In this post I link to and excerpt from Guidelines for the Use of Echocardiography in the Evaluation of a Cardiac Source of Embolism [PubMed Abstract] [Full-Text HTML] [Full-Text PDF]. J Am Soc Echocardiogr. 2016 Jan;29(1):1-42.
All that follows is from the above resource.
Embolism from the heart or the thoracic aorta often leads to clinically significant morbidity and mortality due to transient ischemic attack, stroke or occlusion of peripheral arteries. Transthoracic and transesophageal echocardiography are the key diagnostic modalities for evaluation, diagnosis, and management of stroke, systemic and pulmonary embolism. This document provides comprehensive American Society of Echocardiography guidelines on the use of echocardiography for evaluation of cardiac sources of embolism.
It describes general mechanisms of stroke and systemic embolism; the specific role of cardiac and aortic sources in stroke, and systemic and pulmonary embolism; the role of echocardiography in evaluation, diagnosis, and management of cardiac and aortic sources of emboli including the incremental value of contrast and 3D echocardiography; and a brief description of alternative imaging techniques and their role in the evaluation of cardiac sources of emboli.
Specific guidelines are provided for each category of embolic sources including the left atrium and left atrial appendage, left ventricle, heart valves, cardiac tumors, and thoracic aorta. In addition, there are recommendation regarding pulmonary embolism, and embolism related to cardiovascular surgery and percutaneous procedures. The guidelines also include a dedicated section on cardiac sources of embolism in pediatric populations.
Outline
- Keywords
- Abbreviations
- Introduction
- “INTRODUCTION
Embolism from the heart or the thoracic aorta often leads to clinically significant morbidity and mortality due to transient ischemic attacks (TIAs), strokes, or occlusions of peripheral arteries.- Stroke is the third leading cause of death in the United States and other industrialized countries. Echocardiography is essentialfor the evaluation, diagnosis, and management of stroke and systemic embolism.
- Cardiac embolism accounts for approximately one third of all cases of ischemic stroke. Paradoxical embolism and embolism from the thoracic aorta, especially of its atheroma contents, are responsible for additional cases of stroke and systemic embolism.
This document provides the first set of guidelines of the American
Society of Echocardiography (ASE) guidelines specific to this topic.- Methodology
- General Concepts of Stroke and Systemic Embolism
- Stroke Classification
- Stroke Classification
It is estimated that 87% of all strokes are ischemic, and the remaining
13% are hemorrhagic. Using the Trial of Org 10172 in Acute Stroke
Treatment criteria,2 ischemic strokes may be further subdivided into
following types:- 1. Thrombosis or embolism associated with large vessel atherosclerosis
2. Embolism of cardiac origin (cardioembolic stroke)
3. Small blood vessel occlusion (lacunar stroke)
4. Other determined cause
5. Undetermined (cryptogenic) cause (no cause identified, more than one
cause, or incomplete investigation)- The incidence of each cause is variable and depends on patient age,
sex, race, geographic location, risk factors, clinical history, physical
findings, and the results of various tests. This guidelines document
deals primarily with cardioembolic strokes but also includes discussions of the role of echocardiography in evaluation of embolic strokes from the thoracic aorta (atheroembolism) and in cryptogenic strokes.
Embolism of cardiac origin accounts for 15% to 40% of all ischemic
strokes,3 while undetermined (cryptogenic) causes are responsible
for 30% to 40% of such strokes.- Type and Relative Embolic Potential of Cardiac Sources of Embolism
- In patients who are at risk for or have already had potentially embolic
strokes, the primary role of echocardiography is to establish the existence of a source of embolism, determine the likelihood that such a
source is a plausible cause of stroke or systemic embolism, and guide
therapy in an individual patient.
Cardiac sources of embolism include blood clots, tumor fragments,
infected and bland (noninfected) vegetations, calcified particles, and
atherosclerotic debris. Conditions that are known to lead to systemic
embolization are listed in Table 1 and subdivided into a high-risk and a
low-risk risk group on the basis of their embolic potential. However, in many conditions more than one embolic source may be present
(coexistence of embolic sources) or one cardioembolic condition
may lead to another (interdependence of embolic sources). For instance, mitral stenosis is associated with spontaneous echocardiographic contrast (SEC), atrial fibrillation, left atrial (LA) clot, and even endocarditis.- Diagnostic Workup in Patients with Potential Cardiac Sources of Emboli
- Evaluation of suspected cardiac source of embolism requires rapid
diagnostic efforts, which should include detailed history, comprehensive physical examination, blood workup, and imaging of the heart and the organs damaged by the embolus. Echocardiography should
be the primary form of cardiac imaging, supplemented by chest xray, computed tomography (CT), magnetic resonance imaging
(MRI), and nuclear imaging when necessary. CT or MRI as well as
angiography may be indispensable in the evaluation of organs and tissues affected by cardiac sources of embolism.- Prevention and Treatment
- Echocardiography plays an important role not only in the diagnosis but also in the treatment and prevention of cardiac sources of embolism. This aspect of echocardiography is beyond the scope of this guidelines document; references to appropriate treatment and prevention guidelines are given in individual sections of this document.
- Role of Echocardiography in Evaluation of Sources of Embolism
- Since its earliest days, echocardiography has been considered an
important tool in the evaluation of possible cardiac source of embolism. Even the one-dimensional M-mode technique, which was first introduced in 1953 by Swedish cardiologist Inge Edler (1911–2001)
and engineer Hellmuth Hertz (1920–1990), was capable of demonstrating conditions associated with embolic stroke and systemic
emboli, such as mitral stenosis, LA dilatation, LA myxoma, and left ventricular (LV) systolic dysfunction.- The introduction of two-dimensional (2D) echocardiography in the early 1970’s further expanded the diagnostic capability and accuracy of ultrasound imaging in the evaluation of cardiac sources of embolism; wall motion abnormalities could be better defined, and various normal and abnormal cardiac structures could be better assessed.
- The introduction of Doppler techniques in the 1970’s and transesophageal echocardiography (TEE) in the 1980’s allowed more precise quantification of normal and abnormal intracardiac structures and blood flows. Finally, the advent of real-time three-dimensional (3D) echocardiography at the turn of the 21st century has provided
unprecedented anatomic and functional details of many cardiac structures implicated as cardiac sources of embolism and allowed guidance of percutaneous treatments of sources of cardiac embolism (e.g.,
percutaneous closure of LA appendage (LAA) in patients with atrial fibrillation).- The overall use of echocardiography in the evaluation of cardiac sources of emboli should follow established appropriate use criteria.5
Below is an excerpt from the appropriate use criteria guidelines, with entries relevant to cardiac sources of embolism.- Appropriate Use Criteria for Echocardiography in Evaluation of Cardiac Sources of Emboli
- Appropriate Use: Transthoracic Echocardiography (TTE)
- Symptoms or conditions potentially related to suspected cardiac etiology,
including but not limited to chest pain, shortness of breath, palpitations,
TIA, stroke, or peripheral embolic event- Suspected cardiac mass
- Suspected cardiovascular source of embolus
- Initial evaluation of suspected infective endocarditis (IE) with positive blood culture results or new murmur
- Reevaluation of IE at high risk for progression or complication or with a
change in clinical status or cardiac examination results- Known acute pulmonary embolism (PE) to guide therapy (e.g., thrombectomy and thrombolytic therapy)
- Reevaluation of known PE after thrombolysis or thrombectomy for assessment of change in right ventricular (RV) function and/or pulmonary artery pressure
- Appropriate Use: TEE
- As initial or supplemental test for evaluation for cardiovascular source of
embolus with no identified noncardiac source- As initial or supplemental test to diagnose IE with a moderate or high pretest
probability (e.g., staph bacteremia, fungemia, prosthetic heart valve, or intracardiac device)- As initial test for evaluation to facilitate clinical decision making with regard
to anticoagulation, cardioversion, and/or radiofrequency ablation- Uncertain Indication for Use: TEE
- Inappropriate Use: TTE
- Inappropriate Use: TEE
- A Practical Perspective: Echocardiographic Techniques for Evaluation of Cardiac Sources of Embolism: “Echocardiography plays an essential role in the evaluation, diagnosis, and management of cardiac and aortic sources of embolism.6 Standard TTE and TEE are useful but yield to better results when additional imaging techniques are performed as a part of the examination.7 These include, but are not limited to, high-frequency and fundamental imaging, off-axis and nonstandard views, thorough sweeps through chambers and multiple planes, multiplane and 3D imaging, and the use of contrast (both agitated saline and transpulmonary microbubble contrast agents). Such techniques are summarized in Table 2. When assessing specific structures of the heart using 3D imaging, acquisition should be focused on the structure as outlined in the European Association of Echocardiography and ASE recommendations.8 Depending on the patient’s presentation and history, most or some of the imaging techniques previously mentioned in this section should be applied. Examples of various echocardiographic imaging techniques, including still images and video clips, are provided throughout this document in sections dealing with individual cardiac sources of embolism.”
- Recommendations for Performance of Echocardiography in Patients with Potential Cardiac Source of Embolism
- Alternatives to Echocardiography in Imaging Cardiac Sources of Embolism
- Thromboembolism from the Left Atrium and LAA
- Thromboembolism from the Left Ventricle
- Valve Disease
- Cardiac Tumors
- Embolism from the Thoracic Aorta
- Paradoxical Embolism
- Pulmonary Embolism
- Cardiac and Aortic Embolism during Cardiac Surgery and Percutaneous Interventions
- Stroke in the Pediatric Population
- Notice and Disclaimer
- Reviewers
- Supplementary data
- References
Figures
Figure1. Two-dimensional TTE of LV apical thrombus with harmonic and fundamental imaging
Tables
Extras
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