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In March 2010, the National Institute for Health and Clinical Excellence (NICE) published evidence-based recommendations on best practice in the assessment and diagnosis of patients with chest pain that may be of cardiac origin.1 For those with suspected ‘stable angina’, they recommend initial clinical risk assessment to estimate the likelihood of coronary artery disease following which the requirement for diagnostic testing (anatomical testing for obstructive coronary artery disease and/or functional testing for myocardial ischaemia) is ascertained. As such, the guideline aims to provide objective clinical criteria for determining whether diagnostic testing is necessary and if so what test should be used. One of the most controversial decisions in the guidance is the omission of exercise tolerance testing from the diagnostic algorithm. Instead, advanced cardiac imaging modalities feature heavily, including cardiac multi-detector CT (MDCT), nuclear perfusion scintigraphy, stress echocardiography and perfusion cardiac MRI. These are highly specialised and resource-intensive investigations, which not all hospitals will have direct access to, especially in the district general hospital setting.
Adoption of NICE guidelines will result in a major shift in the investigative strategy for many patients, and in this issue of Postgraduate Medical Journal, Garg et al predict the impact on investigation requirements in a large UK teaching hospital based on data collated from 435 patients attending a rapid access chest pain clinic (RACPC) over a 6-month period (see page 445).2 They predict that of these patients 27% would be discharged without further cardiac investigation, 30% would require functional imaging, 22% cardiac MDCT and 21% invasive angiography. NICE guidelines place great importance on risk factor probability-based assessment models for deciding which patients should proceed to investigation, and it is becoming apparent from this and other recently published studies that strict application of the guidelines is likely to result in discharge without further investigation of large numbers of patients deemed to have ‘non-cardiac’ chest pain.3 Indeed, in a recent study undertaken at two large district general hospitals in West London, investigators showed that strict implementation of NICE guidelines would result in up to 74% of patients attending the RACPCs not being investigated further based on history and clinical examination as opposed to only 6% of patients before implementation of NICE guidelines.3 Although pretest probability assessment models have been extensively validated, concerns still exist that some patients will fall through the net as highlighted by a recent multicentre study which showed that around 30% of cardiac events in patients attending RACPCs occurred in those labelled as having ‘non-cardiac’ pain.4 Another important issue with regard to medical consultation without progression to investigation is that it does little to alleviate patient anxiety and may result in frequent reattendance possibly mitigating any potential cost savings.3
For those patients deemed to require further investigation, Garg et al predict that approximately equal numbers are likely to need cardiac MDCT, functional imaging and invasive angiography, which is in contrast to the findings of Patterson et al, who found that only 2% would meet the criteria for MDCT, 12% for functional imaging and 12% for invasive angiography3 and clearly there may be considerable regional variation. Hospitals that do not have cardiac MDCT capability and/or access to certain types of functional imaging may have no choice but to send RACPC patients to specialist regional centres for further investigation, with potential delay to definitive diagnosis. A recent study of 2200 patients attending a NICE-compliant RACPC showed delays of up to 4 months for MDCT scanning and other specialist imaging investigations with some patients experiencing an acute event during this time; similar concerns have also been raised by the Primary Care Cardiovascular Society.5 Even those hospitals with on-site cardiac MDCT may struggle to meet any increase in demand and services may need to be reconfigured to avoid delays in the system. Ideally, such a service would ‘link’ RACPC referrals to reserved MDCT scanning slots, preferably on the same day as the clinic attendance although this may be difficult to achieve in many radiology departments that are already full to capacity with inpatient, emergency and elective work.
The NICE guidelines call for a paradigm shift in the way patients with suspected ‘stable angina’ are investigated and it remains to be seen how widely they will be adopted by UK cardiology departments. One major concern that seems to be coming from preliminary studies concerns high numbers of patients attending RACPCs who do not fulfil criteria for any form of further investigation, a fact that may be unacceptable for many referring clinicians and indeed patients. Exercise tolerance testing has, for many years, been the cornerstone of initial assessment at RACPCs and is unlikely to be completely abandoned, especially in hospitals where there is limited access to advanced cardiac imaging modalities.6 Hospitals considering implementation of NICE guidelines should be cognisant of the potential impact on service provision and would be wise to examine their local RACPC cohorts (along the lines of Garg et al) in this regard.
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