Coronary artery disease (CAD) is the most common type of heart disease, in which the coronary arteries (major artery that supplies blood to the heart muscle) become rigid and narrowed due to buildup of plaque (deposition of cholesterol) in the inner walls of the heart. This restricts the flow of oxygen rich blood to the heart muscle, which may result in angina (chest pain) and shortness of breath. If the plaque ruptures or due to a complete blockage in the artery, it may result in heart attack or sudden cardiac death.
The cause of coronary artery disease is the buildup of plaque in the inner walls of coronary artery, which is called as atherosclerosis.
The plaque makes the inner walls of the artery sticky, so that the inflammatory cells, lipoproteins, and calcium travelling through the blood stream may adhere to the plaque. The plaque gradually enlarges, narrowing the blood vessel and further restricting the blood flow to the heart muscle and reducing the supply of oxygen and nutrients to the heart.
Signs and symptoms:
- Angina (chest pain)
- Shortness of breath
- Palpitations (irregular heartbeats or skipped beats)
- Tachycardia (fast heartbeat)
- Weakness or dizziness
- Fatigue, mainly after exercise or any activity.
- Age: Risk for damaged or narrowed arteries increases with age.
- Gender: Men are at greater risk of developing CAD. In women, risk increases after menopause stage.
- Family history: Risk increases if any family member has coronary artery disease.
- Smoking: People who have the habit of smoking and who are exposed to smoke are at increased risk of CAD.
- High blood pressure: It results in the narrowing and hardening of the walls of arteries.
- High blood cholesterol levels: It can increase the risk of atherosclerosis.
- Diabetes: It is associated with the symptoms of CAD, such as high BP and obesity.
- Obesity: Overweight increases the risk of CAD.
- Life style activities: Reduced physical activity, high stress and unhealthy diet also contribute to the development of CAD.
Other possible risk factors, according to research, include:
- Sleep apnea: It is a condition in which the person may experience intermittent cessation of breathing during sleep, resulting in reduced oxygen levels in the blood. Sleep apnea may cause an increase in the blood pressure and high strain on the heart, leading to CAD.
- Increased C-reactive protein (CRP) levels in blood: CRP levels are increased mostly if there is any inflammation in the body. It is a risk factor for CAD.
- High triglycerides (a type of lipid).
- High homocysteine (amino acid) levels.
- Preeclampsia (high blood pressure during pregnancy).
- Alcohol use can lead to heart muscle damage.
- Autoimmune diseases such as rheumatoid arthritis and lupus.
If left untreated, CAD can lead to life threatening complications such as:
- Angina: Due to narrowed blood vessels, the heart muscles receive inadequate oxygen laden blood, causing chest pain or shortness of breath.
- Heart attack: The plaque may rupture forming a clot and blocking the blood flow to the heart muscle.
- Heart failure: Due to reduced oxygen and nutrient rich blood flow, the heart is unable to pump enough blood, thus increasing its workload. Over time, it may lead to heart failure.
- Arrhythmia: Reduced amount of blood supply may lead to abnormal heart rhythms.
The diagnostic work up includes a physical examination, in addition to medical history, family history, risk factors and any signs and symptoms of CAD. Further diagnostic tests may be recommended:
- Electrocardiogram (ECG): It records the heart's electrical activity and helps to determine the blood flow in the heart as well as heart muscle stress.
- Echocardiogram: It uses sound waves to produce clear images of the heart and helps to identify the damaged heart muscles.
- Stress test: The test involves performing any high intensity activity like treadmill or bicycling under medical supervision, and close monitoring of heart function during the physical activity, to determine if there are any symptoms of CAD.
- Cardiac catheterization and angiogram: A special dye is inserted into the coronary blood vessels using a thin, flexible tube called catheter, which is inserted through a small incision at the groin or an arm to view the blood flow in the heart.
- Heart scan: Computerized tomography (CT) technologies are used to identify the calcium deposits in the blood vessel of the heart, which indicates CAD.
- Quit smoking.
- Avoid processed foods and eat high protein and fiber rich diet.
- Exercise regularly and lose excess weight.
- Manage stress.
- Control diabetes.
The doctor may prescribe medications, which help in reducing the symptoms of CAD, such as:
- Dyslipidemic agents such as statins, niacin, fibrates and bile acid sequestrants a to lower the blood cholesterol levels
- Aspirin, a blood thinner, to prevent blood clots, which might obstruct the coronary arteries
- Beta blockers decrease the heart rate and blood pressure and reduce the oxygen demand of the heart.
- Calcium channel blockers to lower blood pressure
- Ranolazine, an anti-anginal drug, to reduce chest pain
- Nitroglycerin to dilate the coronary arteries and reduce chest pain
- Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) to decrease blood pressure
- Angioplasty and stent placement: It is also called as percutaneous coronary revascularization, and involves inserting a thin, flexible tube (catheter) into the narrowed coronary artery, followed by a wire with deflated balloon to the narrowed area. The balloon is inflated to widen the blood vessel; a stent may also be placed to keep the artery patent.
- Coronary artery bypass surgery: A graft is created using any blood vessel in the body, to bypass the blocked coronary arteries.
To maintain healthy arteries and to prevent coronary artery disease, some measures need to be taken such as lifestyle modifications which includes avoiding smoking and alcohol use, exercising regularly to maintain healthy weight, controlling sugar and cholesterol levels in blood and also eating a healthy diet.