Angina

Chest pain/discomfort caused by an insufficient blood supply to the heart muscle.

Stable angina is angina which occurs during periods of increased oxygen demand on the heart e.g. exercise.  Symptoms are relieved by rest.

Unstable angina is an acute ischaemia of the heart muscle without any clinical features of infarction.  It, nonetheless, requires immediate attention (see ACSs).

Background/Epidemiology

  • Incidence increases with age and it generally has a male preponderance (8% of men 55-64 and 14% 65-74 have, or have had, angina; 3% and 8%, respectively, for women)
  • Most common cause is coronary artery disease
    • Modifiable risk factors include smoking, diet, sedentary lifestyle (commonly associated with poor socio-economic background)
    • Semi-modifiable risk factors include hypertension, diabetes, hyperlipidaemia, obesity

Presentation

  • Chest pain
    • Often described as central, crushing/heavy, deep pain
    • Usually brought on by exertion.  May also be brought on by the cold, or after a large meal, or with intense stress/emotion.
    • Can be mild, moderate or severe in intensity/severity.
    • May radiate up to the jaw or down the left arm
    • May cause difficulty breathing
    • May be relieved slightly by leaning forward.  Almost always relieved by rest after seconds/minutes
    • Relieved by GTN*
      • If the patient is not on GTN spray and there is a suspicion over anginal pain, give GTN.  If the pain disappears, this is likely to be angina
  • If chest pain is not relieved by rest/GTN, this is unlikely to be stable angina.
  • Make sure to ask about previous cardiac disease (in particular MI).

Investigations

  • ECG
    • Can be normal at rest or may show signs of an old MI
      • e.g. pathological Q waves (QS>20ms in V2-3 or Q wave >30ms and >0.1mV deep)
    • If symptoms are present
      • reversible ST-elevation/-depression, with or without T wave inversion.
  • Exercise tolerance is often used in patients with suspected angina (note that if the patient describes a clear history, this investigation may not be necessary)
    • ST-downsloping is the classical diagnostic feature
  • If a patient is not suitable for ETT (e.g. heart failure) but have pre-existing ECG abnormalities, an MRI myocardial perfusion scintigraphy can be performed
  • Rarely, angiography is used for the diagnosis of angina.  However, if the patient presents acutely and ACS is suspected, angiography may be performed acutely with the view for thrombolysis.

Management

  • Where possible, give lifestyle advice e.g. smoking cessation, weight loss
  • For the acute attack- prescribe sublingual glyceryl trinitrate (GTN) spray
    • Advise the patient to stop what they are doing and take the nitrate
    • Give another dose after 5 minutes if the pain remains.
    • If the pain persists after a further 5 minutes, call 999
  • For prevention, prescribe
    • A beta-blocker e.g. bisoprolol
    • If the patient is not able to use a beta-blocker (e.g. severe asthma), consider a rate-limiting calcium channel blocker e.g. verapamil
      • Combination (BB and CCB) may be better, depending on the reason for discontinuation/failure of monotherapy
      • Occasionally, if neither is suitable, long-acting nitrates or nicorandil can also be options
  • For underlying heart disease
    • Low dose aspirin (75mg) and statin treatment must be considered
    • If the patient also has diabetes, ACE inhibitor treatments should also be considered
  • Revascularisation therapy (e.g. PCI, CABG) can be considered in patients who are either high risk and/or not responding well to pharmacological treatment
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