Randall A. Sochowski

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.

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.

Reference values for normal adult transesophageal echocardiographic measurements

Normal transesophageal echocardiographic measurements have not been presented previously relative to the effects of age, sex, and body surface area. This comparison was obtained by measuring cardiac and aortic dimensions in 60 patients (20 to 75 years old; 33 women) with normal transesophageal echocardiograms. We found a variable and usually important relationship between body surface area and 11 of 20 structures measured. A gender effect was not significant after indexing for body surface area for all but one structure. Age correlated with the diameter of the aortic root, descending aorta, superior vena cava, and right pulmonary artery. Similar dimensions were noted for certain paired structures as the two atria, the mitral and tricuspid annuli, and the aortic root and right ventricular outflow tract. Although multiple factors underlie what is normal in a given individual, our reference values serve to facilitate recognition of cardiac and aortic disease.

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.

Comparison of accuracy of transesophageal versus transthoracic echocardiography for the detection of mitral valve prolapse with ruptured chordae tendineae (flail mitral leaflet)

The accuracy of transesophageal echocardiography was compared with that of transthoracic echocardiography in the detection of ruptured chordae tendineae (flail mitral leaflet) in 27 patients with mitral valve prolapse (MVP) who underwent valve repair or replacement for mitral regurgitation. Confirmation of the presence of ruptured chordae resulting in a flail leaflet was available at surgery in all cases. The echocardiographic studies were read blindly by 2 independent observers with any differences resolved by a third. Mean (+/- standard deviation) age was 63 +/- 13 years. Men (n = 20) outnumbered women (n = 7) (p less than 0.02), and tended to be younger (p = 0.06). Flail leaflets were identified in 20 of 27 patients. In 1 patient, both leaflets were involved and in the remaining 19 patients posterior leaflets (15 patients) were more frequently affected than anterior leaflets (4 patients). Transesophageal echocardiography correctly identified all 20 patients with flail leaflets, but 1 false positive study occurred among the 7 patients without a flail leaflet. In contrast, transthoracic echocardiography identified only 12 of 20 patients with flail leaflets, with no false positive studies. Transesophageal echocardiography was more accurate, correctly classifying 26 of 27 (96%) cases versus 19 of 27 (70%) by the transthoracic approach (p less than 0.01). This study suggests a higher incidence of chordal rupture to the posterior leaflet in patients with MVP and demonstrates improved accuracy of transesophageal over transthoracic echocardiography in the detection of flail leaflets.

Dobutamine and dipyridamole stress echocardiography in patients with a low incidence of severe coronary artery disease.

The aim of this study was to determine the relative sensitivity, specificity, accuracy, and tolerance of dobutamine and dipyridamole stress echocardiography in patients with a lower likelihood of severe coronary artery disease. Previous comparative studies, which included patients with a history of myocardial infarction or a high incidence of coronary artery disease, showed both methods to have similar and acceptable diagnostic accuracy. To assess the role of these agents in evaluating patients with a lower likelihood of significant coronary artery disease, a lower-risk group was selected by excluding patients with known coronary artery disease, myocardial infarction, unstable angina, or strongly positive stress test results. Dobutamine and dipyridamole stress echocardiographic studies were performed in random order, before coronary angiography. Of the 46 patients enrolled (31 men and 15 women), 24 had atypical chest pain or none at all. Coronary angiography revealed no significant disease in 22 (48%), single-vessel disease in 11 (24%), and multivessel disease in only 13 patients (28%). Dobutamine and dipyridamole stress echocardiography were equally well tolerated, with identical accuracy (76%) that was maintained in patients with atypical symptoms. This confirms the usefulness of both dobutamine and dipyridamole stress echocardiography in evaluating patients with suspected coronary artery disease and extends this role to a lower-risk group for severe disease who often have atypical symptoms. The choice of which agent is used should reflect an institutions experience.

Association of mitral annular calcification and aortic valve morphology: a substudy of the aortic stenosis progression observation measuring effects of rosuvastatin (ASTRONOMER) study

AIMS Mitral annular calcification (MAC) is characterized by calcium and lipid deposition in the annular fibrosa of the mitral valve. Although individuals with MAC are at increased risk of cardiovascular events, little is known about the significance of this finding in patients with concurrent aortic stenosis (AS). The aim of this study was to describe the association of baseline MAC and aortic valve morphology in asymptomatic patients enrolled in the ASTRONOMER study, a multicentre study to assess the effect of Rosuvastatin on the progression of AS. METHODS AND RESULTS At baseline, transthoracic echocardiography was performed with two-dimensional and Doppler imaging following a standardized protocol. Echo measurements including left ventricular (LV) dimensions and aortic root dimensions were obtained according to the ASE recommendations. MAC was identified by bright echoes at the base of the mitral leaflets or annulus on 2D imaging, and aortic valve calcification by visualization of bright echoes on the aortic valve leaflets. The degree of calcification was semi-quantitated from absent to severe. The study population included 219 patients (57 +/- 14 years; 129 males), divided into two pre-specified categories; bicuspid (n = 133) and tricuspid (n = 86) aortic valves. Baseline LV dimensions, aortic valve haemodynamics, and cholesterol profiles were similar between the two groups at baseline. Individuals with tricuspid aortic valves were older, more hypertensive, with higher degrees of MAC and AV calcification (P < 0.001). The higher degree of MAC persisted in patients with tricuspid AV after adjustment for age and systolic blood pressure (P = 0.004). CONCLUSION In patients with asymptomatic mild to moderate AS, MAC is more prevalent in those individuals with tricuspid AV, independent of age, and systolic blood pressure. Whether the degree of MAC may be a surrogate for atherosclerosis, and predict the subset of patients who will respond to statin therapy in preventing the progression of AS, remains to be determined.

Sonicated albumin in exercise echocardiography: Technique and feasibility to enhance endocardial visualization

Left ventricular cavity opacification can be produced by the intravenous injection of sonicated albumin (Albunex 422). A recent study suggested that sonicated albumin may be useful in dobutamine stress echocardiography, but its use in exercise echocardiography has not been reported. The purposes of the study were to assess the feasibility of using Albunex to enhance endocardial visualization and to evaluate the factors affecting Albunex kinetic in exercise echocardiography. Fifteen healthy volunteers underwent two exercise echocardiograms on the same day, with intravenous injection of Albunex during one of the studies. Two injections up to a maximum of 20 ml of Albunex per injection were given to enhance the four- and two-chamber views, both at rest and immediately after exercise. The degree of left ventricular enhancement and the percentages of endocardial visualization were measured in both resting and exercise images. Variables relating to the kinetics of Albunex, which included volume of contrast injected, transit time, heart rate, and cardiac output at the time of image acquisition, were also assessed. There was no difference in the image acquisition time between the two exercise echocardiograms. Albunex produced good left ventricular opacification both at rest and after exercise. More endocardial border was visualized with contrast injection than without (91.2% +/- 11.5% vs 85.8% +/- 14.2%, p = 0.007). The transit times and volumes of Albunex injected were significantly less after exercise than at rest. The parameters were inversely related to heart rate and cardiac output. In conclusion, intravenous injection of Albunex is a promising means to enhance left ventricular endocardial visualization in exercise echocardiography and can be readily incorporated without causing a significant delay in obtaining images after exercise. Whether its use can improve diagnostic accuracy of exercise echocardiography requires further studies.

A prospective comparison of the multiplane probe with the biplane probe in structure visualization and doppler examination during transesophageal echocardiography

To compare the imaging capability of the multiplane probe with that of the biplane probe, 317 consecutive patients were randomized to undergo transesophageal echocardiography with either probe. Images of 24 cardiac structures and nine Doppler signals were graded prospectively on a three-grade system. Both multiplane and biplane probes provided excellent visualization of cardiac structures and Doppler signals, but the multiplane probe was significantly superior to the biplane probe. There were no differences in the number of attempts at esophageal intubation, the amount of sedation used, and the examination time. The number of complications was similar, although all failed intubations occurred with the multiplane probe.

Spontaneous Drainage of Paravalvular Abscess Diagnosed by Transesophageal Echocardiography

Paravalvular abscesses, which occur in up to 30% of cases of native valve endocarditis, are being detected with increasing frequency with the use of transesophageal echocardiography. Abscesses of the mitral aortic intervalvular fibrosa have been described but only in association with native or prosthetic aortic valve endocarditis. We describe a patient with native mitral valve endocarditis complicated by an abscess in the fibrosa. A 51-year-old diabetic man presented with Staphylococcus aureus mitral valve endocarditis. A transesophageal echocardiographic study done 8 days after admission revealed two large masses at the base of the anterior mitral leaflet with extension into the fibrosa consistent with a paravalvular abscess that was not detected by precordial echocardiography. A repeat transesophageal echocardiographic study done 20 days after admission showed spontaneous drainage of the abscess and a subsequent fistula between the left atrium and left ventricle. This case highlights the important role that transesophageal echocardiography has in suspected and known cases of endocarditis. Its major advantage of delineating posterior cardiac structures allowed accurate diagnosis and serial evaluation of this previously unreported complication of endocarditis.