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Rapid Responses to:
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Electronic letters published:
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Elderly Patients Are the Achilles’Heel of Non-invasive Coronary Angiography
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Gianluca Rigatelli, MD, FACP Service of Cardiovascular Diagnosis and Interventions, Rovigo General Hospital, Rovigo, Italy
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jackyheart{at}hotmail.com Gianluca Rigatelli
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We read with interest the article of Dewey et al [1] about non invasive coronary angiography, but although I found it extremely elegant , I believe we should clarify some points before giving recomandations about non invasive coronary angiography. While CMR had great promise as a radiation-free and contrast-free "one- stop" procedure, as nicely demonstrated by Dewey et al, its technology currently lags behind CTA in the non-invasive imaging of coronary artery but to use only CT as non invasive modality poses some limits. Firstly, elderly patients (age >70 years old) are the most likely to suffer from coronary artery disease (CAD), and as matter of fact, they are the 77% of patients investigated for CAD in our institution. Secondly, the elderly patients have high incidence of coronary calcium deposits [2]: dense calcification could result in overestimating the severity of the lesion (false positive) or prevent assessment of the lesion (considered as underestimate or false negative by the authors) [3- 4]. The false positive results might lead to unnecessary invasive coronary angiography and the underestimated results gives false assurance to the patient who might need coronary interventions. Moreover, despite the patient radiation exposure to CT angiography is similar than coronary angiography alone, the amount of contrast used in a false positive CTA plus invasive coronary angiography could be prohibitive for the elderly patient population with borderline renal function. Thirdly, as recently suggested [5], in patients with suspected CAD, the pretest likelihood of disease, a clinical assessment, becomes the most important determinant of the initial test. If the likelihood is very low, no testing is needed. However, even if the likelihood is low, recent data suggest provocatively that assessment of early atherosclerosis is likely to be the most useful and cost-effective test because the majority of acute myocardial infarction is caused by mild plaques without calcification. In the elderly patients with high likelihood of CAD, myocardial perfusion SPECT may be the initial test of choice, since a high proportion of these patients has too much coronary calcium deposits to allow accurate assessment of coronary stenoses. PET/CT or SPECT/CT could emerge as important modalities combining the advantages of each modality. CT angiography may be preferable in case of surgical revascularized patients, who has been already evaluated for both coronary and peripheral vascular distributions and may benefit from a non-invasive control of graft patency [5]. Finally, the conclusive assumption of Dewey et al about effectiveness of non-invasive angiography before conventional coronary angiography, in my opinion is somewhat optimistic at the moment: in coronary artery management an image technique is really useful when it can guide coronary interventions, the essence of coronary artery management. This certainly will append In the next 5-10 years, when 125 and 240 slice MDCTs would be normal standard of care for detecting coronary artery stenoses. References 1. Dewey M, Teige F, Schnapauff D et al. Noninvasive detection of coronary artery stenoses with multislice computed tomography or magnetic resonance imaging- Ann Intern Med 2006; 145:407-15. 2. Cordeiro MA, Miller JM, Schmidt A, Lardo AC, Rosen BD, Bush DE, Brinker JA, Bluemke DA, Shapiro EP, Lima JA. Non-invasive half millimetre 32 detector row computed tomography angiography accurately excludes significant stenoses in patients with advanced coronary artery disease and high calcium scores. Heart. 2006; 92:589-97. 3. de Feyter PJ. Can multislice CT detect coronary artery disease accurately? Nat Clin Pract Cardiovasc Med. 2005 Nov;2:560-1. 4. Beck T, Burgstahler C, Reimann A, Kuettner A, Heuschmid M, Kopp AF, Schroeder S. Technology insight: possible applications of multislice computed tomography in clinical cardiology. Nat Clin Pract Cardiovasc Med. 2005; 2:361-8. 5. Berman DS, Hachamovitch R, Shaw LJ, Friedman JD, Hayes SW, Thomson LE, Fieno DS, Germano G, Slomka P, Wong ND, Kang X, Rozanski A. Roles of Nuclear Cardiology, Cardiac Computed Tomography, and Cardiac Magnetic Resonance: Assessment of Patients with Suspected Coronary Artery Disease. J Nucl Med. 2006;47:74-82. Conflict of Interest:None declared |
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