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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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