Smoking not only increases the risk of various types of cancer, but did you know that smoking also increases the risk of coronary artery disease? According to the World Health Organization, more than 25% of those who die from coronary artery disease are regular smokers. Today, we will help everyone better understand coronary artery disease.

What is Coronary Artery Disease?

Coronary artery disease is a common heart condition caused by blockage within the arteries that supply blood to the heart, resulting in insufficient oxygen delivery to the heart muscle, eventually leading to heart ischemia.

Why do coronary arteries become narrowed?

Coronary artery disease occurs due to hardening of the arteries combined with the accumulation of fatty plaques inside the coronary arteries. As the blockage from fatty plaques increases, blood flow to the heart is reduced, leading to heart ischemia.

Who is at risk for coronary artery disease?

The risk factors for coronary artery disease can be divided into two main categories:

Uncontrollable factors

These include age, genetics, and gender. It is found that males have a higher risk than females during their menstruating years, but after menopause, the risk is considered similar for both genders.

Controllable factors

Smoking, diabetes, high blood pressure, high blood cholesterol, and obesity.

Symptoms to watch out for coronary artery disease

Symptoms of coronary artery disease vary depending on the severity of the artery blockage. Some may have no symptoms. To simplify, symptoms can be divided into:

Acute symptoms, which usually occur suddenly and severely

Severe chest tightness
Sudden shortness of breath
Fainting or loss of consciousness
May be severe enough to cause cardiac arrest

Chronic symptoms

Or to put it simply, the coronary artery is partially blocked but not completely, so blood flow is reduced but still present.

Some individuals show no abnormal symptoms
Some show symptoms occasionally, especially during heavy exertion, because the heart muscle requires more blood during exertion, and if blood flow is insufficient, symptoms may appear
Symptoms include shortness of breath, easy fatigue, and incomplete breathing

Common symptoms include chest tightness in the middle or left side of the chest, described as a pressing sensation, which may radiate to the left arm or left jaw. Additionally, sweating and palpitations may also occur.

How many methods are there to diagnose coronary artery disease?

Electrocardiogram (EKG)

This is a preliminary test that is quick and can diagnose heart ischemia, especially acute heart ischemia.

Cardiac Enzyme Test

The levels of these enzymes increase in the blood when the heart muscle is ischemic, helping to diagnose acute heart ischemia.

Echocardiogram

This uses ultrasound waves to visualize the shape and function of the heart, including the strength of heart contractions and the opening and closing of heart valves.

Exercise Stress Test

This test increases heart rate and contraction, essentially stressing the heart to see if the heart muscle receives enough oxygen. Common methods include treadmill running or cycling, also known as EST (Exercise Stress Test).

During the test, abnormal symptoms such as chest tightness, palpitations, or dizziness are observed, and continuous EKG monitoring is done to assess heart ischemia. Another method to evaluate heart ischemia is stress echocardiogram, which uses ultrasound during exercise to detect abnormal heart muscle contractions and valve function.

CT Scan

Cardiac CT scan to assess coronary artery disease risk by measuring the calcium score in the heart (CT Calcium Score)

The advantage is that no contrast dye injection is needed, and the test takes less than 15 minutes. It quantifies calcium levels, with higher scores indicating higher risk of coronary artery disease. Doctors can use this information to decide on appropriate treatment.

Coronary CT Angiography

This examines the coronary arteries for narrowing or other abnormalities. It provides detailed assessment of the severity of blockages and can be used to monitor treatment after coronary artery surgery. Contrast dye is injected to obtain clear X-ray images.

Cardiac MRI

Advantages include providing multiple types of information such as size, thickness, contraction of the heart, and assessment of valve stenosis or leakage. It can also measure scar tissue and evaluate the severity of heart ischemia. Limitations include longer test duration and the need to remain still and hold breath as instructed.

Coronary Angiography

This procedure can diagnose and treat simultaneously by inserting a small catheter (1-2 mm diameter) through an artery in the wrist or groin, then injecting contrast dye to visualize coronary artery blockages. If severe blockages are found, a stent can be placed to widen the artery during the same procedure. This is done under local anesthesia without general anesthesia.

Coronary artery narrowing can be treated

If the patient is evaluated and found to have symptoms and diagnostic evidence warranting treatment, doctors will proceed with treatment. Currently, there are two main methods:

Balloon angioplasty involves inserting a small catheter with a balloon at the tip through an artery to the narrowed area, inflating the balloon to widen the artery, and placing a stent to support the artery and reduce the chance of re-narrowing.

Coronary artery bypass surgery is usually performed in patients with severe or multiple blockages that cannot be treated with balloon angioplasty. The surgeon uses veins from the chest or leg to bypass the blocked artery, allowing more blood to reach the heart.

Regardless of the treatment method, patients must take antiplatelet medication for life to prevent recurrent coronary artery narrowing. However, coronary artery disease is not curable, so patients must take care of themselves by avoiding risk factors mentioned above to reduce the chance of further narrowing.

Dr. Jutatip Petchrat
Cardiologist, Heart Center
Phyathai 3 Hospital