ACC 2004 ANNUAL SESSION HIGHLIGHTS
Noninvasive imaging
Bijoy K. Khandheria, MD, FACC*,*
* Mayo Clinic College of Medicine, Rochester, Minnesota, USA
*
Reprint requests and correspondence: Dr. Bijoy K Khandheria, Mayo Medical School, 200 First Street SW, Rochester, Minnesota 55905-0001, USA.
khandheria{at}mayo.edu
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Coronary calcium
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Tande et al. (1) demonstrated that the modified Diamond-Forrester (MDF) score accurately identifies asymptomatic patients with a high coronary calcium score and thereby may serve as a useful and cost-effective tool to determine appropriate use of calcium scoring. Electron beam computed tomography (EBCT) is of greatest value in patients with an intermediate to high MDF score (1). Schermund et al. (2) reported that high-sensitivity C-reactive protein (CRP) and coronary calcium do not seem to show any association after adjusting for traditional risk factors and body mass index in the general population. The same group of authors reported that approximately one of six subjects in the general population of the German Ruhr area is classified discordantly as "high-risk" by the Framingham algorithm or by coronary calcium score. The utilization of CRP in conjunction with coronary calcium must be defined. Finally, exciting data were provided by Schmid et al. (3), who showed a statistically significant relationship between the extent of calcification of the aortic valve and systemic inflammation, especially in patients with a high amount of calcification in the aortic valve and coronary artery. These data lend credence to the possibility that these may be manifestations of the same disease.
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Multislice computed tomography (MSCT) for coronary artery disease (CAD)
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The diagnostic accuracy of EBCT and four-slice MSCT was found to be limited based on an analysis of 25 published studies involving 1,439 patients. In contrast, the potential of 16-slice MSCT was found to be equivalent (4). Habert et al. (5) showed that coronary angiography with MSCT, but not the coronary calcium score, can help reduce the number of catheter procedures for the diagnosis of CAD by up to 35% in symptomatic patients with suspected CAD.
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Magnetic resonance imaging (MRI)
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There was an explosion in the number of abstracts presented on this imaging modality at the American College of Cardiology (ACC) Annual Session Highlights of 2004. Insofar as anatomy of the heart is concerned, MRI is useful in a wide variety of diseases. A new technique called Dyn-3D can acquire a substantial amount of information in a short period and hence can be employed if time is limited (6).
The message that resonated loudly in the field of MRI was the detection of viable myocardium and myocardial perfusion. It was shown that MRI was as good as, if not better than, scintigraphy for detecting viable myocardium and myocardial perfusion (7–9).
Not finding a scar on contrast-enhanced MRI demonstrates a high negative predictive value for inducible monomorphic ventricular tachycardia, justifying its use in the evaluation of patients who had sudden cardiac death (10).
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Positron emission tomography (PET)
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The promise of detecting viable myocardium and predicting functional recovery by PET was brought to fruition (11). However, the predictive accuracy was similar to that of single-photon emission computed tomography (SPECT). The beneficial effects of lipid lowering may require evaluation by PET, as a quarter of the patients presumed to be adequately treated for lipid lowering by current guidelines had perfusion abnormalities detected by PET and had poor outcomes (12).
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Nuclear perfusion imaging
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Some of the exciting data on the use of nuclear perfusion imaging presented at this meeting dealt with the epidemic of metabolic syndrome. The role of nuclear perfusion studies as a screening test in patients with diabetes mellitus, test for risk factor stratification, and test to demonstrate the value of glucose lowering on coronary circulation and myocardial ischemia was established in presentations made by several groups of investigators (13,14). The prevalence of silent myocardial ischemia is high in patients with diabetes as compared with those without diabetes (15). It is cost effective to use nuclear techniques for screening asymptomatic patients with diabetes mellitus.
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Echocardiography
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Highlights in the field of echocardiography included validation of the role of myocardial contrast echocardiography in the detection of viable myocardium, measurement of blood volume, and detection of perfused versus nonperfused myocardium. These studies were further proof that myocardial contrast echocardiography is coming of age (16,17).
Application of myocardial strain and strain rate imaging in heart failure, cardiac resynchronization therapy, and hypertrophy of the myocardium, in conjunction with stress echocardiography for accurate detection of viable myocardium, were the subject of numerous presentations. The entire area of Doppler myocardial imaging continues to show promise in diagnosis of cardiac muscle disease (18,19).
It is a predictor of mortality in patients with a normal QRS complex, raising the intriguing possibility that the current Food and Drug Administration criteria for implantation of biventricular pacemakers in patients with heart failure may undergo changes in the near future (20).
Doppler myocardial imaging was observed to have an edge over brain natriuretic peptide in prognostication of patients with heart failure. A comprehensive Doppler examination, which included measurement of the E/Ea ratio, was the only significant predictor of prognosis in patients with heart failure in this study of 81 patients (21).
Hand-carried ultrasound as an adjunct to physical examination for use by medical students and house staff was found to be superior to experienced cardiologists performing a cardiac physical examination (22). The era of stethoscope may be headed toward a sunset with the development of compact ultrasonic devices.
Three-dimensional echocardiography occupied a prominent role among the abstracts presented at this meeting. Three-dimensional echocardiography provides better quantitative information on left ventricular (LV) function and valve regurgitation than two-dimensional echocardiography (23).
Intracardiac echocardiography is becoming the standard of care when performing radiofrequency ablation procedures (24). Its role in percutaneous atrial septal defect closure and left atrial appendage occlusion was emphasized in presentations (25).
Workflow in the echocardiography laboratory is immensely important in these times of limited resources. New transducer technology demonstrated that one can do more with less: less time and more information (26).
Stress echocardiography continues to mature and has become an established technique. Schinkel et al. (27) from the Netherlands demonstrated that dobutamine stress echocardiography had incremental prognostic value in predicting long-term prognosis over clinical variables and was comparable to dobutamine SPECT in a large number of consecutive patients undergoing both tests. Strain and strain rate response to infusion of dobutamine are feasible markers of viability as compared with wall motion alone (28).
The value of real-time, full-volume three-dimensional echocardiography was investigated, and, in six consecutive patients undergoing dobutamine stress echocardiography, Pulerwitz et al. (29) could demonstrate its feasibility, leading to provocative suggestion that all stress echocardiography in the future could be performed using full-volume three-dimensional acquisition technique. The implications of this on workflow and accuracy, if validated by larger studies, is enormous.
Diastolic function is best assessed by echocardiography and Doppler myocardial imaging. Incremental advances presented at ACC 2004 included the finding that the echocardiographic grade of diastolic function reflects ventricular wall stress and stiffness, independent of LV hypertrophy and co-morbidities. This was demonstrated by Cauduro et al. (30) in 47 consecutive patients undergoing simultaneous Doppler and catheter studies.
In a high-volume clinical laboratory, it is difficult to obtain all parameters, and more importantly, the incremental utility of each of these depends on the ability to obtain the measurements and interobserver variability. Mitral flow velocity and tissue Doppler indexes were found to have the highest success in recording and also had the lowest variability, leading Khan et al. (31) to conclude that these were the most practical measures to obtain when performing Doppler studies for diastolic function.
Finally, the role of transesophageal echocardiography (TEE) as the modality of choice for imaging atherosclerosis of the aorta and left atrial appendage was reinforced during a poster session on TEE. Demonstration that atherosclerosis of the aorta is not independently associated with LV diastolic function and the role of TEE in follow-up of patients with transcatheter occlusion of left atrial appendage were shown during this session (32,33).
What did ACC 2004 tell us? Noninvasive imaging is in its infancy. There is robust growth in the field of noninvasive imaging. Some of the modalities compete and, in many instances, play a complementary role. The field remains vibrant and healthy, thus poised for growth.
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References
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- Tande AJ, Haroldson J, Bodeau G, et al. A modified Diamond-Forester score accurately identifies asymptomatic patients with a high coronary artery calcium score. J Am Coll Cardiol. 2004;43(Suppl A):334A abstr
- Schmermund A, Stang A, Moebus S, et al. Is there an association of high-sensitive C-reactive protein with coronary calcium? The Heinz Nixdorff Recall Study. J Am Coll Cardiol. 2004;43(Suppl A):334A abstr
- Schmid M, Kusus M, Ropers D, et al. Association of elevated C-reactive protein levels to aortic valve calcification as quantified by electron beam tomography. J Am Coll Cardiol. 2004;43(Suppl A):335A abstr
- Hoffmann U, Jadvar H, Dunn E, et al. Is computed tomography-based coronary angiography ready for prime time? A meta analysis. J Am Coll Cardiol. 2004;43(Suppl A):312A abstr
- Haberl R, Boehme E, Steinbigler P, et al. Does cardiac multislice computed tomography change the indication for invasive coronary angiography in symptomatic patients with suspected coronary artery disease? J Am Coll Cardiol. 2004;43(Suppl A):24A abstr
- Fogel M, Simonetti O, McNeal G, et al. Utility of subsecond, three-dimensional maximum intensity projection of time resolved dynamic gadolinium magnetic resonance imaging in congenital heart disease. J Am Coll Cardiol. 2004;43(Suppl A):389A abstr
- Seo H, Moon JY, Ko YG, et al. Comparison between myocardial contrast echocardiography and contrast enhanced magnetic resonance imaging in prediction of the myocardial viability after direct percutaneous transluminal angioplasty in acute myocardial infarction. J Am Coll Cardiol. 2004;43(Suppl A):24A abstr
- Ekinci O, Dill T, Hansl J, et al. Diagnostic value of adenosine stress magnetic resonance (MR) perfusion imaging and delayed MR hyperenhancement compared to Tl-201 SPECT and coronary angiography for detection of coronary artery disease and myocardial scar tissue. J Am Coll Cardiol. 2004;43(Suppl A):354A abstr
- Klem I, Hetner J, Shah D, et al. Clinical evaluation of patients with suspected coronary artery disease using a multimodality stress magnetic resonance imaging protocol. J Am Coll Cardiol. 2004;43(Suppl A):365A abstr
- Klem I, Heitner J, Weinsaft J, et al. Diagnostic utility of contrast enhanced magnetic resonance imaging for screening patients at risk for sudden cardiac death. J Am Coll Cardiol. 2004;43(Suppl A):353A abstr
- Shirasaki H, Lee J, Nakano A, et al. Utility of fluorodeoxyglucose-positron emission tomography for predicting left ventricular functional recovery in patients with acute myocardial infarction after successful revascularization: comparison with technetium-99m tetrofosmin SPECT. J Am Coll Cardiol. 2004;43(Suppl A):337A abstr
- Merhige M, Watson G, Oliverio J, et al. Efficacy of lipid lowering therapy in inducing arrest or reversal of coronary disease as assessed with positron emission tomography. J Am Coll Cardiol. 2004;43(Suppl A):332A abstr
- Abbott B, Arright J. Screening stress myocardial perfusion imaging for risk stratification in asymptomatic diabetic men. J Am Coll Cardiol. 2004;43(Suppl A):339A abstr
- Navare SM, Noble GL, Ahmed S, et al. Risk stratification of diabetic patients with rest/stress ECG-gated Tc-99m sestamibi SPECT imaging: significance of mild perfusion abnormalities. J Am Coll Cardiol. 2004;43(Suppl A):339A abstr
- Anand V, Fourie S, Hopkins D, et al. Prevalence of silent ischemia in diabetic patients with subclinical atherosclerosis: detection by stress myocardial perfusion imaging. J Am Coll Cardiol. 2004;43(Suppl A):340A abstr
- Hickman M, Janardhan R, Dwivedi G, et al. Can resting myocardial contrast echocardiography replace 99m-technetium sestamibi SPECT for the diagnosis of myocardial viability following myocardial infarction. J Am Coll Cardiol. 2004;43(Suppl A):314A abstr
- Ronderso R, Boskis M, Charlante C, et al. Long-term prediction of coronary events according to the results of high dose dipyridamole contrast echocardiography myocardial perfusion studies. J Am Coll Cardiol. 2004;43(Suppl A):315A abstr
- Kanzaki H, Raveen B, Dohi K, et al. Echocardiographic tissue synchronization imaging predicts acute response to biventricular pacing therapy. J Am Coll Cardiol. 2004;43(Suppl A):333A abstr
- Notabartolo D, Merlino J, Smith A, et al. Myocardial strain and displacement following cardiac resynchronization therapy. J Am Coll Cardiol. 2004;43(Suppl A):333A abstr
- Cho GY, Park WJ, Han SW, et al. Dopper tissue imaging assessment of dysschnronixity is a powerful predictor of mortality in severe congestive heart failure with normal QRS duration. J Am Coll Cardiol. 2004;43(Suppl A):361A abstr
- Dokanish H, Ambriz E, Zoghbi W, et al. Tissue Doppler echocardiography and B-type natriuretic peptide in the prognosis of congestive heart failure. J Am Coll Cardiol. 2004;43(Suppl A):346A abstr
- Kobal S, Trento L, Baharami S, et al. Rebirth of bedside cardiovascular examination using hand-carried ultrasound. J Am Coll Cardiol. 2004;43(Suppl A):309A abstr
- Caini EG, Sugeng L, Corsi C, et al. Direct quantification of left ventricular volumes by real-time three-dimensional echocardiography: validation by cardiac magnetic resonance imaging. J Am Coll Cardiol. 2004;43(Suppl A):343A abstr
- Jongbloed M, Bax J, Kies P, et al. Utility of intracardiac echocardiography to guide radiofrequency catheter ablation of ventricular tachycardioa of different etiologies. J Am Coll Cardiol. 2004;43(Suppl A):359A abstr
- Bartel T, Konorza T, Eggebrecht H, et al. Patients benefit from intracardiac echocardiography used as a novel guiding tool for device closure of interatrial communication. J Am Coll Cardiol. 2004;43(Suppl A):359A abstr
- Sengupta P, Chandrasekharan K, Prince D, et al. Routine implementation of biplane echocardiography in large volume clinical practice. J Am Coll Cardiol. 2004;43(Suppl A):309 abstr
- Schinkel A, Bax J, Elhendy A, et al. Comparative long-term prognostic value of dobutamine stress echocardiography versus dobutamine stress myocardial perfusion SPECT. J Am Coll Cardiol. 2004;43(Suppl A):331A abstr
- Hanekom L, Jenkins C, Short L, et al. Accuracy of strain rate techniques for identification of viability at dobutamine stress echo: a follow-up study after revascularization. J Am Coll Cardiol. 2004;43(Suppl A):360A abstr
- Pulerwitz T, Hirata K, Rodriquez C, et al. Feasibility of using new real-time volume rendering three-dimensional dobutamine stress echocardiography. J Am Coll Cardiol. 2004;43(Suppl A):361A abstr
- Cauduro S, Rihal C, Modesto K, et al. Echocardiographic diastolic function grade accurately reflects changes in ventricular wall stress and stiffness. J Am Coll Cardiol. 2004;43(Suppl A):356A abstr
- Khan S, Bess R, Rosman H, et al. Which echo-Doppler left ventricular diastolic function measurement should be made in the clinical echo laboratory? J Am Coll Cardiol. 2004;43(Suppl A):356A abstr
- Agmon Y, Meissner I, Tajik A, et al. Is atherosclerotic vascular disease associated with left ventricular diastolic function in subjects with normal systolic function? A population-based transesophageal echocardiographic study. J Am Coll Cardiol. 2004;43(Suppl A):349A abstr
- Poppas A, Nakai T, Sievert H, et al. Serial echocardiographic follow-up of Percutaneous Left Atrial Appendage Transcatheter Occlusion (PLAATO) in patients with atrial fibrillation. J Am Coll Cardiol. 2004;43(SupplA):348A abstr
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Coronary calcium
Multislice computed tomography...