Transesophageal dobutamine stress echocardiography in the evaluation of coronary artery disease

Echocardiography in the Era of Obesity

Patients with obesity are at increased risk for coronary artery disease and heart failure and often present with symptoms of dyspnea, fatigue, edema, or chest pain. Echocardiography is frequently used to help distinguish whether these symptoms are due to cardiac disease. Unfortunately, obesity has a significant impact on image quality because of signal attenuation. Ultrasound-enhancing agents may improve the detection of structural remodeling and subclinical left ventricular dysfunction in patients with obesity. Assessment of chamber sizes and cardiac remodeling in severely obese subjects must be interpreted with caution, however, as the current recommendations for indexing cardiac chamber sizes to body size may lead to false conclusions about chamber volumes or mass, particularly in settings in which weight is changing. As a result of increases in stroke volume and cardiac output, obesity may exacerbate hemodynamic compromise in obstructive structural or valvular disease. With regard to assessment of ischemic heart disease, stress echocardiography can effectively risk-stratify patients with obesity and may have advantages over other noninvasive modalities. In general, transesophageal echocardiography is safe in patients with obesity, although some precautions should be observed. Stress echocardiography using the transesophageal approach is an alternative for preoperative or ischemia evaluation in patients with suboptimal transthoracic views.

Usefulness of an accelerated transoesophageal stress echocardiography in the preoperative evaluation of high risk severely obese subjects awaiting bariatric surgery

Background

Severe obesity is associated with an increased risk of coronary artery disease (CAD). Bariatric surgery is an effective procedure for long term weight management as well as reduction of comorbidities. Preoperative evaluation of cardiac operative risk may often be necessary but unfortunately standard imaging techniques are often suboptimal in these subjects. The purpose of this study was to demonstrate the feasibility, safety and utility of transesophageal dobutamine stress echocardiography (TE-DSE) using an adapted accelerated dobutamine infusion protocol in severely obese subjects with comorbidities being evaluated for bariatric surgery for assessing the presence of myocardial ischemia.

Methods

Subjects with severe obesity [body mass index (BMI) >40 kg/m²] with known or suspected CAD and being evaluated for bariatric surgery were recruited.

Results

Twenty subjects (9M/11F), aged 50 ± 8 years (mean ± SD), weighing 141 ± 21 kg and with a BMI of 50 ± 5 kg/m² were enrolled in the study and underwent a TE-DSE. The accelerated dobutamine infusion protocol used was well tolerated. Eighteen (90%) subjects reached their target heart rate with a mean intubation time of 13 ± 4 minutes. Mean dobutamine dose was 31.5 ± 9.9 ug/kg/min while mean atropine dose was 0.5 ± 0.3 mg. TE-DSE was well tolerated by all subjects without complications including no significant arrhythmia, hypotension or reduction in blood arterial saturation. Two subjects had abnormal TE-DSE suggestive of myocardial ischemia. All patients underwent bariatric surgery with no documented cardiovascular complications.

Conclusions

TE-DSE using an accelerated infusion protocol is a safe and well tolerated imaging technique for the evaluation of suspected myocardial ischemia and cardiac operative risk in severely obese patients awaiting bariatric surgery. Moreover, the absence of myocardial ischemia on TE-DSE correlates well with a low operative risk of cardiac event.

Head to head comparison of transesophageal and transthoracic contrast-enhanced echocardiography during dobutamine administration for the detection of coronary artery disease

Dobutamine stress echocardiography (DSE) has been shown to be a very useful non-invasive technique for the detection of coronary artery disease. However, inadequate transthoracic images preclude the use of DSE in a significant proportion of patients. Transesophageal (TEE) or transthoracic contrast echocardiography (CE) can however overcome this limitation. The comparison between the two techniques has never been investigated during a stress test. Therefore, we designed a prospective study to compare DSE-CE and DSE-TEE for the detection of coronary artery disease in patients with poor echo image quality. We studied 42 patients scheduled for quantitative coronary angiography. Prospective DSE-CE and DSE-TEE with maximum one day interval were performed in a random order. Significant coronary artery disease was detected in 30 patients, nine with single vessel disease and 21 with multivessel disease. Sensitivity of DSE was higher with CE than with TEE (90% vs 87%, p=NS). There was no significant difference with respect to specificity in both groups (100% vs 92%, p=NS). The diagnostic accuracy was similar in both groups (93% vs 88%, NS). The kappa value for identical interpretation of a stress echocardiography study was nearly identical with both modalities 0.75 to 0.78. In poorly echogenic patients, DSE-CE is a valuable alternative for the detection of myocardial ischemia in comparison with DSE-TEE. Because DSE-CE is more comfortable than TEE, it should be used in patients with suboptimal transthoracic echocardiograms for the evaluation of coronary artery disease during DSE.

Safety of dobutamine stress transesophageal echocardiography in obese patients for evaluation of potential ischemic heart disease

The purpose of this study was to determine the safety of dobutamine stress transesophageal echocardiography (DS-TEE) in the evaluation of potential coronary artery disease in obese patients. Obese patients tend to have a higher prevalence of hypertension, coronary artery disease, and sleep apnea conditions that could potentially predispose to complications during endoscopic procedures such as DS-TEE. In addition, obese patients are more likely to have oxygen desaturation during upper gastrointestinal endoscopy. Thus, the safety of DS-TEE in 90 obese patients (body mass index (BMI) > or = 27.5 kg/m2) and 86 nonobese patients (BMI < 27.5 kg/m2) was compared. Minor complications (i.e., complications of transient duration and requiring no or only simple intervention) occurred with almost equal frequency in the nonobese and obese groups (28% vs. 29%, P = ns). Transient hypotension was observed in 9% of the obese group compared to 22% in the nonobese group (P < 0.025). However, transient hypertension was noted in 20% of the obese patients compared to 6% in the nonobese group (P < 0.01). A major complication occurred in three obese patients (3.3%), which included hypotension, marked elevation of systolic blood pressure, or ventricular fibrillation. Four patients (4.7%, P = ns) of the nonobese group had a major complication, which included sustained ventricular tachycardia in one, hypertension in one, and hypotension in two patients. No deaths occurred in either group. Although obesity should remain a consideration in the risk assessment of whether or not to perform DS-TEE, when proper precautions are instituted DS-TEE appears equally safe in obese as compared to nonobese patients.

A meta-analytic comparison of echocardiographic stressors

BACKGROUND

The relative performance of alternative stressors for stress echocardiography for the diagnosis of coronary artery disease (CAD) is not well established.

METHODS

All studies published between 1981 to December 2001 who met inclusion criteria were included in this analysis. We performed a summary receiver operator characteristic (SROC) analysis and calculated weighted mean of the likelihood ratio and sensitivity/specificity. A covariate analysis using meta-regression methods was also performed.

RESULTS

Forty-four studies presented data on Exercise, 11 on Adenosine, 80 on Dobutamine, 40 on Dipyridamole, 16 on transatrial pacing transesophageal echocardiography (Tap-TEE), and 7 on transatrial pacing transthorasic echocardiography (Tap-TTE). SROC analysis showed that the following order of most discriminatory to least: Tap-TEE, Exercise, Dipyridamole, Dobutamine and Adenosine. Weighted means sensitivity/specificity were Exercise: 82.6/84.4%, Adenosine: 68.4/80.9%, Dobutamine: 79.6/85.1%, Dipyridamole: 71.0/92.2%, Tap-TTE: 90.7/86.1%, and Tap-TEE: 86.2/91.3%. Covariate analysis showed that the discriminatory power of Exercise decreased with increasing mean age.

CONCLUSIONS

Tap-TEE is a very accurate test for both ruling in and ruling out CAD although its invasiveness may limit its clinical acceptability. Exercise is a well-balanced satisfactory test for both ruling in and ruling out but performance might be lower for the elderly. Dobutamine offers a reasonable compromise for Exercise. Dipyridamole might be good for ruling in but not for ruling out CAD. The incapability in ruling-out CAD was a major problem in clinical application of the stress. Adenosine was the least useful stressor in diagnosing CAD.

[Physiologic evaluation of coronary circulation. Role of invasive and non invasive techniques]

For many years, the evaluation of the extent and severity of coronary artery disease has been mainly anatomical, carried out by coronary angiography. However, this technique has methodological limitations and interobserver variability is considerable. Quantification of coronary reserve with pressure guidewires and intracoronary Doppler now provides more precise physiologic evaluation of coronary circulation. Myocardial perfusion single proton emission computed tomography and echocardiography, combined with stress and/or pharmacological challenge testing, though they are only semiquantitative techniques, also offer appropriate complements to coronary angiography in the functional evaluation of coronary patients. The aim of this paper is to discuss the clinical value of these techniques.

Transesophageal dobutamine stress echocardiography with tissue Doppler imaging for detection and assessment of coronary artery disease

BACKGROUND

Transesophageal dobutamine stress echocardiography (T-DSE) has been shown to be a sensitive and specific technique for the detection of myocardial ischemia. A major limitation of echocardiographic study interpretation, however, is the subjective visual analysis of endocardial motion and wall thickening, which is only semiquantitative.

METHODS

To analyze whether T-DSE with the use or tissue Doppler imaging (TDI) during graded dobutamine infusion may be useful to detect and quantify stress-induced myocardial ischemia by changes in myocardial velocities, 70 patients undergoing coronary arteriography were studied with T-DSE and TDI. Midesophageal and transgastric short- and long-axis images were obtained at each level of dobutamine infusion. T-DSE was successful in 67 patients (96%). Baseline resting pulsed and color peak systolic (S) and early diastolic (E) velocities of the anterior, septal, lateral, and inferior walls were examined.

RESULTS

Pulsed and color TDI correlated well at rest and after stress. Fifteen patients had a normal response to dobutamine, and 52 patients had inducible ischemia by two-dimensional criteria. In the normal group, there was a significant dose-dependent increase in S and E velocities. Compared with those in the normal group, patients with coronary artery disease (CAD) had lower resting S and E velocities and blunted S wave increase or E wave decrease during DSE.

CONCLUSIONS

T-DSE with TDI is a feasible and accurate test for the quantitative assessment of patients with CAD who have impaired augmentation of systolic and diastolic myocardial velocities during dobutamine infusion.

Value of transesophageal dobutamine stress echocardiography in assessing coronary artery disease

The introduction of digital echocardiography has significantly enhanced our ability to select the best set of frames for analysis. However, despite the beneficial attributes of transthoracic dobutamine stress echocardiography, poor quality 2-dimensional images continue to be a significant limiting factor in patients with chest deformities, severe chronic obstructive lung disease, marked obesity, and previous chest surgery. Transesophageal echocardiography provides a new window to monitor left ventricular contractility without the interference of bone and air-filled structures of the thoracic cage. The transesophageal dobutamine stress test is a logical but poorly explored modality to image/stress the heart in certain patients with known or suspected myocardial ischemia. Overall sensitivity (< or = 85%) and specificity (< or = 95-100%) of transesophageal dobutamine stress echocardiography appear to be similar to that of previous transthoracic studies, although no direct comparison has been accomplished between transthoracic and transesophageal stress images. False negative transesophageal dobutamine stress echocardiography results have been described in patients with single-vessel disease in whom ischemic regions may not have been visualized throughout the entire study. False positive study results may be present in patients with hypertension and myocardial hypertrophy that may have signs and symptoms of myocardial ischemia in absence of obstructive disease of the epicardial coronary arteries, presumably related to either microvascular disease or impaired vasodilatory reserve. The proportion of patients with coronary artery disease who need a transesophageal examination for reliable assessment of echocardiographic response to stress varies depending on the operators' skills, the interpreters' experience, and the use of videotape or digitizing systems for image analysis. Although clinically useful in its present transthoracic and transesophageal form, a major limitation of dobutamine stress echocardiographic study is the subjective visual interpretation of endocardial motion and wall thickening, which is only semiquantitative. Color kinesis and tissue Doppler imaging (TDI) are 2 novel echocardiographic techniques that color code endocardial motion and myocardial velocity online and have the potential to objectively quantify regional left ventricular function. Quantitative standardization of transthoracic and transesophageal data interpretation, such as establishing endocardial motion by color kinesis or velocity thresholds by TDI for an abnormal segmental response to stress, has the potential to decrease interobserver variability and increase interinstitutional agreement.

[Complications of transesophageal echocardiography with dobutamine]

The transesophageal echocardiographic approach improves the diagnostic power of transthoracic stress echocardiography. However, it is a seminvasive test and its safety is not well established. Our objective was to compare the incidence of complications of transesophageal and transthoracic dobutamine echocardiography. We collected data from 63 patients with inadequate transthoracic window, who underwent transesophageal dobutamine echocardiography and were compared with 100 patients in whom the transthoracic approach was diagnostic. Baseline blood pressure and heart rate were higher in the first group. There were no differences in those parameters at the end of the test. Neither were atropine administration and side effects more frequent in any of the groups. There were no cases of ventricular fibrillation, ventricular tachycardia, acute myocardial infarction, intractable angina or intolerance to the probe. Side effects were equally present in both groups. Transesophageal dobutamine stress echocardiography is a safe test that can be used in patients with coronary artery disease and poor transthoracic window.

Prognostic value of negative transesophageal dobutamine stress echocardiography in men at high risk for coronary artery disease

Recently published reviews have called into question the sensitvity of transthoracic stress echocardiography to predict cardiac events, especially when the test is negative, compared with myocardial perfusion imaging studies. To our knowledge there are a lack of data assessing the prognostic value of transesophageal echocardiography-dobutamine stress echocardiography (TEE-DSE) in predicting cardiac events. Because TEE-DSE has been reported to be highly accurate for detecting ischemia in patients with suspected coronary artery disease, we tested the hypothesis that a negative TEE-DSE can identify a low-risk group in a population with a high likelihood of coronary artery disease. Between October 1996 and December 1997, 46 high-risk patients with negative TEE-DSE were identified. Annualized pretest risk for all cardiac events using the Framingham model was 4% based on risk factors. Mean age was 64 years. Mean follow-up time was 16.2 months. There were no cardiac deaths. There were 6 soft and 1 hard cardiac event. The annualized combined ischemic cardiac event rate was 3.8%, and for hard cardiac events it was 1.1%. By Kaplan-Meier analysis, 97% of the population remained free of any ischemic event at the end of 1 year and 93% were free at 22 months. We conclude that optimal image quality and enhanced endocardial definition for assessing wall motion changes with TEE translates into better prognostication and approaches that of myocardial perfusion imaging for negative studies. Advances in ultrasound medicine such as contrast enhancement of myocardial definition, which improve diagnostic accuracy of DSE, should translate into better prognostication.

Transesophageal echocardiography with stress for the evaluation of patients with coronary artery disease

Echocardiography permits a comprehensive assessment of resting regional and global left ventricular function, the presence and extent of inducible myocardial ischemia, and the identification of myocardial viability. Accordingly, stress echocardiography has become a valuable tool for the evaluation of patient with known or suspected coronary artery disease. In some patients however, a suboptimal transthoracic echocardiogram may limit the performance of interpretation of the test. Transesophageal echocardiography in combination with stress has been recently used for the evaluation of patients with coronary artery disease. This technique is semi-invasive, more time-consuming, and requires a greater degree of expertise on the part of the personnel assisting with the test. In general, complications and side-effects are self-limited and rarely affect the diagnostic accuracy of the test. Based on its ability to provide high quality images, transesophageal stress echocardiography should be considered in patients who have suboptimal transthoracic ultrasound window for the quantitative assessment of myocardial wall-thickening in clinical investigations of ischemic heart disease.

Stress Echocardiography: A Review of the Principles and Practice

Stress echocardiography, both pharmacologic and physiological, is an established noninvasive diagnostic method of detecting coronary artery disease. It also has a role in the assessment of patients with chest pain, the assessment of cardiovascular risk before noncardiac surgery, the assessment of patients after a myocardial infarction, the detection of viability in dysfunctional myocardium, and the prediction of functional recovery. The prognostic value of stress echocardiography is emerging. In this article, we discuss the methodology, diagnostic accuracy, and various clinical applications of stress echocardiography. We also review its limitations and compared it with other noninvasive methods of assessing patients with coronary artery disease.

Transnasal Transesophageal Stress Echocardiography

Exercise echocardiography is a widely used modality for the noninvasive assessment of coronary artery disease. However, limitations exist inherent to the acquisition of transthoracic echocardiographic images. Although transesophageal echocardiography has been used during pacing or pharmacological stress, its use during exercise stress testing has not been clinically feasible due to the large probe size. Recently, a miniaturized transesophageal probe was developed, and we sought to test the feasibility of using this probe during graded treadmill exercise testing. Normal subjects were studied with transnasal echocardiography during upright treadmill exercise testing. The transnasal probe was passed in 13 of the 15 subjects. Excellent-quality monoplane two-dimensional echocardiographic images were obtained in all patients in the upright position. During exercise treadmill testing, high quality clinically useful echocardiographic images of the left ventricular short axis could be maintained. We conclude that transnasal transesophageal stress echocardiography may offer a new modality for the exercise assessment of ischemic heart disease.

[Elective noninvasive test in the diagnosis of coronary disease in the aged]

BACKGROUND AND PURPOSE

The purpose of this study was to determine the best noninvasive test to diagnose coronary artery disease in the elderly. PATTERNS AND METHODS: We conducted a study on 56 elderly patients (> 65 years) with chest pain and no previous history of coronary artery disease. They underwent exercise stress test, dipyridamole echocardiography (0.84 mg/kg), dobutamine echocardiography (up to a total dose of 40 microgram/kg/min and atropine when it was necessary), dobutamine MIBI-SPECT and coronary angiography.

RESULTS

Angiography detected significant coronary artery disease in 41 patients. All tests used in this study had a similar sensitivity (conclusive exercise stress test 87%, dipyridamole echocardiography 83%, dobutamine echocardiography 80% and MIBI-SPECT 87%; p = NS). Coronary angiography did not identify significant lesions in 15 patients. Specificity of conclusive exercise stress test, dipyridamole and dobutamine echocardiography was similar (75%, 100% and 93% respectively; p = NS). However, the specificity of stress echocardiography was higher than that of scintigraphy (100% vs 66%; p = 0.02 for dipyridamole echocardiography and 93% vs 66%; p = 0.07 for dobutamine echocardiography). Diagnostic accuracy of each test was similar.

CONCLUSIONS

Exercise stress test remains the non invasive diagnostic test of choice to detect coronary disease in the elderly. If this test is inconclusive, both stress echocardiography and isotopic studies are useful, although the specificity of stress echocardiography is higher than that of scintigraphy.

Improved specificity of transesophageal dobutamine stress echocardiography compared to standard tests for evaluation of coronary artery disease in women presenting with chest pain

The detection of coronary artery disease (CAD) by noninvasive methods has been hindered in women by the high rate of false-positive results. To determine the feasibility and accuracy of transesophageal dobutamine stress echocardiography for identification of CAD in women, we studied 84 patients (age 51 +/- 11 years) who underwent symptom-limited exercise treadmill testing, exercise thallium-201 scintigraphy, and coronary angiography for evaluation of anginal chest pain. Of the 84 patients, 62 had normal coronary arteries or nonsignificant coronary lesions, and 22 had significant stenosis of > or = 1 major coronary artery. During treadmill exercise, repolarization changes were observed in 16 of 21 patients with CAD and in 19 of 60 patients with normal coronary arteries. With thallium scintigraphy, a reversible defect was observed in 19 of 22 patients with CAD and in 12 of 60 patients with normal coronary arteries. Regional wall motion abnormalities during dobutamine infusion developed in 18 of 22 patients with CAD and in none of the 62 patients with normal coronary arteries. All 3 tests had similar sensitivity for detection of CAD (76% for exercise treadmill test, 86% for thallium scintigraphy, and 82% for transesophageal dobutamine stress echocardiography). However, transesophageal dobutamine stress echocardiography had significantly higher specificity than the other 2 tests (100% vs 68% for exercise treadmill test and 80% for thallium scintigraphy; p = 0.0001). Thus, transesophageal dobutamine stress echocardiography is accurate for evaluation of CAD among women presenting with chest pain; its use should be considered when more conventional tests are equivocal or technically suboptimal.

Breath-hold dobutamine magnetic resonance myocardial tagging: normal left ventricular response

Analysis of the changes in myocardial deformation produced by adrenergic stress has been limited by the imaging techniques used. We used rapid magnetic resonance imaging (MRI) myocardial tagging to map the dose-dependent response to incremental dobutamine in the normal human left ventricle. Thirteen volunteers underwent breath-hold tagged cine MRI during dobutamine infusion. Images were acquired throughout systole to a peak dose of 20 microg/kg/min. End-systolic percent circumferential shortening (%S) was measured at 3 transmural locations and 4 circumferential locations at 3 long-axis positions. Mean circumferential shortening velocity (CSV) was also calculated at each location and dose. Mean %S reached a maximum of 26 +/- 3% at 10 microg/kg/min compared with 21 +/- 4% at baseline (p <0.003). Peak %S was reached by 10 microg/kg/min before a significant increase in heart rate or blood pressure and was unchanged at higher doses. In contrast, CSV increased linearly with dobutamine dose from 4.4 +/- 0.9 mm/s at baseline to 9.8 +/- 1.4 mm/s at 20 microg/kg/min (p <0.0001). Breath-hold tagged dobutamine MRI is safe and effective in detecting regional and transmural changes in function during incremental dobutamine. CSV increased continuously across the dobutamine dose range. At low dose (< or =10 microg/kg/min) %S increased without any change in blood pressure or heart rate. Maintenance of peak %S beyond 10 microg/kg/min in the presence of decreasing systolic intervals resulted from a continued increase in CSV. Thus, CSV may be the preferred measure of contractile function during dobutamine stimulation in human myocardium.

Investigation of the mechanism of chest pain in patients with angiographically normal coronary arteries using transesophageal dobutamine stress echocardiography

OBJECTIVES

The present study sought to determine whether myocardial contractile abnormalities accompany the development of chest pain in patients with normal coronary angiograms.

BACKGROUND

The mechanism of chest pain in patients with angina despite a normal coronary arteriogram is controversial. Although previous studies postulated the existence of coronary microvascular dysfunction, others failed to find evidence of myocardial ischemia, and recent studies have demonstrated abnormal cardiac sensitivity in these patients that can lead to chest pain on a nonischemic basis.

METHODS

Seventy patients (26 men and 44 women, mean age 49 +/- 10 years) with angina-like chest pain and angiographically normal coronary arteries underwent exercise treadmill testing, radionuclide angiography at rest and during exercise, thallium stress testing and transesophageal dobutamine stress echocardiography. The results of exercise treadmill testing and stress echocardiography were compared with those obtained in 26 normal control subjects (19 men and 7 women, mean age 56 +/- 7 years).

RESULTS

Abnormalities consistent with myocardial ischemia were noted in 31% of the patients during exercise treadmill testing, in 16% during exercise radionuclide angiography and in 18% during thallium stress testing. The findings of the radionuclide studies were not concordant with one another and were not related to the presence of repolarization changes during exercise testing. During infusion of dobutamine, chest pain developed in 59 patients (84%) and in none of the control subjects (p < 0.0001); repolarization changes occurred in 22 patients (34%) and in 2 control subjects (8%) (p < 0.04). None of the patients or the control subjects developed regional wall motion abnormalities with dobutamine. The quantitative myocardial contractile response to dobutamine was similar in patients and control subjects, with an 80% power to detect a 25% difference in systolic wall thickening at the maximal dose of dobutamine.

CONCLUSIONS

There was no agreement in the results of noninvasive tests in our patients. Despite the frequent provocation of chest pain and electrocardiographic abnormalities with dobutamine, the patients demonstrated a quantitatively normal myocardial contractile response without development of wall motion abnormalities. These observations strongly suggest that myocardial ischemia is not the cause of chest pain in patients with a normal coronary arteriogram.

[II. Role of Doppler echocardiography in the management of chronic ischemic cardiopathy]

Doppler echocardiography is a simple, fast and non-invasive method to identify abnormal regional and global left ventricular function. One could consider this method the best application for this end within the techniques of imaging. This chapter reviews the role of Doppler echocardiography in the management of chronic coronary artery disease, as well as for studying the global and regional function at rest, as in the applications derived from their use during stress testing. Frequent techniques of stress echocardiography for the diagnosis of ischemic heart disease, their utility in the study of myocardial viability, and the establishment of recommendations for their use in clinical practice are analyzed.

Transesophageal dobutamine-atropine stress echocardiography: diagnostic accuracy for coronary stenosis detection and localization

Transesophageal echocardiography with dobutamine-atropine stress (TE-DASE) is a recently described technique for evaluation of coronary artery disease (CAD). We undertook this study prospectively to determine the feasibility, reliability and safety of this procedure in patients with known CAD and to evaluate its diagnostic accuracy for coronary stenoses of varying severity. Thirty-seven patients who underwent coronary arteriography (CART) and TE-DASE within a 3-month interval without intervening ischemic events or revascularisation were included in the study CART and stress echograms were independently evaluated by different observers. Stenosis was measured with calipers and a > or = 50% lumen diameter stenosis was considered significant. A reduction or lack of endocardial motion and/or wall thickening on progressive incremental stress was considered an abnormal response. TE-DASE could be successfully completed in 33/37 (90%) patients. Using a modified 16-segment model of the left ventricle (LV), 15.2 +/- 0.8 segments/patient and 501/528 (95%) segments overall could be optimally evaluated. Inter-observer concordance for an abnormal response was 94%. Predictive accuracies for one-vessel disease (1-VD), two-vessel disease (2-VD) and three-vessel disease (3-VD) were 88, 58 and 23% respectively. Overall sensitivity for detection of a significant (> or = 50%) stenosis was 72% (32% for moderate (50-69%), 90% for severe (> or = 70%) stenosis) and specificity was 96%. Diagnostic accuracy for localisation of significant stenosis was 95% for the left anterior descending artery (LAD), 86% for the left circumflex artery (LCX) and 88% for the right coronary artery (RCA). There were no major complications. We conclude that TE-DASE is a safe, reliable and easily-performed procedure and provides excellent visualisation of myocardial segments. Diagnostic accuracy for detection of severe stenosis and its localisation is excellent.

Transesophageal echocardiography

This article presents an overview of the benefits and efficacy of transesophageal echocardiography (TEE) in the critically ill patient. The echocardiographic evaluation of ventricular function both regional and global, is discussed with special emphasis on ischemic heart disease; assessment of preload, interrogation of valvular heart disease (prosthetic and native) and its complications; endocarditis and its complications; intracardiac and extracardiac masses, including pulmonary embolism; aortic diseases (e.g., aneurysan, dissection, and traumatic tears); evaluation of patent foramen ovale and its association with central and peripheral embolic events; advancements in computer technology; and finally, the effect of TEE on critical care.