Angina pectoris

Is caused by a mismatch between myocardial oxygen supply and demand

Overview:

• Diagnosis is largely based on the clinical history
• The chest pain is typically described as ‘heavy’, ‘tight’ or ‘gripping’
• Typically, the pain is central/retrosternal and may radiate to the jaw and/or arms
• Angina can range from a mild ache to a most severe pain that provokes sweating and fear
• May be associated breathlessness

Types of angina:

• Classical (exertional) angina
• Decubitus angina
• Variant (Prinzmetal’s) angina
• Cardiac syndrome X
• Unstable angina

Exertional angina:

• The pain is provoked by physical exertion, especially after meals and in cold, windy weather
• Is commonly aggravated by either anger or excitement
• Pain fades within minutes of resting
• May, occasionally, disappear with continued exertion (‘walking through the pain’)

Decubitus angina:

• Occurs when the patient is lying down
• Usually occurs in association with impaired LV function, as a result of severe coronary artery disease

Prinzmetal’s angina:

• Refers to an angina that occurs without provocation, usually at rest, as a result of coronary artery spasm
• Occurs more frequently in women
• Arrhythmias (both VT and heart block) can occur during the ischaemic episode

Cardiac syndrome X:

• Refers to those patients with a good history of angina, a positive exercise test and angiographically normal coronary arteries
• This forms a heterogeneous group in whom there may be functional abnormalities of the coronary microcirculation
• Much more common in women than in men
• Good prognosis but are difficult to treat#

Unstable angina:

• Refers to angina of recent onset (less than 1 month), worsening angina or angina at rest

Examination:

• Usually no abnormal findings
• Occasionally a fourth heart sound may be heard

Signs that should be sought include:

• Anaemia
• Thyrotoxicosis
• Hyperlipidaemia (e.g. lipid arcus, xanthelasma, tendon xanthoma)

It is essential to exclude aortic stenosis as this can present with angina-like symptoms:

• Slow-rising carotid impulse
• Ejection systolic murmur radiating to the neck

It is also important to measure the BP to identify coexistent HT

Investigations for angina:

• Resting ECG:
• Usually normal between attacks
• During an attack, transient ST depression may occur
• May be evidence of past MI or LBBB
• Exercise ECG
• Cardiac scintigraphy (myocardial perfusion scans)
• Echocardiography
• Coronary angiography

General management:

• Inform patients of their condition
• Reassure them that the prognosis is good (<2% mortality per year)
• Manage coexistent diseases (e.g. DM, HT)
• Minimise risk factors:
• Smoking
• Obesity
• Hyperlipidaemia

• Encourage regular exercise

Medical treatment – prognostic therapies (those that improve prognosis):

Aspirin 75mg daily (unless contraindicated)

Lipid-lowering therapy:

• Considered in patients with total cholesterol >4.8mmol/L despite a low-fat diet
• If the TGs are <3.5mmol/L one of the statins (HMG-CoA reductase inhibitors) should be used
• If the TGs are >3.5mmol/L a fibrate should be considered

Medical treatment – symptomatic treatment:

Glyceryl trinitrate (GTN):

• Used sublingually, either as a spray or a tablet
• Gives prompt relief in a few minutes

ß-blockers:

• E.g/ atenolol 50-100mg daily
• Decrease HR and SV, therefore decreasing myocardial O₂ demand

Ca²⁺-channel blockers:

• E.g. amlodipine

• Block both calcium flux into the cell and the its utilization within the cell
• Leads to:
• Peripheral vasodilatation
• Relaxation of coronary arteries
• Decreased SV

Long-acting nitrates:

• E.g. isosorbide mononitrate
• Particularly useful for patients who respond to sublingual GTN
• Reduce venous return and hence intracardiac diastolic pressures
• They also relax the tone of the coronary arteries

Invasive therapies:

• Coronary artery bypass grafting (CABG)
• Percutaneous transluminal coronary angioplasty (PTCA)

Percutaneous transluminal coronary angioplasty:

• Involves the passage of a catheter into a coronary artery followed by the inflation of a balloon or insertion of a stent into the artery in order to maintain its patency

Risks:

• Mortality (1%)
• MI (2%)
• Need for an urgent CABG (2%)

Indications for CABG:

1. Symptom control in patients who remain symptomatic despite optimal medical therapy and whose disease is not suitable for PTCA
2. Prognostic disease in patients with severe 3-vessel coronary artery disease (significant proximal stenoses in all 3 main coronary vessels)

Coronary artery bypass grafting:

Vessels that can be used for the procedure:

• Internal mammary artery/arteries
• Saphenous vein

Mortality is well below 1%

Perioperative strokes occur in up to 2% of cases