Angina or angina pectoris is chest pain which occurs due to a reduced blood flow to the muscles of the heart. This decreases oxygen supply and creates more pressure on the muscles while pumping blood. This condition is also called ischaemic chest pain.
Angina is not a disease but a symptom of an underlying heart disease. It serves as a warning for a future heart attack. Patients describe the pain as a heaviness or squeezing of the chest. Women may feel it as a stabbing pain more than pressure.
Pain may also be felt over the neck, lower jaw, and back. This may be accompanied by sweating, nausea, and breathlessness.
Types and symptoms
Stable angina: Chest pain develops due to an activity like walking up the stairs or lifting something heavy. The pain is relieved when the activity ceases. This condition is referred to as stable angina. It is quite common and although pain is recurrent, it lasts only for a few minutes. It can be managed with medication.
Unstable angina: This is quite lethal as the pain starts without any exertion. It can last for more than a few minutes and cannot be managed by medication. If it is not treated quickly, it can lead to a heart attack. It is classified as a medical emergency.
Variant angina: This condition is due to spasms in the coronary arteries where there is a temporary reduction in blood flow. Pain is severe and it is recurrent. It can be managed with medication.
Microvascular angina: Caused by defects in smaller coronary vessels called arterioles, it is seen more often in women than in men.
How and why it occurs
Anginal pain occurs when blood vessels supplying oxygen to the heart muscles become narrow and damaged, a condition called atherosclerosis. Smooth and adequate blood flow is blocked as a result. This can arise due to excess cholesterol leading to deposits (plaque) along the inner lining of vessels. Vessels can also lose their elasticity due to effects of chronic smoking. Other risk factors include:
- High blood pressure
- Family history of heart disease
- Metabolic syndrome
- Usually an electrocardiogram (ECG) test is done to determine the cause of the pain.
- Stress tests can show how the heart works during physical activity and diagnose coronary artery disease.
- Blood tests are done to determine if the damaged heart muscles have released proteins called troponins into blood. The higher the troponin levels, the greater is the muscle damage. Cholesterol and triglyceride levels are also determined to see if they are the risk factors.
- Chest X-rays can be used to rule out other problems.
- Computerised tomography (CT) scans and magnetic resonance imaging (MRI) help to diagnose the exact condition of the heart.
- Cardiac catheterisation: A thin tube inserted into an artery can determine the flow and the pressure of blood pumped from the heart. Dyes may be injected during this procedure to provide a clear image of blocked vessels.
Medication: The following medicines are advised for management of angina:
- First line is the nitro-glycerine by-products (sub-lingually) – NTG are the products that dilate the blood vessels, enhancing blood flow to the heart.
- Calcium channel blockers act by relaxing muscle cells in the arterial walls and thus increase the blood flow by widening the vessels.
- Beta-blockers act by blocking the effects of adrenaline to decrease the heart rate, and force required to pump blood.
- Aspirin and other blood-thinners to prevent clotting of blood. These are prescribed for long-term use and should never be missed.
- Statins to reduce cholesterol and to try to reabsorb the cholesterol that is built up within the arteries.
Surgical intervention is sometimes indicated along with medicines.
- Angioplasty: A thin tube is inserted into an artery in the thigh and manipulated till it reaches the blocked vessel. It is then inflated like a balloon to widen the blocked passage. A bio-compatible stent is placed at the site to maintain proper width. It may also be coated with medication that is periodically released to prevent blockage.
- Coronary artery bypass graft (CABG): Coronary Artery Bypass Graft (CABG) in which a blood vessel from another part of the body (chest, leg, or arms) is grafted below and above the blockage area of the coronary artery to divert the blood flow and improve blood supply to the heart. It is done when there are several blockages in the artery or there are many branches coming off from the blocked artery.