Stable angina

Angina is chest pain or discomfort that is caused when heart muscle does not get enough blood. Angina results from the demands of the myocardium being unable to be met by blood supply. This usually implies narrowing of one of more coronary arteries and it tends to occur at times when the heart has to do more work, e.g. exercise or emotional stress.

Angina can much less often be caused by valve disease, especially aortic stenosis, hypertrophic obstructive cardiomyopathy, hypertensive heart disease, arrhythmias, arteritis and anaemia.

  • Stable angina is when the pain is precipitated by predictable factors - usually exercise.
  • Unstable angina: angina occurs at any time and should be considered and managed as a form of acute coronary syndrome.

Epidemiology

  • 8% of men and 3% of women aged 55-64 years have, or have had, angina.1
  • 14% of men and 8% of women aged 65-74 years have, or have had, angina.
  • People of South Asian origin in the UK have an increased risk of ischaemic heart disease but black Caribbean people have a reduced risk compared with the overall UK population rate.
  • In both men and women the rate is significantly higher in lower socio-economic groups

Risk factors

Presentation2

If chest pain is present at the time of consultation - give some sublingual glyceryl trinitrate (GTN) and, if the pain doesn't resolve within a few minutes, treat as in the Acute Coronary Syndrome article.

  • Always consider any history of angina, acute coronary syndrome, coronary revascularisation or other cardiovascular disease and any cardiovascular risk factors. Anginal pain is:
    • Constricting discomfort in the front of the chest, neck, shoulders, jaw or arms.
    • Precipitated by physical exertion.
    • Relieved by rest or GTN in about 5 minutes.
  • People with typical angina have all the above anginal pain features; people with atypical angina have two of the features, and people with non-anginal chest pain have one or none of the features.
  • Typical and atypical features of anginal and non-anginal chest pain should not be defined differently in men and women or among ethnic groups.
  • Factors making stable angina more likely include increasing age, male gender and the presence of cardiovascular risk factors, including smoking, diabetes, hypertension, dyslipidaemia, family history of premature coronary artery disease (CAD), a history of established CAD (e.g. previous myocardial infarction, coronary revascularisation), and other cardiovascular disease.
  • Features which make a diagnosis of stable angina unlikely include when the chest pain is continuous or very prolonged, unrelated to activity, worse on inspiration, or associated with symptoms such as dizziness, palpitations, tingling or difficulty swallowing.
  • Examination should include body mass index, blood pressure, examination of the pulse (including rate and regularity), presence of heart murmurs and any indications of other cardiovascular disease, e.g. peripheral vascular disease.

Stenting diagram

Differential diagnosis

  • Acute myocardial infarction: pain lasts longer than 5 minutes and is not relieved by rest.
  • Prinzmetal's angina occurs at rest and exhibits a circadian pattern, with most episodes occurring in the early hours of the morning.
  • Acute pericarditis: tends to be a more constant pain, which is aggravated by inspiration, lying flat, swallowing and movement.
  • Musculoskeletal pain: worse on movement but it is the movements rather than general exercise that cause the pain. There may be injury to the chest wall or pain from the thoracic spine. Deep inspiration and rotation are likely to aggravate the pain and there may be local tenderness.
  • Gastro-oesophageal reflux: often a burning pain, most common on lying down and after meals. Exercise may aggravate the pain, which is relieved by acid/alginate mixtures and much reduced by a course of a proton pump inhibitor.
  • Pleuritic chest pain: the pain is sharp on deep inspiration. It may occur with infection, especially pneumonia, or with infarction following a pulmonary embolism. There may well be purulent sputum or haemoptysis.
  • Aortic dissection: causes a more constant pain.
  • Gallstones can cause acute cholecystitis but the pain is not related to exercise.

Initial investigations

  • A full 12-lead ECG may show some ischaemic changes but a normal ECG does not rule out a diagnosis of angina. Changes on a resting 12-lead ECG that are consistent with CAD include:
    • Pathological Q waves.
    • Left bundle branch block (LBBB).
    • ST-segment and T-wave abnormalities (e.g. flattening or inversion).
  • FBC is required to exclude anaemia.
  • Renal function and electrolytes to assess renal function.
  • Fasting blood glucose if diabetes is not known to exist. If diabetes is known and recent figures are not available then glycosylated haemoglobin and microalbuminuria should be checked.
  • Fasting blood cholesterol and triglycerides, including the ratio of total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C).
  • Baseline LFTs before starting statins.
  • Check TFTs: thyrotoxicosis will increase the work of the heart whilst hypothyroidism is associated with raised cholesterol.
  • Troponins or cardiac enzymes will be needed if there is a suggestion of permanent myocardial damage (from history or recent ECG changes). These cases need emergency admission in most circumstances.
  • Echocardiography may be required to assess cardiac function or if hypertrophic cardiomyopathy or aortic valve disease is suspected.

Assessment3

  • The diagnosis of stable angina is based on clinical assessment alone or clinical assessment with diagnostic testing (i.e. anatomical testing for obstructive coronary artery disease (CAD) and/or functional testing for myocardial ischaemia).

    National Institute for Health and Clinical Excellence (2010) CG CG 95 Chest pain of recent onset: assessment and diagnosis of recent chest pain or discomfort of suspected cardiac origin. London: NICE. Available from www.nice.org.uk/CG95 Reproduced with permission.

  • If there are typical features of angina based on clinical assessment and their estimated likelihood of CAD is greater than 90% (see 'Further investigations' below), further investigation is unnecessary and the patient should be managed as having angina.
  • In people without confirmed CAD, in whom stable angina cannot be diagnosed or excluded based on clinical assessment alone, estimate the likelihood of CAD.

Referral to a cardiologist

  • Urgent hospital assessment and admission should be arranged for people with any symptoms suggesting possible acute coronary syndrome including:
    • Pain at rest (may occur at night).
    • Pain on minimal exertion.
    • Angina that seems to be progressing rapidly despite increasing medical treatment.
  • Refer urgently all people with suspected angina (to be seen within 2 weeks) to a Rapid Access Chest Pain Clinic for confirmation of the diagnosis and assessment of the severity of coronary heart disease.2

Further investigations

Most patients with suspected angina were traditionally referred for exercise ECG testing. Exercise ECG testing has a relatively high sensitivity but only moderate specificity for the diagnosis of CAD. A normal exercise test may reassure many patients but it does not exclude a diagnosis of CAD.2 The 2010 National Institute for Health and Clinical Excellence (NICE) guidance for patients presenting with chest pain recommends that neither exercise ECG nor MR coronary angiography should be used to diagnose or exclude stable angina for people without known CAD.3

Once the estimated likelihood of CAD is calculated from the table above:

  • If the patient is already confirmed to have CAD (known previous myocardial infarction, revascularisation, previous coronary angiography):
    • Treat as stable angina if symptoms are typical of stable angina.
    • If it is suspected that chest pain is not caused by myocardial ischaemia, then offer either non-invasive functional imaging (see below) or refer for exercise ECG testing.
  • If the estimated likelihood of CAD is more than 90% and the person has features of typical angina:
    • Arrange blood tests for conditions which exacerbate angina.
    • Treat as stable angina with no further diagnostic tests.
  • If the estimated likelihood of CAD is between 10-90%:
    • Arrange blood tests for conditions which exacerbate angina.
    • Consider aspirin only if chest pain is likely to be stable angina (do not offer if being taken regularly or if the person is allergic).
    • Treat as stable angina while waiting for the results if symptoms are typical of stable angina.
      • If the estimated likelihood of CAD is 61-90%:
        • Offer invasive coronary angiography.
        • If coronary revascularisation is not being considered or invasive coronary angiography is not clinically appropriate or acceptable to the person, offer non-invasive functional imaging. Options for non-invasive functional testing include:
          • Myocardial perfusion scintigraphy (MPS) using single photon emission computed tomography (SPECT).
          • Stress echocardiography.
          • First-pass contrast-enhanced magnetic resonance (MR) perfusion.
          • MR imaging for stress-induced wall motion abnormalities.
      • If the estimated likelihood of CAD is 30-60%:
        • Offer non-invasive functional imaging for myocardial ischaemia (see above).
      • If the estimated likelihood of CAD is 10-29%, offer CT calcium scoring (coronary artery calcification scanning). If the calcium score is:
        • Zero: consider other causes of chest pain.
        • 1-400: offer 64-slice (or above) CT coronary angiography.
        • Greater than 400: offer invasive coronary angiography (or non-invasive functional imaging if angiography is inappropriate or unacceptable to the person).
  • If the estimated likelihood of CAD is less than 10%:
    • Consider other causes of chest pain, e.g. gastrointestinal or musculoskeletal.
    • Only consider chest X-ray if other diagnoses (e.g. lung tumour) are suspected.
    • Consider investigating other causes of angina (e.g. hypertrophic cardiomyopathy) if there is typical angina-like chest pain.

Management of angina

  • The management of angina includes modification of cardiovascular risk factors and specific treatment for angina. Treatment of angina should not wait for exercise testing or referral to a cardiologist, even if the drugs have to be stopped for the test.
  • The patient must be informed of the diagnosis and its implications.
  • The patient should be advised that, when an attack of angina occurs, they should:
    • Stop what they are doing and rest.
    • Use glyceryl trinitrate (GTN) spray or tablets as instructed.
    • Take a second dose of GTN after 5 minutes if the pain has not eased.
    • Take a third dose of GTN after a further 5 minutes if the pain has still not eased.
    • Call 999 for an ambulance if the pain has not eased after another 5 minutes (i.e. 15 minutes after onset of pain), or earlier if the pain is intensifying or the person is unwell.

Modification of risk factors is described in the separate article Secondary Prevention of Cardiovascular Disease.

Pharmacological treatment

The following is based on the latest NICE guidance:1

  • Offer either a beta-blocker or calcium-channel blocker as first-line treatment.
  • If the symptoms are nor adequately controlled (or the patient cannot tolerate one option) consider switching to the other option, or using a combination of the two.
  • If a patient's symptoms are not adequately controlled on one drug and the other is either contra-indicated or not tolerated, consider adding:
    • A long-acting nitrate.
    • Ivabradine ( a selective inhibitor of sinus node pacemaker activity).
    • Nicorandil.
    • Ranolazine (reduces myocardial ischaemia by acting on intracellular sodium currents).
  • If using a calcium-channel blocker with either beta-blocker or ivabradine, use a slow-release nifedipine, amlodipine or felodipine.
  • If the patient cannot tolerate beta-blockers or calcium-channel blockers (or they are contra-indicated), consider monotherapy with:
    • A long-acting nitrate
    • Ivabradine
    • Nicorandil
    • Ranolazine
  • Only add a third anti-angina drug when:
    • The person's symptoms are inadequately controlled with two drugs.
    • The person is waiting for revascularisation or it is not considered appropriate or acceptable.
    When choosing between drugs, make the decision after considering comorbidities, contra-indications, patient preference and drug cost.

Other treatment:

  • Unless there is contra-indication, aspirin should be started. Clopidogrel is an alternative for those who cannot take aspirin but it is much more expensive. Aspirin may be used at doses of 75-300 mg daily. The evidence for the optimum dose is inconclusive in terms of risk:benefit and it is best to follow local protocols. Most people with angina are prescribed 75 mg or 150 mg daily.
  • Patients with stable angina and diabetes should be considered for treatment with an angiotensin-converting enzyme (ACE) inhibitor.2
  • Statins should be prescribed for all patients with stable angina due to atherosclerotic disease, according to NICE guidance.4

Coronary revascularisation

See separate Coronary Revascularisation article.

  • Coronary revascularisation is required in those at high risk and those who have failure to be controlled by medical therapy.
  • A cardiac rehabilitation programme should be arranged following revascularisation.2
  • Both coronary artery bypass grafting and percutaneous transluminal angioplasty have their indications and advocates.
  • For the low-risk patient with stable angina, medical management carries the lowest risk.

NICE recommends that transmyocardial laser revascularisation and percutaneous laser revascularisation for refractory angina pectoris show no efficacy and may pose unacceptable safety risks.5,6

Patients who do not respond to treatment

If a patient's symptoms of stable angina do not respond to medical therapy or revascularisation, they should be offered a full assessment and advice. This may include:1

  • Exploring the patient's understanding of their condition.
  • Establishing how their symptoms affect their quality of life.
  • Reviewing the diagnosis and considering other causes of pain.
  • Explaining how the patient can self-manage.
  • Explaining the role of psychological factors in pain.

There is no evidence currently to support the use of transcutaneous electrical nerve stimulation (TENS) or acupuncture in the management of this pain.

Advice to patients

  • Reduce cardiovascular risk, including smoking cessation, dietary advice (including to maintain a healthy weight), physical activity and limiting alcohol consumption.
  • Driving: the DVLA's medical rules regarding angina are:
    • For group 1 entitlement (cars, motorcycles):
      • Driving must cease when symptoms occur at rest, with emotion, or at the wheel.
      • Driving may recommence when satisfactory symptom control is achieved.
      • The DVLA need not be notified.
    • For group 2 entitlement (lorries, buses):
      • Refusal or revocation of a driver's licence may occur if symptoms (treated or untreated) continue.
      • Relicensing may be permitted thereafter provided that the person has been free from angina for at least 6 weeks, exercise or other functional test requirements can be met, and there is no other disqualifying condition.
    • The person should check with their insurer that they are still covered for driving.
  • Sexual activity:
    • If the patient can climb up and down two flights of stairs briskly without any symptoms of angina, sexual activity is unlikely to precipitate an episode of angina.
    • If sexual activity does precipitate an episode of angina, sublingual glyceryl trinitrate (GTN) taken immediately before intercourse may help prevent subsequent attacks.
    • The use of nitrates or nicorandil with phosphodiesterase inhibitors (sildenafil, tadalafil and vardenafil) is contra-indicated.
    • Patients with angina who take a phosphodiesterase inhibitor should be advised that:
      • They should not use GTN for at least 24 hours before or after taking sildenafil or vardenafil, and for at least 48 hours before or after taking tadalafil.
      • If the patient has an episode of angina during sexual intercourse, they must not use GTN. They should stop sexual activity and, if their pain does not resolve, they should call for an ambulance.

Complications

  • Cardiovascular complications, e.g. unstable angina and myocardial infarction.
  • Anxiety and depression.
  • Reduced general health and quality of life.

Prognosis

  • 1 patient in 10 will suffer a nonfatal or fatal myocardial infarction within a year of diagnosis.7
  • This is not a benign condition and it must receive energetic and evidence-based treatment.
  • One review found that the annual total mortality rate is 2.8-6.6%, annual cardiovascular death rate is 1.4-6.5% and the annual nonfatal myocardial infarction rate is 0.3-5.5%.8


Document references

  1. Stable angina, NICE Clinical Guideline (July 2011); The management of stable angina
  2. Management of stable angina, Scottish Intercollegiate Guidelines Network - SIGN (2007)
  3. Chest pain of recent onset, NICE Clinical Guideline (March 2010); Assessment and diagnosis of recent onset chest pain or discomfort of suspected cardiac origin
  4. Lipid modification, NICE Clinical Guideline (May 2008); (Cardiovascular risk assessment and the modification of blood lipids for the primary and secondary prevention of cardiovascular disease.) amended May 2010
  5. Transmyocardial laser revascularisation for refractory angina pectoris, NICE Interventional Procedure Guideline (May 2009)
  6. Percutaneous laser revascularisation for refractory angina pectoris, NICE Interventional Procedure Guideline (May 2009)
  7. Gandhi MM, Lampe FC, Wood DA; Incidence, clinical characteristics, and short-term prognosis of angina pectoris; Br Heart J. 1995 Feb;73(2):193-8 [abstract]
  8. Jones M, Rait G, Falconer J, et al; Systematic review: prognosis of angina in primary care. Fam Pract. 2006 Oct;23(5):520-8. Epub 2006 Jul 27. [abstract]

Internet and further reading

© EMIS 2011Author: Dr Hayley WillacyReviewer: Dr Helen Huins
Document ID: 1329Document Version: 25Last Reviewed: 27 Sep 2011
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