Stable Angina

Original article by Tom Leach | Last updated on 7/6/2014
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Introduction

Stable angina is a common presentation of CHD and IHDsee the CHD article
‘Angina pectoris’ is a clinical syndrome rather than a disease. It occurs when there is insufficient oxygen supply to the heart to meet demand. It is generally transient, and most commonly occurs on exertion.
The blood flow to the myocardium is unable to meet demand due to narrowing of the coronary artery, usually by atheroma, and commonly exaggerated by a co-existing spasm of the artery. In patients who also have the vasoconstriction, the exercise limitation is greater.

Causes

  • Atheroma
  • Aortic valve disease
  • Hypertrophic cardiomyopathy
  • Oxygen demand factors – heart rate, blood pressure, left ventricular hypertrophy (more muscle to supply!), valve disease – e.g. aortic stenosis – so the heart has to work hard to pump
  • Oxygen supply – duration of diastole (needs to be long enough to allow sufficient blood to flow to the heart), coronary vasomotor tone, haemoglobin levels, oxygen saturation.

People normally experience angina as exertional chest pain that is relieved by rest.
People may also experience myocardial ischaemia as shortness of breath or without symptoms (silent ischaemia)
 

Other precipitating factors

  • Cold weather
  • Heavy meals
  • Intense emotion

Differentiating angina and ACS

  • If the pain doesn't resolve within 5 minute of using GTN spray, treat as ACS

MI causes heart muscle damage, stable angina does not. They have similar symptoms, although the pain of MI is often greater than angina. Any diagnosis of sudden onset chest pain should be treated as ACS until proven otherwise (unless does not resolve as a above and already has a diagnosis of stable angina)

Diagnosing Stable Angina

  • This is mainly based on clinical history – and patients will usually present in the Primary care (GP) setting.
  • Chest Pain -  is ‘tight’, heavy’, or ‘gripping’.
    • The pain is usually felt behind the sternum and can radiate to the neck, jaw, arms, and sometimes back.  
  • Shortness of breath (SOB)
  • Both pain and SOB brought on by exertion, and relieved by rest
  • Symptoms typically last several minutes after the precipitating event has stopped (e.g. exercise or stress)
  • Classically relieved by GTN

The likelihood of a diagnosis of angina increases when there are RF’s of cardiovascular disease present:

Investigations

For further information on investigations, see the Investigations and Interventions article
Many cases of stable angina are diagnosed in primary care without the need for further investigations, however, sometimes you might want to do:

Canadian Cardiovascular Society Angina Classification
This is sometimes used to class the severity of Angina from I-IV. It is very similar to the NYHA classification of Heart Failure

  • Class I – ‘Ordinary Activity’ (e.g. walking or climbing stairs) does not precipitate angina
  • Class II – Angina precipitated by walking upstairs, cold weather, or meals
  • Class III – marked limitation of normal physical activity
  • Class IV – Symptoms present at rest, unable to carry out many normal physical activities

Management of stable Angina

This can be divided into lifestyle modifications to reduce the risk of cardiovascular disease, and pharmacological interventions

Pharmacological

There are two main mechanisms used to relieve the symptoms of angina:

  • Increasing bloodflow to the heart muscle (by dilating coronary arteries) - e.g. wth GTN (Glycerytrinitrate)
  • Decreasing the workload on the heart (e.g. with beta-blocker or calcium channel blocker long term)

First line treatment

(either; or of the below)

Patients will also likely carry GTN spray or pills with them at all times to relieve acute episodes.

Second line treatment

Consider adding...

  • Long acting nitrate
  • Nicorandil
  • Ivabradine
  • Ranolazine