Angina can be defined as pain, muscle fatigue, or tighteningfelt in the chest region (at or around the heart). The discomfort results mainly from low oxygen supply to the heart tissue which is caused by narrowing or obstruction of coronary vessels. Angina is not a disease, but a symptom of cardio vascular illness that may prove life threatening if no action is taken.

The primary pathophysiological event in angina is the vascular obstruction of coronary vessels because of several reasons, such as vascular degeneration, advanced atherosclerosis, thrombosis, embolism, low oxygen content of the blood or anemia. In untreated or poorly managed cases, risk of severe complications increases, such as heart attack or myocardial infarction, necrosis of blood vessels or even death.

Symptoms of Angina

Chest pain is the most common symptom of angina, but that pain sensation may be different for different people. Some people may experience a burning sensation in the chest, while others may only have slight discomfort or heaviness. Some also complain about feeling fullness in the chest along with a squeezing sensation.

There may also be pain behind your breastbone, which may spread to your arms, shoulders, throat, neck, back, or jaw. Some people do not take this pain seriously and often blame it on heartburn or gas. However, it is a good idea to seek medical assistance if you have a burning sensation in the chest along with pain or discomfort in your neck, jaw, belly, back, or shoulders. Seek immediate medical attention if you experience dizziness or shortness of breath.

Types of Angina

1. Stable Angina

Stable angina is the chest pain felt after excessive physical activity or in any situation when your heart is working harder than it should be (such as after exercise). This type of pain is chronic in nature and is usually predictable. The pain may last up to five minutes or a little more, depending on the nature of interventions employed to manage angina. Your doctor may prescribe an angina medicine or suggest you to limit the intensity of physical activity in order to alleviate chest pain.

2. Unstable Angina

This kind of angina usually occurs before heart attack or stable angina. Unstable angina does not follow the route of a regular angina and is not related with heavy physical exercising. It does not succumb after rest or with medication, and the pain can last up to half an hour in duration. Such angina is more serious in nature than stable angina and are directly associated with a higher risk of cardiac damage.

3. Prinzmetal's Angina

It is the most uncommon variety of angina that presents with most serious symptoms and complications. It may happen when you are rest.

Here is a video link explaining the types of angina with more details:

Causes of Angina

The primary cause of angina is reduced or no blood flow toward the heart. Cardiac muscles are nourished by coronary arteries that are responsible for carrying oxygen rich blood toward the heart. If any blockage occurs in these arteries, your heart tends to underperform its primary function. When you perform physical work, you heart is burdened and pain of angina is felt. This also explains why many people do not feel chest pain when they rest.

Here are some of the causes of different types of angina.

Risk Factors of Angina

• Smoking: Smoking causes irregular fat deposition in the interior walls of the arteries, leading to advanced atherosclerosis. Therefore, individuals who are chronic or chain smokers have great possibility to experience angina in later stages of their life. People who are exposed to passive smoking are also at a risk.

• Diabetes: Diabetes is the inability of a person to secrete insulin, leaving large amounts of unconverted glucose in the blood. This can lead to irregular deposition of fats in the walls of artery over time, predisposing the person to angina and stroke.

• Hypertension: When people are constantly under high pressure, they have higher risk of vascular damage over time. In the healing process of vessel, large collagen and fat deposits can occur, which will become hardened over time. This can further result in obstruction to blood flow, leading to angina.

• Unhealthy Cholesterol Level: Cholesterol is an element that can narrow arteries. Low density lipid (LDL), a kind of high level cholesterol, is typically classified as bad lipids, because of its tendency to accumulate and clog small arteries. This eventually leaves part of heart hypoxic.

• Genetics: Coronary heart diseases have the tendency to be carried genetically within family members, so care must be taken in diet and lifestyle by people who are genetically predisposed to the problems.

• Older People: Elderly population is at much higher risk of developing degenerative changes in the organs, because arteries at that time become weak, stiff and narrow. Any significant changes in the biochemical or physical environment of the body can further aggravate the risk of angina.

• Obesity: Obesity is directly associated with elevated blood cholesterol levels and directly promotes the formation of plaques in combination with collagen and salt, which will stick in small arterioleslater. This can cause direct blockade of blood supply, which can cause heart attack or angina.

Treatment for Angina

In case of stable angina, you start to feel better after some rest. However, unstable angina may get worse with time and often requires surgery. Your doctor usually begins treatment by administering certain medications that help open up blocked arteries. Lifestyle changes may also help to improve blood flow to heart and manage the symptoms.

1. Medications

• Nitrates: Nitrates dilate blood vessels, which greatly increases the available space or volume for the passage of blood.
• Clot-reducing drugs: Drugs, such as aspirin and ticagrelor, are suggested for long-term management of angina patients. These drugs prevent aggregation of blood platelets and increase the flow of blood in narrow vessels.
• Cholesterol-lowering drugs: Drugs like statins have function to block the compounds that make cholesterol. Patients who are in need of long-term management of cholesterol should consider statins. Statins also block absorption of cholesterol from intestines and help in reducing body cholesterol levels greatly.
• Blockers: Beta-blockers and calcium channel blockers dilate blood vessels and increase the blood flow towards the heart.

2. Lifestyle Changes

Certain lifestyle changes can prevent angina attacks and any further complication associated with it. These include exercising regularly, keeping healthy and natural dietary habits, such as keeping diet low in cholesterol and salt and high in antioxidants. Keeping a tab on cholesterol levels and living a life free from stress, smoking and alcohol can minimize the risk of angina greatly.

3. Surgery

If medications fail to produce desired results, your doctor may suggest a medical procedure or surgery. They may suggest the following procedures:

• Angioplasty/Stenting: The procedure involves threading a tiny tube, which has a balloon inside it, through one of your blood vessels. It goes straight to your heart, and once there, your doctor inflates the balloon to help widen your narrowed artery to restore blood flow. A stent, which is a small tube made of metal, is left inside the artery to ensure that it stays open. Your doctor may decide to use a stent that contains medicine to help prevent any blockage within the artery. The whole procedure usually takes about 2 hours.
• Coronary Artery Bypass Grafting (CABG): Also called bypass surgery, the procedure involves taking healthy veins or arteries from another body part and using them to go around your narrowed or blocked blood vessels. You usually need to stay in the hospital for about a week or even longer in some cases. You will have to stay in the intensive care unit for a day or so to ensure that your blood pressure, heart rate, and oxygen levels do not fluctuate after the procedure.