• Stable angina - Stable angina is the most common form of angina. It usually happens during activity (exertion) and goes away with rest. For example, pain that comes on when you're walking uphill.

Stable angina pain is predictable and usually similar to previous episodes of chest pain. The chest pain typically lasts a short time, perhaps five minutes or less.

• Unstable angina – This isunpredictable chest pain and occurs at rest. Or the angina pain is worsening and occurs with less physical effort. It's typically severe and lasts longer than stable angina, maybe 20 minutes or longer. The pain doesn't go away with rest or the usual angina medications. If the blood flow doesn't improve, the heart is starved of oxygen and a heart attack occurs. Unstable angina is dangerous and requires emergency treatment.
• NSTEMI (Non ST Segment Elevation Myocardial infarction) this is a partial blockage of any part of the coronary.
• STEMI (St Elevation myocardial infarction). This is the last stage and total blockage of any part of the coronary artery and this result to the death of the patient. 

Coronary artery disease starts when fats, cholesterols and other substances collect on the inner walls of the heart arteries. This condition is called atherosclerosis. The buildup is called plaque. Plaque can cause the arteries to narrow, blocking blood flow. The plaque can also burst, followed by bleeding and eventually leading to formation of a blood clot which results in heart attack.

Besides high cholesterol, damage to the coronary arteries may be caused by:

• Diabetes or insulin resistance
• High blood pressure
• Not getting enough exercise (sedentary lifestyle)
• Smoking or tobacco use

Coronary artery disease risk factors include:

• Age. Getting older 50 years and above increases the risk of damaged and narrowed arteries.
• Sex. Men are generally at greater risk of coronary artery disease. However, the risk for women increases after menopause.
• Family history. A family history of heart disease makes you more likely to get coronary artery disease. This is especially true if a close relative (parent, sibling) developed heart disease at an early age. The risk is highest if your father or a brother had heart disease before age 55 or if your mother or a sister developed it before age 65.
• Tobacco smoking. People who smoke have a significantly increased risk of heart disease. Breathing in secondhand smoke also increases the risk as well.
• High blood pressure. Uncontrolled high blood pressure can make arteries hard and stiff (arterial stiffness). The coronary arteries may become narrow, slowing blood flow.
• High cholesterol. Too much bad cholesterol in the blood can increase the risk of atherosclerosis.
• Diabetes. Diabetes increases the risk of coronary artery disease. Type 2 diabetes and coronary artery disease share some risk factors, such as obesity and high blood pressure.
• Overweight or obesity. Excess body weight is bad for overall health. Obesity can lead to type 2 diabetes and high blood pressure. Ask your health care provider what a healthy weight is for you.
• Chronic kidney disease. Having long-term kidney disease increases the risk of coronary artery disease.
• Not getting enough exercise. Physical activity is important for good health. A lack of exercise (sedentary lifestyle) is linked to coronary artery disease and some of its risk factors.
• A lot of stress. Emotional stress may damage the arteries and worsen other risk factors for coronary artery disease.
• Unhealthy diet. Eating foods with a lot of saturated fat, trans fat, salt and sugar can increase the risk of coronary artery disease.
• Alcohol use. Heavy alcohol use can lead to heart muscle damage. It can also worsen other risk factors of coronary artery disease.
• Amount of sleep. Too little and too much sleep have both been linked to an increased risk of heart disease.

The chest pain that occurs with angina can make doing some activities, such as walking, uncomfortable. However, the most dangerous complication is a heart attack.

• Quit smoking.
• Control high blood pressure, high cholesterol and diabetes.
• Exercise regularly.
• Maintain a healthy weight.
• Eat a low-fat, low-salt diet that's rich in fruits, vegetables and whole grains.
• Reduce and manage stress.

Test to help diagnose or monitor coronary artery disease include:

• Electrocardiogram (ECG or EKG). This quick and painless test measures the electrical activity of the heart. It can show how fast or slow the heart is beating. Your provider can look at signal patterns to determine if you're having or had a heart attack.

• This test uses sound waves to create pictures of the beating heart. An echocardiogram can show how blood moves through the heart and heart valves.

Parts of the heart that move weakly may be caused by a lack of oxygen or a heart attack. This may be a sign of coronary artery disease or other conditions.

• Exercise stress test. If signs and symptoms occur most often during exercise, your provider may ask you to walk on a treadmill or ride a stationary bike during an ECG. If an echocardiogram is done while you do these exercises, the test is called a stress echo. If you can't exercise, you might be given medications that stimulate the heart like exercise does.

• Cardiac catheterization and angiogram. During cardiac catheterization, a heart doctor (cardiologist) gently inserts a flexible tube (catheter) into a blood vessel, usually in the wrist or groin. The catheter is gently guided to the heart. X-rays help guide it. Dye flows through the catheter. The dye helps blood vessels show up better on the images and outlines any blockages.

If you have an artery blockage that needs treatment, a balloon on the tip of the catheter can be inflated to open the artery. A mesh tube (stent) is typically used to keep the artery open.

• Lipid Profile Test - A lipid panel is a blood test that measures the amount of certain fat molecules called lipids in your blood.

Having too many lipids (cholesterol and triglycerides) in your blood can lead to buildup in your blood vessels and arteries, which can cause damage and increase your risk of cardiovascular problems. People who have too much cholesterol are at risk of cardiovascular diseases like heart disease, heart attack (myocardial infarction) and stroke.

• Cardiac enzymes (cardiac biomarkers) your heart releases cardiac enzymes (cardiac biomarkers) when there’s heart damage or stress due to low oxygen. Troponin and creatinine phosphokinase (CPK) levels rise after a heart attack. Elevated heart enzyme levels can also indicate acute coronary syndrome or ischemia.