Stable angina

What is angina?¹

Angina is pain (or constricting discomfort) in the chest, neck, shoulders, jaw, or arms caused by an insufficient blood supply to the myocardium. It is usually caused by coronary artery disease, and symptoms occur when blood flow does not provide adequate amounts of oxygen to the myocardium when oxygen demand increases (such as during exercise). Less often, angina is caused by valvular disease (eg, aortic stenosis), hypertrophic obstructive cardiomyopathy, or hypertensive heart disease.

• Stable angina usually occurs predictably with physical exertion or emotional stress, lasts for no more than 10 minutes (usually less), and is relieved within minutes of rest, as well as sublingual nitrates.

• Unstable angina is new-onset angina or abrupt deterioration in previously stable angina, often occurring at rest. Unstable angina usually requires immediate admission or referral to hospital.

Angina epidemiology

• 8% of men and 3% of women aged 55-64 years have, or have had, angina.²

• The prevalence increases with age for both men and women.

• People of South Asian origin in the UK have an increased risk of coronary heart disease but black Afro-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.

Angina risk factors

• Risk factors for cardiovascular disease include family history, smoking, diabetes mellitus, metabolic syndrome, hyperlipidaemia, hypertension, obesity and lack of exercise.

• Cardiac abnormalities, especially outflow obstruction such as aortic stenosis or hypertrophic obstructive cardiomyopathy.

Angina symptoms¹

• 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 five minutes.

• People with typical angina have all the above anginal pain features; people with atypical angina have two of the features; 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 (eg, 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 - eg, peripheral vascular disease.

Angina differential diagnosis¹

See also the separate Chest Pain article.

• Acute myocardial infarction: pain lasts longer than five 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 investigations¹

• 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 (eg, 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

See also the separate Cardiac-type Chest Pain Presenting in Primary Care article.

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

• If there are typical features of angina based on clinical assessment and their estimated likelihood of CAD is greater than 90%, 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 two weeks) to a Rapid Access Chest Pain Clinic for confirmation of the diagnosis and assessment of the severity of coronary heart disease.

Further investigations⁴

The Scottish Intercollegiate Guidelines Network (SIGN) guideline on the management of stable angina recommends that in patients with suspected stable angina, the exercise tolerance test should not be used routinely as a first-line diagnostic tool. They also suggest that computerised tomography-coronary angiography should be considered for patients with chest pain where the diagnosis of stable angina is suspected but not clear from history alone.⁵

Most patients with suspected angina were traditionally referred for exercise ECG testing. The National Institute for Health and Care Excellence (NICE) recommends:³

• Exercise ECG should not be used to diagnose or exclude stable angina for people without known CAD.

• For people with confirmed CAD, non-invasive functional testing should be offered when there is uncertainty about whether chest pain is caused by myocardial ischaemia, and an exercise ECG may be used instead of functional imaging.

• Non-invasive imaging or exercise ECG should not be offered routinely in the initial assessment of acute cardiac chest pain.

Angina treatment and management^{6 7}

• 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 GTN spray or tablets as instructed.

  • Take a second dose of GTN after five minutes if the pain has not eased.

  • Take a third dose of GTN after a further five minutes if the pain has still not eased.

  • Call 999/112/911 for an ambulance if the pain has not eased after another five minutes (ie 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 Cardiovascular Risk Assessment article.

Pharmacological treatment of angina

The following is based on the latest NICE guidance:²

• GTN for rapid symptom relief.

• 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).

  • Ranolazine: moderate quality evidence has indicated that people with stable angina who received ranolazine as add-on therapy have fewer angina episodes but increased risk of presenting non-serious adverse events compared to those given placebo.⁸

• 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

  • 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. Only consider nicorandil when other medicines are unsuitable, because of the risk of ulceration.

Other angina treatment:

• Unless there is contra-indication, aspirin should be started. Clopidogrel is an alternative for those who cannot take aspirin. 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.

• Statins should be prescribed for all patients with stable angina due to atherosclerotic disease, according to NICE guidance.⁹

Coronary revascularisation

Despite increasing effectiveness of prevention and medical therapy, coronary artery revascularisation remains a very important management option, particularly for patients with angina not adequately controlled by medical treatment, severe left ventricular systolic dysfunction, or high-risk coronary anatomy.¹⁰

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. Trials in stable coronary artery disease show that percutaneous coronary intervention (PCI) does not reduce mortality. PCI does appear to reduce spontaneous myocardial infarction rates but at the expense of causing some peri-procedural myocardial infarction. Therefore, the main purpose of PCI is to relieve angina.¹¹

A cardiac rehabilitation programme should be arranged following revascularisation.⁵

NICE recommends that transmyocardial laser revascularisation and percutaneous laser revascularisation for refractory angina pectoris show no efficacy and may pose unacceptable safety risks.^{12 13}

See also the separate Coronary Revascularisation article.

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:²

• 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.

Coronary sinus narrowing device implantation for refractory angina

This procedure uses a percutaneously inserted, balloon-expandable device to narrow the coronary sinus. The coronary sinus is a large venous structure formed by the merging of veins that drain blood away from the myocardium. It receives most of the cardiac venous blood, which then flows into the right atrium (along with deoxygenated blood from the superior and inferior venae cavae).

NICE recommends that, in light of well-recognised complications and limited evidence of efficacy, this procedure should only be used with special arrangements for clinical governance, consent, and audit or research.¹⁴

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:¹⁵
  

  • For group 1 entitlement (cars, motorcycles):
    

    • Must not drive when symptoms occur at rest, with emotion, or at the wheel.

    • Driving may resume after satisfactory symptom control.

    • Need not notify DVLA.

  • For group 2 entitlement (lorries, buses):
    

    • Must notify DVLA.

    • Must not drive when symptoms occur.

    • A licence will be refused or revoked if symptoms continue (treated or untreated).

    • May be relicensed/licensed (provided there is no other disqualifying condition) if:

      • No angina for at least six weeks.

      • The requirements for exercise or other functional tests can be met.

  • 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 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.

Angina complications

• Cardiovascular complications - eg, unstable angina and myocardial infarction.

• Anxiety and depression.

• Reduced general health and quality of life.

Angina prognosis⁶

• Estimates for annual mortality rates range from 1.2-2.4% per annum, with an annual incidence of cardiac death between 0.6 and 1.4% and of non-fatal myocardial infarction between 0.6% and 2.7%.

• Risk factors for the development of coronary heart disease (hypertension, hypercholesterolaemia, diabetes, sedentary lifestyle, obesity, smoking and a family history) also have an adverse influence on prognosis in those with established disease.