In 2010, the National Institute for Health and Care Excellence (NICE) introduced new guidelines for the assessment of people with recent-onset chest pain, recommending investigations based upon one’s pre-test likelihood of having coronary artery disease. We aim to determine the impact these guidelines have made on the numbers of patients being discharged and referred for further investigations. We retrospectively analysed a database of 337 consecutive patients seen in the rapid access chest pain clinic: 162 patients were seen in the three months preceding, and 175 were seen in the three months following implementation of the new guidelines. We found that after implementation of the new guidelines, fewer patients (25% vs. 37%, p=0.018) were discharged at the first visit, and a greater number of patients were referred for an angiogram (20% vs. 6%, p=0.0001). The number of referrals for stress imaging significantly reduced from 57% to 37%. According to the new guidelines, 18% of patients were referred for coronary calcium scoring. This reflects a definite change in clinical practice with reduced direct discharges from the chest pain clinic, reduced reliance on functional imaging and increased direct referrals for invasive coronary angiography, resulting in higher investigational costs of the chest pain service.
Introduction
There are 2.3 million people living with coronary heart disease in the UK, which results in a healthcare burden of 1% of all GP and 40% of all accident and emergency (A&E) visits.1
It is estimated that 20–40% of the general population will experience chest pain during their life. Chest pain caused by coronary artery disease has a potentially poor prognosis, emphasising the importance of prompt and accurate diagnosis. Treatments are available to improve symptoms and prolong life, hence, the need for the development of the National Institute for Health and Care Excellence (NICE) guidelines for the diagnosis of chest pain.1
NICE updated guidelines in March 2010 for the assessment and diagnosis of people with recent-onset chest pain. Previously, in the rapid access chest pain clinic (RACPC), patients referred by the GP with recent-onset chest pain underwent a clinical assessment, after which, an exercise tolerance test (ETT) was the first diagnostic test performed to diagnose myocardial ischaemia, generally during the same visit. Further functional imaging, in the form of a myocardial perfusion scan or a dobutamine stress echocardiogram were recommended if the test was inconclusive.2 A patient was referred directly for a diagnostic coronary angiogram if the test was positive, which may have progressed to angioplasty, if necessary, or, if the patient was unable to undergo exercise electrocardiogram (ECG). A negative ETT would usually result in a patient being discharged from the RACPC.
In the 2010 NICE guidelines, the Diamond–Forrester algorithm is employed to measure the ‘pre-test probability’ (PTP) of coronary artery disease based on age, gender and typicality of symptoms. The presence of all three features of: constricting chest pain, which is exacerbated by exertion, and relieved with rest or glyceryl trinitrate (GTN), is defined as typical angina, while the presence of only two or one feature is defined as atypical angina and non-cardiac chest pain, respectively. This probability estimate of coronary artery disease has been modified by taking into account additional risk factors, such as smoking, diabetes and hypercholesterolaemia, giving rise to a range of probabilities. NICE recommends further investigations depending on the PTP of coronary artery disease for each individual case. If the probability is <10%, the patient is discharged without any further investigation. For a probability of 10–29%, computerised tomography (CT) calcium scoring is recommended for an anatomical assessment of the coronary arteries, which might include a 64-slice CT angiogram, if the CT calcium score is between 1 to 400. For a PTP of 30–60%, functional testing is recommended, such as a stress echocardiogram, stress cardiac magnetic resonance imaging (CMR) or myocardial perfusion scan (MPS). A probability of >60% would warrant a coronary angiogram.3
While there have been data published addressing some of the specific issues in implementing NICE guidance 95,4 we sought to investigate the overall anticipated impact on clinical practice, service provision and cost-effectiveness in a district general hospital (DGH), where most patients with new-onset chest pain are seen. We have carried out this study to assess the actual impact of these updated guidelines on the rapid access chest pain service by comparing a similar number of patients being seen before and after the current guidelines were introduced.
Methods
We retrospectively analysed a database of 337 consecutive patients seen in the RACPC between June and November 2010: 162 of these were seen before implementation of the current guidelines, between June and August 2010; 175 patients were seen after implementation of current guidelines, between September and November 2010.
Risk factors for coronary artery disease, including diabetes and hypertension, were documented on the referral from the GP or information provided by the patients themselves. Hypertension was not included in the Diamond–Forrester algorithm of the new guidance. A fasting blood cholesterol level of 6.4 mmol/L was applied to define hypercholesterolaemia in both populations. Any patient already on statins, prior to attending the RACPC, was also considered to have hypercholesterolaemia, regardless of their current fasting cholesterol level. Patients were considered to be smokers if they were still smoking at the time of consultation or had stopped within the previous year.
Patients who were seen between June to August 2010, underwent an ETT according to Bruce Protocol5 after a clinical assessment. Patients whose ETTs were negative were discharged at the first visit. Patients who were unable to use the treadmill, or had an inconclusive ETT, were referred for a dobutamine stress echocardiogram or MPS. Patients who had a positive ETT were referred for a coronary angiogram.
The new NICE guidelines for chest pain were implemented in September 2010 in our trust. Clinical practices strictly followed the new NICE guidance based upon the PTP of each patient, with the exception of a few high-risk patients who were apprehensive of the invasive procedure that is coronary angiography, opting for functional imaging instead.
We made comparison between patients who were seen before and those who were seen after the implementation of new NICE guidelines. Chi-square test was used for non-continuous parameters. A p value of <0.05 was considered as statistically significant.
Results
The two patient groups who were managed according to the 2003 and 2010 NICE guidelines were similar in age, gender and numbers of cardiovascular risk factors.
Following the implementation of the 2010 guidelines, fewer patients were discharged at first visit (25% vs. 37%, p=0.018), and more patients were referred for coronary angiogram (20% vs. 6%, p=0.0001). The number of referrals for stress imaging reduced from 57% to 37% after implementation of the 2010 guidelines (p=0.008). Since the new guidelines, 18% of patients were referred for CT calcium scoring (table 1).
The estimated cost according to NHS tariff was increased by £50 per patient after implementation of the new guidance (table 2).
Discussion
Following implementation of the 2010 NICE guidelines, we report a statistically significant reduction in the number of patient discharges and functional imaging studies performed, but an increase in the number of coronary angiograms. In addition, 18% of all patients were referred for CT calcium scoring, but none had ETT. This reflects a definite trend towards more specialised imaging techniques and has implications for the RACPC, particularly those held in DGHs.
Impact on service provision
Specialised cardiac investigations are still unavailable in many DGHs, where patients with chest pain are first seen, causing a delay in establishing a diagnosis as patients await referral to a tertiary centre.
Although fewer patients were discharged at first visit, they were discharged on clinical grounds alone, without any investigations. While PTP scoring is considered to be credible in identifying patients who would not benefit from further testing for the diagnosis of coronary artery disease,3 many physicians would hesitate to discharge a patient without investigations. Likewise, many patients will not feel reassured after being informed by the referring physician that they are at risk of heart disease.
Impact on cost-effectiveness
and observed incidences
The cost-effectiveness model of NICE is based upon their predictions of the proportion of patients within each category of likelihood of coronary artery disease.6 Table 3 demonstrates that NICE’s predictions appear to underestimate the incidence of the 30–60% PTP group, while over-estimating the >60% PTP group. Using the recommended NHS tariffs to compare the investigational cost of running the RACPC service, we find the average costs per patient were significantly higher following implementation of the new guidelines (table 2). Similar findings have been reported by other centres.7,8 Our costings do not take into consideration subsequent patient visits, which are expected to increase with the lower patient discharge rate.
Our calculations will have their limitations, and may not be representative for the whole UK, given the generally higher risk of coronary artery disease in the London inner city area. Second, the individual doctors who deal with patients in the chest pain clinic may have personal preferences to cardiac tests, despite the recommendation of the guidelines. Finally, one could argue that the cost is only a snap shot of the lifelong healthcare of the patients, and is too simple and short-term a measure.
Of interest, the European Society of Cardiology (ESC) has more recently published guidelines, which differ from NICE by advising that patients with <15% or >85% PTP should generally not receive stress testing, as it is more likely to produce a falsely positive or negative result in patients at extremes of probability when the specificity of most functional testing techniques are estimated to be 85%.9 Implementation of the ESC guidelines will probably reduce the number of invasive coronary angiography referrals by our local centre.10
Conclusion
Implementation of NICE chest pain guidelines at our DGH has significantly reduced direct discharges from the chest pain clinic, reduced our reliance on functional imaging and increased direct referrals for invasive coronary angiography. This has resulted in higher investigational costs of the chest pain service, and further investigations may well be fruitful in addressing how to reduce cost, while fulfilling the merits of the new guidelines.
Conflict of interest
None declared.
Key messages
- Strict application of National Institute for Health and Care Excellence (NICE) chest pain guidelines has reduced direct discharges, reduced reliance on functional imaging, and increased coronary angiography referrals
- Reliance on specialised cardiac investigations may delay establishing a diagnosis, as patients await referral to a tertiary centre
- The short-term investigational cost of the rapid access chest pain service has increased
References
1. National Institute for Health and Care Excellence. CG95. Chest pain of recent onset: assessment and diagnosis of recent onset chest pain or discomfort of suspected cardiac origin. London: NICE, 2010. Available from: https://www.nice.org.uk/guidance/cg95/chapter/guidance
2. National Institute for Health and Care Excellence. TA73. Myocardial perfusion scintigraphy for the diagnosis and management of angina and myocardial infarction. London: NICE, 2003. Available from: https://www.nice.org.uk/guidance/ta73/chapter/1-guidance
3. Pryor B, 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;118:81-90. http://dx.doi.org/10.7326/0003-4819-118-2-199301150-00001
4. Ormerod JO, Wretham C, Beale A et al. Implementation of NICE clinical guideline 95 on chest pain of recent onset: experience in a district general hospital. Clin Med 2015;15:225–8. http://dx.doi.org/10.7861/clinmedicine.15-3-225
5. Bruce R. Exercise testing of patients with coronary heart disease. Principles and normal standards for evaluation. Ann Clin Res 1971;3:323–32.
6. National Institute for Health and Care Excellence. Chest pain of recent onset. Costing report. London: NICE, 2011. Available from: https://www.nice.org.uk/guidance/cg95/resources
7. Ghosh A, Qasim A, Woollcombe K et al. Cost implications of implementing NICE guideline on chest pain in rapid access chest pain clinics: an audit and cost analysis. J Public Health 2012;34:397–402. http://dx.doi.org/10.1093/pubmed/fdr118
8. Rogers T, Dowd R, Yap H et al. Strict application of NICE Clinical Guideline 95 ‘chest pain of recent onset’ leads to over 90% increase in cost of investigation. Int J Cardiol 2013;166:740–2. http://dx.doi.org/10.1016/j.ijcard.2012.09.180
9. Monalescot G, Sechtem U, Achenbach S et al. 2013 ESC guidelines on the management of stable coronary artery disease: the Task Force on the management of stable coronary artery disease of the European Society of Cardiology. Eur Heart J 2013;34:2949–3003. http://dx.doi.org/10.1093/eurheartj/eht296.
10. Demir OM, Dobson P, Papamichael ND et al. Comparison of ESC and NICE guidelines for patients with suspected coronary artery disease: evaluation of the pre-test probability risk scores in clinical practice. Clin Med 2015;15:234–8. http://dx.doi.org/10.7861/clinmedicine.15-3-234
