Clinical applications of transesophageal echocardiography

Delineation of extended lengths of coronary arteries by multiplane transesophageal echocardiography

OBJECTIVES

The purpose of this study was to evaluate the utility of multiplane transesophageal echocardiography in assessing the coronary artery tree.

BACKGROUND

Evaluation of coronary disease with single-plane and biplane transesophageal echocardiography is limited to the very proximal vessels. The numerous views provided by multiplane imaging may enhance visualization of coronary arteries and detection of their abnormalities.

METHODS

Intraoperative multiplane transesophageal echocardiography was performed in 45 consecutive adults who had recently undergone angiography. Recordings were reviewed in blinded manner.

RESULTS

We describe the coronary segments visualized with the different imaging planes and define new views. The left main coronary artery with its bifurcation was visualized in all 45 patients. Sensitivity and specificity for detection of coronary narrowings were 100% when results were compared with angiographic data. Visualization of proximal, mid and distal segments of the left anterior descending coronary artery was possible in 69%, 31% and 16% of patients, respectively. Among patients in whom the proximal segment was visualized, sensitivity and specificity for detection of significant narrowings were 80% and 100%. Proximal, mid and distal portions of the left circumflex coronary artery were visualized in 80%, 51% and 20% of patients. Among patients in whom the proximal portion was well seen, sensitivity and specificity were 89% and 100%. The proximal, mid and distal portions of the right coronary artery were visualized in 84%, 16% and 11% of patients. Among patients in whom the proximal segment was visualized, sensitivity and specificity were 82% and 100%. Color Doppler examination was less useful because it detected only 52% of all patients with proximal stenosis.

CONCLUSIONS

Multiplane transesophageal echocardiography allows enhanced visualization of extended lengths of coronary arteries and the reliable identification of coronary artery abnormalities.

Transesophageal echocardiography in the intensive care unit: impact on diagnosis and decision-making

Transesophageal echocardiography (TEE) is widely used in the management of patients in intensive care units. The present study assesses the specific value of this technique in various categories of these patients. We reviewed 113 studies performed in 100 such patients for: suspected aortic dissection (25), suspected endocarditis (33), source of emboli assessment (19), hemodynamic instability (15), and miscellaneous (21). TEE provided diagnostic information in all patients with aortic dissection, in 53% of the cases with hemodynamic instability, in 50% of the cases with septic states with high likelihood of endocarditis, and in 29% of the cases where the question was the source of emboli. When the clinical probability for endocarditis was low, all transesophageal echocardiograms performed in septic patients were negative. The information provided by TEE was considered crucial in one-third of the positive cases; in about one-half of these special cases, the results were instrumental for further surgical management. There were no significant side effects related to the procedure. TEE is easily performed in the intensive care unit setting and yields useful information in almost half of the cases. Special benefit is expected in suspected aortic disease, hemodynamic instability, suspected endocarditis, and embolic events. The overall yield as screening procedure in febrile patients is low.

Assessment of viable myocardium by dobutamine transesophageal echocardiography and comparison with fluorine-18 fluorodeoxyglucose positron emission tomography

OBJECTIVES

The aim of this study was to assess whether dobutamine transesophageal echocardiography can identify viable myocardium in patients with chronic myocardial infarction.

BACKGROUND

Experimental and clinical studies have shown that dobutamine can recruit a contraction reserve in postischemic viable but akinetic segments, indicating that dobutamine-induced functional recovery is a potential ultrasound marker of myocardial viability.

METHODS

Forty patients underwent rest and dobutamine transesophageal echocardiography (dobutamine 5, 10 and 20 micrograms/kg body weight per min) and fluorine-18 (F-18) fluorodeoxyglucose positron emission tomography at rest. Three representative short-axis tomograms and a transverse four-chamber-view were used for wall motion and F-18 fluorodeoxyglucose-uptake analysis in corresponding myocardial regions. A basally asynergic segment was considered viable by transesophageal echocardiography if dobutamine-induced systolic wall motion could be observed. Viability by positron emission tomography was defined as F-18 fluorodeoxyglucose uptake > or = 50% of the maximal uptake in a region with normal wall motion by left ventriculography.

RESULTS

Functional recovery within the infarct region was found in 21 (53%) of 40 patients during dobutamine infusion. Infarct region-related viability by F-18 fluorodeoxyglucose uptake was diagnosed in 25 (63%) of 40 patients, yielding a diagnostic agreement between both techniques in 90% of patients. In 210 (89%) of 235 akinetic segments at rest, data on myocardial viability were concordant by the two techniques. The positive and negative predictive accuracy of dobutamine transesophageal echocardiography for viability defined by F-18 fluorodeoxyglucose uptake was 81% and 97%, respectively. Such uptake was significantly different (p < 0.001) between segments remaining akinetic (mean +/- SD 45 +/- 9%) during dobutamine infusion and segments with a dobutamine-induced contraction reserve (68 +/- 11%).

CONCLUSIONS

Dobutamine transesophageal echocardiography provides a promising low cost and widely available approach to unmask myocardial viability in patients with chronic myocardial infarction, and results compare favorably with those of F-18 fluorodeoxyglucose positron emission tomography.

Clinical usefulness of multiplane transesophageal echocardiography: comparison to biplanar imaging

The increased diagnostic usefulness of multiplane over biplane transesophageal echocardiography has not yet been conclusively determined. In this study the diagnostic yield of multiplanar and biplanar imaging was compared blindly by using the information content obtained from multiplane transesophageal echocardiography to that derived from biplanar type of imaging planes available in the multiplane echocardiography recordings in 80 patients with a variety of cardiac disorders. Among these patients 9 new abnormalities were identified by multiplane transesophageal echocardiography in 8 patients. Multiplane imaging yielded better delineation of 40 various lesions in 31 patients. Thus multiplane transesophageal echocardiography has a greater diagnostic yield than biplane imaging by depicting more lesions in 10% of patients and by enhanced delineation of the extent of pathologic characteristics in 39% of patients. This versatility, coupled with the ease of obtaining a vast assembly of imaging planes without undue probe manipulations, makes multiplane transesophageal echocardiography more useful than biplanar imaging.

Scintigraphic detection of inflammatory heart disease

Inflammatory diseases of the heart encompass myocarditis, endocarditis and pericarditis. This paper discusses the diagnostic potential of scintigraphy in these entities. In myocarditis, indium-111 antimyosin Fab imaging can visualize active myocyte damage and thus contribute substantially to the diagnosis. Antimyosin uptake is also seen in a large subset of patients with dilated cardiomyopathy, indicating ongoing myocyte injury in these cases. In endocarditis, immunoscintigraphy using monoclonal technetium-99m-labelled antigranulocyte antibodies provides useful diagnostic information in patients with equivocal echocardiographic findings. Immunoscintigraphy seems to indicate the floridity of the inflammatory process in endocarditis and may be used to monitor antibiotic therapy. In pericarditis, the clinical value of scintigraphy has not been convincingly demonstrated.

Comparison of transthoracic and transesophageal echocardiography in the diagnosis of intracardiac tumors in adults

To compare transthoracic and transesophageal echocardiography in the diagnosis of intracardiac tumors, 17 patients (8 men and 9 women, aged 19 years to 67 years) whose intracardiac tumors were detected by echocardiography were studied in a 4-year period. Of these, 14 patients underwent cardiac surgery and 13 were proved to have tumors. There were 4 false-positive and 2 false-negative diagnoses by transthoracic echocardiography, but only one false-positive and no false-negative diagnosis by transesophageal echocardiography. The stalk of a myxoma was detected clearly in 5 of 11 patients by transthoracic echocardiography, whereas in 10 of 11 it was detected by transesophageal echocardiography. The detailed morphologic characteristics of the tumor, such as contour of the tumor, and the presence of cysts and calcification in the tumor, were seen more clearly with transesophageal echocardiography than with transthoracic echocardiography.

Application of transthoracic and transesophageal echocardiography in the diagnosis and management of infective endocarditis

Infective endocarditis continues to be a cause of significant cardiac morbidity and mortality. To improve the prognosis of patients with this disorder, early diagnosis is crucial but difficult to establish on the basis of clinical parameters alone. Echocardiography, both transthoracic and transesophageal techniques, has a major role in the detection of vegetations that are the hallmark of endocarditis. Valvular and perivalvular complications can also be well assessed by echocardiography. With the improved resolution provided by recent technologic advances in echocardiography, vegetations can be reliably detected in most patients with endocarditis. We propose that present diagnostic criteria for endocarditis be revised to include echocardiographic findings as a major parameter in the diagnosis. Finally, a diagnostic approach incorporating transthoracic and transesophageal echocardiography in these patients will be discussed taking into consideration the different degrees of clinical suspicion for the existence of the disease.

Transthoracic and transesophageal echocardiographic diagnosis of a De Vega tricuspid anuloplasty rupture

Severe tricuspid regurgitation developed in a 51-year-old woman with rheumatic heart disease and a previous replacement of the mitral valve 8 years after a De Vega anuloplasty. At transthoracic echocardiography, rupture of the anuloplasty material was suspected, which was definitely confirmed at transesophageal echocardiography. She underwent operation solely by echocardiographic diagnosis, which was completely confirmed at operation.

Immunoscintigraphy using technetium-99m-labeled anti-NCA-95 antigranulocyte antibodies as an adjunct to echocardiography in subacute infective endocarditis

OBJECTIVES

This study was performed to assess the clinical value of immunoscintigraphy in subacute infective endocarditis.

BACKGROUND

Radiolabeled granulocytes can reveal inflammatory lesions.

METHODS

Using technetium-99m-labeled anti-NCA-95 anti-granulocyte antibodies, planar scintigraphy and single-photon emission computed tomography of the thorax were performed in 72 consecutive patients with suspected endocarditis. Each patient also underwent transthoracic and, if findings were negative, transesophageal echocardiography.

RESULTS

Thirty-three patients were found to have endocarditis on the basis of clinical criteria (surgical confirmation in 17 patients), and the remaining 39 served as control subjects. Initial scintigraphy was true positive in 26 patients (sensitivity 79%) and false positive in 7 (specificity 82%). Echocardiography was true positive in 29 patients (sensitivity 88%) and false positive in 1 (specificity 97%). Scintigraphy was positive in the four patients with false negative echocardiography, and echocardiography was positive in the seven patients with false negative scintigraphy. Thus, the combination of scintigraphy and echocardiography yielded a sensitivity of 100% and a specificity of 82%. In 10 of the 11 patients with two to three follow-up studies, scintigraphy became negative parallel to clinical improvement, indicating decreasing floridity of the inflammatory process.

CONCLUSIONS

Immunoscintigraphy in patients with subacute infective endocarditis provides valuable diagnostic information in equivocal echocardiographic findings and may be used to monitor antibiotic therapy.

Assessment of flow profile of left anterior descending coronary artery in hypertrophic cardiomyopathy by transesophageal pulsed Doppler echocardiography

This study assessed the flow velocity profiles of the left anterior descending coronary artery (LAD) in 7 patients with nonobstructive hypertrophic cardiomyopathy (HC) and in 6 normal subjects by transesophageal pulsed Doppler echocardiography, and evaluated their characteristics and the hemodynamic determinants. Systolic peak flow velocity of the LAD (7 +/- 30 cm/sec) was significantly lower in patients with HC than in normal subjects (34 +/- 11 cm/s, p < 0.05), and there was a significant inverse correlation between systolic peak flow velocity and the thickness of the ventricular septum (r = 0.81, p < 0.01). In 2 cases of HC with ventricular septal thickness of > 20 mm, a remarkable systolic reverse flow was observed in the LAD. However, there was no significant difference in diastolic peak flow velocity between HC and normal subjects. During early diastole, the acceleration time of LAD flow velocity was significantly prolonged (210 +/- 67 vs 95 +/- 15 ms, p < 0.01) and the acceleration rate was significantly decreased (3.6 +/- 2.0 vs 6.6 +/- 1.8 m/s2, p < 0.02) in patients with HC. The time constant of the left ventricular pressure decay was significantly prolonged in patients with HC (55 +/- 6 ms) compared with normal subjects (39 +/- 2 ms, p < 0.001). In HC, increased intramural perivascular pressure of the thickened ventricular septum during systole may be attributed to systolic LAD flow pattern. However, the early and mid-diastolic LAD flow pattern may be affected by impaired left ventricular relaxation.

Usefulness of transesophageal echocardiography in the treatment of critically ill patients

To evaluate the usefulness of transesophageal echocardiography (TEE) in the treatment of critically ill patients, 80 patients (51 male and 29 female; mean age, 53 years) undergoing both transthoracic echocardiography (TTE) and TEE were studied in a 2-year period. Of these, 48 patients were studied in the ICU, while the other 32 patients were directly referred from the emergency departments. Indications for the study included suspected aortic dissection (34 patients), hemodynamic instability (22 patients), suspected cardiac source of embolism (11 patients), evaluation of the severity of mitral regurgitation (7 patients), and suspected infective endocarditis (6 patients). The probe was passed successfully in 78 of 80 attempts (98 percent). No significant complications were recorded during the transesophageal echocardiographic study. Transesophageal echocardiography provided critical information that was not obtained by TTE in 39 of 78 studies (50 percent, p < 0.005). Cardiac surgery was prompted by TEE findings in 14 patients (18 percent) and these findings were all confirmed at operation. Transesophageal echocardiography was a safe, well-tolerated, and valuable diagnostic approach for the rapid detection of specific cardiac abnormalities in patients with critical illness; TEE should be considered in the treatment of critically ill patients especially when TTE provided inadequate information.

Usefulness of transesophageal echocardiography in the pediatric catheterization laboratory

Transesophageal echocardiography was performed in 51 children (aged 2 to 14 years, mean 4; weight 9 to 50 kg, mean 21) undergoing elective diagnostic or therapeutic cardiac catheterization. The interventional procedures were percutaneous balloon dilation of pulmonary (n = 8) and aortic (n = 2) valve stenosis, percutaneous closure of patent ductus arteriosus (n = 8), and attempted occlusion of Pott's anastomosis by the double umbrella device (n = 1). The diagnostic catheterizations were performed on preoperative children of whom 5 had undergone previous palliative procedures. Precise placement of the balloon across the valve, timing of balloon inflation and deflation according to real-time monitoring of ventricular function and immediate evaluation of results and complications were accomplished with transesophageal monitoring. The exact position of distal and proximal umbrellas of patent ductus occlusive devices was checked on transesophageal imaging and completeness of occlusion controlled on color Doppler. The only relevant information in the preoperative cases was the detection of a septic thrombus in a severely ill patient. With more experience and smaller probes, transesophageal echocardiography may become a new method of monitoring cardiac catheterization also in smaller children where it may reduce duration of the procedure and amount of contrast material.

Transesophageal echocardiography for detecting intracardiac thrombi in embolic stroke

The authors studied 56 patients with cardioembolic stroke to search for intracardiac thrombi by use of transesophageal and transthoracic echocardiography. Forty consecutive patients were examined within four weeks of stroke onset and the remaining 16 in the chronic stage. They also performed ultrafast computed tomography in 9 of them. Underlying heart disease was present in all subjects. Anticoagulant therapy had already been started in 29 at the time of examinations. Using their own criteria for echocardiography, they diagnosed intracardiac thrombus in 7 cases and valvular vegetation in 1. Six thrombi were located in the left atrial appendage, 4 of which were smaller than 10 mm in diameter. These small thrombi were not found by either transthoracic echocardiography or computed tomography. Transesophageal echocardiography appears to be superior to the other two methods, especially for detecting small intracardiac thrombi in the left atrial appendage.

Diagnosis of right atrial mass lesions by transesophageal and transthoracic echocardiography

The echocardiographic findings by transesophageal and transthoracic techniques were compared in 16 patients with right atrial mass lesions diagnosed by transesophageal echocardiography. In only 8 of the 16 patients were the masses imaged by transthoracic echocardiography. Masses in the main body of the right atrium (three of five), as well as those associated with indwelling catheters and pacer wires (three of four) were more likely to be imaged by transthoracic echocardiography than masses in the right atrial appendage (zero of three) or in the superior or inferior vena cava (one of three). Associated masses in other cardiac chambers were detected by transthoracic echocardiography in three of six patients. Other features such as size, mobility, and site of attachment of right atrial masses in general were better defined by transesophageal echocardiography. Thus, patients with suspected right atrial masses should be investigated with transesophageal echocardiography.

Outpatient transesophageal echocardiography with intravenous propofol anesthesia in children and adolescents

Outpatient transesophageal echocardiography (TEE) was performed in 10 children and adolescents (aged 3 to 19.5 years, mean 13.5 years; weight 12 to 91 kg, mean 49 kg), including two with Down's syndrome and one with autism, for diagnostic evaluation of issues unresolved by transthoracic echo examination (TTE). Issues for TEE: evaluation for atrial septal defect (two patients); anatomy of left ventricular outflow tract obstruction (one patient); aortic valve anatomy before valvuloplasty for insufficiency (one patient); evaluation for cause of cyanosis after Fontan operation (one patient); determination of source of high-velocity intracardiac turbulence after atrioventricular septal defect repair (one patient); rule out cardiac embolic source in patient with stroke (one patient); evaluate prosthetic valve function and rule out thrombus (one patient); determination of anatomic relationship of mitral valve to a ventricular septal defect before surgery for complex cyanotic heart disease (one patient); and evaluation for aortic dissection in Marfan's syndrome (one patient). Intravenous propofol anesthesia administered without endotracheal intubation by an anesthesiologist allowed successful outpatient TEE in nine patients; midazolam-conscious sedation was used in one. Outpatient TEE resolved diagnostic issues in all patients without complication, thereby avoiding cardiac catheterization in six patients and supplementing catheterization for preoperative planning in four patients. TEE can be performed safely and effectively with propofol anesthesia in the outpatient setting in carefully selected children and adolescents to provide vital diagnostic information. However, given the invasive nature of the procedure and the use of anesthesia, outpatient pediatric TEE should be used judiciously.

Usefulness of transesophageal echocardiography in identifying small left ventricular apical thrombus

OBJECTIVES

The aim of this study was to determine whether transesophageal echocardiography could clarify the nature of equivocal echodense structures in the left ventricular apical region frequently found on transthoracic echocardiography by directing the ultrasound beam from the left ventricular base to the apex and achieving better image quality.

BACKGROUND

Transthoracic echocardiography often reveals an echogenic structure suggesting thrombus in the left ventricular apical region because of limited near-field resolution and echo vibration artifact in apical views.

METHODS

Thirty-six patients with coronary artery disease or dilated cardiomyopathy who had apical wall motion abnormalities and equivocal transthoracic echodense structures were studied with transesophageal echocardiography using special manipulation of the transesophageal probe for adequate imaging of the apical region. Left ventricular thrombus was defined when echogenic structures with a clearly delineated margin adjacent to but distinct from the endocardium were observed in at least two different tomographic views in the four-chamber and left ventricular long-axis views during both systole and diastole.

RESULTS

Left ventricular thrombus (mean size 1.3 +/- 0.7 cm2) was defined by transesophageal echocardiography in 19 (53%) of 36 patients with suspected thrombus on transthoracic echocardiography in the four-chamber or left ventricular long-axis view. Heavy trabeculation or extremely high echo reflection, or both, was observed in the apical region in 12 patients (33%). No extra structures in the apical region were found in five patients. In 19 patients with transesophageal echocardiographically defined thrombus, 6 patients (31%) experienced arterial embolic events before the transesophageal procedure. In contrast, none of 17 patients without transesophageal echocardiographically defined thrombi had systemic embolism (p < 0.03).

CONCLUSIONS

1) Transesophageal echocardiography is useful in identifying left ventricular apical thrombus in patients with unclear echogenic structures on transthoracic apical images; and 2) the high incidence of arterial embolism in patients with transesophageal echocardiographically detected left ventricular thrombus indicates the clinical importance of such thrombus.

Methodology for three-dimensional reconstruction of the left ventricle from transesophageal echocardiograms

A technique is presented for three-dimensional (3-D) reconstruction of the left-ventricular endocardial surface from multiplanar transesophageal echocardiograms, using both commercial software and investigator written Fortran programs for Intel 80286 and 80386 microcomputers. The approach provides quantitative global and regional cardiac performance measures and allows viewing the endocardial surface, at end-diastole and end-systole, from chosen perspectives. Anatomical landmarks are incorporated to aid in orientation. For regional calculation, the surface is divided into equal angular elements with each conceptually connected to the left-ventricular end-diastole centroid, forming a pyramidal volume element. This angular division automatically normalizes for heart size. The fractional change of these elements over the cardiac cycle provides a regional ejection fraction measure which is color-coded on the reconstructed endocardial surface. Composite perspective views, regional ejection fraction histograms and calculations of global end-diastolic, end-systolic, and stroke volumes, are all performed by the method.

Prospective study of blood culture during transesophageal echocardiography

To ascertain the incidence and significance of bacteremia associated with transesophageal echocardiography (TEE), 132 consecutive patients (aged 17 to 73 years) free of apparent infection who were undergoing 135 transesophageal echocardiographic procedures from October 1990 to August 1991, were prospectively studied. For each procedure, two sets of blood cultures were obtained for culture 30 to 60 minutes before TEE, immediately after, and 180 to 240 minutes after the procedure. For each blood culture, 10 ml of venous blood was evenly inoculated into aerobic and anaerobic culture bottles and inoculated for 7 days using a radiometric system. A throat swab was obtained immediately before each procedure. Three of 270 preprocedure blood cultures were positive for Bacillus cereus, Staphylococcus simulans, and Peptostreptococcus species, respectively. No blood culture was positive in the immediate postprocedure period. Two of 270 late blood samples grew Staphylococcus epidermidis in the same patient. Nevertheless, the microorganisms isolated from blood cultures were different from those isolated from the throat swab. No patients had fever or evidence of infective endocarditis after TEE during the follow-up period. It is concluded that the incidence of TEE-related bacteremia is extremely low, and a general recommendation for antibiotic prophylaxis during TEE is not warranted.

Bedside cardiac catheterization using transesophageal echocardiographic guidance

We describe for the first time the use of transesophageal echocardiography to guide cardiac catheterization performed at the bedside in the pediatric cardiac intensive care unit. The procedure was performed on a 2.6-kg infant with ventricular and atrial septal defects after repair of coarctation of the aorta. Poor hemodynamic status prevented obtaining the required hemodynamic information from cardiac catheterization in the cardiac catheterization laboratory. Transesophageal echocardiography provided cardiac and vascular imaging, which helped guide catheter placement where the small size of the infant and the extensive thoracic postoperative bandages prevented obtaining the echocardiographic information from other windows.

Pericardial complications of cardiac surgery: emphasis on the diagnostic role of echocardiography

Pericardial effusions are common following cardiac surgery; uncommonly they are large in size and may cause tamponade, either in the early or late postoperative period. Such effusions causing tamponade may be circumcardiac, but are frequently loculated, in which case one or more cardiac chambers is selectively compressed. Fortunately, echocardiography is capable of imaging not only the presence, location, and size of the pericardial effusion, but also indicating the presence of tamponade. Constrictive pericarditis resulting from cardiac surgery is being recognized with increasing frequency and has been associated with various echocardiographic abnormalities. This review also discusses certain other pericardial complications of cardiac surgery including supraventricular arrhythmias, chylopericardium, and posttransplant problems.

What's new in monitoring the coronary surgery patient?

Monitoring has been extensively reviewed in most textbooks of cardiothoracic surgery and anaesthesia, particularly in the recent textbooks on monitoring edited by Carol L Lake 1 and Casey D Blitt 2 and in the Journal of Clinical Monitoring. Although monitoring properly includes both pre- and postoperative periods, this review will concentrate exclusively on the operative period. I will also concentrate on new approaches or information which relate to more traditional approaches to monitoring. The emphasis in this review will not be on what we can monitor, but rather on what we should monitor. In this regard, I will analyse accuracy and identify sources of error and try to answer the following questions. Does the device or parameter measure (monitor) what we want to know? Does it improve patient outcome and safety? Is it cost-effective? Unfortunately, data are not always available to answer all these questions at present, but hopefully the discussions will make us aware of what we do and do not know, and what we should look for in the near future.

The role of transesophageal echocardiography in critical care: UCSF experience

The applications of transesophageal echocardiography (TEE) now encompass the arena of critical care. We reviewed the indications, findings, and outcome of TEE in the critical care setting in a tertiary care hospital and report our experience. Eighty-three transesophageal echocardiograms were performed in 69 critically ill patients for the following indications: endocarditis (43%), embolic source (13%), hypotension (10%), mitral regurgitation (10%), left ventricular function (6%), aortic dissection (4%), prosthetic valve dissection (4%), and other (10%). Findings were unexpected in 21 of 83 studies and led to a change in management in 17%. On the basis of the results of TEE, 22% of patients had further evaluation by a more invasive technique, and 19% of patients had surgical intervention without further study. No significant complications attributable to TEE were noted. We conclude that TEE is a safe and useful diagnostic technique with fairly broad applications in the critical care setting.

Protruding aortic atheromas predict stroke in elderly patients undergoing cardiopulmonary bypass: experience with intraoperative transesophageal echocardiography

Protruding atheromas of the aortic arch identified by transesophageal echocardiography have been implicated as a cause of stroke in elderly patients. One hundred thirty patients greater than or equal to 65 years of age were studied with intraoperative transesophageal echocardiography to detect aortic arch protruding atheromas and determine if these patients were at higher risk for perioperative stroke. Protruding atheromas were identified in 23 (18%) of 130 patients. In 19 (83%) of these 23 patients, palpation of the aortic arch at operation did not identify significant abnormalities. Five patients (4%) had perioperative stroke. Logistic regression identified aortic arch atheroma as the only historical or procedural variable that was predictive of stroke (odds ratio 5.8, 95% confidence interval 1.2 to 27.9, p less than 0.03). A history of peripheral or cerebrovascular disease, presence of aortic calcification, cardiac risk factors, age and duration of cardiopulmonary bypass did not predict stroke. In contrast, patients with protruding atheromas with mobile components were at highest risk. There were 3 (25%) of 12 patients with a mobile atheroma who had a stroke versus 2 (2%) of 118 patients without a mobile atheroma (chi-square = 10.3, p = 0.001). Displacement and detachment of the frail, protruding atherosclerotic material by aortic arch cannulation or by the high pressure jet emanating from the cannula tip may play an important role in the creation of embolization and stroke.

Cardiac evaluation

Over the past decade there has been a dramatic, rapid development of new imaging modalities used in the evaluation of the cardiac patient. These newer techniques are frequently complex and specialized in their application and interpretation. Nonetheless, the prevalence of cardiac disease in the United States, and the wide application of these diagnostic tests, mandate that the well-rounded clinician has a basic understanding of the utility of these diagnostic modalities. Unfortunately, the burgeoning field of cardiac imaging seems at times to overshadow our most important basic diagnostic tools, namely, the history, physical exam, chest radiograph, and electrocardiogram (ECG). This review will attempt to impart a basic understanding of the newer cardiac diagnostic tests and their utility in various disease states. Emphasis on the importance of the basic clinical exam and the precise integration of specific diagnostic tests into the cardiac evaluation will be emphasized. The article will deliver a basic review of exercise treadmill testing, echocardiography, radionuclide imaging techniques, magnetic resonance imaging, and cardiac catheterization. It is hoped that this review will impart to the noncardiologist clinician a basic understanding of the cardiovascular diagnostic techniques so that an accurate, precise, cost-effective, efficient diagnostic plan for the patient with cardiovascular disease can be developed and applied.

Evaluation of the severity of mitral regurgitation by transesophageal Doppler flow echocardiography

The severity of mitral regurgitation (MR) was assessed by transesophageal Doppler flow echocardiography (TEE) using new criteria in 87 patients. The severity of MR assessed by TEE (TEE-MR) was compared with that obtained by left ventriculography (LVG-MR). Although the severity of TEE-MR has been evaluated by MR jet area, it is often difficult because the MR jet extends beyond a single frame image in severe MR. We found that (1) when the MR area was larger than 3 cm2, the severity of MR was more than second-degree by LVG; (2) there was systolic turning flow (STF) of the MR jet within the left atrial cavity in 27 of 30 patients with third- and fourth-degree LVG-MR; and (3) there was late systolic backward flow (SBF) in the pulmonary veins in 9 of 10 patients with fourth-degree LVG-MR. A new grading of the severity of MR by TEE was proposed, which combined the findings of STF, SBF, and the MR area. These new criteria of the severity of TEE-MR excellently correlated with that by LVG (y = 0.94x + 0.08; r = 0.95, p less than 0.01). The criteria for MR by TEE were also useful for assessment of MR in patients with prosthetic mitral valve dysfunction (y = 0.96x + 0.04; r = 0.97, p less than 0.01). We conclude from this study that the severity of MR can be accurately assessed with TEE by measuring the MR area and the specific flow patterns in the left atrium and pulmonary veins.

Percutaneous closure of a secundum atrial septal defect and double balloon valvotomies of a severe mitral and aortic valve stenosis in a patient with Lutembacher's syndrome and severe pulmonary hypertension

This is a 43-yr-old female presenting with recurrent atrial septal defect, closed surgically, 10 years prior, severe aortic and mitral stenosis, and severe tricuspid regurgitation. She was considered inoperable because of the severe pulmonary hypertension and the complexity of the disease. A percutaneous umbrella closure of the atrial septal defect in conjunction with mitral and aortic balloon valvotomies could be safely and successfully performed. After significant clinical and hemodynamic improvement, surgery was judged feasible, but was refused by the patient who suddenly expired 8 weeks later. The usefulness of percutaneous therapy as a rescue procedure and the management of patients with Eisenmenger's physiology are discussed.

Transesophageal dipyridamole echocardiography for diagnosis of coronary artery disease

The value of transthoracic dipyridamole echocardiography has been extensively documented. However, in some patients, because of a poor acoustic window, the rest transthoracic examination is not always feasible and the transesophageal approach is more convenient. Therefore, transesophageal echocardiography with high dose dipyridamole (up to 0.84 mg/kg body weight over 10 min) was performed in 32 patients in whom the transthoracic dipyridamole test either was not feasible (n = 29) or yielded ambiguous results (n = 3). The transesophageal echocardiographic test results were considered abnormal when new dipyridamole-induced regional wall motion abnormalities were observed. All 32 patients underwent coronary angiography; significant coronary artery disease was defined as greater than or equal to 70% lumen diameter narrowing in at least one major vessel. All patients also performed a bicycle exercise test 1 day before transesophageal dipyridamole echocardiography. Transesophageal stress studies were completed in all patients, with a maximal imaging time (in tests with a negative result) of 20 min. No side effects or intolerance to drug or transducer was observed. The left ventricle was always visualized in the four-chamber and transgastric short-axis views. High quality two-dimensional echocardiographic images were obtained in all patients both at rest and at peak dipyridamole infusion and were digitally analyzed in a quad-screen format. Coronary angiography showed coronary artery obstruction in 24 patients: 6 had single-, 9 double- and 9 triple-vessel disease. The transesophageal dipyridamole test showed a specificity of 100% and an overall sensitivity of 92%. The sensitivity of this test for single-, double- and triple-vessel disease was 67%, 100% and 100%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Evaluation of mitral regurgitation by Doppler echocardiography

The diagnosis and assessment of mitral regurgitation has been one of the main challenges for cardiac ultrasound. Imaging techniques (M-mode and two-dimensional echocardiography) provide direct morphologic and etiologic information of the evaluation of patients with suspected mitral regurgitation. The advent of cardiac Doppler increased tremendously the ability to evaluate mitral regurgitation noninvasively. Continuous-wave and pulsed Doppler have been found to be sensitive and specific in the detection of mitral regurgitation. The introduction of color flow Doppler simplified enormously the assessment of patients with suspected mitral regurgitation. The maximal regurgitant area and maximal regurgitant area corrected for left atrial size have become the most commonly used parameters to evaluate mitral regurgitation by color flow Doppler in the clinical setting. However, the color regurgitant jet area is highly dependent on anatomical, hemodynamic, and equipment factors. A new method, based on the proximal isovelocity surface area, is being evaluated and appears to be relatively independent of equipment factors. Transesophageal echocardiography has been shown to be exquisitely sensitive in the detection of mitral regurgitation. Quantitation of mitral regurgitation by transesophageal echocardiography is currently based on the maximal regurgitant area and this parameter appears to correlate closely with the angiographic degree of mitral regurgitation. Pulmonary venous flow analysis had been used in conjunction with color flow mapping for the evaluation of mitral regurgitation by transesophageal echocardiography. The presence of reversed systolic flow has been shown to be sensitive and specific for the diagnosis of severe mitral regurgitation. Patients with clinically difficult surface studies, flail mitral valve leaflets, and prosthetic mitral valve are best evaluated by the transesophageal approach with interrogation of pulmonary venous flow.

Pathologic and angiographic correlations of transesophageal echocardiography in prosthetic heart valve dysfunction

To determine the diagnostic accuracy of transesophageal echocardiography (TEE) in prosthetic valve dysfunction, the pathologic and/or angiographic data from 37 valves were compared with that obtained by transesophageal and transthoracic echocardiography. Of the 21 prostheses with severe regurgitation, TEE identified all 14 mitral, the five aortic, and one of the two tricuspid valves; on the other hand transthoracic echocardiography identified 2 of the 14 mitral, the five aortic, and one of the two tricuspid valves. Of the 10 prostheses with flail cusp(s), nine (90%) were correctly identified by TEE and four (40%) were correctly identified by transthoracic echocardiography. All five prostheses with paravalvular regurgitation were detected through the esophageal window and one detected through the precordial window. TEE was unable to document the two prosthetic aortic stenoses, whereas the transthoracic examination correctly quantified the gradient in one but underestimated it in the other case. Seven patients underwent valve replacement on the basis of the clinical and TEE information alone. In assessing cause, origin, and severity of prosthetic mitral regurgitation, TEE is the method of choice. In selected cases, TEE can avoid angiography and facilitate optimal timing of reoperation. In selected aortic and tricuspid dysfunction, TEE may provide additional morphologic, but limited hemodynamic information.

Biplane transesophageal echocardiography utilizing transverse and sagittal imaging planes: technique, echo-anatomic correlations, and display approaches

The recent development of biplane transesophageal probes equipped with both transverse plane and sagittal plane imaging transducers allows a more complete examination of cardiac and aortic anatomy than is possible with conventional single plane transesophageal instruments. While the imaging planes used in transverse plane transesophageal imaging have been standardized, several different approaches have been suggested for the orientation and display of the newer sagittal plane images. An accepted display convention for the transverse and sagittal plane images would ease interpretation of the multiple complex images obtained during the biplane transesophageal examination. In this article, the different transverse plane and sagittal plane echocardiographic images that may be acquired during the biplane transesophageal examination are described and correlated with cardiac anatomy. A method for image display orientation is suggested that is most consistent with that previously used for the single plane transesophageal examination.