Coronary heart disease is the term used to describe the condition that develops when the major blood vessels (called coronary arteries) that supply your heart with blood, oxygen, and nutrients become damaged or diseased. This damage/disease is usually the result of inflammation and cholesterol-containing deposits (called plaques) forming in your arteries. Coronary heart disease may also be referred to as coronary artery disease.
What causes coronary heart disease?
Damage to the inner lining of a coronary artery is thought to initially cause coronary heart disease. Sometimes this damage can occur as early as childhood, but symptoms may not show for decades later.
Once the inner wall of an artery is damaged, cholesterol-rich deposits start to accumulate at the site of injury in a process called atherosclerosis. This forms a fatty plaque that narrows the artery, restricting blood flow. If the surface of the plaque breaks or ruptures, platelets and other clotting substances will clump at the site to try to repair the artery. Sometimes this clump can fully block the artery, starving the heart tissue beyond the blocked area of oxygen. This is what happens during a heart attack.
There are several different factors that can cause or increase the risk of damage to the artery linings, such as:
- High blood pressure
- High cholesterol
- Diabetes or insulin resistance
- Lack of physical activity.
What are the symptoms of coronary heart disease?
In many people, coronary heart disease develops slowly, and symptoms may be vague and include fatigue, tiredness, or slight shortness of breath on exercise. Sometimes there will be no symptoms at all until the person has a significant blockage or a heart attack.
In others, symptoms depend on how significantly the plaque narrows the artery (or arteries) and decreases blood flow. Symptoms may be more noticeable during times of stress or when the heart is beating hard, such as during physical activity. Symptoms may include:
- Chest pain or tightness (angina), usually in the middle or left side of the chest. The pain usually resolves within minutes after stopping the stressful activity. In women, the pain may be felt more like a fleeting or sharp pain in the neck, arm, or back.
- Shortness of breath or extreme tiredness with exertion
- Heart rhythm disturbances (arrhythmia)
- A heart attack, which may be felt like a crushing pressure in the chest which radiates up your neck or down your arm, sometimes with shortness of breath and sweating. Heart attack symptoms in women may be more subtle, and are more likely to include indigestion, dizziness or nausea, or discomfort between the shoulder blades; in addition to chest pressure.
Who is more likely to develop coronary heart disease?
The following factors increase a person’s risk of developing coronary artery disease:
- Age: As you age your arteries get narrower and stiffer
- Sex: Males generally have a greater risk of coronary artery disease; however, the risk for women increases after menopause
- Family history: People with a close relative with a history of coronary artery disease are at higher risk of developing it themselves, especially if it occurred at a younger age (such as a father/brother developing heart disease before age 55, or mother/sister before age 65)
- High blood pressure: If left uncontrolled or untreated, high blood pressure can cause hardening and thickening of the arteries, making it harder for blood to flow through
- High cholesterol levels: Particularly high levels of LDL cholesterol (bad cholesterol) can increase the formation of plaques and low levels of HDL cholesterol (good cholesterol) can contribute to the development of atherosclerosis
- Diabetes: People with type 2 diabetes are typically overweight and have high blood pressure
- Obesity: Excess weight increases the likelihood of other risk factors
- Physical inactivity
- Smoking or persistent exposure to second-hand smoke
- Unhealthy eating: Diets rich in salt, trans or saturated fat, and sugar increase the risk of coronary heart disease.
Having one risk factor can lead to the development of other risk factors, for example, being obese increases your risk of diabetes and high blood pressure. People with a particular cluster of risk factors, ie, elevated blood pressure, high triglycerides, low HDL, a reduced response to insulin, and excess body fat around the waist, known as the metabolic syndrome, have a particularly high risk of coronary heart disease.
Other possible risk factors include:
- Sleep apnea: Sudden drops in blood oxygen levels that occur during sleep apnea strain the cardiovascular system, possibly leading to coronary artery disease
- High sensitivity C-reactive protein: this is a marker for inflammation and may be a risk factor for coronary heart disease
- High triglycerides: These are a type of fat and are associated with a higher risk of coronary artery disease, especially for women
- Homocysteine: This is an amino acid that your uses to make protein and to build and maintain tissue - High levels may increase your risk of coronary artery disease
- Preeclampsia: This is a condition that can develop during pregnancy that has been associated with a higher risk of heart disease later in life
- Excessive alcohol use: This can lead to muscle damage and worsen other risk factors of coronary artery disease
- Presence of autoimmune diseases (eg, rheumatoid arthritis, lupus).
How is coronary heart disease diagnosed?
If you or your doctor think you may have coronary heart disease, a thorough physical assessment will be undertaken. Your doctor will ask you about your symptoms, listen to your heart, and ask about any risk factors or family history of coronary heart disease. Other tests may also be conducted, such as:
- Blood tests to check your levels of electrolytes, blood cells, clotting factors, or hormones or specific enzymes and proteins that can indicate problems with the heart
- An electrocardiogram (ECG): Different types of ECG test for different things. A resting ECG records the electrical activity of the heart when at rest, and may show changes that indicate the heart muscle is not receiving enough oxygen. An exercise ECG/ Exercise Tolerance Test (ETT) assesses the heart’s response to exercise and stress and involves walking on an exercise treadmill or riding an exercise bike for up to 12 minutes at varying degrees of speed and incline, under the supervision of a doctor and ECG technician
- An echocardiogram. This uses ultrasound waves to display the movements of the heart as it beats, allowing doctors to precisely calculate the dimensions of the heart, view its internal structures (such as the heart valves), and to assess any damage to the heart muscle. Stress echocardiography involves the administering of medications that stimulate the heart and mimic the effects of exercise into the bloodstream during the echo
- An angiogram (which may also be called cardiac catheterization) involves inserting a small, flexible tube (called a catheter) into an artery in the wrist or groin. This is then threaded up through the artery, into the aorta and positioned at the entrance to the coronary arteries. A specialized x-ray dye is then injected through the catheter and into the coronary arteries, which allows the arteries to be visualized on an x-ray, highlighting any narrowing or blockages. How well your heart pumps can also be determined
- CT Angiography is a type of x-ray technology that uses multiple cross-sectional x-ray images to create a detailed three-dimensional picture of the heart, indicating any areas where narrowing, or fat or calcium deposits exist, and to also assess how well the heart and valves function
- Nuclear Isotope Imaging involves the injection of a radioactive compound (called a tracer) into the bloodstream. Pictures are then taken of the tracer as it moves through the heart, determining heart function and detecting any narrowed or blocked blood vessels.
How do you treat coronary heart disease?
Treatment of coronary heart disease depends on tests results and the cause of your coronary heart disease. Treatment may include medication, procedures such as coronary angioplasty (with or without coronary artery stenting), or coronary artery bypass surgery (commonly known as coronary artery bypass grafting or CABG). Treatment aims to reduce or eliminate symptoms and reduce your risk of having a heart attack.
Medications typically used to treat coronary heart disease include:
- Beta blockers: slow the heart rate and reduce blood pressure reducing how hard the heart has to work to pump blood around the body
- Isosorbide dinitrate or nitroglycerin: These dilate (open up) the coronary arteries making it easier for blood to flow through
- Calcium channel blockers/calcium antagonists: These relax arteries by slowing the entry of calcium through the artery walls, lowering blood pressure and reducing how hard the heart has work to pump blood around the body
- Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs): These prevent blood vessel narrowing, widening them and therefore reducing the pressure against which the heart must pump. They may also reduce the progression of coronary heart disease
- Antiplatelet agents, such as aspirin or clopidogrel, are usually prescribed (unless they are contraindicated) as they help prevent blood clot formation, reducing the risk of having a heart attack or stroke
- Statins (eg, simvastatin, atorvastatin, pravastatin) or other cholesterol-lowering medications may be required by some people whose cholesterol levels are high. These help reduce plaque build-up in the arteries, reducing the risk of a heart attack
- Ranolazine: May be used to treat chronic angina alongside other medications.
Some people may be candidates for coronary angioplasty and stenting or coronary artery bypass grafting (CABG).
Coronary angioplasty is a non-surgical technique that involves inserting a balloon-tipped catheter into a narrowed coronary artery. The catheter is inserted through an incision in the groin or wrist, and sometimes the patient is mildly sedated for the duration of the procedure. The balloon is inflated at the site of the narrowing in the coronary artery, compressing the plaque and slightly stretching the artery wall. This widens the artery and improves blood flow to the heart.
Most angioplasties also involve the placement of a stent. This is a small mesh tube that is placed in the narrowed coronary artery during the angioplasty procedure, which acts as a scaffold to keep the artery open.
Coronary artery bypass grafting (CABG) involves grafting one end of a blood vessel taken from elsewhere in the body (such as the chest wall, forearm, or legs) to the blocked coronary artery below the area of blockage, so that blood flow is restored. The operation takes approximately three to four hours.
How can I prevent coronary heart disease?
Choosing to live a healthy lifestyle can reduce your risk of developing coronary heart disease. To reduce your risk, you should:
- Not smoke or stop smoking if you do smoke. Avoid second-hand smoke whenever possible
- Take your medication as directed if you have high blood pressure, high cholesterol, diabetes, or any other medical condition that requires treatment
- See your doctor for regular check-ups or if you develop any type of chest pain, irregular heartbeat or shortness of breath. Call for an ambulance if you think you may be having a heart attack
- Keep active and exercise daily
- Eat a healthy, low-fat, low-salt diet that's rich in fruits, vegetables, and whole grains
- Maintain a healthy weight
- Try to manage your exposure to stress and take time out to relax daily
- Try for eight hours sleep a night and talk to your doctor if you think you might have sleep apnea.