The medical profession should play a central role in evaluating the evidence related to drugs, devices, and procedures for the detection, management, and prevention of disease. When properly applied, expert analysis of available data on the benefits and risks of these therapies and procedures can improve the quality of care, optimize patient outcomes, and favorably affect costs by focusing resources on the most effective strategies. An organized and directed approach to a thorough review of evidence has resulted in the production of clinical practice guidelines that assist physicians in selecting the best management strategy for an individual patient. Moreover, clinical practice guidelines can provide a foundation for other applications, such as performance measures, appropriate use criteria, and both quality improvement and clinical decision support tools.

In the United States, more than a million people are hospitalized annually with unstable angina or myocardial infarction without ST-segment elevation, so-called acute coronary syndromes. For these patients, several treatments have proved to be effective in reducing the incidence of death, infarction or reinfarction, and recurrent ischemia. These treatments include intensive medical therapy and coronary angiography followed by revascularization, if indicated.1,2 Given the sheer number of medical interventions that are now available for these conditions, knowing which therapy to administer and when to do so is confusing for many physicians. The studies by Giugliano et al.3 and Mehta et . . .

HomeCirculationVol. 118, No. 5Noninvasive Coronary Artery Imaging Free AccessReview ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessReview ArticlePDF/EPUBNoninvasive Coronary Artery ImagingMagnetic Resonance Angiography and Multidetector Computed Tomography Angiography: A Scientific Statement From the American Heart Association Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention, and the Councils on Clinical Cardiology and Cardiovascular Disease in the Young David A. Bluemke, MD, PhD, FAHA, Chair, Stephan Achenbach, MD, Matthew Budoff, MD, FAHA, Thomas C. Gerber, MD, FAHA, Bernard Gersh, DPhil, MD, FAHA, L. David Hillis, MD, W. Gregory Hundley, MD, FAHA, Warren J. Manning, MD, FAHA, Beth Feller Printz, MD, PhD, Matthias Stuber, PhD and Pamela K. Woodard, MD, FAHA David A. BluemkeDavid A. Bluemke , Stephan AchenbachStephan Achenbach , Matthew BudoffMatthew Budoff , Thomas C. GerberThomas C. Gerber , Bernard GershBernard Gersh , L. David HillisL. David Hillis , W. Gregory HundleyW. Gregory Hundley , Warren J. ManningWarren J. Manning , Beth Feller PrintzBeth Feller Printz , Matthias StuberMatthias Stuber and Pamela K. WoodardPamela K. Woodard Originally published27 Jun 2008https://doi.org/10.1161/CIRCULATIONAHA.108.189695Circulation. 2008;118:586–606Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: June 27, 2008: Previous Version 1 Since the early 1960s, selective x-ray coronary angiography has provided the only means of visualizing the coronary arterial system in vivo. However, it has several disadvantages. First, the incidence, albeit relatively low, of so-called major adverse events (death, myocardial infarction, or stroke) during or within 24 hours of selective coronary angiography is reported to be 0.2% to 0.3%, and the incidence of so-called minor complications (most of which are related to problems with the peripheral vessels through which catheters are inserted) is roughly 1% to 2%.1–3 Second, x-ray coronary angiography is accompanied by a modest amount of discomfort, because the placement of catheters is invasive. Third, it is expensive: the required equipment is costly, and the performance of the procedure necessitates considerable time and skill of highly trained physicians and support personnel. Last, the information obtained via catheter-based coronary angiography pertains to the coronary arterial lumen alone. As a result, alternative methods of visualizing the coronary arterial system that would allow one to avoid these disadvantages are desirable.Over the past 15 years, substantial advances have been made in noninvasive cardiac imaging in general and in visualization of the coronary arteries in particular. Magnetic resonance angiography (MRA) of the coronary arteries was advanced in the early 1990s with the development of high-speed gradient techniques and dedicated cardiac coils. The primary advantage of this technique is the patient’s lack of exposure to ionizing radiation or iodinated contrast media. Coronary MRA may also be combined with other magnetic resonance (MR) imaging techniques for assessment of cardiac function, structure, blood flow, and viability.4Electron-beam computed tomography (CT) with iodinated contrast injection was originally used to perform coronary angiograms, but this has been supplanted by multidetector CT (MDCT) scanners that have 16 to 256 rows of detectors. MDCT can provide visually compelling images of the coronary arterial tree, although at present, the necessary radiation dose is higher than that associated with x-ray coronary angiography.In this statement, we discuss and summarize these two noninvasive modalities, MRA and computed tomographic angiography (CTA), which may be used for coronary artery evaluation. Because the advantages and limitations of CT to assess the presence and extent of coronary arterial calcification are discussed in a separate document sponsored by the American Heart Association, the assessment of coronary arterial calcification is not presented in this statement. For both MRA and CTA, we provide a discussion of technical issues, applications, advantages, and limitations, after which we offer recommendations for current and future uses. To accomplish this, the Writing Committee conducted a comprehensive review of the literature published between 1990 and 2006. Literature searches of the PubMed/MEDLINE databases were undertaken to identify pertinent articles. Searches were limited to the English language. The major search terms included the following: coronary angiography, coronary disease, coronary vessels, humans, magnetic resonance angiography, tomography, and x-ray computed.MRA of the Coronary ArteriesTechnical Considerations for Coronary MRAImages of the heart must be obtained rapidly and with high temporal resolution to reduce motion artifacts that could otherwise cause blurring in coronary MRA images. Unlike angiographic images obtained via catheter, MRA (and CTA) images take a long time to acquire; for example, high-resolution MRA visualization of the entire coronary arterial tree takes minutes rather than seconds. In addition, cardiac motion must be accounted for during this time period.Cardiac MotionTwo sources of motion are associated with coronary MRA: motion related to intrinsic cardiac contraction/relaxation and motion attributable to superimposed diaphragm and chest wall movement during respiration. Because the extent of motion exceeds the diameter of the coronary artery, blurring artifacts of the coronary artery lumen will occur unless adequate motion-suppression techniques are applied. ECG gating is used to account for intrinsic cardiac motion.Coronary artery motion occurs in a triphasic pattern during the cardiac cycle. Mid-diastole is the preferred time for image acquisition, because cardiac motion is minimized while coronary flow is high. The patient-specific diastasis period (of reduced coronary motion) is usually determined by visual inspection of cine images perpendicular to the long axis of the proximal/mid-right coronary artery (RCA). Multiple heartbeats are required to generate a coronary MRA. The beat-to-beat variation in the duration of the cardiac cycle and the period of diastasis results in image blurring. β-Blockade prolongs the period of coronary diastasis and may help to improve the quality of coronary MRA images.Respiratory MotionA straightforward approach to suppressing respiratory motion involves the use of breath-holding during coronary MRA. However, breath-holding strategies have several limitations. First, spatial and temporal image resolution is limited by the patient’s ability to hold his or her breath. Some patients may have difficulty sustaining adequate breath-holds, particularly when the procedure lasts longer than a few seconds. Additionally, it has been shown that during a sustained breath-hold, there is up to 1 cm of cranial diaphragmatic (and thus cardiac) drift.5–7 Thus, at present, breath-hold strategies for coronary MRA have limited applicability to the broad range of patients with cardiovascular disease.To overcome these limitations, so-called navigator echoes8–11 (similar to M-mode echocardiographic beams) can be used during free-breathing coronary MRA to track a patient’s diaphragmatic motion. MRA images are acquired only when the diaphragm is within 3 to 5 mm of its end-expiratory position. Respiratory blurring is minimized with this method and may be further reduced by using real-time tracking of the imaged volume position.9Free-breathing navigator coronary MRA offers improved patient comfort as compared with breath-holding techniques and does not require significant patient motivation. However, this method prolongs the duration of the coronary MRA, because image data are collected only when the end-expiratory position of the diaphragm coincides with the period of coronary artery diastasis.12 Typical examination times for free-breathing 3D navigator coronary MRA are 7 to 15 minutes.Spatial ResolutionThe spatial resolution achievable with 3D MRA imaging (0.7 to 0.8 mm in-plane resolution and 1 to 3 mm through-plane resolution) is inferior to that obtainable with x-ray coronary angiography (<0.3 mm).For MRA imaging, improvement in spatial resolution is generally accompanied by reduction in the signal-to-noise ratio (SNR). As the voxel size is reduced toward the resolution achievable with x-ray angiography, methods to reduce motion artifacts from both intrinsic and extrinsic motion of the coronary arteries become increasingly important.13Contrast Enhancement in Coronary MRACoronary MRA examinations are typically performed without the addition of intravenously administered contrast agents. The relative signal of the coronary arteries is augmented using fat-saturation prepulses,14 magnetization transfer contrast prepulses,15 or T2 preparatory pulses,16,17 which take advantage of natural T2 differences between the blood and the surrounding myocardium. When these techniques are used, the coronary lumen appears bright, whereas the surrounding myocardium has reduced signal intensity. The lack of exposure to ionizing radiation and the absence of exogenous contrast agents facilitate repeat MRA studies when clinically warranted.With the use of intravenous MR contrast agents, the T1 relaxation time for blood can be shortened, which allows for an increased contrast-to-noise ratio for coronary MRA.18,19 The extravascular contrast agents that are presently available in the United States for coronary MRA quickly extravasate from the coronary lumen. Use of these agents requires rapid first-pass imaging, which necessitates breath-holding20 and results in images with reduced spatial resolution (as discussed in Spatial Resolution, above).Recent Technical DevelopmentsTechnical improvements in coronary MRA include the development of MR methods that generate improved coronary signals and support reduced scanning times while simultaneously minimizing the complexity of the examination.Steady-State With Free-Precession Coronary MRAUse of the steady-state with free-precession (SSFP) method to perform MRA makes it possible to obtain high signal intensity from the coronary arteries and very high contrast between the ventricular blood pool and the myocardium without the need for contrast agents.21 SSFP imaging permits high-quality coronary MRA during free-breathing with substantial improvements in SNR, contrast-to-noise ratio, and vessel sharpness as compared with standard T2-prepared gradient-echo imaging.22 Therefore, SSFP imaging may lead to improved identification of significant coronary artery stenoses. At present, SSFP is being evaluated at many clinical and research centers.Phase-Contrast MR ImagingThe phase-contrast technique measures blood-flow velocity23 combined with arterial diameter to yield a quantitative measurement of blood flow (in milliliters per minute). Blood flow can be determined when a patient is at rest or after he or she is stressed for measurement of coronary artery blood-flow reserve.23,24 Although it has been demonstrated in clinical research, this method can be applied on most 1.5-Tesla and some 3.0-Tesla MR scanners. Coronary blood flow is measured along a 2-cm straight proximal or mid-arterial segment in vessels that are >2 mm in diameter.25Parallel Imaging for Coronary MRAParallel imaging is an MR method for reducing MR scanning time by a factor of 2 to 3.26 However, the trade-off for reduced acquisition time is reduced SNR for visualization of the coronary arteries.3-Tesla Coronary MRAMost coronary MRA examinations are performed on 1.5-Tesla MR systems. Higher field, 3-Tesla systems provide better signal and contrast values relative to 1.5-Tesla systems. The recent availability of 3-Tesla systems equipped with dedicated cardiac hardware (eg, real-time spectrometer, parallel receiver technology with high bandwidth, body radiofrequency send coil, vector ECG) and software (parallel imaging, navigators, interactive interface) may provide a means for substantial coronary MRA improvements in the future.27Whole-Heart Coronary MRAUntil recently, coronary MRA was performed with only portions of each arterial tree visible in each set of images.28 This method requires the MR imaging technologist to have extensive experience and familiarity with coronary artery anatomy. The recent development of whole-heart coronary MRA, which is analogous to coronary CTA, allows for imaging of the entire coronary artery tree in an axially acquired 3D volume. Postprocessing of the 3D images is performed in a manner similar to that for coronary CTA. To collect such large volumetric data sets, spatial resolution is somewhat lower (usually >1 mm in-plane and through-plane resolution), data are collected over approximately 100 ms of each cardiac cycle (with potential for blurring), and scan times are lengthy (10 to 15 minutes), thereby mandating the use of navigator echoes. Nevertheless, the whole-heart coronary MRA approach has gained rapid acceptance on the basis of promising initial results.29Clinical Applications and ResultsAnomalous Coronary ArteryProjection x-ray angiography has traditionally been the imaging test of choice for the diagnosis and characterization of coronary artery anomalies. However, the presence of an anomalous coronary artery origin is sometimes only suspected after the invasive procedure, particularly in the case of unsuccessful engagement or visualization of a coronary artery. In addition, the declining use of pulmonary artery catheters during routine x-ray coronary angiography has made it more difficult to discern the anterior versus the posterior trajectory of the anomalous vessels.Multiple published series exist30–33 of patients who underwent blinded comparison of coronary MRA with x-ray angiography (Table 1). Early coronary MRA studies often used a 2D breath-hold ECG-triggered segmented k-space gradient-echo approach.30–36 These 2D coronary MRA studies uniformly reported excellent accuracy, including several studies in which coronary MRA was determined to be superior to x-ray angiography.31,32 At most centers, 3D coronary MRA is now used, because it offers superior reconstruction capabilities with similarly excellent results.37 For these reasons, coronary MRA is the preferred test for younger patients in whom an anomalous artery origin is suspected or a known anomalous coronary artery origin needs to be clarified and for patients who have another cardiac anomaly associated with coronary anomalies (eg, tetralogy of Fallot). Table 1. Coronary MRA for Anomalous Coronary Artery EvaluationReferenceNo. of PatientsCorrectly Classified Anomalous Vessels, n (%)*Numbers include 3 patients originally misclassified with x-ray angiography.†Numbers include 5 patients who could not be classified with x-ray angiography.‡Numbers include 11 patients who could not be classified with x-ray angiography.McConnell et al301514 (93)Post et al321919 (100)*Vliegen et al331211 (92)†Taylor et al312524 (96)Bunce et al372626 (100)‡Razmi et al361212 (100)Coronary Artery Aneurysms/Kawasaki DiseaseAlthough coronary artery aneurysms are relatively uncommon, recent studies indicate an important role for coronary MRA for assessment of this condition. The vast majority of acquired coronary aneurysms in children and younger adults are due to Kawasaki disease, a generalized vasculitis of unknown etiology that usually occurs in children under 5 years old. Approximately 5% of patients develop coronary artery ectasia or aneurysms despite appropriate therapy.38–40 Good correlation between coronary MRA and x-ray coronary angiography has also been reported for ectatic coronary arteries (distinct from Kawasaki disease) among adults.41Coronary MRA for Identification of Native Vessel Coronary StenosesThe results of coronary MRA in single-center trials are presented in Table 2. No efficacy data have been reported regarding “screening” coronary MRA in high-risk populations. Table 2. MRA for the Detection of Coronary Artery StenosisReferenceTechniqueNo. of PatientsSensitivity, %*Specificity, %*Negative Predictive Value, %*Remarks2D BH indicates 2-dimensional breath-hold; 3D Nav, retro, 3-dimensional navigator, retrospective gating; 3D Nav, pros, 3-dimensional navigator, prospective gating; 3D BH, three-dimensional breath-hold; and LAD, left anterior descending artery.*Sensitivity, specificity, and negative predictive value based on luminal stenosis >50%.†Multicenter trial.Manning et al2062D BH39909288Per-artery analysis, proximal and mid segmentsPennell et al2072D BH3985……Per-artery analysisPost et al2082D BH35638981Per-artery analysis, proximal and mid segmentsWoodard et al2093D Nav, retro1070……Per-artery analysis, proximal and mid segmentsKessler et al2103D Nav, retro73658892Per-patient analysis, 52% evaluable segmentsSandstede et al2113D Nav, retro308189…Per-patient analysis, all segmentsvan Geuns et al2123D Nav, retro20735090Per-segment analysis, proximal and mid segmentsHuber et al2133D Nav, retro325091…Per-artery analysis, proximal and mid segmentsSardanelli et al2143D Nav, retro42828993Per-segment analysis, all segmentsWittlinger et al2153D Nav, retro2075100…Per-segment analysis, proximal and mid segmentsKim et al216†3D Nav, pros109934281Per-artery analysis, proximal and mid segmentsWeber et al2173D Nav, pros15889496Per-patient analysis; all segments for LAD, 70% segments evaluable for RCASakuma et al293D Nav, pros39829193Per-segment analysis, all segmentsDewey et al453D Nav, pros30657471Per-segment analysis, all segmentsJahnke et al2183D Nav, pros557891…Per-segment analysis, all segmentsRegenfus et al2193D BH50945780Per-patient analysis, proximal and mid segments, 77% evaluable segmentsvan Geuns et al563D BH38689794Per-patient analysis, distal segments for RCA only, 69% evaluable segmentsA multicenter single-vendor study of 3D coronary MRA in 109 patients demonstrated 93% sensitivity, 58% specificity, and 81% negative predictive value for the identification of ≧50% diameter stenosis by quantitative coronary angiography (Table 3).28 The sensitivity and negative predictive value were particularly high for the identification of left-main or multivessel disease, thereby demonstrating a role for coronary MRA for this subset. Accordingly, coronary MRA may be valuable for rendering a diagnosis for patients who present with dilated cardiomyopathy/congestive heart failure in the absence of clinical infarction and for determining whether the problem is ischemic or nonischemic. A limitation of this study for general application of the results was the use of MR scanners from the same vendor at all sites. Table 3. Three-Dimensional Navigator Coronary MRI: Multicenter Trial ResultsPer-Patient Analysis, %Left Main/3-Vessel Disease, %Adapted from Kim et al.216Sensitivity93100Specificity4285Prevalence5915Positive predictive value7054Negative predictive value81100Single-center data obtained from using free-breathing navigator-gated whole-heart MRA suggest that the whole-heart approach provides faster acquisitions (<15 minutes) and superior accuracy,29,42–46 with sensitivities of 80% to 90% and specificity of >90%. Two comparison studies of coronary MRA and 16-slice MDCT demonstrated similar accuracy when compared with free-breathing coronary MRA47 and superior results for MDCT when compared with a combination of free-breathing and lower-resolution breath-hold coronary MRA.48At experienced research centers, phase-contrast MR coronary artery flow measurements can provide supplemental information regarding the physiological importance of coronary artery luminal narrowing.49–54 Impaired coronary flow reserve measured by MR identifies coronary arterial luminal stenosis of >70% in the left-main and proximal coronary artery segments when the angiographic appearance of the stenosis is of intermediate severity.49–51 In individuals who have undergone percutaneous coronary artery stent placement in the left anterior descending coronary artery, impaired phase-contrast MR flow-reserve measurements reliably identify luminal renarrowing of >50% for symptomatic patients 3 months or more after stent implantation.52,55The results discussed above were obtained at research-oriented centers that have the capability to perform high-quality MRCA in either single-center or single-vendor trials. The utility of coronary MRA in general practice has not been established, and multivendor trials have not been conducted.Coronary MRA for Coronary Artery Bypass Graft AssessmentConventional free-breathing ECG-gated 2D spin-echo MRA56–59 and 2D gradient-echo MRA60–63 in the transverse plane have both been used with knowledge of the origin and touchdown site of each graft to reliably assess bypass graft patency (Table 4). Additionally, both 3D noncontrast64 and contrast-enhanced coronary MRA have been used for assessment of graft patency,65,66 with slightly improved results. The accuracy of ECG-gated SSFP sequences appears to be similar to that of spin-echo and gradient-echo approaches.67Table 4. Evaluation of Coronary Artery Bypass Graft Patency by Coronary MRAReferenceTechniqueNo. of GraftsPatency, %Sensitivity, %*Specificity, %*Accuracy, %GRE indicates gradient-recalled echo; IMA, internal mammary artery graft; SVG, saphenous vein graft; and gad MRA, gadolinium MRA.*Sensitivity and specificity based on luminal stenosis >50%.White et al592D spin-echo7269865978Rubenstein et al2202D spin-echo4762907283Jenkins et al2212D spin-echo4163897383Galjee et al612D spin-echo9874988589White et al602D GRE2850938689Aurigemma et al622D GRE45738810091Galjee et al612D GRE9874988896Engelmann et al632D GRE17 IMA100100…10038 SVG66928589Molinari et al643D GRE5176.5919796Bunce et al673D SSFP23 IMA96731007456 SVG82894080Wintersperger et al663D gad MRA28 IMA899667…48 SVG739485…Vrachliotis et al653D gad MRA4468939795A practical limitation of coronary MRA bypass graft assessment is related to local signal loss and artifacts that are caused by nearby metallic objects (hemostatic clips, ostial stainless steel graft markers, sternal wires, coexistent prosthetic valves and supporting struts or rings, and graft stents). Although coronary MRA has been successfully used for identification of graft occlusion, the inability to identify various degrees of luminal narrowing in diseased yet patent grafts is also a hindrance to clinical utility and acceptance.CTA of the Coronary ArteriesCTA Techniques and Technical IssuesBecause of the high motion velocity of the coronary arteries, CT scanners must have sufficiently high temporal resolution to provide images of the beating heart with minimal motion artifact. Depending on the patient’s heart rate during the scan and the phase of the cardiac cycle at which the coronary arteries are captured, a temporal resolution of 19 to 75 ms is desirable for coronary CTA.68,69 Similar to coronary MRA, coronary CTA temporal resolution is currently lower than is optimal for coronary artery depiction.Multidetector Computed TomographyMDCT scanners (also known as multislice CT) with x-ray tubes rotating fast enough to allow coronary artery imaging (500 ms or less per rotation) became available in the late 1990s.70,71 The temporal resolution of MDCT is approximately half the time it takes for the x-ray gantry to complete a 360° rotation around the patient when a half-segment reconstruction is used. The nominal temporal resolution can be improved by a factor of 2 to 3 (depending on the heart rate) by segmented reconstruction techniques that combine projection data acquired during 2 or more cardiac cycles into 1 image.70,72 Currently, MDCT scanners can acquire up to 64 slices simultaneously with a maximum temporal resolution as low as 83 ms (dual-source MDCT).73In MDCT coronary CTA, image data are acquired throughout the cardiac cycle while the patient table continuously advances through the gantry. Electrocardiographic information is used to retrospectively reconstruct images from projection data acquired during the phase of the cardiac cycle with the least cardiac motion. The speed of the patient table relative to the speed of the gantry rotation (called pitch) is such that each cross-sectional level of the heart is imaged during more than 1 cardiac cycle. The number of image slices acquired during each gantry rotation (currently ranging from 16 to 320) determines the overall duration of the MDCT scan but does not directly influence the temporal resolution.Spatial ResolutionThe smallest x-ray beam collimation possible with a given CT scanner dictates the minimal thickness of the image slices that can be reconstructed. The slice thickness affects spatial resolution. High spatial resolution allows assessment of small side branches of the coronary arteries, decreases artifacts due to partial-volume effects, and leads to better assessment of calcified coronary artery segments and in-stent stenoses. However, to have sufficiently low image noise with smaller x-ray beam collimation, a large increase of the x-ray dose is necessary.Spatial resolution has improved with each advance in MDCT technology. Submillimeter resolution has been achieved in MDCT scanners ranging from 16 to 320 slices. The spatial resolution of the present 64-slice MDCT scanners is ≈0.4 mm.74 This is an improvement over the 0.7-mm resolution of 16-slice MDCT but not as high as can be obtained with catheter-based cine angiography (<0.3 mm).Contrast Medium AdministrationCoronary CTA requires intravenous administration of an iodinated contrast medium. Power injectors are programmed to administer 50 to 160 mL of iodinated contrast medium at a rate of 4 to 6 mL/s through a cannula designed for this injection rate (typically 18 gauge or greater) that is usually placed in an antecubital vein. Accurate timing of the CT scan relative to the start of the contrast injection is the major determinant of overall image quality and enhancement of the coronary arteries. To optimize this timing, a test bolus of 10 to 20 mL of contrast medium can be injected to measure the time to peak enhancement of the aortic root; this time period is then programmed into the MDCT scanner when the coronary CTA is performed. Alternatively, the CT scanner can be set to automatically initiate scanning when the enhancement of the aortic root exceeds a predetermined threshold.The volume of intravenous contrast medium required for coronary CTA is proportional to the injection rate chosen and the duration of the CT scan. Approximately 60 to 100 mL of contrast medium is injected for coronary CTA with present MDCT scanners.Pharmacological Patient PreparationBecause of the limited temporal resolution of MDCT scanners, low heart rates are desirable to avoid motion artifacts.75–78 Several studies have convincingly shown that lowering the heart rate to 60 beats per minute or less by oral administration of β-receptor blocking agents 60 to 90 minutes before the scan, or intravenous administration immediately before the scan, or both, can decrease the frequency and extent of motion artifacts on the coronary CTA scan75,79 by prolonging the rest period (the time during the cardiac cycle at which coronary artery velocity is low).80 Image quality on lower temporal resolution MDCT scanners reveals the greater benefit of lower heart rates. For example, for scanners with a temporal resolution of ≥250 ms, a heart rate of <60 beats per minute is needed to minimize coronary motion artifacts.75,79 For scanners with a temporal resolution of at least 167 ms, a heart rate of ≤75 beats per minute results in acceptable image quality.81 For new dual-source CT scanners, acceptable image quality of the coronary arteries has been obtained at up to 90 beats per minute.82 Therefore, pharmacological heart-rate control may not be necessary for many of the patients who undergo coronary CTA on dual-source scanners.Some investigators and practitioners of coronary CTA administer sublingual nitroglycerin immediately before the scan to achieve vasodilatation.83 The use of nitroglycerin has been shown to improve image quality in one small study performed using 16-slice MDCT.83Radiation DoseCoronary CTA can expose a patient to considerably higher amounts of ionizing radiation than standard radiographs, CT calcium scoring, or x-ray angiography.84 The reasons for the higher radiation dose are that continuous x-ray irradiation occurs during the entire 8- to 20-second MDCT scan, and this is coupled with overlapping slices and specific requirements for x-ray tube current and voltage. To maintain low levels of image noise and thus high image quality, x-ray tube current (mA) and tube voltage (kVp) must be increased with increasing patient body size or decreasing slice thickness or scan time. For a given slice thickness, radiation dose increases linearly with tube current and by the square of the ratio between the original and increased tube voltage setting.85The radiation doses for coronary CTA reported in the literature vary, mostly because of technical differences between scanner generations (eg, 16 versus 64 slice) and between scanners from various manufacturers. The most meaningful parameters of CT dosimetry are the volume CT dose index (CTDIvol) and the effective dose (E). The CTDIvol, expressed in SI units of milliGray (mGy),86 represents the average radiation dose over the center slice of a CT scan and is useful for comparing absorbed radiation doses from different CT scanning protocols. The CTDIvol value increases with decreasing pitch (defined as the patient-table advance relative to the width of all simultaneously acquired slices and not relative to the width of a single slice). The CTDIvol is typically displayed on the

L. David Hillis, W. Gregory Hundley, Warren J. Manning, Beth Feller Printz, Matthias Stuber David A. Bluemke, Stephan Achenbach, Matthew Budoff, Thomas C. Gerber, Bernard Gersh, Cardiology and Cardiovascular Disease in the Young the Council on Cardiovascular Radiology and Intervention, and the Councils on Clinical American Heart Association Committee on Cardiovascular Imaging and Intervention of Multidetector Computed Tomography Angiography: A Scientific Statement From the Noninvasive Coronary Artery Imaging: Magnetic Resonance Angiography and Print ISSN: 0009-7322. Online ISSN: 1524-4539 Copyright © 2008 American Heart Association, Inc. All rights reserved. is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Circulation doi: 10.1161/CIRCULATIONAHA.108.189695 2008;118:586-606; originally published online June 27, 2008; Circulation. http://circ.ahajournals.org/content/118/5/586 World Wide Web at: The online version of this article, along with updated information and services, is located on the

During the past four decades an evolution in cardiac catheterization has taken place. The role of the cardiac catheterization laboratory has progressed from study of cardiac function and anatomy for purposes of diagnosis to evaluation of candidates for surgery and finally to providing catheter-based, nonsurgical interventional treatment. This progress has stimulated an increase in demand for cardiac catheterization services. However, as a result of the need to decrease health care costs, there have also been major changes in the types of patients admitted to hospitals. Accordingly, an increasing proportion of catheterizations are being conducted in settings other than traditional hospital-based catheterization laboratories. As newer cardiac diagnostic and treatment modalities are developed, it is highly likely that the role of cardiac catheterization will continue to evolve. From this evolution a number of concerns have been raised about the ability of catheterization services to meet constantly changing patient care needs while maintaining patient safety and restricting possible overutilization.

Background. Thrombolysis has altered treatment of acute myocardial infarction (AMI). Therefore, reevaluation of predictors of outcome and treatment strategies is appropriate. Methods and Results. Clinical variables collected prospectively for the 3,339 patients of the Thrombolysis in Myocardial Infarction II study were analyzed retrospectively to identify predictors of clinical events at 42 days and earlier and to identify subgroups in which an invasive or conservative strategy might be superior. Pulmonary edema/cardiogenic shock presented as the strongest independent correlate with death (relative risk, 6.0). In two subgroups, mortality differed between the invasive and conservative strategies: 1) Patients with versus without prior AMI had a higher mortality in the conservative strategy (11.5% versus 3.5%, p<0.001); in the invasive strategy, the mortality rates were similar (6.0%o and 5.1%). 2) Patients with diabetes mellitus and no prior AMI had a higher mortality in the invasive than in the conservative strategy (14.8% versus 4.2%, p<0.001). Reinfarction was not independently correlated with baseline characteristics except with history of angina (relative risk, 1.9). Mortality was lower in current smokers and ex-smokers versus never-smokers (3.6% and 4.8% versus 8.0%, p<0.001). Current smokers had a lower risk profile (p<0.001), including age, pulmonary edema/cardiogenic shock, history of hypertension, and diabetes. The rate of reinfarction was lower in current smokers versus ex-smokers and never-smokers (4.6% versus 8.3% and 8.8%, p<0.001). "Not current smoker" was an independent correlate with reinfarction (relative risk, 1.9). The coronary anatomy did not differ among the current smokers, ex-smokers, and never-smokers. Conclusions. The strong independent correlation of pulmonary edema/cardiogenic shock with death suggests that thrombolysis is not sufficient to improve survival in these patients. The higher mortality in patients with versus without priorAMI in the conservative strategy suggests that early catheterization and revascularization of these patients might be beneficial. Conversely, the higher mortality in diabetics without prior AMI in the invasive than in the conservative strategy suggests that early aggressive management might not be suitable in this subgroup except for clinical indications. Reinfarction was not predictable by clinical variables except by history of angina. The finding that "not current smoker" was

Patients with coronary artery disease (CAD) and concomitant left bundle branch block have increased mortality compared with those with CAD but without left bundle branch block. We retrospectively analyzed the extent of CAD in 200 patients with left bundle branch block referred for coronary angiography. Only 13% had left main or 3-vessel CAD. These findings were irrespective of left ventricular (LV) function. Of the 65 patients with normal LV function, only 5 (8%) had left main or 3-vessel disease, and of the 135 patients with depressed LV function, only 21 (16%) had left main or 3-vessel disease.

BACKGROUND There are few data assessing the relative value of clinical factors and sensitive cardiac markers in determining the long-term prognosis of patients with chest pain. Likewise, little information exists about the long-term outcome of patients with chest pain who have negative markers of myocardial cell necrosis. This study addresses these issues in a cohort of patients with nonspecific chest pain and nondiagnostic electrocardiograms (ECGs). METHODS Eligible subjects (n = 501) had experienced >15 minutes chest pain at rest during the previous 24 hours, but were found to be at low-risk for acute myocardial infarction (AMI) by means of a well-validated clinical algorithm. Cardiac troponin I, creatine kinase MB(mass), myoglobin, and myosin light chain-1 were collected at presentation and 3, 6, and 12 hours later. Patients were observed for a median of 31 months. The composite end point was death or AMI subsequent to the index admission. RESULTS Cardiac troponin I was the best single biochemical predictor of outcome (risk ratio 2.34, 95% CI 1.31-4.17, P =.004), but was of less independent prognostic value than age and an abnormal presenting ECG. It was also inferior to a combination strategy, using all 4 markers tested (risk ratio 2.37, 95% CI 1.44-3.91, P <.001). Fifty of 428 patients (12%) with a cardiac troponin I level < or =0.2 ng/mL and 25 of 287 patients (9%) without elevation of any marker tested sustained an adverse event during follow-up. CONCLUSIONS Cardiac troponin I is the most useful single biochemical predictor of long-term outcome, but the best determinants are age, an abnormal presenting ECG, and an "any marker positive" strategy. Patients without elevated cardiac markers have an adverse event rate of approximately 10% in the subsequent 31 months.

Background: Sensitive and specific cardiac markers convey important short-term prognostic information about patients with an acute coronary syndrome. There are, however, few data assessing their value as long-term predictors.Hypothesis: The aim of the current study was to assess the relative value of three such markers and clinical characteristics in determining the long-term prognosis of patients with chest pain.Methods: Cardiac troponin I (cTnI), myosin light chain-1 (MLC-1), and creatine kinase-MBmass levels were obtained on admission (0 h) and at 4, 8, 16, and 24 h in 208 patients with chest pain. Eligible subjects were determined, at the time of hospital admission, to be at >7% risk of acute myocardial infarction (MI), but without new ST-segment elevation on their presenting electrocardiogram. Follow-up was performed a median of 28 (range 1-46) months later. The primary study endpoint was death or nonfatal MI, subsequent to the index admission.Results: Cardiac TnI levels greater than or equal to0.2 ng/ml (odds ratio [OR] 1.93, 95% confidence interval [CI] 1.09-3.40) and MLC-1 levels greater than or equal to1 ng/ml (OR 3.24, 95% CI 1.83-5.73) were both significant predictors of death or MI during long-term follow-up; MLC-1 was, however, the only independent biochemical predictor (OR 2.11, 95% CI 1.14-3.93).Conclusions: Both cTnI and MLC-1 predict the long-term outcome of patients with chest pain, but, in this cohort, MLC-1 proved to be a better predictor of mortality and nonfatal acute MI.

Coronary arterial occlusion due to thrombosis is the cause of most cases of myocardial infarction accompanied by ST-segment elevation. Rapid restoration of blood flow to jeopardized myocardium limits necrosis and reduces mortality. This can be accomplished medically, with a thrombolytic agent, or mechanically, with so-called primary balloon angioplasty or stenting (see figure). Each method has its advantages and limitations.Thrombolytic therapy is widely available and effective, but its use is sometimes associated with bleeding complications. In 10 to 15 percent of patients who receive a thrombolytic agent, clot lysis is not achieved. Only half the patients in whom antegrade coronary . . .

Congenital anomalies of the tricuspid and pulmonic valves constitute 10% to 15% of all congenital heart disease. Pulmonic stenosis is the most common congenital right-sided valvular abnormality and is effectively treated by balloon valvuloplasty. Pulmonic regurgitation usually results from pulmonary arterial hypertension, and its prognosis is largely determined by the underlying disease process. Tricuspid stenosis is nearly always caused by rheumatic disease and is never seen without concomitant mitral or aortic involvement. Tricuspid regurgitation (TR) usually results from right ventricular dilatation; patients with TR present with right-sided heart failure. KeywordsPulmonary Arterial HypertensionInfective EndocarditisTricuspid ValveTricuspid RegurgitationPulmonic RegurgitationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Post-PCI TIMI flow grade 3 in infarct-related artery not always is associated with follow-up improvement in myocardial perfusion and function. We compared the improvement in myocardial perfusion and function in cases of rapid and slow electrocardiographic (ECG) stage dynamics between patients with TIMI-3 flow after primary angioplasty for acute myocardial infarction (MI).Ten patients with post-PCI TIMI-3 flow were divided into group A (n = 50, no rapid change of ECG stages) and group B (n = 50, with a ≥2 ECG stages per 2 days change rate).There were no significant changes after 3 months in scintigraphic (ejection fraction 44.6 ± 9.3% vs. 42.0 ± 3.4%, P = 0.4; perfusion deficit severity 3.0 ± 0.7 vs. 2.3 ± 0.8, P = 0.1) and echocardiographic (dysfunction score 1.9 ± 0.2 vs. 1.6 ± 0.5, P = 0.2) data in group A. Scintigraphic data improved (ejection fraction 34.6 ± 3.9% vs. 52.0 ± 7.3, P = 0.03; perfusion deficit severity 2.8 ± 0.6 vs. 1.5 ± 0.8, P = 0.03) and changes in echocardiographic data were of borderline significance (dysfunction score 1.8 ± 0.2 vs. 1.4 ± 0.4, P = 0.06) in group B.There was not any change in myocardial perfusion and function in a case of slow change of ECG stages after reached post-PCI TIMI flow grade 3, while myocardial perfusion improved and function tended to improve in a case of the rate at least two ECG stages in 2 days after primary angioplasty for acute MI.

Several studies in the prethrombolytic era on the treatment of acute myocardial infarction identified selected variables from the patient's history, physical examination, chest roentgenogram and electrocardiogram that could be used to estimate mortality in patients with evolving infarction. To extend such assessment to patients receiving thrombolytic therapy, this study evaluated the prognostic utility of several risk factors in the 3,339 patients (2,742 men, 597 women, aged 24 to 78 years) enrolled in Phase II of the Thrombolysis in Myocardial Infarction (TIMI) trial. Before intravenous tissue plasntinogen activator was given, the presence of each of eight risk factors was noted: age ≥ 270 years, female gender, a history of diabetes mellitus or previous myocardial infarction, electrocardiographic evidence of evolving anterior infarction or atrial fibrillation, evidence on physical examination of mild pulmonary congestion or hypotension (systolic pressure < 100 mm Hg) and sinus tachycardia (heart rate > 100 beats/min).