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Implementation of NICE Clinical
Guideline 95 for assessment of stable
chest pain in a rapid access chest pain
clinic reduces the mean number of
investigations and cost per patient
Alvin J X Lee,
1,2,3
Michael Michail,
1
Shumonta A Quaderi,
1
James A Richardson,
1
Suneil K Aggarwal,
1
M Elsya Speechly-Dick
1
To cite: Lee AJX, Michail M,
Quaderi SA, et al.
Implementation of NICE
Clinical Guideline 95 for
assessment of stable chest
pain in a rapid access chest
pain clinic reduces the mean
number of investigations and
cost per patient. Open Heart
2015;2:e000151.
doi:10.1136/openhrt-2014-
000151
Received 24 May 2014
Revised 4 November 2014
Accepted 20 January 2015
1
The Heart Hospital,
University College London
Hospitals NHS Foundation
Trust, London, UK
2
University College London,
Medical School, London, UK
3
Medical Sciences Division,
Academic Foundation
Programme Doctor at the
University of Oxford, Oxford,
UK
Correspondence to
Dr Suneil Kumar Aggarwal;
suneilaggarwal@doctors.org.
uk
ABSTRACT
Objective: In 2010, the National Institute for Health
and Care Excellence (NICE) in the UK published Clinical
Guideline 95 (CG95) advocating risk stratification of
patients using ‘CADScore’to guide appropriate cardiac
investigations for chest pain of recent onset.
Implementation of the guideline in the University
College London Hospitals NHS Foundation Trust was
evaluated to see if it led to a reduction in the average
cost of the diagnostic journey per patient and fewer
investigations per patient in order to confirm a
diagnosis.
Methods: This was a single centre study at a Tertiary
Centre in Central London. The investigative journey for
each patient presenting to the Rapid Access Chest Pain
Clinic (RACPC) at University College London Hospitals
NHS Foundation Trust was recorded. Retrospective
analysis on this data was performed.
Results: Data for 4968 patients presenting to the
RACPC from 2004 to 2012 was analysed and a size-
matched cohort of 1503 patients preimplementation
and postimplementation of the guidelines was
compared. The mean cost of investigations
postimplementation was £291.83 as compared to
£319.54 preimplementation of the guidelines despite
higher costs associated with some of the
recommended initial investigations. The mean number
of tests per patient postguidelines was 0.78 compared
to 0.97 for preguidelines. An approximate twofold
increase in patients not requiring tests was seen post-
CG95 implementation (245 pre-CG95 vs 476 post-
CG95).
Conclusions: The implementation of the NICE
guidelines in our trust has reduced the average cost of
the investigative journey and the number of
investigations required per patient.
INTRODUCTION
Coronary artery disease (CAD) remains the
biggest cause of mortality in the UK, causing
around 80 000 deaths each year.
1
Accurate
diagnosis of CAD in patients presenting with
stable recent onset chest pain is important to
aid the management of this disease.
Advances in diagnostic technologies, such as
myocardial perfusion imaging, stress echocar-
diography, MRI and cardiac CT have
increased the investigative options available
to aid the diagnosis of CAD. Nevertheless,
selecting the appropriate investigations to aid
cost-effective and accurate diagnosis of CAD
remains a challenge.
In 2010, the National Institute for Health
and Care Excellence (NICE) published
Clinical Guideline 95 (CG95),
2
advocating
risk stratification of patients using ‘CADScore’
KEY MESSAGES
What is already known about this subject?
▸Previous reports looking at the economic impact
of implementing National Institute for Health and
Care Excellence (NICE) Clinical Guideline 95 (CG
95) in assessing pain of suspected cardiac
origin have suggested either cost neutrality or an
increase in costs postimplementation.
What does this study add?
▸This report presents findings from the largest
cohort of patients seen so far in the literature,
representative of a large teaching hospital cover-
ing patients of a wide range of ethnicities and
backgrounds. This study suggests that imple-
mentation of the guideline leads to lower
average costs per patient, with a reduction in
number of tests required per patient.
How might this impact on clinical practice?
▸These observations suggest that implementation
of NICE CG95 Guideline in Rapid Access Chest
Pain Clinics in the UK have led/will lead to a
faster diagnosis, an increase in patient safety
and also in cost savings.
Lee AJX, Michail M, Quaderi SA, et al.Open Heart 2015;2:e000151. doi:10.1136/openhrt-2014-000151 1
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to guide appropriate cardiac investigations for chest pain
of recent onset. This risk score is calculated based on the
symptoms, age, sex, risk factors (including diabetes,
smoking and hyperlipidaemia) and ECG findings of the
patient. The NICE guideline proposes that for people
without confirmed CAD, in whom stable angina cannot
be diagnosed or excluded based on clinical assessment
alone, further diagnostic testing would be recommended
as follows:
1. If the pretest likelihood for CAD is high (61–90%),
consider invasive coronary angiography as the first-
line diagnostic investigation, if appropriate.
2. If the pretest risk is intermediate (30–60%), consider
functional imaging.
3. If the pretest risk of CAD is low (10–29%), offer
cardiac CT as the first-line diagnostic investigation.
The guideline also recommends the depreciation of
exercise ECG as a diagnostic test and the elimination of
screening tests for the lowest risk patients or those with
non-cardiac chest pain. The recommended investigations
according to the guideline is summarised in table 1.
In the UK, the Rapid Access Chest Pain Clinic
(RACPC) is a cardiologist-led service assessing patients
with recent onset chest pain. CG95 was implemented in
July 2010 in the RACPC at the University College
London Hospitals NHS Foundation Trust in London, a
tertiary cardiology centre. The impact of the implemen-
tation of the guideline on service provision in this
RACPC, in terms of number of investigations and the
cost consequence, was evaluated. Despite the higher
costs of the new recommended initial investigations
compared to previous first-line investigations, such as
exercise ECG, it was hypothesised that the implementa-
tion of the guideline would reduce average cost of the
patient’s diagnostic journey and would reduce the
number of investigations per patient due to better diag-
nostic accuracy, thus allowing for better patient safety.
MATERIALS AND METHODS
Data collection
This was a single centre study at the University College
London Hospitals NHS Foundation Trust. Institutional
approval was obtained for the study and ethical approval
was not required. The investigative journey for each
patient was recorded and this included calculating a risk
score based on symptoms, age, sex, risk factors and ECG
findings. Retrospective analysis of this data was
performed.
The cost of each tests is summarised in table 2 and is
based on the 2011 costing report that accompanies the
CG95 clinical guideline.
3
Data analysis
Retrospective analysis was performed on all 4968
patients presenting to the RACPC from 2004 to 2012.
Analysis for comparison was performed on size-matched
cohorts (1503 patients) preimplementation and postim-
plementation of CG95, excluding a number of patients
(335 patients) peri-implementation when some early
shift in practice occurred. The number of cardiac inves-
tigations per patient was summed up and cost of all
cardiac investigations for each patient from presentation
to discharge was calculated. Investigations were priced as
per NICE CG95 ‘Costing Report’2011. Mean cost per
patient was derived for size-matched cohorts preimple-
mentation and postimplementation of CG95. The
Mann-Whitney U Test was used to assess statistical signifi-
cance between groups, assuming non-normal
distributions.
The number of investigations for each patient’s investi-
gative journey was compared in size-matched cohorts
preimplementation and postimplementation of CG95,
and assessed for statistical significance using the
Mann-Whitney U Test and Pearson’sχ
2
test.
Microsoft Excel was used to aid data collection.
Microsoft Excel and Graphpad Prism were used for stat-
istical analysis and production of graphs.
RESULTS
Table 3 shows the baseline characteristics of size-
matched cohorts (1503 patients) preimplementation
and postimplementation of CG95, excluding 335
patients’peri-implementation when some early shift in
practice occurred.
Table 4 summarises the number of patients, the per-
centage undergoing each test for each year and the
mean number of investigations per patient.
Table 1 Recommended investigations for stable chest
pain according to CADscore
CADscore, risk Recommended diagnostic testing
10–29%, low CT calcium scoring followed by CT
angiography if calcium score >0
30–60,
intermediate
Functional imaging (dobutamine stress
echocardiography, myocardial perfusion
scan, cardiac MRI)
61–90, high Invasive coronary angiography
Table 2 Costs of each diagnostic investigation according
to NICE CG95 costing report
Test Cost
Exercise treadmill test £75
CT angiography £173
CT calcium scoring £113
Stress MRI £313
Echocardiography £86
Stress echocardiography £236
Myocardial perfusion imaging £293
Invasive coronary angiography £1052
CG95, Clinical Guideline 95; NICE, National Institute for Health
and Care Excellence.
2Lee AJX, Michail M, Quaderi SA, et al.Open Heart 2015;2:e000151. doi:10.1136/openhrt-2014-000151
Open Heart
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A total of 1503 patients were seen postimplementation
of CG95 and they were compared with a size-matched
cohort of 1503 consecutive patients seen preimplemen-
tation. The mean cost of all investigations for the patient
postimplementation was £291.83 compared to £319.54
preimplementation of the guidelines (figure 1). This dif-
ference was statistically significant (Mann-Whitney U,
p<0.001). Based on this cohort, this approximates a cost
reduction to the clinic of about £15 300 per year.
Next, it was investigated to determine if within the
same cohort of patients, there was a reduction in the
number of investigations per patient. A total of 1503
patients investigated postimplementation of CG95 were
looked at and the mean number of tests per patient was
0.78. In the size-matched cohort of 1503, consecutive
patients were seen preimplementation and the mean
number of tests per patient was 0.97, and again the dif-
ference was statistically significant (Mann–Whitney U,
p<0.001; figure 2).
Three hundred and thirty-five patients were excluded
from the preimplementation cohort due to some early
shift in practice prior to the introduction of the guide-
lines. If these patients were included in the preimple-
mentation cohort, the mean costs would decrease from
£319.54 to £305.80, and the mean number of tests
would decrease from 0.97 to 0.83. This is largely due to
the huge decrease in the number of exercise tolerance
tests performed in the peri-implementation group (2010
pre-CG95, table 4).
Post-CG95 there was a reduction in the number of
patients needing one or more tests. The difference in pro-
portion of patients requiring none, one or more than one
test preimplementation and postimplementation of CG95
was statistically significant (χ
2
test, p<0.000; figure 3), with
an approximate twofold increase in patients requiring no
tests post-CG95 implementation (245 pre-CG95 vs 476
post-CG95)
Next the total number of investigations within each
risk category was evaluated for the post-CG95 cohort.
Table 3 Baseline characteristics of patients
Pre-CG95
(2007–2009)
Post-CG95
(2010–2012)
Total patients 1503 1503
Mean age±SD (years) 56.8±13.4 57.3±13.0
Male (%; not routinely
recorded before 2009)
195 (54.9) 816 (54.3)
Female (%; not routinely
recorded before 2009)
160 (45.1) 686 (45.6)
Type 1 diabetes mellitus
(%)
22 (1.5) 15 (1.0)
Type 2 diabetes mellitus
(%)
235 (15.6) 243 (16.2)
Hyperlipidaemia (%) 604 (40.2) 634 (42.2)
Current smoker (%) 355 (23.6) 322 (21.4)
Ex-smoker (%) 347 (23.1) 393 (26.1)
Table 4 Number of tests and breakdown of investigations per year for the years 2004 to 2012
Year
Exercise
testing
(%)
Myocardial
perfusion
scan (%)
Dobutamine
stress echo
(%)
MRI
(%)
Angiogram
(%)
CT
angiogram
(%)
CT
calcium
scoring
(%)
Mean
number
of tests
per
patient
Number
of
patients
2004 47.6 40.2 NA NA 22.0 NA NA 1.1 378
2005 29.3 50.8 NA NA 19.5 NA NA 1.0 437
2006 29.4 55.5 NA NA 17.8 NA NA 1.0 472
2007 30.8 50.7 NA NA 17.8 NA NA 1.0 600
2008 29.3 54.7 NA NA 15.9 NA NA 1.0 618
2009 17.0 51.3 16.4 0.1 7.0 NA NA 0.9 684
2010
pre-CG95
5.4 53.6 12.7 0.0 6.9 NA NA 0.8 276
2010
post-CG95
6.9 44.7 9.1 0.3 7.2 0.6 5.0 0.7 318
2011 3.2 40.2 8.4 1.7 16.2 5.4 8.4 0.8 634
2012 3.1 37.6 7.1 3.1 10.9 6.0 6.7 0.7 551
Figure 1 Mean costs of investigations per patient pre-CG95
(Clinical Guideline 95) and post-CG95.
Lee AJX, Michail M, Quaderi SA, et al.Open Heart 2015;2:e000151. doi:10.1136/openhrt-2014-000151 3
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Table 5 shows that the lower the risk, the higher the pro-
portion of patients who did not require any investiga-
tions. The proportion of patients requiring increasing
number of tests increased with the risk category.
Table 6 reports the numbers of each test required,
divided by NICE risk category. A total of 106 patients
underwent CT calcium scoring, of which 30 patients
then went on to have a CT angiogram. CT angiograms
were directly requested in 39 patients.
In total 57.2% of patients in the low-risk category did
not undergo investigations. The characteristics of these
patients were interrogated to better understand why the
majority of the patients did not undergo a test. Within
this group of 162 patients, 88 (54.3%) had a CAD risk of
<10 and 74 (45.7%) had a CAD risk of >10. Table 7
looks at the type of pain these patients presented with
and reveals that the majority of these patients (96.9%)
had either non-anginal chest pain or atypical angina.
Finally, the effect of the implementation of CG95 on
the time taken by each patient on their investigative
journey from first presentation to the RACPC to their
final investigation, was evaluated. In patients requiring
investigations, the average time from presentation to
final investigation was 18 days pre-CG95 compared to
20.7 days post-CG95 ( p=0.63), representing a small but
non-statistically significant increase in the time taken for
the total investigative journey.
DISCUSSION
In this analysis, the clinical and economic implications
that implementing the NICE CG95 guideline would
have on tertiary referral centre RACPCs have been evalu-
ated. As per the CG95 guidelines, a reduction in
Exercise Tolerance Tests (ETTs) performed on patients
in this trust has been observed and this is consistent with
evidence showing that ETTs have limited additional
diagnostic value over clinical judgement.
4
However, we
acknowledge that ETTs were still used in our trust. This
may reflect clinicians’familiarity with this test.
Additionally, the NICE CG95 guidelines state that for
people with confirmed CAD (including previous myocar-
dial infarction, revascularisation and previous angiog-
raphy), ETTs may be used when there is uncertainty
about whether chest pain is caused by myocardial
ischaemia.
One hundred and six patients underwent CT calcium
scoring, of which 30 patients then went on to have a CT
angiogram. This was consistent with the CG95 guideline
regarding the assessment of low-risk patients where a CT
angiogram is to be requested if the CT calcium score is
positive. However, CT angiograms were directly
requested in 39 patients without initially requesting a CT
calcium score. This may reflect the clinician’s preference
and also the influence from the British Society of
Cardiovascular Imaging, who advise that despite the
NICE CG95 guidelines, CT calcium scoring is to be used
only as a fall back if a patient is unsuitable for full CT
angiography.
5
Studies comparing CT calcium scores with
CT coronary angiography suggest that the use of a CT
calcium score of 0 to exclude further additional testing
would result in a significant proportion of patients being
misdiagnosed or requiring further testing
6–8
even in
low-risk groups, suggesting that CT angiography may be
more cost-effective in the longer term compared to CT
calcium scoring alone.
A reduction in the mean number of tests per patient
was observed. This is important as it may help to allevi-
ate anxiety in patients as less tests are require to confirm
or exclude a diagnosis of CAD. After the implementa-
tion of the current NICE guidelines, there was a higher
proportion of patients who did not require any further
investigations after presenting to the RACPC. This is
important as it avoids unnecessary tests that may entail
risk or lead to additional worry for patients. This also
suggests that good clinical acumen still plays a key role
Figure 2 Mean number of investigations per patient
preimplementation and postimplementation of CG95 (Clinical
Guideline 95).
Figure 3 Number of tests per patient preimplementation and
postimplementation of CG95 (Clinical Guideline 95).
4Lee AJX, Michail M, Quaderi SA, et al.Open Heart 2015;2:e000151. doi:10.1136/openhrt-2014-000151
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in the assessment of CAD under the new guidelines.
Implementation of CG95 gives physicians more confi-
dence to not order unnecessary tests for patients while
still thoroughly assessing a patient for CAD.
A total of 4968 patients were analysed and a size-
matched cohort of 1503 patients, preimplementation
and postimplementation of CG95, were compared. This
represents the largest published analysis of changes fol-
lowing the implementation of CG95 in this country.
However, several limitations of this study must be
acknowledged. First, this was a single-site study and the
findings may be limited in application to this trust. Local
tariffs vary and this may result in differences in the cost
of investigations at a different centre. Second, while
efforts have been made to provide a NICE-compliant
service, not all individual clinicians in the RACPC have
been completely adherent to the guidelines. This may
reflect the role of the guidance as advice for clinicians
and not a replacement for a clinician’s individual judge-
ment that must be employed for each patient who pre-
sents to clinic. The data presented reflects a real world
implementation of these guidelines and how the prac-
tice changed in relation to the guidelines. The propor-
tion of patients within each risk category may also differ
from year to year, and this may cause the economic costs
to change accordingly from year to year. However, it was
demonstrated that the patient characteristics pre-CG95
and post-CG95 were similar in this trust, suggesting true
economic savings.
This analysis builds on previous reports looking at the
impact of implementing NICE CG95 on economics
costs. Previous studies have suggested either cost neutral-
ity or an increase in costs postimplementation
910
However, this report presents findings from the largest
cohort presented to date. Furthermore, the data
obtained from this cohort is representative of a large
teaching hospital covering patients of a wide range of
ethnicities and backgrounds.
It is interesting to see that despite using costlier initial
investigations postimplementation of NICE CG95, there was
asignificant overall cost reduction resulting from fewer
overall referrals for investigations. A reduction in average
costs for the investigation of each patient was demonstrated.
This is probably due to the combination of eliminating
ETTs as a diagnostic test, a higher proportion of patients
not requiring any tests and fewer mean number of investiga-
tions. A reduction in the number of patients undergoing
coronary angiograms and an increase in non-invasive and
less expensive tests, such as CT angiograms, was seen,
reflecting the increase in investigative options available to
the clinician and guidance from NICE on the appropriate
investigations to use. Despite the introduction of tests such
as CT calcium scoring and MRI which were associated with
longer waiting time in this trust, the average length of the
investigative journey for patients has remained almost the
same postimplementation of CG95.
Although a reduction in the number of tests and cost per
patient was seen, the effects of implementing NICE CG95
on the clinical outcomes of patient with regards to mortality
and morbidity has yet to be investigated. Investigating the
clinical outcomes of patients and the longer term economic
impact of implementing these NICE guidelines would be
an ideal follow-up. This could be used to confirm the evi-
dence used by NICE in developing the current clinical
guidelines and to help shape revisions of the guideline.
CONCLUSIONS
Progress towards a NICE CG95-compliant RACPC
service at the Heart Hospital, University College London
Hospitals has been made. When used in the RACPC,
CG95 demonstrated clear cost benefits. This is likely
explained by patients having the most appropriate first-
line investigation and requiring fewer second-line tests.
Many patients did not require unnecessary tests follow-
ing clinical assessment. A potential reduction in patient
Table 5 Number and percentage of patients requiring zero, one or more than one investigations, divided by NICE CG95 risk
category
0 Investigations (%) 1 Investigation (%) >1 Investigations (%)
Low 162 (57.2) 116 (41.0) 5 (1.8)
Intermediate 124 (34.9) 212 (59.7) 19 (5.4)
High 179 (21.0) 578 (67.8) 96 (11.3)
CG95, Clinical Guideline 95; NICE, National Institute for Health and Care Excellence.
Table 6 Number of investigations, divided by NICE CG95 risk category
Exercise
testing
CT calcium
scoring
CT
angiogram
Myocardial
perfusion scan
Dobutamine
stress echo MRI Angiogram
Low 12 20 12 58 22 2 1
Intermediate 14 35 13 141 34 5 10
High 33 51 44 396 65 22 175
CG95, Clinical Guideline 95; NICE, National Institute for Health and Care Excellence.
Lee AJX, Michail M, Quaderi SA, et al.Open Heart 2015;2:e000151. doi:10.1136/openhrt-2014-000151 5
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morbidity from common cardiac investigations is sur-
mised, particularly invasive angiography. CG95 offers a
concise and objective method for diagnosing cardiac
chest pain. It is hoped that these observations prove that
implementation of NICE CG95 Guidelines RACPCs in
the UK have led/will lead to a faster diagnosis, an
increase in patient’s safety and also cost savings.
Contributors AJXL prepared the manuscript with contribution from all
coauthors. All authors contributed to study design, data collection and data
analysis.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Open Access This is an Open Access article distributed in accordance with
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which permits others to distribute, remix, adapt, build upon this work non-
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Table 7 Number and percentage of patients in low risk
NICE CG95 category requiring zero, investigations, divided
by type of chest pain
Number of patients (%)
Non-anginal 92 (56.8)
Atypical angina 65 (40.1)
Typical angina 5 (3.1)
CG95, Clinical Guideline 95; NICE, National Institute for Health
and Care Excellence.
6Lee AJX, Michail M, Quaderi SA, et al.Open Heart 2015;2:e000151. doi:10.1136/openhrt-2014-000151
Open Heart
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number of investigations and cost per patient
access chest pain clinic reduces the mean
rapidfor assessment of stable chest pain in a
Implementation of NICE Clinical Guideline 95
Richardson, Suneil K Aggarwal and M Elsya Speechly-Dick
Alvin J X Lee, Michael Michail, Shumonta A Quaderi, James A
doi: 10.1136/openhrt-2014-000151
2015 2: Open Heart
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