Muhamed Saric

Cholesterol Embolization Syndrome

Cholesterol embolization syndrome refers to embolization of the contents of an atherosclerotic plaque (primarily cholesterol crystals) from a proximal large-caliber artery to distal small to medium arteries causing end-organ damage by mechanical plugging and an inflammatory response. Synonyms used in the medical literature include atheromatous embolization, cholesterol crystal embolization, and atheroembolism. Cholesterol embolization syndrome should be distinguished from the related and much more common syndrome of arterio-arterial thromboembolism in which fragments of a thrombus that forms atop an atheromatous plaque in the aorta or a large artery travel distally and occlude medium to large arteries.1 Cholesterol embolization syndrome is generally characterized by a multitude of small emboli (showers of microemboli) occurring over time. This is in contrast to arterio-arterial thromboembolism, which is usually characterized by an abrupt release of 1 or a few large emboli, leading to severe ischemia of target organs. Cholesterol embolization syndrome has a variety of clinical presentations. Cholesterol emboli originating in the descending thoracic and abdominal aorta may lead to renal failure, gut ischemia, and emboli to the skeletal muscles and the skin. Dermatologic manifestations (most commonly livedo reticularis and blue toe syndrome) are usually confined to the lower extremities but may extend to the abdomen and the chest. Cholesterol emboli originating in the ascending aorta may in addition cause neurological damage that is typically diffuse and due to small infarcts. Cholesterol embolization syndrome is also characterized by a nonspecific acute inflammatory response leading to constitutional symptoms (such as fever and malaise) and abnormalities in laboratory tests (such as hypereosinophilia and elevated erythrocyte sedimentation rate). These manifestations will be discussed in detail later in the text. Danish physician Fenger and his colleagues appear to have provided the first description of atheroembolism in the Danish medical brochure Ugeskrift for Laeger (Doctors’ Weekly).2 In 1844, they …

Mitochondrial development in Trypanosoma brucei brucei transitional bloodstream forms

Intermediate and short stumpy bloodstream forms of Trypanosoma brucei brucei are transitional stages in the differentiation of mammal-infective long slender bloodstream forms into the procyclic forms found in the midgut of the tsetse vector. Although the mitochondria of the proliferative long slender forms do not accumulate rhodamine 123, the mitochondria of the transitional forms attain this ability thus revealing the development of an electromotive force (EMF) across the inner mitochondrial membrane. The EMF is inhibited by 2,4-dinitrophenol, rotenone and salicylhydroxamic acid but not by antimycin A or cyanide. Consequently, NADH dehydrogenase, site I of oxidative phosphorylation, is the source of the EMF and the plant-like trypanosome alternative oxidase (TAO) supports the electron flow serving as the terminal oxidase of the chain. Although the TAO is present in the long slender forms as well, it serves only as the terminal oxidase for electrons from glycerol-3-phosphate dehydrogenase. The data presented here, combined with older data, lead to the conclusion that the mitochondria of transitional intermediate and short stumpy forms likely produce ATP. This putative production is either by F1F0 ATPase driven by the complex I proton pump or by mitochondrial substrate level phosphorylation, or most likely by both. These conclusions contrast with the previously held dogma that all bloodstream form mitochondria are incapable of ATP production.

Approach to dextrocardia in adults: review.

OBJECTIVE The educational objectives of this article are to describe an approach to analyzing imaging studies in adults with dextrocardia and to present the appearances of the most common underlying disorders. Topics reviewed include the morphology of the cardiac chambers, the concept of situs, and the relevant embryologic principles. The disorders discussed include situs inversus totalis (mirror-image dextrocardia), dextroversion, congenitally corrected transposition of the great arteries, and polysplenia syndrome. CONCLUSION In this article we describe an approach to dextrocardia in adult patients and illustrate the imaging manifestations of the most common underlying disorders.

Guidelines for the Use of Echocardiography in the Evaluation of a Cardiac Source of Embolism

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.

Mitral Bioprosthetic Valve Endocarditis Caused by an Unusual Microorganism, Gemella morbillorum, in an Intravenous Drug User

ABSTRACT We report a case of Gemella morbillorum mitral bioprosthetic valve endocarditis with perivalvular extension in a 44-year-old human immunodeficiency virus-positive man who is an active intravenous drug user together with review of all published cases. This is only the second reported case of Gemella morbillorum endocarditis in a patient with a prosthetic valve.

Aortic Atherosclerosis and Embolic Events

Aortic plaques are a manifestation of the general process of atherosclerosis in which there is a progressive accumulation of cholesterol and other lipids in the intimal-medial layer of the aorta with secondary inflammation, repetitive fibrous tissue deposition, and eventually luminal surface erosions and appearance of often mobile thrombi protruding into the lumen of the aorta. Aortic plaques may give rise to two types of emboli: thromboemboli and atheroemboli (cholesterol crystal emboli). Thromboemboli are relatively large, tend to occlude medium to large arteries, and cause strokes, transient ischemic attacks, and renal infarcts and other forms of peripheral thromboembolism. Cholesterol crystal emboli are relatively minute, tend to occlude small arteries and arterioles, and may cause the blue toe syndrome, new or worsening renal insufficiency, gut ischemia, etc. Transesophageal echocardiography remains the gold standard for visualization of aortic plaques in the thoracic aorta. There are no proven therapies for aortic embolism per se; general atherosclerosis management strategies are recommended.

Cholesterol embolization syndrome.

Purpose of review To describe cholesterol embolization syndrome (CES) and its risk factors, pathophysiology, clinical presentation, diagnosis and treatment. Recent findings To date, no specific diagnostic test (other than biopsy) for CES has been developed. Effective treatments for CES are yet to be developed. Summary CES (also referred to as cholesterol crystal embolization, atheromatous embolization or atheroembolism) occurs when cholesterol crystals and other contents of an atherosclerotic plaque embolize from a large proximal artery to smaller distal arteries, causing ischemic end-organ damage. Clinical manifestations of CES include constitutional symptoms (fever, anorexia, weight loss, fatigue and myalgias), signs of systemic inflammation (anemia, thrombocytopenia leukocytosis, high erythrocyte sedimentation rate, elevated levels of C-reactive protein, hypocomplementemia), hypereosinophilia, eosinophiluria, acute onset of diffuse neurologic deficit, amaurosis fugax, acute renal failure, gut ischemia, livedo reticularis and blue-toe syndrome. CES may occur spontaneously or after an arterial procedure. There is no specific laboratory test for CES. Retinal exam demonstrating Hollenhorst plaques supports the diagnosis of CES. Biopsy of target organs (usually skin, skeletal muscles or kidneys) is the only means of confirming the diagnosis of CES. Treatment consists of supportive care and general management of atherosclerosis and arterial ischemia.

Optimal imaging for guiding TAVR: transesophageal or transthoracic echocardiography, or just fluoroscopy?

THE FOLLOWING iFORUM DEBATE FEATURES 3 VIEWPOINTS related to the most practical and effective imaging strategy for guiding transcatheter aortic valve replacement (TAVR). Kronzon, et al. provide evidence that enhanced analysis of abrtic valve anatomy and improved appreciation of complications mandate the use of transesophageal echocardiography as front-Line imaging modality for ALL patients undergoing TAVR. On the other hand, Saric and colleagues compare and contrast the approach of performing TAVR under transthoracic guidance. Lastly, Kasel and co-workers provide preliminary evidence that TAVR could be performed under fluoroscopic guidance without the need for additional imaging technique. Although the use of Less-intensive sedation or anesthesia might reduce the procedural time, we need more randomized data to establish the most cost-effective approach in guiding TAVR.

Catheter-based left atrial appendage occlusion procedure: role of echocardiography

Atrial fibrillation is a common, clinically significant arrhythmic disorder that results in increased risk of morbidity and mortality in affected patients. Atrial fibrillation is more prevalent among men compared with women and the risk for developing atrial fibrillation increases with advancing age. Ischaemic stroke is the most common clinical manifestation of embolic events from atrial fibrillation. While anticoagulation treatment is the preferred treatment, unfortunately, many patients have contraindications for anticoagulation treatment making this option unavailable to them. Previous data have shown that most thrombi that form in association with non-valvular atrial fibrillation occur in the left atrial appendage (LAA). It has been suggested that isolating the LAA from the body of the left atrium might reduce the risk of embolic events and that LAA obliteration may be a treatment option for patients with atrial fibrillation who are not candidates for anticoagulation treatment. Several procedures have been developed for isolation of the LAA, including surgical procedures as well as catheter-based ones. In this paper, we will review the currently available techniques, emphasizing the catheter-based ones. We will examine the increasing role of real-time three-dimensional transoesophageal echocardiography for appropriate screening and patient selection for these procedures, intra-procedural guidance, and follow-up care.

Esophageal perforation, the most feared complication of TEE: early recognition by multimodality imaging.

Esophageal perforation is the most feared complication of transesophageal echocardiography (TEE), although the overall risk is extremely low. We report a case of esophageal perforation in a 77‐year‐old woman who had no apparent contraindications to TEE. Chronic steroid therapy for symptoms of asthma as well as osteophytic changes of the cervical vertebrae contributed to her increased risk of perforation. Unlike in prior reports, the perforation in this case was fortuitously recognized rapidly due to ingestion of a carbonated beverage for evaluation of a hiatal hernia suspected during a subsequent transthoracic echocardiogram performed because of inadequate TEE images after a difficult intubation. The incidence of esophageal perforation in our series (1 in 5,000 TEEs, 0.02%) is similar to that reported in the literature. Early recognition and prompt surgical repair of the esophageal perforation led to favorable outcome in our patient. (Echocardiography 2011;28:E56‐E59)