Echocardiography in infective endocarditis: reassessment of prognostic implications of vegetation size determined by the transthoracic and the transesophageal approach

Echocardiography in the evaluation of cardiac sources of emboli: the role of transthoracic echocardiography

Cardioembolism is responsible for a significant number of systemic emboli including approximately 15% of all ischemic strokes. Transthoracic echocardiography has contributed to the understanding of cardioembolism and has been used to detect specific and potential cardiac sources of systemic emboli and risk stratify patients with specific clinical findings for subsequent cardiovascular events. Findings from transthoracic echocardiography indicate that stasis is an important prerequisite for intracardiac thrombosis while reversal of stasis and thrombolysis appear operative in embolism of existing thrombus. Transthoracic echocardiography allows a sensitive and specific noninvasive means to detect left ventricular thrombus, valvular vegetation, and intracardiac tumor, lesions that are directly responsible for cardioembolism. Transthoracic echocardiography can also detect lesions that could potentially contribute to cardioembolism but are not specific causes. Examples of these potential lesions include mitral valve prolapse, patent foramen ovale, and interatrial septal aneurysm. Finally, population-based studies and prospective clinical trials have indicated that the results of transthoracic echocardiography have predictive value for subsequent cardiovascular events and hence provide a means for stratification of patients at risk for cardioembolism. The latter is most notable for the group of patients with nonvalvular atrial fibrillation where left ventricular dysfunction and increased left atrial size are independent predictors for subsequent stroke.

Transesophageal echocardiography as a tool in the evaluation of patients with embolic disorders

TEE has become one of the most powerful tools for evaluating patients with unexplained stroke, TIA, and peripheral and pulmonary embolization. This is especially encouraging in view of the previously disappointing results of TTE in these patients. In addition to the dramatic results in terms of clot visualization and the other intracardiac sources of embolization described previously, a new extracardiac source has been identified, namely protruding atheromas in the thoracic aorta. These atheromas have been seen for the first time because of the new diagnostic window that has been opened by the development of TEE. Their recognition and follow-up may lead to information that will change the approach to a significant number of patients with embolic ischemic episodes.

The safety of transesophageal echocardiography in the elderly

The safety of transesophageal echocardiography (TEE) in elderly patients (aged > or = 70 years) and young patients (aged < or = 50 years) was compared in a retrospective study of 283 examinations in each group. A greater percentage of studies was performed in an intensive care unit in the elderly group (22%) as compared with the younger group (13%, p < 0.02). In studies performed in an intensive care unit, 39% (24/61) of patients in the elderly group and 45% (17/38) in the young group were on ventilators. Transient systemic hypotension complicating TEE was 3.5 times more frequent in the elderly (5%) as compared with the young group (1.4%, p < 0.02). Life-threatening complications associated with TEE were rare (< 0.01%) and included third-degree atrioventricular block in one patient and profound vasovagal reaction in one patient in the elderly group and myocardial ischemia in one patient in the young group. Being elderly and on a ventilator were independent predictors of the development of systemic hypotension during TEE. Overall, TEE is a low-risk procedure but is associated with a 3.5 times greater risk of systemic hypotension in elderly patients as compared with younger subjects. The benefit and risk should be assessed in all patients before TEE, particularly in the elderly.

Transesophageal echocardiography for prosthetic valve evaluation: is it always necessary?

Transesophageal echocardiography provides excellent images of mitral and aortic prostheses, due to its higher resolution and less interference from other cardiac structures. Since the introduction of transesophageal echocardiography, it has proved to be valuable for the evaluation of prosthetic heart valves. "Classic" indications include the evaluation of prosthetic valve endocarditis, the search for paravalvular abscesses, and the assessment of regurgitation in mechanical, especially mitral, prostheses. New technical developments such as biplane or multiplane transducers enhance the diagnostic capabilities of the technique. Transesophageal echocardiography can also have advantages in recognizing obstructive lesions such as thrombi or pannus, and help understand the complex morphology of prostheses in grafts. Transesophageal echocardiography should be considered a backup technique whenever transthoracic echocardiography, which always remains the primary approach, is inconclusive or negative in the presence of clinically suspected prosthetic valve malfunction.

Transesophageal echocardiography in right-sided endocarditis

OBJECTIVES

Our aim was to determine the diagnostic value of transesophageal echocardiography in right-sided endocarditis.

BACKGROUND

Recent studies have demonstrated that transesophageal echocardiography is superior to transthoracic echocardiography in the detection of vegetations associated with left-sided endocarditis. Its diagnostic value in right-sided endocarditis has not been established.

METHODS

Transthoracic and transesophageal echocardiography were prospectively performed in 48 patients who met specific criteria for the suspicion of right-sided endocarditis. All were intravenous drug abusers.

RESULTS

Vegetations were found in 22 of 48 patients by both transthoracic and transesophageal echocardiography. The vegetations were more precisely characterized by transesophageal echocardiography in 14 (63%) of 22 patients. In the remaining 26 patients, no vegetations were found by either transthoracic or transesophageal echocardiography. No statistically significant differences were found between the two techniques in the assessment of tricuspid regurgitation, which was detected in 21 (44%) of 48 patients.

CONCLUSIONS

We conclude that transesophageal echocardiography does not improve the diagnostic accuracy of transthoracic echocardiography in the detection of vegetations associated with right-sided endocarditis in intravenous drug abusers. Transesophageal echocardiography may not be indicated as a routine procedure in patients suspected of having right-sided endocarditis.

Pitfalls in the echo-Doppler diagnosis of prosthetic valve disorders

Assessment of artificial heart valves is a classic example of pitfalls in Doppler and color flow echocardiography. These limitations should be analyzed in the context of the most common clinical conditions associated with prosthetic valve dysfunction, that is, assessment of stenosis, regurgitation, endocarditis, and source of emboli. Estimation of the mean transvalvular gradient in addition to valve areas may avoid potential problems of over- or underestimation of stenotic lesions. The combination of acoustic attenuation, acoustic shadowing, and jet(s) eccentricity makes accurate grading of prosthetic regurgitation difficult and often frustrating. Reverberations and side lobe are frequent artifacts that decrease the ability of two-dimensional echocardiography to identify endocarditis-induced lesions such as vegetations and abscesses, as well as potential sources of emboli such as thrombus and atrial septal abnormalities. Transesophageal echocardiography has provided a new window in the evaluation of prosthetic cardiac valve function. With this approach, high frequency, high resolution transducers greatly improve the quality of ultrasound and color flow Doppler images that result in a higher diagnostic yield. In patients with suspected mitral prosthesis malfunction, transesophageal echocardiography is the method of choice. Contrast study during the transesophageal examination increases the sensitivity to detect potential sources of emboli such as patent foramen ovale. The improvement in diagnostic accuracy may allow one to avoid further diagnostic tests and, in selected patients, it may facilitate optimal timing of a surgical intervention.

The febrile parenteral drug user: a prospective study in 121 patients

OBJECTIVE

To determine the most efficient approach to the diagnosis of infective endocarditis (IE) in febrile parenteral drug users (PDUs) and evaluate possible effects of human immunodeficiency virus (HIV) infections or acquired immunodeficiency syndrome (AIDS) on susceptibility to IE and final outcome.

DESIGN

A prospective study of appropriate patients admitted on 149 random sampling days during a 14-month period and review of past experience with IE, HIV, and AIDS admissions to hospital.

SETTING

An urban university hospital.

PATIENTS

Prospectively, 121 febrile PDUs plus an additional 16 found to have IE on nonsampling days during the study period. Retrospectively, all PDUs with IE from 1985 to 1991 and all patients with HIV infections with or without AIDS from July 1990 through December 1991.

MEASUREMENTS

Physical examination, hemograms, urinalysis, blood cultures (plus other body fluids when indicated), echocardiography, laboratory testing for HIV status.

MAIN RESULTS

Five categories of patients were identified: I. Infective endocarditis (n = 16); II. Other infections with bacteremia (n = 21); III. Bacteremia with unidentified source of infection (n = 14); IV. Infections without bacteremia (n = 52); V. Fever of unknown origin (n = 18). Physical findings and standard laboratory testing did not differentiate Group I from any of the other diagnostic categories. Adding additional IE cases from nonstudy days brought the total to 32. Vegetations were found on echocardiography in 94%; blood cultures, available in 30 of 32 instances, were all positive. HIV or AIDS status was not found to alter susceptibility to IE or influence mortality. While hospital admissions for HIV and especially AIDS have continued to increase among PDUs, the number of cases of IE has decreased since 1988 to 1989.

CONCLUSIONS

Based on the high incidence of blood culture positivity and the sensitivity of echocardiography in detecting vegetations in IE, a simple algorithm has been developed for the initial diagnostic management of febrile PDUs admitted with the possible diagnosis of IE. HIV infection, with or without full-blown AIDS, does not appear to affect the incidence or outcome of IE among these patients. Current practices among PDUs may be effecting a decline in IE but not HIV infections.

Comparison of transthoracic and transesophageal echocardiography for detection of abnormalities of prosthetic and bioprosthetic valves in the mitral and aortic positions

Two-dimensional echocardiography is the diagnostic procedure of choice for evaluation of prosthetic valve abnormalities. However, transthoracic echocardiography (TTE) may be limited owing to acoustic shadowing and poor acoustic windows. Some of these limitations may be overcome by transesophageal echocardiography (TEE). One hundred twenty-six patients with 148 prosthetic valves (113 bioprostheses and 35 mechanical devices) were studied by M-mode and 2-dimensional TTE and TEE. Prosthetic valve morphology was confirmed by surgery or autopsy in all cases; 124 prostheses were classified as diseased (33 endocarditis, 8 thrombi, and 83 degeneration defined as leaflet thickening > 3 mm with restricted motion) and 24 as normal. Prosthetic valve endocarditis and thrombi were correctly identified by TTE in 12 of 33 (36%) and 1 of 8 (13%) prostheses, respectively, but could be diagnosed by TEE in 27 of 33 (82%; p < 0.001) and 8 of 8 (100%; p < 0.01), respectively. Compared with TTE, TEE had a higher sensitivity for morphologic prosthetic valve abnormalities in patients with either bioprostheses (88 [87%] vs 66 [65%] of 101 prostheses; p < 0.01) or mechanical devices (19 [83%] vs 5 [22%] of 23 prostheses; p < 0.01) and in patients with a prosthesis in either the aortic (49 [77%] vs 32 [50%] of 64; p < 0.01) or mitral (58 [97%] vs 39 [65%] of 60; p < 0.001) position. Overall, sensitivity and specificity were 57 and 63%, respectively, for TTE, and 86 and 88%, respectively, for TEE.(ABSTRACT TRUNCATED AT 250 WORDS)

Implication of negative results on a monoplane transesophageal echocardiographic study in patients with suspected infective endocarditis

OBJECTIVES

This study was conducted to determine the implications of negative findings on a transesophageal echocardiographic study in which neither a vegetation nor an abscess is identified in patients with clinically suspected infective endocarditis.

BACKGROUND

Echocardiography is the procedure of choice for evaluating suspected infective endocarditis in patients. Transesophageal echocardiography has been shown to be superior to transthoracic imaging. Although the importance of positive results or a diagnostic study is known, the significance of negative findings on a transesophageal study is not clear.

METHODS

All transesophageal echocardiographic studies performed over a 2-year period for suspected infective endocarditis were reviewed and the clinical course of patients with an initially negative study result was assessed to determine their final diagnosis.

RESULTS

Of the 105 patients identified, 65 had a negative transesophageal study result. In the majority of this group (56 of 65), an alternate diagnosis was made or there was no infective endocarditis on follow-up examination, or both. Of the remaining nine patients, four were treated for endocarditis without a definite diagnosis and five had infective endocarditis proved by either repeat transesophageal study (n = 3), pathologic findings (n = 1) or a diagnostic clinical course (n = 1). Gram-positive bacteremia and the presence of a prosthetic valve in the aortic position tended to be more common in the latter group.

CONCLUSIONS

A negative transesophageal study result reduces the likelihood that endocarditis is present. Repeat examination, however, should be considered in high risk patients, such as those with prosthetic valves or unexplained bacteremia, to avoid a missed diagnosis.

[Contribution of transesophageal echocardiography in intensive care: a prospective assessment]

The benefits of transoesophageal echocardiography (TOE) were assessed prospectively in intensive care patients. The doctors carrying out TOE were not the same as those who ordered it. TOE was performed in 32 patients, all of whom but one were intubated and artificially ventilated, to elucidate the cause of circulatory shock, or to search for valvular vegetations or an intracardiac mass. TOE confirmed the diagnosis previously obtained with pulmonary arterial catheterization (10 patients), transthoracic echocardiography (3 patients) or ventriculography (1 patient) in 54% of cases. In 28% of cases, TOE invalidated the suspected diagnosis, and, in the remaining 28% of patients, TOE invalidated provided a previously unsuspected diagnosis. TOE was particularly useful in confirming the presence of valvular vegetations, endocarditis, or intracardiac thrombi, and to assess left ventricular function and preload in patients in shock. Like others, this study confirms the benefits of TOE in the intensive care setting.

[Staphylococcus aureus endocarditis: an unusual clinical picture]

We describe an unusual presentation of bacterial endocarditis due to Staphylococcus aureus in a 50 year-old woman with mitral insufficiency. The disease began by a vascular purpura without fever and a digital embolism. The source of infection was anal ulcerations. Diagnosis of endocarditis was made possible by trans-oesophagus echocardiography but not by trans-thoracic echocardiography. The patient was successfully treated by surgery associated with antibiotherapy. This observation emphasizes the indications of surgery at the acute phase of endocarditis. The anal source of endocarditis is original, no other case has been found in the literature.

Utility of transesophageal echocardiography in the conservative management of prosthetic valve endocarditis

Prosthetic valve endocarditis is a formidable complication following cardiac valve replacement. Surgical intervention has resulted in a significant reduction in mortality when certain complications prevail. We report two such cases of prosthetic valve endocarditis in which the use of transesophageal echocardiography permitted close surveillance during medical therapy and thus avoided the need for surgical intervention. Therefore, with the improved ability to monitor disease progression with transesophageal echocardiography, nonsurgical management of prosthetic valve endocarditis remains an option.

Transesophageal echocardiography: normal variants and mimickers

An accurate diagnosis of cardiac pathology using TEE is contingent upon the ability to recognize and differentiate normal cardiac structures and normal variants from pathologic conditions. We describe several normal cardiac structures commonly imaged using TEE of the atria, interatrial septum, aorta, valves, and extracardiac spaces that may mimic diverse pathologic states, such as intracardiac tumor and thrombus, valvular vegetations, mitral and tricuspid valve prolapse, atherosclerotic plaque, and aortic dissection. Methods to aid in the differentiation of normal cardiac structures from pathology are offered.

Comparison of transthoracic and transesophageal echocardiography in evaluation of 47 Starr-Edwards prosthetic valves

OBJECTIVES

Our objectives were to characterize by transesophageal echocardiography the normal appearance of the Starr-Edwards prosthetic heart valve and to compare the utility of transesophageal and transthoracic echocardiography in detection of valve abnormality.

BACKGROUND

The Starr-Edwards prosthetic heart valve, the first mechanical valve to be used, has demonstrated excellent durability.

METHODS

Fifty transthoracic and transesophageal echocardiographic studies on 37 patients with 47 Starr-Edwards prosthetic valves were analyzed retrospectively. Six cases of surgically confirmed infective endocarditis were studied.

RESULTS

Vegetation or abscess formation, or both, was identified by transesophageal echocardiography in all six cases of infective endocarditis but was found in only one of these cases by transthoracic echocardiography. Thrombus was detected by transesophageal echocardiography in 9 of 11 patients with transient ischemic attacks or stroke and in 2 patients by transthoracic echocardiography with 3 confirmed at surgery. In 26 of the 30 patients with a mitral Starr-Edwards valve, the valve demonstrated a trivial or mild "closing volume" early systolic or holosystolic leak on transesophageal echocardiography alone. Transthoracic evaluation identified significant mitral regurgitation in six of the eight patients who had this finding on transesophageal echocardiography. Serial studies were performed to assess response to treatment or need for surgical intervention in eight patients. Seventeen valves have been implanted for 12 years; six of these had significant leakage without apparent cause, a finding not observed more recently implanted valves.

CONCLUSIONS

These observations demonstrated the unique utility of transesophageal echocardiography in patients with Starr-Edwards prosthetic valve dysfunction, endocarditis or thrombus formation, and of the clear superiority of transesophageal echocardiography over transthoracic echocardiography in these situations.

Transesophageal echocardiographic diagnosis of right-sided cardiac masses in patients with central lines

Transesophageal echocardiography provides excellent images of intracardiac masses; however, its use among a series of patients with central venous lines has not been fully described. Nineteen patients (aged 52 +/- 16 years; 10 women) had masses detected by transesophageal echocardiography in the presence of a permanent (0.2 to 16 years) pacing wire (n = 8), and a current (n = 9) or recent (n = 2) (1 to 281 days) indwelling catheter. Transthoracic echocardiography suggested the presence of a mass in 5 patients (26%), although in only 2 cases were its findings consistent with transesophageal findings. Transesophageal echocardiography indicated the presence of a mass in or near the superior vena cava in 13 patients, in the right atrium in 6, and adjacent to the tricuspid valve in 3. Discrete masses measured 1.6 +/- 2.1 cm2 in area during transesophageal echocardiography. Eleven patients had positive blood cultures, 7 with staphylococcal species. Mass size was not significantly altered by the type of line or sepsis, but showed a weak correlation with line age (r = 0.56). Transesophageal echocardiography altered the management of 9 patients, prompting surgery (n = 3) and line removal (n = 3), and antibiotic (n = 2) or anticoagulation (n = 3) therapy.

Mobile strands are frequently attached to the St. Jude Medical mitral valve prosthesis as assessed by two-dimensional transesophageal echocardiography

Two-dimensional transesophageal echocardiographic findings are reported in 13 patients with structurally and functionally normal St. Jude Medical bileaflet mitral valve prostheses. Multiple mobile linear echogenic densities attached to the pivot of the prosthesis were present in 9 of 13 patients. These densities may represent fibrin strands. These mobile strands alternatively resolve and reform over a period of 5 to 14 months after mitral valve replacement. No adverse clinical events were attributable to these prosthetic mitral valve strands. We conclude that mobile stands are frequently attached to the structurally and functionally normal St. Jude Medical mitral valve prosthesis. The clinical significance of these prosthetic mitral valve strands requires clarification.

Nonbacterial thrombotic endocarditis. Assessment by transesophageal echocardiography

Nonbacterial thrombotic endocarditis (NBTE) is difficult to detect antemortem and is often not suspected until embolic events occur. Transthoracic echocardiography is useful in diagnosing NBTE, but it may be limited by suboptimal imaging and resolution. Herein we describe the first reported case of NBTE diagnosed by transesophageal echocardiography. As early detection and treatment may avert significant embolic complications, transesophageal echocardiography should be strongly considered if other techniques are nondiagnostic and clinical suspicion of NBTE remains high.

Spontaneous echo contrast imaging in infective endocarditis: a predictor of complications?

Infective endocarditis is associated with significant morbidity and mortality. Valvular destruction and congestive heart failure are more common in patients with echocardiographically detectable vegetations. In addition, spontaneous platelet aggregation is increased when vegetations are present on cardiac valves. The aim of the study was to assess the prognostic value of spontaneous echo contrast (SEC) imaging, as SEC is supposed to reflect red blood cell aggregates stimulated by platelet activity. We studied 293 patients with clinical signs of infective endocarditis. Vegetations, attached to the aortic or mitral valve, were found in 130 patients (44.4%) who were followed for a mean period of 12 months. In 34 of these 130 patients (26.2%) SEC was imaged during the initial transesophageal echocardiographic examination. In these patients SEC indicated a prolonged healing of infective endocarditis with a specificity of 91.2%, a sensitivity of 77.3%, a positive accuracy of 77.3%, a negative accuracy of 74.3%. Multivariate analysis revealed that SEC is a risk factor for valve replacement (p less than 0.001) and for embolic events (p less than 0.001), less for mortality (p less than 0.01), and lowest for abscess formation (p less than 0.05). The dose of ADP to induce half-maximal platelet aggregation was significantly lower in patients with SEC (0.71 +/- 0.15 microliters) than without SEC (1.05 +/- 0.12 microliters; p less than 0.05), implying an increased spontaneous platelet aggregation in the presence of SEC. Our data provide evidence that systemically activated coagulation plays an important role in infective endocarditis. SEC, the echocardiographic implication of an increased platelet aggregation, predicts complications such as thromboembolic events and the need for surgery and is closely related to the prolonged healing period of infective endocarditis. In addition to demonstrating vegetations, transesophageal echocardiography provides information helpful in assigning patients to a high-risk subgroup. Transesophageal echocardiography may play an important role in assessing the clinical outcome of these patients.

Transesophageal echocardiographic recognition of subaortic complications in aortic valve endocarditis. Clinical and surgical implications

BACKGROUND

Secondary involvement of the mitral-aortic intervalvular fibrosa and the anterior mitral leaflet (subaortic structures) can occur in patients with aortic valve endocarditis. The secondary involvement of these structures occurs as a result of direct extension of the infection from the aortic valve or as a result of an infected aortic regurgitant jet striking the ventricular surfaces of the mitral-aortic intervalvular fibrosa and the anterior mitral leaflet. The abscess of mitral-aortic intervalvular fibrosa can expand to form an aneurysm. Subsequently, this mitral-aortic intervalvular fibrosa aneurysm can develop a perforation and communicate with the left atrium, resulting in the systolic regurgitation of blood from the left ventricular outflow tract into the left atrium. Secondary infection can also occur on the ventricular surface of the anterior mitral leaflet and result in the formation of an aneurysm or perforation of anterior mitral leaflet.

METHODS AND RESULTS

This study examines the utility of transesophageal echocardiography in the detection of these subaortic complications in 55 consecutive patients with aortic valve endocarditis. A total of 24 patients (44%) had involvement of subaortic structures, including four with an abscess in the mitral-aortic intervalvular fibrosa, four with mitral-aortic intervalvular fibrosa aneurysm, seven with perforation of the mitral-aortic intervalvular fibrosa with communication into the left atrium, two with an aneurysm of the anterior mitral leaflet, and seven with perforation of the anterior mitral leaflet. The transesophageal echocardiographic findings were confirmed at surgery in 20 patients and at necropsy in two. By comparison, transthoracic echocardiography visualized these lesions in five of 24 patients (21%), including none of four with mitral-aortic intervalvular fibrosa abscesses, two of four with mitral-aortic intervalvular fibrosa aneurysms, one of seven with mitral-aortic intervalvular fibrosa perforations, one of two with anterior mitral leaflet aneurysms, and one of seven anterior mitral leaflet perforations. Eccentric mitral regurgitation-type systolic jets were noted in eight additional patients by transthoracic color flow imaging, and this finding suggested the possibility of these unusual subaortic complications. If these patients are included, then transthoracic echocardiography suggested the presence of these subaortic complications in 13 of 24 patients (54%).

CONCLUSIONS

The results indicate that 1) involvement of the subaortic structures in patients with aortic valve endocarditis may be more common than previously recognized, 2) patients with aortic valve endocarditis and eccentric jets of mitral regurgitation on transthoracic echocardiography should undergo further evaluation by transesophageal echocardiography to exclude these unusual complications, 3) precise recognition of these complications is of value in the optimal medical and surgical management of these patients, and 4) these complications may be responsible for unexplained congestive heart failure and hemodynamic deterioration in some patients with aortic valve endocarditis.

Subacute bacterial endocarditis secondary to Streptococcus pneumoniae

Pneumococcal endocarditis characteristically presents as an acute illness, often accompanied by purulent meningitis, rapid destruction of the heart valves, congestive heart failure, and high mortality. We describe two patients with subacute pneumococcal endocarditis without a known primary source of pneumococcal bacteremia, fever, meningitis, or congestive heart failure. Both patients were cured with medical therapy. Pneumococcal endocarditis can present as an indolent illness resembling viridans streptococcal endocarditis.

Transesophageal echocardiography

Transesophageal echocardiography has provided a new acoustic window to the heart, the great vessels, and the mediastinum. It provides anatomical, functional hemodynamic, and blood flow information. High-quality visualization of left atrial appendage, thoracic aorta, atrial septum, and mitral valvular apparatus can be obtained readily. We discuss historical and technical aspects of transesophageal echocardiography, anatomical views, and major clinical indications for this procedure. These indications include intracardiac masses, thoracic aortic dissection, endocarditis, prosthetic and native cardiac valve function assessment, as well as its value in the detection of intracardiac source of systemic emboli. Furthermore, the role of transesophageal echocardiography in the assessment of coronary artery and congenital heart disease and as an intraoperative diagnostic and monitoring technique is discussed.

Risk of bacteremia induced by transesophageal echocardiography: analysis of 100 consecutive procedures

The incidence of bacteremia induced by transesophageal echocardiography (TEE) and, consequently, the need for an antibiotic prophylaxis before TEE is still controversial. Therefore, we studied the incidence of bacteremia associated with TEE prospectively in 100 consecutive patients without clinical or laboratory signs of bacterial infection. Blood samples were drawn immediately before and at 0, 5, and 15 minutes after TEE. In addition, swabs were taken from the pharyngeal region before TEE and from the distal part of the TEE-probe before and after TEE. All blood cultures taken before TEE remained sterile. After TEE, three positive blood cultures were found in two patients: the first patient had two different species of coagulase-negative staphylococci in cultures taken at 0 minutes (Staphylococcus capitis) and 15 minutes (Staphylococcus cohnii) after TEE, whereas the sample taken after 5 minutes remained sterile. In the second patient, Propionibacterium species appeared after 7 days of processing in a culture taken immediately after TEE, but not in the samples taken after 5 and 15 minutes. None of the three microorganisms found in the blood were simultaneously isolated in pharyngeal specimens or TEE-probe specimens of the same patient. Thus positive blood cultures in both patients were considered contaminated. This study demonstrates that TEE, when performed by an experienced investigator, is not associated with an increased risk of bacteremia. Accordingly, it is justified to perform TEE examinations (also in high-risk patients) without antibiotic prophylaxis.

Pulmonary valve endocarditis: improved diagnosis with biplane transesophageal echocardiography

Pulmonary valve endocarditis is an uncommon disease. Improved visualization of the pulmonary valve on the longitudinal views provided by biplane transesophageal echocardiography (TEE) improves the diagnostic utility of TEE in pulmonary valve endocarditis. We report three cases of isolated pulmonary valve endocarditis diagnosed with biplanar TEE.

Endocarditis complicating parenteral nutrition: the value of repeated echocardiography

Cardiac complications of parenteral nutrition are well recognized but the diagnosis of such complications may be difficult. Two-dimensional echocardiography has been shown to be of value in establishing the diagnosis of valvular vegetations and right atrial thrombus. We describe two patients who developed endocarditis while receiving parenteral nutrition via central venous catheters. In both cases initial echocardiography was normal and the tricuspid valvular vegetations were only picked up after one or more additional echocardiograms. This highlights the necessity for repeated echocardiography in patients receiving parenteral nutrition in whom infective central venous catheter complications fail to resolve quickly after appropriate treatment.

Clinical assessment of prosthetic valve function

The advent of high-quality ultrasound technology has made the assessment of prosthetic valve function quicker, easier, and more accurate than ever before. By using cross-sectional imaging, colour flow mapping, and spectral Doppler techniques from both the precordium and the oesophagus, it is possible to assess a prosthetic valve fully. Cardiac catheterization with its attendant risks can be avoided. Echocardiography gives detailed morphological information, and it can be used for routine serial follow-up of individual patients. Using the patient as his or her own control avoids the problems caused by poorly-defined 'normal ranges' for prosthetic function.

Incidence of bacteremia in transesophageal echocardiography: a prospective study of 140 consecutive patients

The incidence of bacteremia related to transesophageal echocardiography was studied in 140 consecutive patients (71 women and 69 men with a mean age of 53.7 +/- 15 years). Thirty-four patients had one or more prosthetic heart valves. Blood cultures were obtained from each patient through separate venipuncture sites immediately before and after transesophageal echocardiography. An additional late blood culture was obtained in 114 patients 1 h later. The skin was cleaned with povidone-iodine and venipunctures were performed with separate butterfly needles with use of sterile gloves and drapes. Blood samples were drawn into separate syringes, transferred to aerobic and anaerobic culture bottles and processed with use of a semiautomated system. The overall incidence of blood cultures positive for bacteremia was 2% (8 of 394 bottles) and all positive cultures grew in a single blood culture bottle. Positive cultures occurred in 4 (1.4%) of 280 bottles before the procedure, in 2 (0.7%) of 280 bottles immediately after the procedure and in 2 (0.9%) of 228 late (1-h) blood culture bottles. Bacterial isolates were coagulase-negative staphylococci (n = 5), Propionibacterium (n = 2) and Moraxella (n = 1). All were considered contaminants. Mean endoscopic time in these patients was not significantly different from that in the other patients. Follow-up of patients with a blood culture positive for bacteremia revealed no clinical evidence of systemic infection. It is concluded that 1) the incidence of bacteremia related to transesophageal echocardiography is very low, and 2) the incidence of blood cultures positive for bacteremia after transesophageal echocardiography is indistinguishable from the anticipated contamination rate.

Complications of transesophageal echocardiography in ambulatory adult patients: analysis of 1500 consecutive examinations

Transesophageal echocardiography is a new approach that can be used to image cardiac structures. It combines two existing technologies: cardiac ultrasound and endoscopy. To obtain a cardiac image, the transesophageal probe has to be positioned properly within the esophagus. The first 1500 consecutive transesophageal echocardiographic examinations in ambulatory adult patients from one center were analyzed to identify conditions associated with failed esophageal intubation and procedural complications. Esophageal intubation was not achieved in 11 patients (0.73%). The reasons for the failure of intubation were operator inexperience, hypersensitive pharynx despite topical anesthesia, and cervical spondylosis. Six of those patients also had a history of dysphagia. Procedural complications were identified in seven patients (0.47%). Tracheal intubation was present in four patients, with immediate development of stridor and incessant cough in two patients. Atrial fibrillation developed in two patients--one had atrial myxoma and one had mitral stenosis. Bronchospasm developed during the transesophageal examination in one patient who was receiving long-term treatment for bronchial asthma. We conclude that transesophageal echocardiography is feasible in most adult patients in the ambulatory setting and that the complication rate is very low. Proper patient selection and preparation are crucial to the successful performance of this procedure.

Two-dimensional transesophageal echocardiographic determination of aortic valve area in adults with aortic stenosis

To determine if aortic stenosis severity could be accurately measured by two-dimensional transesophageal echocardiography (TEE), 62 adult subjects (mean age 66 +/- 12 years) with aortic stenosis had their aortic valve area (AVA) determined by direct planimetry using TEE, and with the continuity equation using combined transthoracic Doppler and two-dimensional echocardiography (TTE). Eighteen subjects had AVA calculated by the Gorlin method during catheterization. An excellent correlation (r = 0.93, SEE = 0.17 cm2) was found between AVA determined by TEE (mean 1.24 +/- 0.49 cm2; range 0.40 to 2.26 cm2) and TTE (mean 1.23 +/- 0.46 cm2; range 0.40 to 2.23 cm2). The absolute (0.13 +/- 0.12 cm2) and percent (10.8 +/- 8.9%) differences between AVA determined by TEE versus TTE were small. Excellent correlations between AVA by TEE and TTE were also found in subjects with normal systolic function (r = 0.95, SEE = 0.14 cm2; n = 38) and impaired function (r = 0.91, SEE = 0.21 cm2; n = 24). AVA determined by catheterization correlated better with AVA measured by TEE (r = 0.91, SEE = 0.15 cm2) than AVA measured with TTE (r = 0.84, SEE = 0.19 cm2). These data demonstrate that AVA can be accurately measured by direct planimetry using TEE in subjects with aortic stenosis. TEE may become an important adjunct to transthoracic echocardiography in the assessment of aortic stenosis severity.

Comparison of transesophageal to transthoracic color Doppler echocardiography in the identification of intracardiac mycotic aneurysms in infective endocarditis

We report on cases of mycotic aneurysms in a group of 14 patients with infective endocarditis, all of whom were evaluated with transthoracic (TTE) and transesophageal (TEE) color Doppler echocardiography. Four mycotic aneurysms were found, one each in the left ventricular outflow tract, the right coronary sinus of Valsalva, the anterior mitral leaflet, and the atrial septum. With TTE, only three of four cases of mycotic aneurysms could be detected. Utilizing TEE, however, all were detected and their connections with the heart chambers or great vessels could be readily and clearly depicted, especially those in the atrial septum and mitral leaflet. We are of the opinion that TEE is superior to TTE in the identification and detailed analysis of mycotic aneurysms complicating infective endocarditis. In addition, we feel that echocardiography may help evaluate the progress of the disease, the location and direction of infection, and the extent of involvement of the mycotic aneurysms, providing useful information for guiding surgical intervention.

Echocardiographic assessment of patients with infectious endocarditis: prediction of risk for complications

To enhance the echocardiographic identification of high risk lesions in patients with infectious endocarditis, the medical records and two-dimensional echocardiograms of 204 patients with this condition were analyzed. The occurrence of specific clinical complications was recorded and vegetations were assessed with respect to predetermined morphologic characteristics. The overall complication rates were roughly equivalent for patients with mitral (53%), aortic (62%), tricuspid (77%) and prosthetic valve (61%) vegetations, as well as for those with nonspecific valvular changes but no discrete vegetations (57%), although the distribution of specific complications varied considerably among these groups. There were significantly fewer complications in patients without discernible valvular abnormalities (27%). In native left-sided valve endocarditis, vegetation size, extent, mobility and consistency were all found to be significant univariate predictors of complications. In multivariate analysis, vegetation size, extent and mobility emerged as optimal predictors and an echocardiographic score based on these factors predicted the occurrence of complications with 70% sensitivity and 92% specificity in mitral valve endocarditis and with 76% sensitivity and 62% specificity in aortic valve endocarditis.

Prediction of rapid versus prolonged healing of infective endocarditis by monitoring vegetation size

The diagnostic value of transesophageal echocardiography in monitoring the clinical course has been evaluated in 83 patients with echocardiographic evidence of infective endocarditis. A total of 103 vegetations attached to the aortic or mitral valves were detected by use of the transesophageal approach. The patients were monitored for a mean of 74 weeks and underwent a minimum of two consecutive transesophageal echocardiographic examinations. Group A included patients with increasing or remaining constant size of vegetation (8.2 +/- 1.5 to 11.2 mm, p less than 0.05) during 4 to 8 weeks of antimicrobial therapy, whereas group B was formed by patients with decreasing vegetation size (8.3 +/- 0.8 to 4.9 +/- 0.8 mm, p less than 0.05). The incidences of complications after diagnosis and onset of therapy was higher in group A than in group B: valve replacement (45% versus 2%, p less than 0.05), embolic events (45% versus 17%, p less than 0.05), perivalvular abscess formation (13% versus 2%, p less than 0.05), and mortality (10% versus 0%, respectively, p less than 0.05). Staphylococcus aureus was the most frequent organism isolated in group A (44% versus 11% in B, p less than 0.05) and Streptococcus viridans in group B (33% versus 18% in A, p less than 0.05). Blood cultures were negative in nearly 50% of the patients in each group. There was no difference in the incidences of complications in patients with positive or negative blood cultures. We conclude that an increase in vegetation size during antibiotic therapy predicts a prolonged healing phase of infective endocarditis. This prolonged healing period is associated with a significantly increased risk of complications, independent of blood culture results. Monitoring vegetation size contributes important information concerning prognosis and stage of risk, and it aids in the choice of patient management in infective endocarditis. Because embolic events after diagnosis and onset of treatment are less frequent in rapid-healing endocarditis, surgery cannot be recommended to prevent further events taking into account the high risk of surgery.

Value of transesophageal echocardiography as an adjunct to transthoracic echocardiography in evaluation of native and prosthetic valve endocarditis

To determine if transesophageal echocardiography provides better visualization of valvular vegetations than transthoracic echocardiography, we used both methods to evaluate 24 consecutive patients (mean age, 54 years; 15 female patients and nine male patients) referred for symptoms suggestive of infectious endocarditis. Ten of the 24 patients had one or more valvular prostheses. Echocardiograms were classified as positive or negative based on visualization of valvular vegetations or abscesses. Of ten patients with a final diagnosis of infectious endocarditis on extended follow-up, transthoracic echocardiography was positive in five patients. Transesophageal echocardiography not only yielded abnormal findings in all ten of these patients, but also revealed additional information in four of the five patients with abnormal transthoracic echocardiographic examinations. Among the 14 patients who, on subsequent follow-up, were found not to have infectious endocarditis, transthoracic echocardiography was normal in 13 and falsely abnormal in one. Transesophageal echocardiography revealed no evidence of infectious endocarditis in any of these patients. The ten patients who were determined to have infectious endocarditis all had positive blood cultures and no alternative cause for their clinical presentation; in seven patients in this group who underwent operative or postmortem evaluation, infectious endocarditis was confirmed. All patients without infectious endocarditis were demonstrated to have other causes for their clinical presentation. We conclude that transesophageal echocardiography is a highly valuable test in the work-up of patients with suspected infectious endocarditis, especially those patients with inconclusive or normal transthoracic echocardiograms. In addition, transesophageal echocardiography may be of benefit to patients with previously documented infectious endocarditis and a complicated clinical course in whom additional cardiac lesions are suspected but not demonstrated by transthoracic echocardiography.

Diagnostic value of transesophageal compared with transthoracic echocardiography in infective endocarditis

To compare the diagnostic value of transesophageal and transthoracic echocardiography in infective endocarditis, paired transesophageal and transthoracic echocardiograms were obtained prospectively for 66 episodes of suspected endocarditis in 62 patients. Echocardiographic results were compared with the presence or absence of endocarditis determined by pathologic or nonechocardiographic data from the subsequent clinical course. All echocardiograms were interpreted by an observer told only that the studies were from patients in whom the diagnosis of endocarditis was suspected. The diagnosis of endocarditis was eventually made in 16 of the 66 episodes of suspected endocarditis (14 by pathologic and 2 by clinical criteria). In 7 of 16 transthoracic and 15 of 16 transesophageal echocardiograms, endocarditis was diagnosed at a probability level of "almost certain," giving a sensitivity of 44% and 94%, respectively (p less than 0.01). For the remaining episodes, 49 of 50 transthoracic and all transesophageal studies yielded normal results, giving a specificity of 98% and 100%, respectively. This study suggests that transesophageal echocardiography is highly sensitive and specific for the diagnosis of infective endocarditis and significantly more sensitive than transthoracic echocardiography. Although echocardiography cannot rule out endocarditis, the high diagnostic sensitivity of transesophageal echocardiography results in a low probability of the disease when the study yields negative results in a patient with an intermediate likelihood of the disease.

Initial clinical experience with a 48 by 48 element biplane transesophageal probe

Recent technologic advances in ultrasound have resulted in the capability of transesophageal echocardiographic imaging in both transverse and longitudinal planes. Previous biplane probes suffered from inferior images because of reduced scan elements. We evaluated the utility of a prototype 48 X 48 element biplane transesophageal probe in 23 consecutive patients. Examinations were well tolerated with no side effects. In comparison to the single transverse plane, imaging with the longitudinal plane gave superior information on prosthetic valve pathology, atrial septal abnormalities, and pathoanatomy of the ascending aorta and mitral valve. Complementary information was provided by the longitudinal plane in patients with endocarditis and vegetations and in mitral protheses. Images obtained with this 48 X 48 element biplane probe along with color and spectral Doppler information were not perceptibly inferior to those obtained by single-plane probes. In conclusion, biplane transesophageal echocardiography with a 48 X 48 element probe indicates a great potential for enhanced three-dimensional understanding of cardiac pathology and diagnostic yield in specific pathologies.