Angina: Causes, Symptoms, Diagnosis, and Treatment

A disease marked by brief sudden attacks of chest pain or discomfort caused by deficient oxygenation of the heart muscles secondary to impaired blood flow to the heart. An estimated 10 million people in the US suffer from angina. According to the Framingham heart study, an estimated 500,000 new cases of stable angina occur every year.

Angina results when there is an imbalance between the demand and supply of oxygen. This imbalance occurs when there is an increase in demand (e.g., during exercise) without a proportional increase in supply (e.g., obstruction or atherosclerosis of the coronary arteries). Non-obstructive coronary disease is more common in females.

It is presented as paroxysmal pain in the substernal or precordial region of the chest which is aggravated by an increase in the demand of the heart and relieved by a decrease in the work of the heart. The pain radiates to the left arm, neck, jaw, or right arm. It is more common in Men in the past 5th decade of life.

Angina: Types

Angina can be of the following types −

• Stable angina – Stable angina is the most common type. Predictable & consistent pain that occurs on exertion and lasts for 5-10 min. It occurs when the heart is working harder than usual. It has a regular pattern. The pain usually goes away a few minutes after taking rest or medicine. It suggests that a heart attack is more likely to happen in the future.

• Unstable angina –  Unstable angina doesn't follow a pattern. Pain occurs more frequently & lasts longer than 20min. It may occur more frequently and be more severe than stable angina, it can occur with or without physical exertion, and may not be relieved by rest or medicine. It is very dangerous and requires emergency treatment. This type of angina is an indication that a heart attack may happen soon.

• Variant / prinzmetal angina – Pain occurs at rest with reversible ST-segment elevation. It occurs due to a spasm in a coronary artery. Variant angina usually occurs at rest, and the pain can be severe. It usually happens between midnight and early morning. Medicine might relieve this type of angina. It occurs commonly in younger women.

• Silent ischemia – Ischemia that occurs in absence of any symptoms.

Angina: Symptoms

The patients suffering from Angina present with the following cardiovascular and respiratory symptoms −

Cardiovascular Symptoms

• Angina pectoris – Patients with angina complain of chest discomfort/pressure rather than actual pain. The discomfort is described as a pressure, heaviness, tightness, squeezing, burning, or choking sensation. Anginal pains are also experienced in the epigastrium (upper central abdomen), back, neck area, jaw, or shoulders (referred pain). Angina is typically precipitated by exertion or emotional stress, a full stomach, and cold temperatures. Breathlessness, sweating, and nausea occur in some cases. Low cardiac output.

• Decrease pulse rate, Diaphoresis – Excessive sweating.

• Chest pain – Chest pain occurs suddenly and severely immobilizing the chest, not relieved by rest, position change, and medications.

• Ischemia – Ischemia is a restriction in blood supply to tissues, causing a shortage of oxygen that is needed for cellular metabolism. BP may be elevated (sympathetic stimulation) or decreased BP (decreased contractility or cardiogenic shock).

• Myocardial infarction – When the blood supply decreases or stops to a part of the heart, causing damage to the myocardium.

• ECG changes – ST segment and T wave changes, also show tachycardia, bradycardia, or dysrhythmias.

Respiratory Symptoms

• Fatigue

• Dyspnea, the difficulty of breathing

• Chest heaviness

• Pulmonary edema

• Shortness of breath

Other symptoms of Angina include gastrointestinal problems such as Nausea and Vomiting. The skin becomes cool, clammy, diaphoretic, and pale.

The complications of Angina include abnormal heart rhythm (arrhythmia) and heart failure.

Angina: Risk Factors

The following are the risk factors of Angina −

• High blood pressure

• Diabetes

• Older age

• Family history of heart disease

• Stress

• Obesity

• Lack of exercise

• High blood cholesterol or triglyceride levels

• Tobacco use

• Large meals

• Vigorous physical workouts

• Extremely hot or cold weather

• Atherosclerosis, MI

Angina: Diagnosis

Angina can be diagnosed either by physical examination or tests −

Physical examination

• Angina should be suspected in patients presenting with tight, dull, or heavy chest discomfort, retrosternal or left-sided, radiating to the left arm, neck, jaw, or back.

• Aggravated by exertion or emotional stress and relieved within several minutes of rest.

• Atypical symptoms include breathlessness, nausea, epigastric discomfort, or burning. Atypical symptoms are common in older people, women, and diabetics.

• Pain not relieved by antacids and simple analgesics 

• Stress test – An exercise ECG test ("treadmill test") may be performed, during which the patient exercises to his/her maximum ability before being intervened by fatigue, breathlessness, or pain. if characteristic ecg changes are observed (more than 1 mm of flat or downsloping ST depression), the test is considered diagnostic for angina.

Tests

• Chest X-ray

• Electrocardiogram (ECG)

• Echocardiogram

• Cardiac catheterization (angiogram)

• C-reactive protein test-the cardiac marker for inflammation of vascular endothelium

• Troponin level

Angina: Treatment

The main goals of treatment in angina pectoris are relief of symptoms, slowing progression of the disease, and reduction of future complications, especially heart attacks, and death. 

Medical Management

• Sublingual Nitrates – Nitroglycerin/ glyceryl trinitrate(GTN), Pentaerythritol tetranitrate, Isosorbide dinitrate, and Isosorbide mononitrate, release nitric oxide. Nitrates are mainly venodilators and also cause arteriolar dilation and as a result reduce both preload and afterload. They cause a rapid reduction in myocardial oxygen demand, resulting in rapid relief of symptoms. The common side effect of nitrates is a headache. High doses can also cause postural hypotension, facial flushing, and tachycardia.

• Beta-adrenergic blockers – Metoprolol, Carvedilol, etc. These drugs improve the blood flow. They are used in the prophylaxis of exertional angina as they reduce the myocardial oxygen demand below the level that would provoke an angina attack.

• ACE – Famipril , captopril, etc.

• Calcium channel blockers – Amlodipine, Nifedipine, Verapamil, etc.

• Nifedipine – Functions mainly as an arteriolar vasodilator. This drug has minimal effect on cardiac conduction or heart rate. The vasodilation effect of nifedipine is useful in the treatment of variant angina. Nifedipine is given as extended-release tablets It can produce side effects such as flushing, headache, hypotension, and peripheral edema.

• Anticoagulants – Heparin, Enoxaparin, etc.

• Thrombolytic agent – Urokinase, Streptokinase, etc.

• Antiplatelet – Clopidogrel, Aspirin, etc. Aspirin and other anti-platelet medications reduce the ability of blood to clot, making it easier for blood to flow through narrowed heart arteries.

Surgical Management

• Angioplasty – A thin tube with a balloon or other device on the end is threaded through a blood vessel to the narrowed or blocked coronary artery. Once in place, the balloon is inflated to push the plaque outward against the wall of the artery. opens blocked or narrowed coronary arteries and restores blood flow.

• CABG – Healthy arteries or veins taken from other areas in your body are used to bypass (that is, go around) your narrowed coronary arteries. Bypass surgery can improve blood flow to the heart, relieve chest pain, and possibly prevent a heart attack. 

Angina: Prevention

Following are the measures to prevent Angina −

• Stop smoking

• Get treatment for conditions that can increase the risk of angina, such as diabetes, high blood pressure, and high blood cholesterol

• Eating a healthy diet with limited amounts of saturated fat, trans fat, salt, and sugar.

• Stress management

• Physical activity

Conclusion

Typical angina pectoris is characterized by retrosternal complaints that are provoked by exertion, cold, emotional stress, or heavy meals and relieved by Sublingual nitrate therapy is used for the short-term control of angina. Ecg gives confirmation.

If more than 2 attacks occur per week, a maintenance treatment consisting of beta-blockers, nitrates, or calcium channel blockers should be started in this order of preference. Lifestyle advice should be given, such as smoking cessation, sufficient physical exercise, and a healthy diet.