Stable angina is a condition characterized by the pain/discomfort in the chest due to the decreased blood supply to the heart muscle that occurs with exertion.
Ischemic heart disease (coronary artery disease) is a common, widespread disorder usually caused by atherosclerosis. Stable angina is a chronic form of ischemic heart disease which occurs due to obstruction of the coronary arteries by atheromatous plaque and transient myocardial ischemia when the heart muscle doesn’t receive enough blood and the tissues suffer from the decreased oxygen supply. Typically stable angina occurs in men over 50 years and women older than 60. The disease interferes with everyday activities of the person and may gradually lead to unstable angina and myocardial infarction – potentially life-threatening conditions.
Stable angina develops when the coronary arteries are narrowed up to 50-70% due to atheromatous plaques. Episodes of stable angina are caused by exertion (exercises, sexual activity or hurrying), emotions (such as stress, anger or fright), exposure to cold temperatures, consumption of carbohydrate-rich meals, all of these situations provoke the vasoconstriction, spasm of the arteries, which reduces the blood flow to the heart muscle even more and the myocardium suffers from hypoxia and, therefore, the pain occurs. Episodes of pain may also occur at rest when the arteries are too narrow to provide the heart muscle with the required amount of oxygen. Sometimes angina may develop even when the arteries are not blocked – in case of cardiomyopathy, heart valve disease, uncontrolled arterial hypertension, etc.
Risk factors for stable angina include both modifiable (which may be controlled) and non-modifiable factors:
- Non-modifiable factors:
- Age: increased age is associated with greater risk of ischemic heart disease;
- Sex: males are predisposed to ischemic heart disease, although in females the risk increases after menopause;
- Family history of coronary artery disease, myocardial infarction;
- Modifiable factors:
- Overweight and obesity;
- High blood cholesterol and triglycerides;
- High blood pressure;
- Diabetes mellitus type 2 and glucose intolerance;
- Sedentary lifestyle, lack of physical activity;
- Overeating and unhealthy diet;
Angina pectoris classes
According to the limitation of everyday activity caused by chronic angina the disease is classified into 4 functional classes:
- Class I – the pain doesn’t occur with ordinary activity or exertion;
- Class II – pain occurs with moderate exertion;
- Class III – mild exertion causes an episode of angina;
- Class IV – angina pain develops at rest of is provoked by minimal activity;
Stable angina presents as episodes of chest discomfort which is usually described as a sensation of tightness, pressure, heaviness, aching, burning, squeezing or chocking and is provoked by exertion, stress, cold temperatures or may occur at rest. A person holds the clenched fist or hands over the chest while describing the pain. The ischemic cardiac pain irradiates to the left arm and shoulder, the lower jaw, less commonly – to the neck, right arm, back, and upper abdomen. The discomfort/pain typically lasts 2 to 5 minutes and relieves by slowing or ceasing activities and the administration of nitroglycerin. The typical episode of angina pectoris develops gradually and reaches its maximum intensity over a period of minutes, rest and nitroglycerin use effectively relieve the pain.
Other symptoms of the disease include the following:
- Malaise, weakness;
- Epigastric pain, belching;
- Confusion, lightheadedness, and syncope;
- Shortness of breath (dyspnea);
- Profuse sweating;
- Tachycardia, arrhythmia;
To evaluate the disease a resting electrocardiogram (ECG) should be obtained. Holter (24 hours monitoring) ECG is performed to monitor myocardial ischemia during daily activities. Exercise treadmill ECG is used to assess the symptoms of the disease in correlation with the ECG changes. Coronary angiography is the mainstay of invasive testing used to visualize the blocked arteries and estimate the lesion severity.
It is recommended to lose weight and adhere to a healthy diet with low content of saturated and trans fats and higher contents of poly- and monounsaturated fats. Physical activity is also necessary for the heart muscle.
Medications are used to both prevent and abrupt the episode of angina chest pain by the means of vasodilatation, which improves blood supply to the muscle and decreased oxygen demand.
Angioplasty is a procedure during which a tiny stent is inserted into the obstructed artery. This helps to widen the artery and renew the blood supply to the heart muscle. The coronary artery bypass graft is required when one or several of the main arteries are severely obstructed. The procedure is performed during open-heart surgery.
- Aspirin (at a dose of 75-325 mg once a day) significantly reduces the risk of myocardial infarction and prevents the progression of angina;
- Nitrates (nitroglycerin, isosorbide dinitrate, isosorbide mononitrate) effectively relieve the pain and abort the episode of angina providing smooth-muscle relaxation, peripheral and coronary artery dilatation mediated by nitric oxide and cyclic guanosine monophosphate. Oxygen supply is improved whilst oxygen demand decreases;
- Beta-blockers (metoprolol, bisoprolol, propranolol) have antiischemic properties due to their ability to reduce oxygen demand by reducing the heart muscle contractions;
- Calcium-channel blockers (verapamil, nifedipine, amlodipine) cause vasodilatation and improve the blood supply to the myocardium and at the meantime decrease the oxygen consumption;
- Statins (rosuvastatin, atorvastatin) help to control the total cholesterol and low-density cholesterol, which are involved in atherogenesis (formation of the atheromatous plaques). Long-term intake of statins reduces the risk of future cardiovascular events and prevents myocardial infarction.