Dr Rajiv Rampat discusses the NICE guideline on the assessment of recent onset chest pain caused by suspected acute coronary syndrome or angina
  • A resting ECG should be obtained as soon as possible in a patient presenting with acute chest pain
  • If ACS is suspected, management should be started immediately
  • Clinical assessment, ECG results, and typicality of angina pain features should be used to estimate the likelihood of CAD
  • The exercise ECG should not be used to diagnose or exclude angina
  • Patients with atypical or typical chest pain who have an intermediate risk of CAD (i.e. 10%–90%) should undergo functional testing

ECG=electrocardiogram; ACS=acute coronary syndrome; CAD=coronary artery disease


Coronary heart disease is a leading cause of mortality and morbidity in the UK and therefore prompt diagnosis and treatment are crucial. Over the last two decades, chest pain clinics have established themselves as an effective way of assessing patients presenting with suspected angina.1 As a result of the lack of guidelines for diagnosing angina, the clinical care provided in different clinics can be quite variable.

In March 2010, NICE published a guideline on the assessment and diagnosis of chest pain of recent onset. It focuses on the diagnosis of chest pain rather than its management, and is divided into two broad categories:2

  • Acute chest pain where an acute coronary syndrome (ACS) is suspected
  • Intermittent stable chest pain where angina is suspected.

The key points for primary care from this guideline are outlined in this article.

Patients presenting with acute chest pain

A complete assessment of acute chest pain should combine history taking, examination, and an electrocardiogram (ECG) recording. If a patient presents with acute chest pain, immediately check if the pain is current or when the last episode was, especially if it occurred in the last 12 hours. Determine whether the chest pain is of a cardiac nature, taking into account:2

  • history of the chest pain
  • presence of cardiovascular risk factors
  • history of ischaemic heart disease and prior treatment
  • previous investigations for chest pain.

The patient should be assessed for signs indicative of an ACS (e.g. pain in the chest and/or other areas lasting longer than 15 minutes).

If an ACS is suspected, management should be started immediately in the order appropriate to the circumstances (see Box 1) and a resting 12-lead ECG should be performed. Patients should be referred to hospital as an emergency if an ACS is suspected and they have experienced chest pain or have had an episode in the last 12 hours, and an ECG is abnormal or unavailable.2

If an ECG is performed, the results should be sent to the hospital before the patient arrives, but this should not delay transfer. A normal resting ECG should not be used to exclude an ACS.2

Once the patient has been admitted to hospital, cardiac biochemical marker testing should be performed to diagnose ACS—a blood sample for troponin level measurement should be taken at baseline and at 12 hours from the onset of the chest pain.2

Oxygen should not routinely be administered but oxygen saturation should be carefully monitored, ideally before hospital admission, using pulse oximetry to assess the need for supplementation.2

Box 1: Immediate management of a suspected ACS2

In the order appropriate to the circumstances, offer:

  • pain relief (glyceryl trinitrate and/or an intravenous opioid)
  • a single loading dose of 300 mg aspirin unless the person is allergic to this therapy. Send a written record with the person if given before arriving at hospital. Other antiplatelet agents should only be offered in hospital
  • a resting 12-lead ECG—if possible, send the results to the hospital before the person arrives
  • other therapeutic interventions as necessary
  • pulse oximetry, ideally before hospital admission. Offer oxygen:
    • if SpO2 is less than 94% with no risk of hypercapnic respiratory failure. Aim for SpO2 of 94%–98%
    • to people with chronic obstructive pulmonary disease who are at risk of hypercapnic respiratory failure. Aim for SpO2 of 88%–92% until blood gas analysis is available
  • monitoring

ACS=acute coronary syndrome; ECG= electrocardiogram; SpO2= oxygen saturation


Intermittent stable chest pain

The diagnosis of angina can be made either through clinical assessment alone or in combination with a diagnostic test. Assessment should include the typicality of chest pain, age, gender, and presence of cardiovascular risk factors.2

Typicality of angina pain features is judged on three characteristics:2

  • Constricting discomfort in front of the chest, neck, shoulder, jaws, or arms
  • Caused by physical exertion
  • Relieved by rest or glyceryl trinitrate within approximately 5 minutes.

Clinical assessment and typicality of anginal pain features should be used to estimate the likelihood of coronary artery disease (CAD). People with:2

  • typical angina have all of the above anginal pain features
  • atypical angina have two of the features
  • non-anginal chest pain have one or none of the features.

The patient should also be risk stratified based on the presence of any one of three cardiovascular risk factors, namely hyperlipidaemia (defined as total cholesterol >6.47 mmol/l), smoking, and diabetes.2 A table showing the percentage of people estimated to have CAD according to typicality of symptoms, age, sex, and risk factors can be found in the NICE guideline.2

The appropriate diagnostic test is chosen depending on the pretest likelihood of CAD as outlined in Figure 1. The clinical assessment and the resting 12-lead ECG should be taken into account when estimating likelihood of this condition.

A diagnosis of angina can be excluded in all patients presenting with non-anginal pain (unless clinical suspicion is raised by other aspects of the history and risk factors) and further diagnostic testing is unnecessary. It is also unnecessary in patients with a low probability of CAD (<10%) for whom other causes of chest pain should be considered.2

Patients with a high probability of CAD (>90%) should be managed as having stable angina and further diagnostic investigation is not needed.2

The exercise ECG should not be used to diagnose or exclude angina.2

Figure 1: Investigation of stable chest pain1
figure 1 CAD=coronary artery disease; MPS= myocardial perfusion scintigraphy; SPECT=single photon emission computed tomography; MR=magnetic resonance; CT=computed tomography

Implications for practice

Acute chest pain
The NICE guideline emphasises the need for prompt diagnosis based on the clinical presentation and the resting ECG.2 A significant departure from conventional practice is the recommendation to use oxygen therapy only if pulse oximetry confirms desaturation. The recommendation for an ECG on first clinical contact may increase the provision of electrocardiography in primary care.

Intermittent stable chest pain
The diagnostic recommendations for intermittent stable chest pain are novel and incorporate more contemporary tests such as computed tomography (CT) angiograms.2 The algorithmic approach based on pre-test likelihood scores will appeal to healthcare professionals seeking a structured approach to diagnosing chest pain and in particular to more junior doctors. However, there is always the risk of clinical complacency with this type of approach because of algorithmic thinking, but this is the case with guidelines in general and healthcare professionals should exercise their clinical judgement.

The most conspicuous change in the assessment of intermittent stable chest pain is the absence of the exercise tolerance test (ETT) as a diagnostic tool. This is because of the relatively low sensitivity and specificity of the ETT compared with the other modalities. This is particularly pertinent in women where the ETT carries a higher false positive rate.3

Discarding the ETT will come with its own problems. At present there is widespread use of this tool to diagnose or exclude angina. This forms the basis behind the ‘one-stop’ service provided by some rapid access chest pain clinics where a diagnosis can be obtained on the same day following an ETT. This allows treatment to be initiated at an earlier stage. Given that neither CT calcium scoring nor non-functional imaging are widely available and not on a same day basis, this may lead to delays in the diagnosis of angina. This is even more pertinent in district general hospitals where access to more sophisticated investigations may be limited and referral to tertiary centres is required.

There is no doubt that the provision of chest pain clinic services will need to be upgraded in many centres. It is more difficult to gauge the rate at which these changes are going to come into effect. The NICE guideline provides a radically new direction of travel for the investigation of patients with suspected angina that will ultimately see ETT give way to more effective diagnostic tests.

Conclusion

The technology used in diagnosing CAD has improved dramatically over the last decade. Newer forms of imaging including CT coronary angiograms are gaining worldwide acceptance as the future of CAD detection.

The NICE guideline provides a much needed framework for the diagnosis of chest pain especially in suspected stable CAD. Implementing these guidelines will be challenging, but will hopefully help to reduce regional variations in the assessment of chest pain.

Acknowledgements

The author would like to thank Professor Adam Timmis, Chair of the NICE Guideline Development Group for Chest pain of recent onset, for reviewing this article.

NICE implementation tools

NICE has developed the following tools to support implementation of Clinical Guideline 95 on Chest pain of recent onset. They are now available to download from the NICE website: www.nice.org.uk

Slide set

The slides are aimed at supporting organisations to raise awareness of the guideline and resulting implementation issues at a local level, and can be edited to cater for local audiences. This information does not supersede or replace the guidance itself.

Audit support

Audit support has been developed to support the implementation of the NICE guideline on chest pain of recent onset The aim is to help NHS organisations with a baseline assessment and to assist with the audit process, thereby helping to ensure that practice is in line with the NICE recommendations. The audit support is based on the key recommendations of the guidance and includes criteria and data collection tools.

Factsheet

The factsheet has been developed to help clarify the role CT calcium scoring can play in ruling out stable angina in people presenting with chest pain of suspected cardiac origin.

Baseline assessment tool

This form can be used to conduct a baseline assessment of a trust’s current activity in relation to the NICE guideline on chest pain of recent onset. Current activity can be included along with actions needed to meet the recommendations and the trust lead.

Questionnaire

The questionnaire aims to collect information from the patient’s perspective and can provide valuable data on activity in the service and on the service’s performance against the guideline. The appropriate sample would be people who have been assessed and investigated for recent onset chest pain or discomfort of suspected cardiac origin.


  • The NICE guideline is best approached by commissioners in terms of two separate clinical pathways:
    • suspected ACS
    • new onset stable chest pain
  • The guideline should prompt the agreement of a local ACS pathway agreed with all key providers (i.e. GP practices, out-of-hours services, ambulance services, hospitals, and walk-in centres)
  • The guideline presents many challenges for implementation to both providers and commissioners
  • A likely interim step is to set up rapid access chest pain clinics where patients are referred and assessed for further investigation (but do not necessarily undergo exercise testing)
  • Commissioners should explore with local acute trusts the possibilities and timescales for making available the necessary diagnostic interventions
  • The guidance states a diagnosis of angina can be made clinically without need for referral—this is in conflict with indicator CHD 2 in the quality and outcomes framework, which requires referral

ACS=acute coronary syndrome

  1. Sekhri N, Feder G, Junghans C et al. Prognosis of incident angina and non-cardiac chest pain in 8762 consecutive patients. Heart 2007; 93 (4); 458–463.
  2. 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
  3. Kwok Y, Kim C, Grady D et al. Meta-analysis of exercise testing to detect coronary artery disease in women. Am J Cardiol 1999; 83 (5): 660–666.G