Horizon Scanning Technology Summary National Horizon Scanning Centre Magnetic resonance angiography (MRA) imaging for the detection of coronary artery disease April 2007 This technology summary is based on information available at the time of research and a limited literature search. It is not intended to be a definitive statement on the safety, efficacy or effectiveness of the health technology covered and should not be used for commercial purposes.
Magnetic resonance angiography (MRA) imaging for the detection of coronary artery disease Target group Diagnosis of coronary artery disease (CAD) in patients with chest pain syndrome a who have an intermediate pre-test probability of CAD and an uninterpretable electrocardiogram (ECG) and/or are unable to exercise. Technology description Magnetic resonance imaging (MRI) is a non-invasive, x-ray free imaging technique in which the patient is exposed to radiofrequency waves in a strong magnetic field, and the pattern of electromagnetic energy released in response is detected and analysed by a computer to generate detailed visual images. Cardiovascular magnetic resonance imaging (CMR) b is an application of MRI that is already used for the evaluation of a range of cardiac parameters, such as cardiac viability, ventricular function and myocardial perfusion and mass. CMR takes around 30-45 minutes to perform. It cannot be used in patients with metallic implants such as pacemakers or stents. Claustrophobia during the procedure may be problematic in around 2% of patients. 1 It is also difficult to perform in patients with irregular cardiac rhythms or who cannot breath-hold for 10-15 seconds. Coronary magnetic resonance angiography (MRA) is a specific anatomical application of CMR imaging technology that is currently in development for the non-invasive detection of coronary artery disease (CAD) through the visualisation of coronary artery stenosis. Innovation and/or advantages MRA uses no radiation, does not require the use of contrast media, and is less invasive, cheaper, and safer than standard invasive coronary angiography for the detection of CAD. Place of use Home care e.g. home dialysis Secondary care e.g. general, non-specialist hospital General public e.g. over the counter Community or residential care e.g. district nurses, physio Tertiary care e.g. highly specialist services or hospital Other: Primary care e.g. used by GPs or practice nurses Emergency care Availability, launch or marketing dates, and licensing plans: CMR technology is available in the UK and is already used extensively for the study of peripheral vasculature (including aortography), renal and carotid arteries to exclude stenosis. However, coronary MRA technology requires additional specific software sequences on scanners capable of fast image acquisition, which are not widely available or used. NHS or Government priority area: Cancer Cardiovascular disease Children Diabetes Chronic conditions Mental health Older people Public health Renal disease Women s health None identified Other: a Chest pain syndrome: e.g. chest pain, chest tightness, burning, dyspnea, shoulder pain, and jaw pain. b Also known as cardiac magnetic resonance imaging (CMR). April 2007 2
This topic relates to the National Service Framework for coronary heart disease. Relevant guidance British Cardiovascular Society working group report on the role of non-invasive imaging in the management of coronary artery disease 2007. 2 European Society of Cardiology and the Society for Cardiovascular Magnetic Resonance consensus panel report. Clinical indications for cardiovascular magnetic resonance (CMR) 2004. 3 European Society of Cardiology. Guidelines for percutaneous coronary interventions 2005. 4 American College of Radiology. Practice guideline for the performance and interpretation of paediatric and adult body magnetic resonance angiography (MRA) 2005. 5 American College of Cardiology Foundation. Appropriateness criteria for cardiac computed tomography and cardiac magnetic resonance imaging 2006. 6 American College of Radiology. Practice guideline for the performance and interpretation of cardiac magnetic resonance imaging (MRI) 2006. 7 American College of Cardiology/American Heart Association/American College of Physicians. Clinical competence statement on cardiac imaging with computed tomography and magnetic resonance 2005. 8 Clinical need and burden of disease CAD is the leading cause of mortality in the UK, causing 88,271 deaths in England and Wales in 2005, 9 and costing the UK economy over 1.7 billion per annum. Around 201,000 invasive coronary angiographies (ICAs) were performed in the UK in 2004 (excluding percutaneous coronary interventions). 2 Estimates of the number of catheterisations that prove to be negative vary: a US study has suggested 25-50%, 10 while a UK expert suggests 14-20%. Within five years there are predicted to be around 350,000 ICAs performed annually. 2 National catheter laboratory facilities have been expanded in recent years, with 90 new laboratories funded by New Opportunities Funding since 2003. However, for patients considered to be at intermediate risk of having high-grade coronary artery stenosis, an accurate and non-invasive means of evaluating CAD would be desirable. A UK expert estimates the pre-test probability distribution for CAD as: Intermediate risk 40% Low risk or normal 30% High risk 30% Existing comparators and treatments Conventional invasive coronary angiography (ICA) involves coronary catheterisation, and is the reference standard for the evaluation of coronary artery stenosis, in-stent stenosis, and the patency of coronary artery bypass grafts. ICA is costly, invasive, and carries a small risk of serious complications (associated mortality 0.07%; low arterial risk <0.25% 2 ). It takes an average of 30-45 minutes. Multidetector computed tomography angiography (MDCTA). A major emerging imaging modality that is non-invasive and provides superior spatial resolution, but April 2007 3
involves exposure to a radiation dose equivalent to that of diagnostic ICA, and an iodinated intravenous contrast agent. A major limiting factor for the accuracy of MDCTA is its ability to visualise coronary arteries with significant calcification. Electron beam computed tomography (EBCT). An emerging technology that is noninvasive, uses less radiation than MDCTA, but is inferior to both MRA and MDCTA in terms of power and slice thickness. EBCT has largely ceded to MDCTA, and is not currently under commercial development. Efficacy and safety Title Status Published 2006 11 Design Meta-analysis Description of study Primary outcome Secondary outcome Key results Comparative diagnostic performance of MRA and MDCTA for non-invasive angiography Studies published in full and in English between Jan 1990 and Jan 2005 on the detection of significant coronary artery stenoses ( 50% diameter) were identified by (i) Medline search, (ii) manual search of leading cardiology and radiology journals, and (iii) reference lists from cited articles. N=52 studies identified: (a) MRA vs ICA 28 studies (903 patients) (b) MDCTA vs ICA 24 studies using 4, 8 and 16-slice machines (1,300 patients) Intervention: evaluation of stenosis by MRA or MDCTA Comparator: conventional invasive coronary angiography (ICA) Patient group: patients with known or suspected coronary artery disease Diagnostic accuracy: sensitivity and specificity. Pooled analysis based on weighted means (i.e. proportional to the sample size of each individual study). Odds ratio and summary odds ratio compared against ICA. Average % of assessable coronary segments (i.e. those with diagnostic imaging quality). Sensitivity Specificity % of assessable % (95% CI) % (95% CI) coronary segments MRA 72% (69%-75%) 87% (86%-88%) 83% MDCTA 85% (83%-87%) 95% (95%) 87% (4-16 slice CT) 96% (16-slice only) MDCTA was significantly more accurate than MRA in detecting CAD compared to ICA. A combined analysis of the odds ratios showed that for MDCTA, there was a 16.9-fold increased probability of significant CAD found at cardiac catheterisation (ICA), which was significantly higher (p<0.0001) than the 6.4-fold increase found for MRA. Estimated cost and cost impact The precise costs of MRA are difficult to identify as it is usually conducted as part of a conventional MRI examination (adding around 15 minutes to the procedure time), although a UK expert estimates that two-stage MRA may have a tariff at around 200 per case. The 2007/08 NHS tariff for ICA is 1,100. 12 April 2007 4
Potential or intended impact speculative The 2007 working group report of the British Cardiovascular Society 2 on the role of noninvasive imaging for CAD concluded that although MRA is unlikely to replace diagnostic ICA due to its inferior spatial resolution, the full implementation of CMR could reduce the need for ICAs by up to 25% over the next 10 years. The working group recommended that all new MRI scanners should be CMR-capable and that the current number of 140 CMR scanners will need to be increased over the next 5-10 years. The majority of MRI scanners are currently based in hospital radiology departments, where there are numerous competing demands from other specialties. Issues of access may affect the UK diffusion of this technology for applications in cardiology. In addition, echocardiography, nuclear cardiology and diagnostic cardiac angiography have mainly been performed by cardiologists rather than radiologists. Patients Reduced morbidity Reduced mortality or increased survival (reduced short-term risk from the procedure) Earlier identification of disease Quicker or more accurate diagnosis Other: faster, safer, and less invasive procedure than the current standard (ICA) Improved quality of life for patients and/or carers Changed pathway of care or outcome Services Increased use e.g. length of stay, out-patient visits Service reorganisation required Staff training required Decreased use - reduced demand for the services of specialist laboratories for diagnostic ICA Costs Increased unit cost compared to alternative Savings: cheaper and faster alternative to diagnostic ICA References Increased costs: more patients coming for treatment Other: staff training needed Increased costs: capital investment needed 1 Francis JM & Pennell DJ. The treatment of claustrophobia during cardiovascular magnetic resonance; use and effectiveness of mild sedation. J Cardiovasc Magn Reson 2000; 2: 139-141. 2 Gershlick A H, de Belder M, Chambers J et al. The role of non-invasive imaging in the management of coronary artery disease current status and future impact. A report from the British Cardiovascular Society working group. Heart 2007; 93: 423-431. 3 European Society of Cardiology and the Society of Cardiovascular Magnetic Resonance consensus panel report. Clinical indications for cardiovascular magnetic resonance (CMR). Eur Heart J 2004; 25: 1940-1965 4 European Society of Cardiology. Guidelines for percutaneous coronary interventions. Eur Heart J 2005; 26: 804-847. 5 American College of Radiology. Practice guideline for the performance and interpretation of pediatric and adult body magnetic resonance angiography. 25/02/2005. http://www.acr.org 6 Appropriateness criteria for cardiac computed tomography and cardiac magnetic resonance imaging. American College of Cardiology Foundation (ACCF) in conjunction with American College of Radiology, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, American Society of Nuclear Cardiology, North American Society for Cardiac Imaging, Society for Cardiovascular Angiography and Interventions, and Society of Interventional Radiology. J Am College Cardiol 2006; 48: 1475-97. 7 American College of Radiology. Practice guideline for the performance and interpretation of cardiac magnetic resonance imaging. 10/01/2006. http://www.acr.org April 2007 5
8 American College of Cardiology/American Heart Association/American College of Physicians. Clinical competence statement on cardiac imaging with computed tomography and magnetic resonance. J Am College Cardiol 2005; 46: 383-402. 9 British Heart Foundation mortality data for ICD code I20-25 ischemic heart diseases (2005), available at http://hwww.heartstats.orgh 10 Poon M. CTA: watershed, soon to be a flood. Article published by Wiley 2005, available at www.imagingeconomics.com/issues/articles/2005-03 11 Schujf J D, Bax J J, Shaw L J et al. Meta-analysis of comparative diagnostic performance of magnetic resonance imaging and multislice computed tomography for noninvasive coronary angiography. Am Heart J 2006; 151: 404-411. 12 NHS tariff for Health Care Resource groups (HRG) code E14 for 2007-08. The National Horizon Scanning Centre is a constituent of the NHS National Institute for Health Research and is managed under contract from the Department of Health's R&D Division. The views expressed in NHSC publications are those of the author(s). They are not necessarily shared by the Department of Health and should not be taken as representing Government policy. The National Horizon Scanning Centre, Department of Public Health and Epidemiology University of Birmingham, Edgbaston, Birmingham, B15 2TT, England Tel: +44 (0)121 414 7831 Fax +44 (0)121 414 2269 www.pcpoh.bham.ac.uk/publichealth/horizon April 2007 6