Overview of angina pectoris
Angina pectoris refers to a recurring chest pain or discomfort that happens as a result of myocardial (heart muscle) ischemia (restriction in blood supply) caused by an imbalance between myocardial blood supply and oxygen demand. Angina is a symptom of coronary heart disease (CHD), which occurs when arteries (that carry blood to the heart) become narrowed and blocked due to atherosclerosis (deposition of fat along the walls of arteries).
The American Heart Association (AHA) had estimated (in a 2004 update) that 6.8 million Americans suffer from angina and about 400,000 new patients present with stable angina every year.1 Angina significantly affects more women than men, both in total numbers and as an age-adjusted percentage.1 The chest pain may be provoked by an activity or exercise or any other physical or mental stress, which increases the heart’s demand for blood. Diagnosis and assessment of angina involve clinical assessment, laboratory tests and specific cardiac investigations.
The treatment of angina and CHD has changed significantly over the past few years owing to improvements in surgical and medical modalities of improving blood flow to the myocardium. The optimal treatment plan involves a number of strategies and should be tailored according to patients’ age, presence of concomitant medical disorders, lifestyle, side-effects of the medication and the risks of procedures.2 With proper management, the symptoms can usually be controlled and the prognosis substantially improved.
Types of Angina pectoris
Angina can be classified into three main types as follows.
It is characterized by discomfort that typically occurs in conditions associated with increased myocardial oxygen consumption such as with increased activity or stress. The pain usually begins slowly and worsens over the next few minutes. This pain is mostly relieved with rest and/or treatment but may recur again with further activity or stress. Many patients with stable angina can have a relatively normal life but in some patients, it may progress to unstable angina.
Angina is unstable if the preexisting angina worsens for no obvious reason or when new angina develops at rest or at a relatively low work load. This angina is often associated with rupture of the atherosclerotic plague and subsequent clot formation within the coronary artery. The chest pain in unstable angina may be more severe and prolonged than that of stable angina. Patients with unstable angina are at increased risk of heart attack, severe cardiac arrhythmia and cardiac arrest.
Variant Angina (Prinzmetal’s Angina)
This type develops spontaneously due to spasm of a coronary artery. Variant angina almost always occurs during the periods of rest, usually at night. Many people with variant angina also have severe atherosclerosis in at least one major vessel on the heart. It can also occur in patients with heart valve disease or uncontrolled high blood pressure.
Causes of angina pectoris (Pathophysiology: how angina develops) and Risk Factors
Angina can result from the following:
- Decrease in myocardial blood supply due to increased coronary resistance in large and small coronary arteries as a consequence of the following:
- Presence of substantial atherosclerotic lesion in the large coronary arteries with at least a 50% reduction in arterial diameter.
- Coronary spasm (Prinzmetal’s angina).
- Abnormal constriction of vessels due to vascular disease.
- Systemic inflammatory or collagen vascular disease such as scleroderma, systemic lupus erythematous or polyarteritis nodosa.
- Reduction in the oxygen-carrying capacity of blood as in severe anemia (hemoglobin <8 g/dL).
- Congenital anomalies of the major epicardial coronary arteries.
- Structural abnormalities of the coronary arteries.
Risk factors for angina pectoris
Identifying and treating risk factors for further CHD is a priority in patients with angina.
The following risk factors increase the risk of CHD and angina:
- Tobacco smoking
- High blood pressure
- High blood cholesterol
- Sedentary lifestyle
- Family history of premature heart disease
Symptoms of angina pectoris (Clinical Features)
Evaluation and Diagnosis of angina pectoris
Diagnosis and assessment of angina involve clinical assessment, laboratory tests and specific cardiac investigations.
In the majority of cases, it is possible to make a sure diagnosis based on the history alone, although physical examination and further tests are necessary to confirm the diagnosis and to evaluate the severity of underlying disease.4
The evaluation of patients with chest pain should take into account symptom characteristics and cardiovascular risk factors, as these may indicate the probability of angina and coronary artery disease (CAD).
If the history and physical examination suggest the presence of angina and CAD, patients are further evaluated by noninvasive tests such as exercise treadmill testing or coronary angiography.
- Complete blood count.
- Comprehensive metabolic panel: Includes assessment of the patient’s kidneys, liver, electrolyte, acid/base balance, blood sugar, lipid profile and blood proteins.
- Cardiac biomarkers: These are proteins that are released when myocardium cells are damaged. They help to differentiate angina from a heart attack. If the cardiac biomarkers are normal, then the chest pain is more likely to be due to angina and much less likely due to heart muscle damage.5
The commonly investigated markers include:
- Troponin: A cardiac-specific marker. It will be elevated within a few hours of heart damage and remain elevated for up to 2 weeks.
- CK-MB: A form of the enzyme creatine kinase found mostly in heart muscle and rises, when the heart muscle cells are damaged.
- An electrocardiography (ECG): Evaluates the heart’s electrical activity and rhythm. During chest pain, depression or elevation of the ST segment may be recorded.
- An exercise stress test.
- Echocardiography: Ultrasound imaging of the heart.
- Radionuclide imaging: A radioactive compound injected into the blood to evaluate blood flow. This shows images of narrowed blood vessels around the heart.
- Coronary catheterization: A thin flexible tube is inserted into an artery in the leg and threaded up to the coronary arteries to evaluate blood flow and pressure in the heart and the status of the arteries in the heart.
- Coronary angiography: X-rays of arteries using a radiopaque dye, performed during coronary catheterization.
Management of angina pectoris
The management of angina requires a thorough approach to the patient and his/her family including attention to the emotional aspects of the illness. Comprehensive risk stratification should be conducted with specific attention to the elements of lifestyle that could have contributed to the condition.4
You May Like To Read
1. American Heart Association. Heart Disease and Stroke Statistics - 2004 Update. Dallas, TX: American Heart Association; 2003.
2. Gibbons RJ, Chatterjee K, Daley J, et al. ACC/AHA 2002 guideline update for the management of patients with chronic stable angina: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines 2002.
3. Braunwald E, Zipes DP, Libby P (eds). Heart Disease. A Textbook of Cardiovascular Medicine. 6th edn. Philadelphia, PA: WB Saunders Co, 2001.
4. Fox K, Alonso Garcia MA, Ardissino D, et al. Guidelines on the management of stable angina pectoris: executive summary. The task force on the management of stable angina pectoris of the european society of cardiology. Eur Heart J. 2006; 27: 1341–1381.
5. Alpert JS, ThygesenK, Antman E, et al. Myocardial infarction redefined-a consensus document of The Joint European Society of Cardiology/American College of Cardiology Committee for the redefinition of myocardial infarction. J Am Coll Cadiol. 2000;36: 959–969.
6. Association of Physicians of India. API expert consensus document on management of ischemic heart disease. J Assoc Physicians India. 2006; 54: 469–480.
Written by: healthplus24.com team
Date last updated: December 11, 2014