of atherosclerosis, narrowing, and plaques in your coronary arteries.  

    Atypical CAD

    Some atypical forms of CAD are characterized by diagnostic findings besides atherosclerosis and plaques. These atypical forms include:

    • Printzmetal's angina: Spasms of the coronary arteries cause pain, shortness of breath, and possible heart attack risk. 
    • Cardiac syndrome X: This disease of the inner lining of the coronary arteries can cause insufficient blood flow to the heart muscle.
    • Female pattern CAD: This involves small plaque extended throughout the coronary arteries, sometimes surrounding the whole circumference. It can cause partial or complete coronary artery obstruction.
    • Coronary artery erosions: This disease of the coronary arteries may cause bleeding, which may produce angina or a heart attack. 

    Treatment

    The treatment of CAD requires a multi-pronged strategy that includes addressing lifestyle factors as necessary, taking prescription medications, and, often, surgical or specialized interventions to repair a severely diseased artery. 

    • Lifestyle factors: If you smoke, quitting is the most effective way to prevent CAD from worsening, and smoking cessation can reverse disease for some people with CAD. Obesity, lack of exercise, an unhealthy diet, and excessive stress all contribute to CAD as well.
    • Medications: Cholesterol-lowering medications are available by prescription and can help reduce atherosclerotic disease and the build-up of plaque. Medications to control diabetes can help to prevent worsening of CAD. Those that lower high blood pressure and prevent blood clots may be necessary to lower the risk of a heart attack or stroke if you have CAD. And, if you have experienced a heart attack as a result of CAD, prescription medications can help alleviate some of the consequences of a heart attack, such as heart failure (a weak heart) and arrhythmias (irregular heart rhythm). 
    • Surgery and special procedures: Arteries can be repaired and replaced with surgical interventions or minimally invasive procedures.
      • Coronary artery bypass graft (CABG) is a surgical procedure in which a healthy artery is used to create a bypass (new pathway) for blood to flow to the heart muscle.
      • An endarterectomy is a procedure in which a coronary artery is surgically "cleaned" of a plaque.
      • A stent is an artificial "tunnel" that is placed into a diseased artery.
      • A balloon catheterization is a procedure in which a device is inflated in the narrow area of a coronary artery to open it up and allow blood to flow. 

      A Word From Verywell

      CAD is very common, so there is no need to panic if you've been diagnosed. However, you should not ignore it either, because your case will worsen over time and is likely to cause serious complications if you are not treated. 

      Acute coronary syndrome (ACS) occurs when a coronary artery plaque breaks off, causing sudden partial or complete blockage of another artery. It is important to take action early in the course of the disease to prevent this from happening. Treatment is more effective if you are diagnosed and begin your treatment in early stages of the disease. 

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