Dr Jonathan Shribman outlines the statements from the NICE quality standard for stable angina and how they relate to previous guidance and clinical practice

  • Healthcare professionals in primary care should be familiar with the table on the likelihood of coronary artery disease and its use in the diagnosis of angina (see Table 2)
  • Be aware of the implications of optimum medical treatment using
    short-acting nitrates with either a beta blocker or a calcium-channel blocker before referring for angiography
  • It is the responsibility of primary care to make sure that the patient has had a multidisciplinary team meeting discussion with their cardiologist and cardiac surgeon if revascularisation is being considered
  • Although patients with angina can become symptom free with medical management, coronary artery bypass graft surgery may offer prognostic benefits over percutaneous coronary intervention or medical management in a minority of patients, and these individuals will need referring for further investigation
  • If the patient has not responded to treatment and still has angina, they should undergo a thorough reassessment of both their original diagnosis and treatment options.

Stable angina is a common condition—in England, approximately 8% of men and 3% of women aged 55 to 64 years, and 14% of men and 8% of women aged 65 to 74 years have, or have had, angina.1 Stable angina is associated with a low, but appreciable risk, of acute coronary events and increased mortality. One in ten patients will have a non-fatal or fatal myocardial infarction (MI) within a year of diagnosis of stable angina.2 In the 5-year period following diagnosis, men are twice as likely as women to have an acute MI and nearly three times more likely to die as a result of a cardiac event.

NICE has published the following guidance on angina:

  • Clinical Guideline (CG) 95 on the assessment and diagnosis of recent onset chest pain (2010)3
  • CG126 on stable angina (2011)1
  • Quality Standard 21 on stable angina (2012).4

NICE quality standards resulted from a recommendation in the NHS next stage review report: high quality care for all.5 Each standard is presented as a set of concise statements and associated measures that focus on topics relevant to healthcare and/or social care. Quality standards describe high-priority areas for quality improvement in a defined care or service area. They are derived from NICE guidance or NICE-accredited sources. Each set of quality standards is designed to be cost neutral as far as possible and is accompanied by a statement to measure compliance. This article aims to relate the quality standard for stable angina to clinical practice and outline its implications for primary care.

Table 1: NICE quality standard for stable angina4
No.Quality statements
1 People with features of typical or atypical angina and an estimated likelihood of coronary artery disease of 10%–90% are offered diagnostic investigation according to that likelihood.
2 People with stable angina are offered a short-acting nitrate and either a beta blocker or calcium-channel blocker as first-line treatment.
3 People with stable angina are prescribed a short-acting nitrate and one or two anti-anginal drugs as necessary before revascularisation is considered.
4 People with stable angina who have had coronary angiography, have their treatment options discussed by a multidisciplinary team if there is left main stem disease, anatomically complex three-vessel disease, or doubt about the best method of revascularisation.
5 People with stable angina whose symptoms have not responded to treatment are offered re-evaluation of their diagnosis and treatment.
National Institute for Health and Care Excellence website. Quality standard for stable angina. Reproduced with kind permission.
Available at: publications.nice.org.uk/quality-standard-for-stable-angina-qs21/list-of-quality-statements (accessed 8 January 2013).

Diagnostic investigation based on likelihood of coronary artery disease—statement 1

People with features of typical or atypical angina and an estimated likelihood of coronary artery disease (CAD) of 10%–90% are offered diagnostic investigation according to that likelihood.4 This statement arises from NICE CG95 on recent onset chest pain3 and is an essential prerequisite for developing an evidence-based management plan for each patient. The new chest pain diagnosis paradigms require that clinical assessment asks three questions:3

  • is the chest pain:
    • constricting discomfort in front of the chest, neck, shoulders, or arms?
    • precipitated by physical exertion?
    • relieved by rest or glyceryl trinitrate (GTN) spray in about 5 minutes?

If there is a positive answer to:3

  • all three questions, the patient has typical angina
  • two questions, the patient has atypical angina
  • one question, the patient has non-anginal chest pain.

Knowledge of the patient’s age, sex, symptoms, and risk factors will help the clinician to estimate the risk of CAD and to decide whether no testing, non-invasive functional testing (e.g. stress echo or exercise perfusion scanning), or anatomical testing (invasive coronary angiography) is needed (see Table 2).3,6 Causes of chest pain other than angina should be sought in patients who have an estimated likelihood of coronary artery disease of <10%.

Patients who have an estimated likelihood of CAD of 10%–29% and in whom stable angina cannot be diagnosed or excluded by clinical assessment should be offered computed tomography (CT) calcium scoring. If the calcium score is:3

  • zero, other causes of chest pain should be considered
  • 1–400, 64-slice (or above) CT coronary angiography should be offered
  • greater than 400: invasive coronary angiography (or non-invasive functional imaging if angiography is inappropriate or unacceptable to the patient) should be offered.

The patient should be offered non-invasive functional imaging for myocardial ischaemia if the estimated likelihood of CAD is 30%–60% and if stable angina cannot be diagnosed or excluded by clinical assessment. Options include:3

  • myocardial perfusion scintigraphy 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 61%–90% and if stable angina cannot be diagnosed or excluded by clinical assessment, offer:3

  • invasive coronary angiography
  • non-invasive functional imaging if coronary revascularisation is not being considered or invasive coronary angiography is not clinically appropriate or acceptable to the patient.

If the estimated likelihood of CAD is more than 90% and the patient has features of typical angina, treat as stable angina; no further investigations are required but blood tests for conditions that exacerbate angina should be performed.3

If the patient has already been confirmed to have CAD (known previous MI, revascularisation, previous coronary angiography):3

  • treat symptoms if they are typical of stable angina
  • the patient should be offered either non-invasive functional imaging or referral for an exercise electrocardiogram if there is uncertainty on whether the chest pain is caused by myocardial ischaemia.
Table 2: Percentage of people estimated to have coronary artery disease according to typicality of symptoms, age, sex, and risk factors3,6
 Non-anginal chest painAtypical anginaTypical angina
 MenWomenMenWomenMenWomen
Age (years)LoHiLoHiLoHiLoHiLoHiLoHi
35 3 35 1 19 8 59 2 39 30 88 10 78
45 9 47 2 22 21 70 5 43 51 92 20 79
55 23 59 4 25 45 79 10 47 80 95 38 82
65 49 69 9 29 71 86 20 51 93 97 56 84

For men older than 70 years with atypical or typical symptoms, assume an estimate >90%.

For women older than 70 years, assume an estimate of 61%–90% EXCEPT women at high risk AND with typical symptoms where a risk of >90% should be assumed.

Values are percent of people at each mid-decade age with significant CAD

Hi = High risk = diabetes, smoking, and hyperlipidaemia (total cholesterol > 6.47 mmol/litre)

Lo = Low risk = none of these three

The darker shaded area represents people with symptoms of non-anginal chest pain, who would not be investigated for stable angina routinely.

Note:

These results are likely to overestimate CAD in primary care populations.

If there are resting ECG ST-T changes or Q waves, the likelihood of CAD is higher in each cell of the table.

CAD=coronary artery disease; ECG=electrocardiogram

National Institute for Health and Care Excellence. Chest pain of recent onset: assessment and diagnosis of recent onset chest pain or discomfort of suspected cardiac origin. Clinical Guideline 95. London: NICE, 2010. Reproduced with kind permission. Available at: www.nice.org.uk/guidance/CG95

Drug treatment for angina—statement 2

People with stable angina are offered a short-acting nitrate and either a beta blocker or calcium-channel blocker as first-line treatment.4 The patient should be advised on how to use the short-acting nitrate:1,4

  • to use it during episodes of angina and immediately before any planned exercise or exertion
  • that side-effects such as flushing, headache, and light-headedness may occur
  • to sit down or find something to hold on to if feeling lightheaded.
  • that the dose should be repeated after 5 minutes if the pain has not eased
  • to 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 they are unwell.

If symptoms are not 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 contraindicated or not tolerated, consider adding:1

  • a long-acting nitrate or
  • ivabradine (a selective inhibitor of sinus node pacemaker activity) or
  • nicorandil or
  • ranolazine (reduces myocardial ischaemia by acting on intracellular sodium currents).

If combining a calcium-channel blocker with either a beta blocker or ivabradine, use a dihydropyridine calcium-channel blocker, for example, slow-release nifedipine, amlodipine, or felodipine.1 If the patient cannot tolerate beta blockers or calcium-channel blockers (or they are contraindicated), consider monotherapy with:1

  • a long-acting nitrate or
  • ivabradine or
  • nicorandil or
  • ranolazine.

A third anti-anginal drug should only be added when:1

  • symptoms are inadequately controlled with two drugs and
  • the person is waiting for revascularisation or revascularisation is not considered appropriate or acceptable.

The choice of drugs should be based on co-morbidities, contraindications, patient preference, and drug cost.1

Medical treatment before revascularisation—statement 3

People with stable angina are prescribed a short-acting nitrate and one or two anti-anginal drugs as necessary before revascularisation is considered.4

There is good quality evidence that optimal medical treatment (OMT)—with a short-acting nitrate and one or two anti-anginal drugs as necessary—should be given to all patients once a diagnosis of stable angina has been made. Patients whose symptoms are not fully controlled when receiving OMT should undergo coronary angiography to guide a revascularisation strategy. If symptoms are controlled satisfactorily on OMT, the following points should be discussed with the patient:1,4

  • their prognosis without further investigation
  • the likelihood that they might have left main stem disease or proximal three-vessel disease
  • the availability of coronary artery bypass graft (CABG) surgery to improve the prognosis of the small subgroup of patients with left main stem or proximal three-vessel disease
  • the process and risks of investigation
  • the benefits and risks of CABG surgery, including the potential survival gain.

Multidisciplinary team—statement 4

People with stable angina who have had coronary angiography, have their treatment options discussed by a multidisciplinary team if there is left main stem disease, anatomically complex three-vessel disease, or doubt about the best method of revascularisation.4

The statement on the role of the multidisciplinary team is based on very low to high-quality evidence derived from randomised controlled trials and on the experience and opinion of the guideline development group for CG126. It is important to ensure that a multidisciplinary team meets regularly to discuss the risks and benefits of continuing pharmacological treatment or revascularisation strategy (CABG surgery or percutaneous coronary intervention [PCI]) for people with stable angina.1

People with stable angina should receive balanced information, and have the opportunity to discuss the benefits, limitations and risks of drug treatment and CABG surgery and PCI to help them make an informed decision about their treatment. When either of these revascularisation interventions is appropriate, it should be explained to the patient that:1

  • the main purpose of revascularisation is to improve the symptoms of stable angina
  • CABG surgery and PCI are effective in relieving symptoms
  • repeat revascularisation may be necessary after either procedure and that the rate is lower after CABG surgery
  • stroke is an uncommon complication of these two procedures (the incidence is similar for both).

Symptoms not responding to treatment—statement 5

People with stable angina whose symptoms have not responded to treatment are offered re-evaluation of their diagnosis and treatment.4

NICE CG95 on stable angina (see recommendation 1.7.1 in the guideline; www.nice.org.uk/cg95) describes the components that may be included in a re-evaluation of diagnosis and treatment. These include: 1,4

  • exploring the patient’s understanding of their condition
  • exploring the impact of symptoms on the person’s quality of life
  • reviewing the diagnosis and considering non-ischaemic causes of pain
  • reviewing drug treatment and considering future drug treatment and revascularisation options
  • acknowledging the limitations of future treatment
  • explaining how the person can manage the pain themselves
  • paying specific attention to the role of psychological factors in pain
  • developing skills to modify cognitions and behaviours associated with pain.
  1. National Institute for Health and Care Excellence. The management of stable angina. Clinical Guideline 126. London: NICE, 2011. Available at: www.nice.org.uk/cg126  nhs_accreditation
  2. O’Flynn N, Timmis A, Henderson R et al. Management of stable angina: summary of NICE guidance. BMJ 2011; 343: d4147.
  3. National Institute for Health and Care Excellence. Chest pain of recent onset: assessment and diagnosis of recent onset chest pain or discomfort of suspected cardiac origin. Clinical Guideline 95. London: NICE, 2010. Available at: www.nice.org.uk/guidance/CG95  nhs_accreditation
  4. National Institute for Health and Care Excellence. Stable angina. Quality Standard 21. London: NICE, 2012. Available at: www.nice.org.uk/guidance/QS21
  5. The Stationery Office. Department of Health. High quality care for all: next stage review final report. London: The Stationery Office, 2008. Available at: www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/@dh/@en/documents/digitalasset/dh_085828.pdf
  6. Pryor D, Shaw L, McCants C et al. Value of the history and physical in identifying patients at increased risk for coronary artery disease. Ann Intern Med 1993; 118 (2): 81–90.G