The risk factors of coronary artery disease can be divided into two main types, as outlined below:

• Unavoidable risk factors :

• • Family history: If you have a close family member who has suffered from coronary artery disease, then you are more likely to develop coronary artery disease.

• • Aging: As you grow older, the quality of your blood vessels will begin to deteriorate.

• • Gender: Men are more likely to develop coronary artery disease than women. However, women who have already reached menopause are at almost equal risk of developing coronary artery disease as men.

• Avoidable risk factors: In a study conducted during the year 2008-2009, researchers monitoring the risk factors of heart disease and coronary artery disease in Thailand found that the condition often develops due to poor lifestyle choices as outlined below.

• • Being overweight or obese: Gaining weight, or having a higher than normal body mass index (BMI), will increase your risk of developing heart disease and coronary artery disease. In Asian countries, healthy individuals should have a BMI of no more than 23kg/m2.

There are a number of symptoms directly caused by being overweight or obese which can significantly increase your chances of developing heart disease or coronary artery disease. Also known as metabolic syndrome or insulin resistance, the condition is usually diagnosed when a patient presents with three of the five following symptoms:

• • (1) Obesity: For women, obesity should be diagnosed when the patient's waist reaches a width of 80 centimeters, while that number is 90 centimeters for men.

• • (2) High blood pressure: If you have a blood pressure level of 130/85 mm Hg or higher.

• • (3) Diabetes and abnormal blood sugar: If you have diabetes or your blood sugar level reaches 110mg/dL or higher after not eating or drinking for eight hours.

• • (4) If your triglyceride count is 150mg or higher after not eating or drinking for 12 or more hours, or if (you are already taking weight loss drugs (also known as diet pills).

• • (5) If your HDL cholesterol level (HDL-C, good or healthy fats) is less than 40 mg in men, or less than 50mg in women.

• High blood pressure: To be diagnosed with high blood pressure, a patient must have a blood pressure of 140/90 mm Hg or higher. High blood pressure causes the lower left ventricle to thicken and become inefficient - a condition also known as hypertrophy. Hypertrophy is a key risk factor for heart disease and coronary artery disease. In terms of diet, studies have shown that eating large amounts of salty foods is another key factor which causes high blood pressure.

• Stress: There are five stress-related factors which are known to increase your chances of developing heart disease and coronary artery disease. These are depression; chronic and unresolved stress; repressed emotions; loneliness and a lack of close relationships, social support and close relatives; and status anxiety.

• High blood sugar level or diabetes: Chronic high blood sugar causes deterioration of the arteries, both large and small, including the coronary arteries. Over time, if you have chronic high blood sugar or diabetes, the cells along the inner walls of your arteries will no longer be able to reproduce efficiently. This causes your arteries to harden and become inefficient, which in turn causes other organs to deteriorate, as well as putting you at greater risk of coronary artery disease.

• High blood lipids (fats): If you have an abnormal level of lipids (fats) in your bloodstream, then your arteries are at a greater risk of becoming clogged. Individuals who are not sick and do not suffer from other health problems related to fat should use the following readings as a guide for protecting themselves against coronary heart disease. Your overall cholesterol level should be less than 200mg/dL; your LDC cholesterol (or bad fats) should be less than 100mg/dL; your HDL cholesterol (good fats) should be more than 40mg/dL in women and more than 50mg/dL in men; and your overall triglycerides count should not exceed 150mg/dL.

• Lack of exercise: Not being physically active and not getting enough exercise makes you 1.5 times more likely to develop heart disease and coronary artery disease.

• Not having enough fruit and vegetables in your diet: Studies have found that most people eat too many sweet, fatty, and high-calorie foods. Not eating enough fruit and vegetables is also a factor which will increase your risk of developing coronary artery disease.

• Smoking: This refers to people who smoke regularly; people who don't smoke but inhale passive smoke from others (second-hand smokers); people who consume smokeless tobacco, such as snuff other chewing tobacco; as well as people who have smoked regularly in the past but have recently quit. Studies have found that smokers are 2.4 times more likely to develop coronary heart disease than non-smokers, due to the high amount of poisonous chemicals contained in cigarettes, such as nicotine, which destroys the inner walls of the arteries; hydrogen cyanide, which causes the blood vessels to harden; and carbon monoxide, which destroys the hemoglobin required to transport oxygen via the red blood cells, causing the body to become starved of oxygen and meaning that the heart has to work harder. Additionally, cigarette smoke causes blood platelets to clump together, meaning that the blood sticks together and develops clots more easily. These different factors can lead to constricted or severely blocked blood vessels.

• A crushing pain in the chest is a typical symptom of coronary heart disease: the pain is severe, and is often likened to a heavy load being placed on top of you, or being squeezed around the chest or underneath the sternum. You may also experience a pain in the neck, jaw, shoulders and arms, especially on your left side, and particularly during exercise, lasting for around 2-3 minutes. When seated, or when taking medication to dilute the blood vessels under the tongue (also known as nitrates), the symptoms should improve.

• You may feel easily tired during physical activity or when exercising. This can take place suddenly and severely in one to two weeks, or it can be a chronic symptom lasting for three weeks or more.

• Fatigue, shortness of breath, difficulty lying on one's side, tightness in the chest, shallow breathing and also a crushing chest pain. These symptoms may appear suddenly or periodically and may last for a long time.

• Fainting, as well as tightness of the chest, which is caused by sudden or severe low blood pressure.

• Unconsciousness or cardiac arrest.

• Together with a physical examination, a review of the patient history should include the history of heart disease in the family, smoking history, diet, exercise, chronic illness, etc. This will help the doctor to know whether the patient is at risk of developing coronary artery disease. 
• Lab investigation and special examination, such as:
  • Electrocardiogram
  • Chest X-ray
  • Cardiac enzyme test
  • Exercise stress test
  • Echocardiogram
  • Computed tomographic angiography
  • Cardiac catheterization or coronary angiogram

• The doctor will offer recommendations of lifestyle and behavior changes that will help you to protect against risk factors, for example, quitting smoking, eating healthily, taking regular exercise, and reducing stress.

• Treatment using medication, such as antiplatelet and anticoagulant medicines, vasodilator medicines, antiarrhythmic medicines and beta blockers, weight loss pills.

• Treating coronary artery disease with angioplasty and stents is a way to expand the coronary artery by using a balloon combined with implant stents to prop up the artery wall.

• Coronary artery bypass surgery / coronary artery bypass grafting

The best way to protect against coronary artery disease is to change your lifestyle and behavior patterns which constitute risk factors, such as:

• Changing your diet: Every individual should eat only enough to meet the physical demands of each day, in order to maintain one's energy balance.

You should eat foods that are low in fat and low in salt. Avoid animal fats, saturated fats, and trans fats. Cut down on sugary drinks and try to eat more and a greater variety of fruits and vegetables. The World Health Organization (WHO) recommends that each person should eat at least 600 grams of fruits and vegetables per day. Avoid salty foods (you should consume no more than 2.4 grams of salt per day, which is no more than a teaspoon of salt, or no more than 1½-2 tablespoons of fish sauce or soy sauce). You should also avoid junk food, fast food, and preserved food.

• Perform regular exercise and be more physically active: Physical activity or exercise can be moderate or slightly more strenuous at your discretion. Your aim is to burn enough energy to increase breathing and raise your heart rate above its normal level. Try exercising continuously for ten minutes or more per session. This could even just mean taking a walk around the office at work, doing some house work, cooking, carrying light objects, performing work-related activities, walking as part of your daily routine, or other activities during your spare time.

• Quit smoking: Studies have shown that when you stop smoking for 20 minutes, your blood pressure falls to a normal level. After quitting smoking for at least 10 years, a former smoker will have a similar risk of developing heart disease and coronary artery disease as non-smokers. And after quitting smoking for more than 15 years, a former smoker will be only as likely as a non-smoker to develop heart disease and coronary artery disease.

• Reduce stress: The best way to manage stress is by doing things you enjoy, such as exercise, yoga, or meditation. You should also strive to have healthy relations with your family members and others in your workplace or community.