Coronary Artery Disease occurs when the major blood vessels that supply the heart become damaged or diseased. The buildup of plaque (cholesterol deposits) and inflammation of the coronary arteries cause coronary artery disease.
The coronary arteries are blood vessels wrapping around the outside of the heart and supply oxygen-rich blood and nutrients to the heart muscle. A reduction of blood flow supplying the heart muscle can be detrimental to heart performance.
Plaque is made up of deposits of cholesterol and other substances in the artery. Plaque buildup causes the inside of the arteries to narrow over time. Plaque can restrict the blood flow either partially or completely. This process is called atherosclerosis.
Eventually, reduced blood flow to the heart muscle may cause chest pain (angina), shortness of breath, or other signs and symptoms suggestive of coronary artery disease. A heart attack occurs when one or more of the coronary arteries suddenly become completely blocked.
Coronary Artery Disease often develops over decades, and the individual might not notice a problem until they develop a significant blockage or a heart attack. However, some steps can be taken to prevent and treat coronary artery disease. Opting for a healthy lifestyle will definitely make a significant impact.
Normal healthy arteries are elastic and flexible. Over time, atherosclerosis arises when the coronary artery walls become thick and stiff due to the build-up of plaque (known as fatty deposits) and inflammation. Plaque consists of fatty substances, cholesterol, cellular waste products, fibrin (a clotting material in the blood) and calcium. Substantial buildup of plaque can narrow the coronary arteries that transport oxygen-rich blood and nutrients to the heart muscle, resulting in a reduction of blood flow to the heart.
If the heart does not receive enough blood, it will not be able to absorb the oxygen and nutrients needed to function properly. The blockage can lead to angina or worse, a heart attack.
Atherosclerosis can begin as early as childhood. Atherosclerosis can be accelerated by several factors such as:
- High Blood Pressure
- High Cholesterol
- Sedentary Lifestyle (Not being active)
The buildup of plaque can also become highly unstable and crack or burst, causing blood to clot in an attempt to repair the injured vessel. If the blood clot blocks off the coronary artery flow completely, this causes a heart attack. Atherosclerosis can occur not just in the heart vessels, but also in other vessels elsewhere in the body.
If the coronary arteries narrow significantly, they will not be able to deliver sufficient oxygen-rich blood to the heart muscles, even more so when the heart is pumping hard, eg. while exercising. Initially, the reduction in blood flow may not cause any symptoms. Eventually, symptoms may develop such as:
- Chest pain (Angina)
- Shortness of Breath (Breathlessness)
- Heaviness in the chest
- Pain in the jaw or radiating to the arms
- Heavy sweating
Let’s explore the common symptoms in detail:
Chest Pain (Angina)
If you suddenly feel a tightness in your chest or heavy pressure, as if someone placed a large block on your chest, you may be experiencing angina. Angina is typically felt in the middle of the chest and is normally triggered by physical stress or strong emotions. Angina is usually temporary and tends to ease away within minutes of stopping the stressful task. Sometimes, the pain may spread to both sides of the chest, neck, jaws, shoulders and down the inner sides of the arm. Some patients may experience the sensation of heartburn, indigestion, nausea or excessive sweating rather than typical angina.
Shortness of Breath (Breathlessness)
If the heart is unable to pump sufficient blood (supply) to keep up with the body’s needs (demand), this could develop into shortness of breath or extreme fatigue during physical activity. This is especially so if you experience breathlessness out of the ordinary while doing activities you are used to.
You may be having a heart attack if you experience any of the following:
- Prolonged or severe chest pain, discomfort or pressure.
- The pain may radiate to the neck, jaws, shoulders, arms, back or upper abdomen.
- Severe shortness of breath.
- Excessive sweating.
- New or very severe palpitation (when you feel your heart is beating very fast).
- Nausea, vomiting, gastric discomfort, dizziness or weakness.
Several risk factors can result in or contribute to the development of coronary artery disease.
Non-modifiable risk factors (factors you cannot change):
Age: As you grow older, your risk of coronary artery disease increases.
Gender: Coronary artery disease is more common in men. Men develop coronary artery disease earlier in life, while the risk increases in women after menopause.
Family History: You could be at higher risk of developing coronary artery disease if there is a family history of heart disease, especially if it involves a direct family member (parents, sibling). Your risk could be significant if a direct family member was diagnosed with heart disease at a young age (<55 years old in women, <45 years old in men).
Modifiable risk factors (factors within your control):
Smoking: Toxic chemicals from cigarettes cause direct damage to blood vessels, decreases the amount of oxygen delivered to the heart, and increases the risk of developing deadly blood clots.
Individuals who smoke are at a higher risk of developing coronary artery disease and heart attack. Even exposure to second-hand smoke can increase an individual’s risk.
High Blood Pressure: High blood pressure that is not under good control places a strain on the heart and directly damages blood vessels, making it easier for plaque to form.
High Cholesterol Levels: High cholesterol in the blood can lead to atherosclerosis, or the build-up of thick, fatty plaque that narrows and blocks arteries. In particular, high levels of low-density lipoprotein (LDL) cholesterol and low levels of high-density lipoprotein (HDL) cholesterol promote atherosclerosis.
Diabetes: Diabetes is an established risk factor of coronary artery disease. High sugar levels can damage nerves and blood vessels in the heart and elsewhere in the body. Patients with diabetes may develop more extensive atherosclerosis as compared to non-diabetic patients.
Obesity: Obesity or excess body fat, particularly around the waist, can be a cause of increased blood pressure and high blood cholesterol.
Physical Inactivity: An inactive lifestyle is strongly linked to coronary artery disease and may worsen the control of other risk factors.
Unhealthy Diet: Diet containing high amounts of saturated & trans-fat, salt, and sugar could increase the risk of coronary artery disease and may worsen the control of other risk factors.
Stress: Unresolved stress in your life may aggravate other risk factors and damage your arteries.
Often, there is a strong interplay of two or more risk factors such that they may occur together or one may affect the other. The more risk factors you have, the higher risk you are at developing coronary artery disease. However, coronary artery disease may develop even in the absence of risk factors.
Active steps can be taken to modify the risk factors to prevent and treat coronary artery disease. A healthy lifestyle can be extremely beneficial.
If you suspect you may be experiencing symptoms suggestive of coronary artery disease or are at an elevated risk, you should consult your doctor. Your doctor will go through your medical history, perform a physical examination and order routine blood tests. Your doctor may recommend some diagnostic tests for coronary artery disease.
Some of the diagnostic tests could be:
Electrocardiogram (ECG): This test records your heart’s electrical activity in order to identify an abnormal heartbeat or damage to the heart muscle.
Echocardiogram: This test utilises sound waves to produce images of the heart movement, chambers, valves, major vessels and heart function. Parts of the heart that move weakly may be a sign of coronary artery disease or other conditions.
Exercise Stress Treadmill Test: This test evaluates your heart rate and rhythm on the ECG, and blood pressure while you are exercising on the treadmill. If you develop symptoms or abnormal ECG tracing during exercise, it may indicate the presence of significant coronary artery disease.
Stress Imaging Tests: These will include echocardiogram or other forms of imaging that is performed before and after exercise on a treadmill. These tests assess how your heart function in response to exercise stress. Sometimes a medication is given to mimic an exercise condition if the patient is not able to exercise on the treadmill.
CT Coronary Angiogram: It is a noninvasive imaging technique that uses a Computed Tomography (CT) scanner to obtain high-resolution images of the heart and coronary arteries. It will be able to diagnose the degree of plaque buildup and narrowing in the coronary arteries.
Coronary Angiogram: It is a minimally invasive procedure performed by a Cardiologist in the cardiac catheterisation laboratory using contrast dye injected in the coronary artery and visualized directly on Xray. It is the most accurate investigation to diagnose the location and severity of the blockages and is essential to plan treatment.
Treatment of Coronary Artery Disease usually begins with lifestyle changes and/or medications that help the heart work more efficiently and improve blood flow to the heart muscle.
For healthier arteries, adopt the following healthy lifestyle changes:
- Stop smoking
- Manage stress
- Exercise regularly
- Eat healthy, nutritious food
- Reduce consumption of alcohol
Common medications used in treating coronary artery disease include:
- Cholesterol-lowering medications like Statins
- Aspirin or other antiplatelet agents
- Calcium Channel Blockers
- Angiotensin-Converting Enzyme (ACE) Inhibitors or Angiotensin ll Receptor Blockers (ARBs)
- Metabolic modifiers
If these initial treatments are unable to control the symptoms of coronary artery disease, an interventional procedure called coronary angioplasty may be required. Coronary angioplasty may be beneficial if the narrowing is so great that the lack of blood flow is starving the heart muscle of oxygen.
Angioplasty and Stent Placement (Percutaneous Coronary Revascularisation
Angioplasty, also known as Stenting, is a procedure that is used to open narrowed or blocked coronary arteries. The Cardiologist will advance a long and narrow tube (catheter) from the wrist or groin artery, and place it at the opening of the coronary artery. A coronary angiogram is done first to provide a ‘road map’ for the angioplasty. This involves injecting a contrast dye and visualising the coronary arteries under a live X-ray.
Angioplasty involves passing a fine wire through the catheter and advanced into the coronary artery across the narrowed segment. This wire serves as a rail over which a balloon catheter is delivered and positioned over the area of narrowing. When the balloon is inflated, it pushes the plaque against the vessel wall and widens the narrowing. The balloon is then deflated and removed, and a stent (small wire mesh tube) is implanted (stenting) which helps to prop the vessel open. The stent stays in the vessel permanently to hold it open and improve blood flow. Modern stents are coated with medications that are slowly released to prevent re-narrowing.
Angioplasty is performed to improve the symptoms of coronary artery disease, such as chest pain (angina) and shortness of breath. It is also performed during a heart attack to immediately open up a blocked artery and minimise the damage to the heart, and this can be potentially life-saving.
Coronary bypass surgery is done under general anaesthesia. During the surgery, the surgeon takes healthy blood vessels from the chest, arm or leg to create a graft to bypass the blocked coronary arteries. This new path allows blood to flow around the blocked or narrowed artery, improving blood flow to the heart muscles. Coronary bypass surgery is usually reserved for patients with multiple and extensive coronary artery blockages not suitable for angioplasty.
If you believe you may be having a heart attack, you must immediately call 995 for an ambulance to go to the A&E. Do inform a family member. Do not drive yourself to the hospital. Take a GTN tablet or spray if you have it with you.
If you have symptoms suggestive of coronary artery disease, have one or more risk factors, or if are thinking of embarking on a new exercise program, do consult a Cardiologist early.