Angina is chest discomfort or pain, usually symptomatic of underlying coronary heart disease (CHD). CHD is the blockage of blood flow through the coronary arteries (i.e. blood vessels that supply oxygenated blood to the heart muscles). Blockage occurs commonly due to deposition of fatty plaques in arteries, also known as atherosclerosis. As a result, the narrowing of coronary arteries restricts blood flow and oxygen to the heart muscles, causing angina.
Angina can also occur due to spasms in the coronary artery walls, which likewise limit oxygenated blood flow to heart muscles.
According to the WHO, there are about 54 million people affected by angina in the world. Among them, 16 million people are from South Asia. A research study found that South Asians have a higher incidence of angina compared to the Caucasian population.
Risk factors
- High blood pressure
- High blood cholesterol
- Smoking
- Diabetes
- Sedentary lifestyle
- Family history of heart attack
- Unhealthy diet
- Obesity
- Old age
- Stress
Types of angina
Stable angina: It is the most common type of angina. It occurs on exertion or when you perform moderate physical activity, as your heart requires more oxygen supply during such times, yet the obstruction impedes oxygenated blood flow to the heart muscle. This type of angina is relieved by rest or medication.
Unstable angina: In unstable angina, fatty plaques in coronary arteries rupture and form blood clots; these obstruct blood flow to the heart and manifest as chest pain. This chest pain occurs even while resting and may not be relieved with medication. If blood flow does not improve, the heart muscle is starved of oxygen and a heart attack ensues. It is a medical emergency.
Prinzmetal angina: It is also known as variant angina. It is caused by the spasmodic contraction of blood vessels supplying your heart muscles. A patient may awaken at night with chest pain and shortness of breath. Some factors that trigger the onset of Prinzmetal angina include cocaine intake, emotional stress, and smoking.
What does angina feel like?
Angina is chest pain that may radiate to the neck and left arm. A patient generally uses the following terms to describe their chest discomfort: squeezing sensation, an elephant sitting on the chest, a band compressing the chest or a pressure-like feeling. Other symptoms include heart racing, sweating, dizziness, nausea, and difficulty breathing.
What to do if you have anginal symptoms?
- Stop the activity that you are doing.
- Call an ambulance and immediately go to an emergency department
- If aspirin is available to you and you have no known allergy to it, then you can chew one aspirin tablet whilst waiting for medical attention. If you have been prescribed Glyceryl Trinitrate (GTN) tablets due to underlying CHD, put one under your tongue every 5 minutes until you get relief or the ambulance arrives.
Conditions mimicking angina
Gastroesophageal reflux disease (GERD): It is the reflux of acid and gastric enzymes from your stomach into the esophagus that irritates the lining of the esophagus.
Aortic dissection: It is a tear in the wall of the aorta. Aorta is the largest artery in the body originating from the left ventricle of the heart.
Aortic stenosis: It is the narrowing of the mouth of the aorta.
Pericarditis: It is an inflammation of the outer layer covering the heart.
Diagnosis
Physicians will take a detailed history and do a physical exam. Then they may order the following tests:
- Electrocardiogram (ECG): It is an electrical recording of the activities of the heart which can detect if there is an obstruction of blood supply and it also helps to assess the site of obstruction.
- Cardiac enzymes: Cardiac enzymes like CK-MB, troponin, and LDH are released into the blood after the death of the heart muscles. In angina, heart muscles are not dead, so these enzymes should not be present. If these enzymes are detected in blood, it tells that the patient has a heart attack.
- Chest X-Ray: A chest X-ray is done to rule other causes of chest pain and to detect if there is an enlargement of the heart.
- Echocardiography: It uses sound waves to take images of the heart. Decreased blood supply can cause decreased contractility of heart muscles which is detected in echocardiography.
- Stress test: ECG and echocardiography are done while a patient is exercising. If the patient can not exercise, then a drug is injected into the blood vessel to make the heart work harder, and then ECG or echocardiography is done.
- Coronary angiography: It evaluates the degree of blood flow obstruction in your coronary arteries by injecting a dye into a peripheral blood vessel.
Management
Lifestyle modifications
- Weight loss
- Exercising regularly
- Maintaining a healthy diet , avoiding fatty foods
- Quitting smoking and drinking
Treatment
- Nitrates: Nitrates dilate the vena cava, i.e the largest blood vessel of the body which brings impure blood from different parts of the body to the heart. This results in blood pooling into the vena cava and less blood reaching the heart. As less blood is poured into the heart chambers, the load on the heart is reduced and the heart requires less oxygen to function.
- Aspirin: Aspirin interferes with the aggregation of platelets and formation of blood clots, thus preventing obstruction of your coronary arteries.
- Beta-blockers: These depress the contractility of the heart muscle. Since heart contraction requires oxygen supply, decreased contractility decreases oxygen requirement and thus helps to relieve chest pain.
- Anti-platelet drugs like clopidogrel, prasugrel, and ticagrelor: These drugs inhibit clumping of platelets because platelet clumping form clots that obstruct the coronary arteries.
- Calcium channel blockers: This group of drugs inhibit the contraction of smooth muscles of blood vessels and widen its lumen.
- Blood pressure-lowering medications: If a patient has high blood pressure, he is advised to continue his blood pressure medications. Drugs like Angiotensin-converting enzyme inhibitors (ACE inhibitors) and Angiotensin receptor blocker (ARBs) are used to lower blood pressure.
- Ranolazine: It inhibits current flow in heart cells and decreases the oxygen demand.
- Coronary angioplasty and stenting: This procedure is also called percutaneous coronary angioplasty (PCI). A stent is placed inside the coronary artery to open up the narrowed blood vessel.
- Coronary artery bypass graft surgery CABG): It is a surgical procedure where a blood vessel from another part of the body is utilized for bypassing the obstruction of the coronary vessels. It is performed by a cardiothoracic surgeon. It is done if a patient does not respond to the above treatment modalities or if a patient has a severe blockage in multiple blood vessels of the heart.
Long Term Outlook Of Angina
Angina increases the risk of having a heart attack. Therefore, it is advised that patients adopt a healthy lifestyle and adhere to medications and the physician’s advice.
