The National Institute for Health and Care Excellence (NICE) released an updated guideline on stable chest pain in 2016. They recommended that all patients with chest pain, typical or atypical, should be investigated with computed tomography coronary angiography (CTCA) in the first instance. Functional imaging tests were reserved for the assessment of patients with chest pain and known coronary artery disease (CAD) and for patients where the CTCA is equivocal or has shown CAD of uncertain significance. The European Society of Cardiology (ESC) guidelines on stable chest pain, however, recommend functional imaging tests for all stable chest pain patients, with CTCA as an alternative in patients with low-to-intermediate likelihood of CAD. The ESC guidelines also allow for the use of the exercise electrocardiogram (ECG) as an alternative to functional imaging tests in patients with low-to-intermediate likelihood of CAD, if functional imaging tests are not available.
Furthermore, traditionally, the aetiology of heart failure or left ventricular (LV) dysfunction was investigated with diagnostic invasive coronary angiography. More recently, cardiac magnetic resonance imaging (MRI) tissue characterisation was proposed as an effective alternative test. We conducted a survey of UK cardiologists’ opinions on the use of CTCA in patients with stable chest pain and in the investigation of the aetiology of heart failure.
Introduction
The National Institute for Health and Care Excellence (NICE) released an updated guideline on stable chest pain in 2016.1 It marked a radical departure from the 2010 NICE and European Society of Cardiology (ESC) guidelines.2 They recommended that the pre-test probability risk score should not be used as it over-estimated the likelihood of coronary artery disease (CAD) and that all patients with chest pain, typical or atypical, should be investigated with computed tomography (CT) coronary angiography (CTCA) in the first instance. Functional imaging tests were reserved for the assessment of patients with chest pain and known CAD, and for patients where the CTCA is equivocal or has shown CAD of uncertain significance. CTCA has excellent negative predictive value, and is a cost-effective test.3,4 The NICE resource impact report states that this is likely to result in more appropriate diagnostic investigations and reduced adverse events, but they concede that there will be limitations in availability of CTCA capable scanners and appropriately trained CT practitioners.5
The ESC guidelines on stable chest pain, however, recommend, functional imaging tests for all stable chest pain patients, with CTCA as an alternative in patients with low-to-intermediate likelihood of CAD. ESC also allow for the use of the exercise electrocardiogram (ECG) as an alternative to functional imaging tests in low-to-intermediate likelihood subgroups, if functional imaging tests are not available.2
Furthermore, traditionally, the aetiology of heart failure or left ventricular (LV) dysfunction was investigated with diagnostic invasive coronary angiography. More recently, cardiac magnetic resonance imaging (CMR) tissue characterisation was proposed as an effective alternative test, but there is debate as to whether CMR alone is sufficient, or if coronary angiography is still required.6,7 CTCA is a low-cost alternative test to image the coronary arteries, but requires a relatively slow regular heart rhythm for a successful scan.8
Our primary aim was to undertake a survey of UK cardiologists’ opinions on the new NICE guideline on stable chest pain, and on the use of CTCA beyond stable chest pain, as in the investigation of the aetiology of heart failure/LV dysfunction.
Methods
In an iterative process, a short questionnaire was designed using electronic survey software and tested on local consultant cardiologists. This was subsequently emailed via a commercial directory to all UK consultant cardiologists with responses obtained over a four-week period.
The first part of the questionnaire was about the consultant cardiologists; work base, length of experience, sub-specialty and whether they considered themselves to be an enthusiast for CTCA or functional imaging tests. The second part of the questionnaire was about how cardiologists investigated patients with stable chest pain, in the light of the new NICE guideline. Specifically, what did they consider the best test to be, in patients with chest pain and low-to-intermediate probability of CAD and in patients with intermediate-to-high probability of CAD. As the new NICE guideline recommends CTCA for all patients, we asked how the cardiologists would investigate patients with a CTCA finding of moderate (50–70%) stenosis and CTCA finding of severe (>70%) stenosis, other than left main stem (LMS) disease. We also asked which guideline (NICE or ESC) was most similar to the cardiologists clinical practice, giving a third choice of neither, and a fourth choice of “I still use the exercise ECG”. The third part of the questionnaire was about the investigation of patients with heart failure/LV dysfunction. Specifically, if cardiologists considered CMR to be sufficient to diagnose ischaemic versus non-ischaemic aetiology, whether invasive coronary angiography was still required, and whether CTCA can be used instead, and what would be the reasons not to use CTCA in this context.
Results
On the first round, a total of 887 consultant cardiologists were emailed, with 257 opening the email. There were 111 cardiologists who responded to the first email. An additional 50 cardiologists responded to a second email, giving us a total of 162 responses. There was a near even split of responses from consultants practising at a district general hospital (52%) and consultants from tertiary cardiac centres (48%); 64% of the consultants had greater than 10 years’ experience. A representative sample of sub-specialties was also obtained, with 22% general cardiologists, 36% interventional cardiologists, 26% cardiac imaging cardiologists, 10% heart failure cardiologists, 4% electrophysiologists and one adult congenital heart disease cardiologist. Just over two-thirds expressed no preference for either functional imaging tests versus CTCA, while the remaining one-third, were divided almost evenly between the two.
In the context of investigating patients for chest pain with low-to-intermediate probability of CAD, 71% of respondents expressed a preference for CTCA as the best test. But this preference decreased to 37% of respondents when investigating patients with intermediate-to-high probability of CAD.
When presented with investigative options for CTCA findings of 50–70% stenosis (excluding LMS), 49% utilised functional imaging test, 38% invasive coronary angiography ± invasive fractional flow reserve (FFR), while 11% opted for medical management, and 2% CT-FFR. When investigating CTCA findings of >70% stenosis (excluding LMS), almost 80% opted for invasive coronary angiography, 15% functional imaging, with 6% opting for medical management, and one respondent electing for CT-FFR.
More than 60% of respondents did not agree with the decision to remove the pre-test probability score from the new guidelines. Only 25.5% felt their clinical practice mirrored NICE guidelines, 41% utilised ESC guidelines, and 22% did not adhere to either, particularly. Of note, 11% still utilised exercise ECG as a first-line test.
With respect to determining aetiology of heart failure/LV dysfunction, 55% of respondents felt CMR alone was sufficient to differentiate ischaemic versus non-ischaemic cardiomyopathy. However, 56% still felt invasive coronary angiography was required, while 70% felt CTCA could be used as an alternative to invasive coronary angiography. Of the 30% of cardiologists who did not agree with the use of CTCA as an alternative to invasive coronary angiography, 22% selected the option that invasive angiography was a superior test, 20% selected the option that CTCA would be technically challenging in heart failure patients and the majority (58%) selected both as reasons not to use CTCA in heart failure/LV dysfunction.
Discussion
We obtained a representative sample of UK cardiologists with a good response rate. The majority of consultants in our sample described themselves as enthusiasts for both CTCA and functional imaging tests. The majority of UK cardiologists would investigate chest pain patients with low-to-intermediate pre-test probability, with CTCA. But for patients with the intermediate-to-high pre-test probability, the majority expressed a preference for functional imaging tests. This corresponded with a larger proportion of cardiologists expressing an inclination for the ESC guidelines over the recent NICE guidelines.
We demonstrated an acceptance for the expanding role of CTCA among UK cardiologists for patients with stable chest pain, although not to the extent recommended by the NICE guidelines. In addition, there is also recognition that CTCA has utility in excluding CAD in other patient populations, such as heart failure/LV dysfunction. The survey shows that UK cardiologists are aware of the strengths and limitations of CTCA, such as the reservation about its role in patients with higher probability of CAD, where there is no evidence-base for its use and where its low positive-predictive value is likely to result in a higher rate of invasive coronary angiography that does not lead to revascularisation. NICE have addressed this particular concern by issuing a second guideline, recommending the use of CT-FFR as a gatekeeper to invasive coronary angiography.9 However, this is an expensive test (£700) with limited evidence-base. The consultants’ preference for the second-line investigation, when moderate CAD is found on CTCA, was mostly for the lower cost, functional imaging tests, which have an extensive evidence-base,10-13 in preference to CT-FFR.
There is limited consensus on the optimal strategy in determining the aetiology of heart failure/LV dysfunction, with CMR still not clearly felt to be an adequate standalone modality to exclude CAD as a differential. Although 70% felt that CTCA could be an alternative to invasive coronary angiography with certain caveats. There was a valid concern about the quality and feasibility of CTCA in heart failure patients who tend to have faster heart rates and a higher number of ectopic beats, which would be challenging on 64-slice CT scanners, but not on high-specification CT scanners. Finally, a few senior cardiologists critiqued our survey in that we limited the responses to the questions and did not allow for ‘none of the above’ answers, and most notably that aetiology of heart failure need not necessarily be sought. We are grateful for this critique and acknowledge this limitation in our questionnaire and we replied to explain that our aim was to keep the survey simple.
Conflict of interest
None declared.
Key messages
- UK cardiologists have a preference for computed tomogaphy (CT) coronary angiography in patients with chest pain and low-to-intermediate pre-test probability of coronary artery disease (CAD). However, they prefer to use functional imaging tests in patients with intermediate-to-high pre-test probability
- UK cardiologists utilise both Natioanl Institute for Health and Care Excellence (NICE) and European Society of Cardiology (ESC) guidelines on stable chest pain, with a preference for the ESC guidelines
- There is recognition for the potential of CT coronary angiography as an alternative to invasive coronary angiography in the diagnosis of aetiology of heart failure
References
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