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Guidelines for Pharmacological Management of
Chronic Stable Angina Pectoris
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| Angina
pectoris |
The term ‘angina pectoris’ is used for chest discomfort due
to myocardial ischaemia associated with coronary artery disease. Angina
pectoris occurs when there is an imbalance between myocardial perfusion
and the demands of the myocardium. This almost always occurs as a result
of narrowing of the coronary arteries due to atherosclerosis. Usually,
a coronary artery must be narrowed by at least 50-70% in luminal diameter
before blood flow is inadequate to meet the metabolic demands of the heart
with exercise or stress.
Anginal symptoms are regarded as stable if they have
been occurring over several weeks without major deterioration. They typically
occur in conditions associated with increased myocardial oxygen consumption
(e.g. during exercise).
Angina is said to be unstable if pre-existing angina
worsens abruptly for no apparent reason or when new angina develops at
a relatively low work load or at rest. This form of angina is often associated
with rupture of the atherosclerotic plaque and subsequent clot formation
within the coronary artery.
Angina is variant or of the Prinzmetal
type if it develops spontaneously with ST elevation on the electrocardiogram.
This is usually due to an increase in coronary tone or spasm.
This booklet outlines the guidelines for the pharmacological management
of chronic stable angina pectoris.
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| Risk
factors for angina pectoris |
Non-modifiable
- Age
- Male gender
- Family history of coronary
heart disease
Modifiable
- Smoking
- High intake of alcohol
- Hyperlipidaemia
- Hypertension
- Diabetes
- Stress
- Obesity
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| Symptoms |
Anginal symptoms have four cardinal features:
a) Location
Discomfort is typically
located in the retrosternal region (central chest region) and may radiate
to both sides of the chest and the arms (more commonly the left) as far
as the wrist, and to the neck and jaw. Quite frequently, the pain starts
in one of the other areas and only later spreads to the central chest.
b) Relationship to exercise
Angina is provoked
by exercise (or other stress) and is quickly relieved by rest. Emotions
may also cause angina.
c) Character
Feeling of pressure
or a strangling sensation in the chest. The intensity may vary from
a slight localised discomfort to severe pain.
d) Duration
Symptoms usually spontaneously
resolve within 1-3 minutes after discontinuation of exercise but may
last up to 10 minutes or even longer after very strenuous exercise.
Anginal pain provoked by emotion may be relieved more slowly than that
provoked by physical exercise.
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| Differential
diagnosis of the symptoms |
If all the above mentioned cardinal features are present, or even only
the first two are quite typical, then the diagnosis of chronic stable
angina is virtually assured. Often, however, the picture is not so clear-cut
and other diagnoses must be considered. Chief amongst these are
- Esophageal reflux and spasm
- Peptic ulcer
- Gallstones
- Musculoskeletal disorders
- Non-specific chest pains often associated
with anxiety states
- Coronary artery spasm
- Myocardial infarction (Here pain is
more prolonged i.e. lasts for more than 30 minutes, and is often associated
with sweating and systemic symptoms)
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| Investigations
for confirming diagnosis |
- Resting electrocardiogram (ECG)
- ECG stress testing
- Ambulatory ECG monitoring (Holter monitoring)
- Echocardiography at rest
- Stress echocardiography
- Myocardial perfusion scintigraphy
- Radionuclide angiography during exercise
- Coronary angiography
- Intravascular ultrasound
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| Treatment |
Life style changes, drugs and interventional techniques all play a part
in the treatment of angina pectoris
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| Aims
of treatment |
- To improve prognosis by preventing myocardial
infarction and death
- To minimize or abolish symptoms
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| General
management |
- Stop smoking
- Limit alcohol intake
- Lose weight, if overweight
- Increase physical activity within the
patient’s limitation
- Limit intake of food rich in fat and
cholesterol. Encourage a high intake of fruits and vegetables
- Control stress and use relaxation techniques
- Control other concomitant disorders
such as diabetes, hypertension and anaemia
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| Drug
therapy |
For prevention of myocardial
infarction (MI) and death
- Use
lipid lowering drugs: All patients with angina pectoris should have
a lipid profile done. Diet modification and use of lipid lowering
drugs are indicated for lowering total cholesterol to below 200 mg/dl
and LDL cholesterol to below 100 mg/dl. All patients with angina pectoris
should be prescribed lipid lowering drugs if they have an abnormal
lipid profile (LDL cholesterol >100 mg/dl).
- Reduce
risk of thrombosis: Aspirin, if not contraindicated, should be administered
routinely to all patients of angina.
For
symptom relief
- Nitrates:
e.g. nitroglycerin, isosorbide dinitrate. Sublingual and spray formulations
of nitrates provide rapid relief of symptoms and are used for treatment
of acute attacks of angina pectoris. Oral and transdermal formulations
of nitrates are used to prevent anginal attacks and should be taken
regularly.
- Beta blockers: e.g. atenolol, metoprolol
- Calcium channel blockers: e.g. diltiazem,
verapamil (non-dihydropyridine calcium channel blockers), amlodipine
(dihydropyridine calcium channel blockers).
- Cytoprotective drugs: e.g. trimetazidine
- Potassium channel openers: e.g. nicorandil
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