Coronary Artery Disease: Achenbach S

Raff GL, Abidov A, Achenbach S, Berman DS, Boxt LM, Budoff MJ, Cheng V, DeFrance T, Hellinger JC, Karlsberg RP, Anonymous00022. · Society of Cardiovascular Computed Tomography, 2400 N Street NW, Washington, DC 20037, USA. · J Cardiovasc Comput Tomogr. · Pubmed #19272853 No free full text.

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Bluemke DA, Achenbach S, Budoff M, Gerber TC, Gersh B, Hillis LD, Hundley WG, Manning WJ, Printz BF, Stuber M, Woodard PK. · No affiliation provided · Circulation. · Pubmed #18586979 links to  free full text

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Achenbach S, Chandrashekhar Y, Narula J. · No affiliation provided · JACC Cardiovasc Imaging. · Pubmed #19356524 No free full text.

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Achenbach S. · No affiliation provided · J Cardiovasc Comput Tomogr. · Pubmed #19083899 No free full text.

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Achenbach S. · No affiliation provided · J Am Coll Cardiol. · Pubmed #18929246 No free full text.

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Achenbach S. · No affiliation provided · Int J Cardiovasc Imaging. · Pubmed #18026848 No free full text.

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Achenbach S, Daniel WG. · No affiliation provided · J Am Coll Cardiol. · Pubmed #15992650 No free full text.

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Achenbach S. · Department of Cardiology, University of Erlangen-Nürnberg, Ulmenweg 18, 91054 Erlangen, Germany. · J Cardiovasc Comput Tomogr. · Pubmed #19083871 No free full text.

Abstract: The recent evolution of multidetector computed tomography (CT) technology has substantially improved the ability of CT to visualize the heart and coronary arteries. After injection of contrast agent, relatively reliable imaging of the coronary arteries can be achieved, even though some restrictions are caused because the spatial and temporal resolutions are still somewhat limited. Several studies have shown that stenoses of the native coronary arteries can be detected with high sensitivity and specificity if image quality is adequate. More challenging situations include imaging of patients with stents and bypass grafts. Several clinical applications have been defined as "appropriate" and include the use of CT angiography in patients who have symptoms but who cannot exercise or who have an uninterpretable stress test result, or in patients with acute chest pain of intermediate likelihood for coronary artery disease but lack of electrocardiographic changes or myocardial enzyme elevations. It can be expected that further improvement of CT technology will help to more firmly establish the clinical role of CT coronary angiography and to explore further applications of this technique.

Di Tanna GL, Berti E, Stivanello E, Cademartiri F, Achenbach S, Camerlingo MD, Grilli R. · Agency for Health and Social Care of Emilia-Romagna, Bologna, Italy. · Int J Cardiol. · Pubmed #18760849 No free full text.

Abstract: Multislice Spiral Computed Tomography (MSCT) is an emerging non-invasive diagnostic modality to detect coronary artery disease, which may alter diagnostic pathways and change the current clinical role of conventional coronary angiography. AIMS: To retrieve and critically assess information from the available literature on MSCT (>/=16-slice) concerning its diagnostic accuracy, safety, applicability, clinical impact and cost-effectiveness. METHODS AND RESULTS: Articles published between January 2002 and March 2007 were identified through searches of the Cochrane Library, MEDLINE, and other websites of manufacturers, cardiac professional societies, guidelines and abstracts from conference meetings. We identified 1768 potentially relevant articles: 262 out of these were considered eligible for full evaluation and 150 were selected (57 assessed diagnostic accuracy, 130 applicability, 103 safety, 1 clinical impact and none cost-effectiveness). The pre test probability of coronary artery disease was 56.7% (95% Confidence Interval: 55.1%-58.3%). A positive MSCT finding (pooled LR+: 5.4 (4.4-6.7)) increased the probability of CAD to 87.7% (84.3%-90.3%), whereas a negative MSCT result (pooled LR-: 0.09 (0.07-0.12)) reduced the probability of CAD to 10.7% (7.9%-14.4%). CONCLUSIONS: MSCT is a promising technology for the assessment of coronary artery stenosis. However, the available literature is of limited value in providing guidance to support the development of policies for its appropriate utilization in clinical practice.

Narula J, Garg P, Achenbach S, Motoyama S, Virmani R, Strauss HW. · University of California Irvine School of Medicine, Orange, CA 92868-4080, USA. · Nat Clin Pract Cardiovasc Med. · Pubmed #18641603 No free full text.

Abstract: Sudden cardiac death and acute myocardial infarction often occur as the first manifestation of coronary artery disease. Otherwise asymptomatic individuals with subclinical atherosclerosis almost always have a classic risk-factor profile and it is essential that they are identified before the occurrence of an acute coronary event. The ability to recognize such individuals requires the development of strategies that can localize unstable atherosclerotic lesions. Plaques that are vulnerable to rupture demonstrate distinct histological characteristics, including large plaque and necrotic core volumes, extensive remodeling of the vessel at the lesion site, and attenuated fibrous caps. Precise metrics of typical vulnerable atherosclerotic plaque dimensions will need to be defined to facilitate their identification by noninvasive imaging modalities.

Achenbach S. · Department of Cardiology, University of Erlangen, Ulmenweg 18, 91054 Erlangen, Germany. · Curr Cardiol Rep. · Pubmed #18417002 No free full text.

Abstract: CT imaging of the coronary arteries by contrast-enhanced CT, termed "coronary CT angiography" or "coronary CTA," has become increasingly stable and robust during the past few years. Several trials have demonstrated rather high diagnostic accuracies in somewhat selected patient groups, and this method can be applied clinically to rule out coronary artery stenoses. Based on clinical considerations, this will most likely be beneficial for symptomatic patients who are not at high risk for coronary artery disease, both with stable symptoms or presenting with acute chest pain. Other applications are more problematic, such as use in patients after stent placement or coronary artery bypass graft surgery. Further improvements in technology are expected to allow expansion of indications for coronary CTA in the future.

Achenbach S, Anders K, Kalender WA. · Department of Cardiology, University Erlangen-Nuernberg, Ulmenweg 18, 91054 Erlangen, Germany. · Eur Radiol. · Pubmed #18299838 No free full text.

Abstract: Computed tomography (CT) imaging of the heart, most prominently coronary CT angiography, is currently subject to intense interest and is increasingly incorporated into clinical decision-making. In spite of tremendous progress in CT technology over the past decade, the limited temporal resolution has remained one of the most severe problems, especially for cardiac imaging. The novel design concept of dual-source CT (DSCT) allows for an effective scan time of 83 ms independent of heart rate. While large trials are still missing, initial studies have shown improved image quality, especially for visualizing the coronary arteries and detecting coronary artery stenoses. Further investigations have shown that routine beta blockade to lower the heart rate is not necessary to reliably achieve diagnostic image quality. Other applications that may particularly benefit from increased temporal resolution are the analysis of ventricular function and of the cardiac valves. Dose issues which are of interest for cardiac CT in general are discussed in some detail, including a quantitative analysis of dose values and three-dimensional dose distributions. Various strategies to lower radiation exposure are available today, and DSCT offers specific potential for this.

Schroeder S, Achenbach S, Bengel F, Burgstahler C, Cademartiri F, de Feyter P, George R, Kaufmann P, Kopp AF, Knuuti J, Ropers D, Schuijf J, Tops LF, Bax JJ, Anonymous00187, Anonymous00188, Anonymous00189. · Department of Internal Medicine, Division of Cardiology, Eberhard-Karls-University Tuebingen, Otfried-Mueller-Strasse 10, 72076 Tuebingen, Germany. · Eur Heart J. · Pubmed #18084017 links to  free full text

Abstract: As a consequence of improved technology, there is growing clinical interest in the use of multi-detector row computed tomography (MDCT) for non-invasive coronary angiography. Indeed, the accuracy of MDCT to detect or exclude coronary artery stenoses has been high in many published studies. This report of a Writing Group deployed by the Working Group Nuclear Cardiology and Cardiac CT (WG 5) of the European Society of Cardiology and the European Council of Nuclear Cardiology summarizes the present state of cardiac CT technology, as well as the currently available data concerning its accuracy and applicability in certain clinical situations. Besides coronary CT angiography, the use of CT for the assessment of cardiac morphology and function, evaluation of perfusion and viability, and analysis of heart valves is discussed. In addition, recommendations for clinical applications of cardiac CT imaging are given and limitations of the technique are described.

Achenbach S, Daniel WG. · Department of Medicine 2, University Hospital Erlangen, Germany. · Herz. · Pubmed #17401752 No free full text.

Abstract: The introduction of recent generations of multidetector computed tomography scanners has brought about substantial improvements in spatial and especially temporal resolution which have made imaging of the heart and, under certain conditions, visualization of the coronary arteries possible. Non-enhanced scans allow visualization of cardiac and coronary artery calcification. After intravenous injection of contrast agent, it is possible to visualize cardiac chambers and to analyze the coronary artery lumen.Morphological imaging of the heart, for example in the context of congenital heart disease, is possible by computed tomography (CT) and can, in some very selected cases, be clinically useful as an adjunct to echocardiography or magnetic resonance imaging. Functional imaging allows to analyze left and right ventricular function by CT.CT plays a more prominent clinical role in the context of coronary artery visualization. Coronary calcifications are indicative of coronary atherosclerosis and the presence and amount of coronary artery calcium have a strong predictive value concerning future cardiovascular events, even in asymptomatic individuals. It can potentially be used for refined risk stratification. Contrast-enhanced "CT coronary angiography" has become quite reliable under certain conditions (e.g., a low heart rate). The negative predictive value to rule out coronary artery stenoses has been found to be high in several studies. Therefore, clinical utility to rule out significant coronary artery stenoses in patients who are symptomatic, but have a low to intermediate pretest likelihood of disease is assumed. Ideally, "negative" coronary angiograms would be avoided by using coronary CT angiography. Large-scale trials that would pinpoint specific patient groups to benefit from "CT coronary angiography" are currently lacking.

Achenbach S. · Department of Cardiology, University of Erlangen-Nürnberg, Erlangen, Germany. · J Am Coll Cardiol. · Pubmed #17112978 No free full text.

Abstract: Recent developments in computed tomography technology have made imaging of the coronary arteries possible. All the same, the rapid motion and small dimensions of the coronary vessels make coronary computed tomography angiography (coronary CTA) challenging. With the last generations of 16- and 64-slice computed tomography and adequate patient preparation (which includes lowering of the heart rate), rates of sensitivity ranging from 83% to 99% and specificity between 93% and 98% have been reported for the detection of coronary artery stenoses in comparison with invasive coronary angiography. The high negative predictive value (95% to 100%) found in these studies suggests that coronary CTA may be a useful diagnostic technique to rule out the presence of coronary stenoses in selected patients, especially those with a rather low pretest likelihood of disease. Imaging of coronary artery bypass grafts is reliable, but clinical applications can be hampered by difficulties in assessing the native coronary arteries in patients after undergoing bypass because of their often-severe calcification. The detection of in-stent restenosis is made difficult by artifacts caused by metal, especially in smaller stents. Finally, initial reports that coronary CTA allows the detection and, to a certain extent, also the characterization and quantification of noncalcified coronary arteriosclerotic plaque are interesting, but they currently do not provide sufficient data to support clinical applications in the context of risk stratification.

Budoff MJ, Achenbach S, Blumenthal RS, Carr JJ, Goldin JG, Greenland P, Guerci AD, Lima JA, Rader DJ, Rubin GD, Shaw LJ, Wiegers SE, Anonymous00098, Anonymous00099, Anonymous00100. · No affiliation provided · Circulation. · Pubmed #17015792 links to  free full text

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Ropers D, Regenfus M, Wasmeier G, Achenbach S. · Department of Internal Medicine II (Cardiology), University of Erlangen-Nuremberg, Erlangen, Germany. · Minerva Cardioangiol. · Pubmed #15514575 links to  free full text

Abstract: New cardiovascular imaging modalities, including computed tomography (CT), magnetic resonance (MR) imaging and real-time three-dimensional echocardiography, have great potential for providing important and additional information concerning cardiac function and pathology. With significant and extremely fast technical improvements, non-invasive cardiac imaging has become a focal point in the diagnosis of cardiac disease. Thereby CT has been shown to allow the visualization of coronary arteries concerning calcifications, significant stenoses and coronary plaques, whereas MR imaging demonstrated its ability to evaluate cardiac morphology and function as well as perfusion imaging and viability assessment. As CT and MR, real-time three-dimensional echocardiography has increasingly progressed in the last years offering the potential for routine clinical application, e.g. in the evaluation of valve disease, the assessment of left ventricular thrombi or the guidance of intracardiac catheter placement. This article will provide a brief overview of each technique, possible clinical applications and their perspectives. Because both, CT and MR, have been successfully applied to visualize the coronary arteries, this article focuses on the abilities and limitations of CT and MR coronary artery imaging.

Achenbach S, Daniel WG. · Medizinische Klinik II mit Poliklinik, Universität Erlangen-Nürnberg, Ulmenweg 18, 91054 Erlangen, Germany. · Curr Atheroscler Rep. · Pubmed #15068746 No free full text.

Abstract: Computed tomography (CT) imaging of the coronary arteries, using either electron beam tomography (EBT) or multidetector row CT (MDCT), offers two possibilities to assess coronary atherosclerosis. Without injection of contrast agent, coronary calcifications can be detected and quantified. Their presence and extent correlates to the presence and amount of coronary atherosclerotic plaque. Prospective studies have demonstrated a high predictive value concerning the occurrence of coronary artery disease events and overall mortality. An emerging consensus seems to indicate that calcium imaging may be clinically useful in patients at intermediate risk for coronary artery disease events as determined based on traditional risk factors. In addition, recent studies have shown that after injection of contrast agent and using high-resolution scan protocols, the visualization of noncalcified plaque is also possible with CT techniques. However, data on the accuracy of plaque detection, quantification of plaque volume, and characterization of plaque (eg, lipid-rich vs fibrous) is currently limited, and the prognostic significance of noncalcifed coronary atherosclerotic plaque detection is unclear.

Budoff MJ, Achenbach S, Duerinckx A. · Division of Cardiology, Saint John's Cardiovascular Research Center, Harbor-UCLA Medical Center Research and Education Institute, Torrance, California 90502, USA. · J Am Coll Cardiol. · Pubmed #14662244 No free full text.

Abstract: OBJECTIVE: The purpose of this study was to provide a comprehensive review of the literature relating to electron beam angiography (EBA), magnetic resonance angiography, and spiral computed tomography, currently the three most promising noninvasive methods to visualize obstructions in the coronary tree. BACKGROUND: Given the high costs and invasiveness of coronary angiography, there is increased interest in noninvasive coronary angiography, which has made great strides to become a clinically useful tool to augment conventional coronary angiography (CCA). METHODS: MEDLINE searches were performed to include all articles related to noninvasive angiography utilizing either magnetic resonance imaging (MRI), multi-row detector spiral computed tomography (MDCT), and electron beam tomography (EBT). Weighted analysis was performed to define the published sensitivity and specificity for each technique. RESULTS: Electron beam angiography (EBA) provides an overall sensitivity of 87% and specificity of 91% for the detection of obstructive coronary artery disease (CAD). Four-level MDCT data demonstrated an overall sensitivity of 59% and specificity of 89%, with higher accuracy in two recent studies of 16-level detector devices. Magnetic resonance angiography demonstrated sensitivity for detection of obstructive CAD of 77% and specificity of 71%. CONCLUSIONS: Noninvasive coronary angiography is a rapidly developing technique and currently not an alternative to CCA in all cases. All three methods are currently used clinically in certain centers with appropriate expertise. Selective use should prove both cost-effective and provide a safer, less-invasive method for patients to determine the need for medical versus revascularization therapy.

Achenbach S, Schmermund A, Erbel R, Silber S, Haberl R, Moshage W, Daniel WG. · CIMIT, Massachusetts General Hospital, 100 Charles River Plaza, Suite 400, Boston, MA 02114, USA. · Z Kardiol. · Pubmed #14634759 No free full text.

Abstract: Coronary calcifications can be detected and quantified using electron beam tomography (EBT) or newer generation multi-slice spiral CT (MSCT) scanners. An abundance of data has been acquired by EBT. It could be shown that the amount of coronary calcium correlates to the coronary plaque burden. The detection of coronary calcium with CT imaging methods therefore provides a unique opportunity to detect and quantify coronary atherosclerosis in a subclinical stage. Consequently, the presence and amount of coronary calcium has been shown to be indicative for an increased coronary event risk in symptomatic and asymptomatic individuals. Several clinical studies found a predictive value that was superior to conventional risk factors. Clinically, the use of coronary calcification assessment may therefore be beneficial in patients who, based on traditional risk factors, seem to be at "intermediate risk" for coronary events (10-year event risk 10-20%) in order to decide on the aggressiveness of risk factor modification. The role of coronary calcium quantification to monitor the progression of disease has not been clarified yet. Large, ongoing trials will provide further data as to the relative merit of coronary calcium assessment for risk stratification and will help to more clearly define its clinical role. The relationship between coronary calcium and coronary stenoses is more complex. While the absence of coronary calcifications makes significant coronary stenoses unlikely, even large amounts of coronary calcium do not necessarily indicate the presence of coronary artery stenoses. Pronounced coronary calcifications as an isolated finding should therefore not be the motivation for invasive diagnostic procedures in the absence of other evidence of ischemic heart disease.

Achenbach S, Hoffmann U, Ferencik M, Wicky S, Brady TJ. · Department of Radiology, Massachusetts General Hospital, Boston 02114, USA. · Prog Cardiovasc Dis. · Pubmed #14505291 No free full text.

Abstract: Fast, cross-sectional computed tomography (CT) imaging permits visualization of the coronary artery lumen after intravenous injection of contrast agent. Electron beam CT and multidetector row spiral CT have both been shown to allow detection of coronary artery stenoses with high sensitivity and specificity in selected patient subsets. However, limitations of image quality may render some coronary artery segments unevaluable, in most cases because of severe calcification or remaining motion artifacts. In the future, these imaging modalities may play a clinically important role in ruling out coronary artery stenoses, especially in patients with relatively low likelihood of disease. Other applications include the analysis of bypass patency and evaluation of coronary anomalies.

Achenbach S. · Massachusetts General Hospital, CIMIT Vulnerable Plaque Program, Boston, MA 02114, USA. i-erlangen.de · Herz. · Pubmed #12669225 No free full text.

Abstract: As compared to conventional CT scanners, multi-slice spiral CT (MSCT) has improved temporal and spatial resolution. Dedicated image reconstruction algorithms permit to create cross-sectional images with a temporal resolution of approximately 150-250 ms, and a slice thickness of 0.75-1.3 mm (see Figure 1). In addition, image reconstruction can be synchronized to the ECG. This permits to use MSCT for visualization of the coronary artery lumen and detection of stenosis (see Figures 2 and 3). Various post-processing techniques can be used to display the coronary arteries. A low heart rate has been identified as an important prerequisite to obtain a sufficiently high image quality, and most authors recommend routine use of beta blocker premedication. Comparisons of 4-slice MSCT to invasive angiography concerning the detection of hemodynamically relevant coronary artery stenoses have resulted in sensitivities ranging from 72-93% and specificities ranging from 84-98%. However, up to 32% of all coronary segments had to be excluded from evaluation due to impaired image quality, in most cases due to severe calcification or insufficient suppression of motion artifacts. Initial results obtained with 16-slice MSCT scanners, which provide somewhat higher temporal and--through decreased slice thickness--improved spatial resolution, show promise that diagnostic accuracy may be increased while the number of coronary artery segments with nondiagnostic image quality may be reduced as compared to the prior generation of 4-slice scanners. Further studies are necessary to identify patient subgroups which might benefit from MSCT "noninvasive coronary angiography" in a clinical setting.

Moshage W, Achenbach S, Daniel WG. · Department of Internal Medicine II, University of Erlangen-Nürnberg, Erlangen, Germany. · Nephrol Dial Transplant. · Pubmed #11208988 links to  free full text

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Achenbach S, Regenfus M, Ropers D, Kessler W, Daniel WG, Moshage W. · Medizinische Klinik II mit Poliklinik Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany. · Z Kardiol. · Pubmed #10907296 No free full text.

Abstract: Magnetic resonance imaging of the coronary arteries is difficult due to the tortuous course of these vessels, their small diameter, and their rapid movement caused by respiration and cardiac contraction. Initial investigations could demonstrate the feasibility of non-invasive magnetic resonance coronary angiography using 2-dimensional turbo-FLASH gradient-echo sequences in repeated breathholds of approximately 16 heart beats duration. Further developments, especially the design of navigator-echo-based respiratory gated 3-dimensional imaging sequences, permitted the acquisition of contiguous volume data sets of the heart which eliminated many limitations of 2-dimensional repeated breathhold sequences. With a spatial resolution of approximately 1.2 x 1.2 x 2 mm and a temporal resolution of approximately 126 ms, several authors reported sensitivities of 70-80% and specificities of approximately 90% for the detection of coronary artery stenoses. Further improvements can be expected from new, intravascular contrast agents and from ultrafast sequences which permit acquisition of a sufficiently large imaging volume within one single breathold.

Moshage W, Ropers D, Daniel WG, Achenbach S. · Medizinische Klinik II mit Poliklinik Friedrich Alexander Universität Erlangen-Nürnberg. · Z Kardiol. · Pubmed #10907295 No free full text.

Abstract: Coronary angiography remains the diagnostic standard for establishing the presence, site, and severity of coronary artery disease. Electron beam computed tomography (EBCT), a non-invasive imaging method with very high spatial and temporal resolution, is well suited for cardiac imaging. Using a standard protocol, EBCT permits the visualization of the coronary arteries. Stenoses and occlusions of the native arteries and of coronary artery bypass grafts can be reliably diagnosed. Extremely calcified segments have to be excluded from evaluation. Reduced image quality, mainly due to fast vessel motion and superposition of large veins, impairs the results obtained for the right and left circumflex coronary artery. Possible clinical applications are the follow-up after angioplasty (PTCA without stent) and bypass surgery, the exclusion of coronary artery disease in patients with low likelihood of disease, and the evaluation of coronary anomalies.