Exercise echocardiography as a screening test for coronary artery disease and correlation with coronary arteriography

Comparison of bicycle, heavy isometric, dipyridamole-atropine and dobutamine stress echocardiography for diagnosis of myocardial ischemia

Several stress echocardiography (SE) modalities have been introduced for diagnosing coronary artery disease (CAD). Exercise and dobutamine SE are considered to have better diagnostic accuracy than vasodilator or isometric SE, but there are no studies in a single group of patients comparing these 3 tests with heavy 2-arm isometric SE. The purpose of this study was to determine the diagnostic characteristics of 4 SE methods in patients with chest pain. Altogether, 60 patients (age +/- SD 55.1 +/- 2.1 years) were tested with bicycle, heavy 2-arm isometric, dipyridamole-atropine and dobutamine SE. CAD (>50% stenosis) was present in 44 patients; 26 patients had 1-vessel disease. During bicycle SE, the double product at peak stress was higher than during dobutamine and dipyridamole-atropine SE (26.5 x 10(3), p <0.005 vs dobutamine and dipyridamole-atropine SE), and peak wall motion score index (1.40) was higher than during dipyridamole-atropine and isometric SE (1.26 and 1.07, respectively, p <0.05 vs bicycle SE). Bicycle, dipyridamole-atropine, and dobutamine SE had higher sensitivity than isometric SE (90%, 93%, 95%, and 30%, respectively, p <0.05 isometric SE vs others). There were no statistically significant differences with regard to specificity. Similarly, bicycle, dipyridamole-atropine, and dobutamine SE had a higher diagnostic accuracy than isometric SE (78%, 88%, 87% and 47%, respectively, p <0.05 isometric SE vs others). We conclude that bicycle, dipyridamole-atropine, and dobutamine SE have an equal diagnostic accuracy in detecting CAD despite higher double product and ischemic burden at peak stress during bicycle and dobutamine SE over dipyridamole-atropine SE. Heavy isometric SE is inaccurate.

Comparison of treadmill exercise echocardiography before and after exercise in the evaluation of patients with known or suspected coronary artery disease

OBJECTIVES

We sought to compare the feasibility and accuracy of peak treadmill exercise echocardiography versus postexercise echocardiography imaging.

BACKGROUND

Although peak exercise echocardiography has been reported for both supine and orthostatic bicycle exercise and has shown higher sensitivity than postexercise imaging, acquiring images at peak exercise with treadmill has not been explored.

METHODS

Peak and post-treadmill exercise echocardiography and coronary angiography were performed on 89 patients with known or suspected coronary artery disease. Positive exercise echocardiography was defined as necrosis or ischemic response. Positive coronary angiography was defined as >/=1 diseased vessels (>/=50% luminal narrowing). Images were analyzed in a blind manner by an expert observer.

RESULTS

Postexercise images were acquired within 80 seconds after exercise (40 +/- 14). Mean heart rate (bpm) was 139 +/- 22 at peak versus 118 +/- 25 at postexercise imaging (P <.001). Interpretable peak and postexercise images were obtained for all 89 patients. Of the 72 classified as having positive exercise echocardiography, 23 had new regional wall motion abnormality at peak (21 with positive angiography), which resolved at postexercise imaging. Sensitivity was higher with peak than with postexercise imaging (94% vs 73%, P <.001). Specificity was similar (68% vs 79%), as was predictive positive value (92% vs 93%). Negative predictive value was again higher with peak imaging (76% vs 44%, P <.05). Total accuracy was higher with peak imaging (89% vs 74%, P <.05).

CONCLUSIONS

Peak treadmill exercise echocardiography is technically feasible and has higher sensitivity and accuracy than post-treadmill exercise echocardiography. Therefore in the clinical setting peak exercise echocardiography should be performed to diagnose ischemia.

A perspective on standardizing the predictive power of noninvasive cardiovascular tests by likelihood ratio computation: 2. Clinical applications

Likelihood ratio measures may be used as a standard for expressing the predictive power of noninvasive cardiovascular tests, calculated from sensitivity and specificity measures or as ratios of the predictive value odds to pretest odds for positive and negative test results. The positive likelihood ratio, (+)LR, expresses the power of a positive test result to augment an estimate of disease probability independent of the pretest prevalence of disease in a given population; the negative likelihood ratio, (-)LR, expresses the power of a negative test result to augment an estimate of the probability of no disease independent of the pretest prevalence of no disease in the same population. The likelihood ratio principle is applicable to the evaluation of the predictive power of single or combined test results reported for either dichotomous or continuous end points. This part of the perspective exemplifies application of the likelihood ratio principle in a wide variety of testing conditions for coronary artery disease followed by a discussion of the limitations of likelihood ratio computation in test power evaluation. Likelihood ratios provide a more concise and unambiguous standard for calibrating the predictive power of single and combined noninvasive cardiovascular test results than are provided by measures of sensitivity, specificity, and predictive value.

Diagnostic and Prognostic Use of Stress Echocardiography and Radionuclide Scintigraphy

Stress echocardiography and radionuclide scintigraphy are effective diagnostic and prognostic techniques in patients with known or suspected coronary artery disease (CAD), myocardial infarction (MI), chronic left ventricular dysfunction (LVD), and those undergoing noncardiac surgery. Both are sensitive and specific for the detection and extent of CAD. Negative tests confer a high negative predictive value for cardiac events irrespective of clinical risk. Positive studies confer a high positive predictive value for ischemic events in patients with intermediate to high clinical risk. Both provide incremental diagnostic and prognostic information relative to clinical, resting echocardiographic, and angiographic data. Meta-analysis studies have shown that the diagnostic and prognostic information provided by stress echocardiography is comparable with radionuclide scintigraphic stress tests. Stress echocardiography may be more specific for the detection and extent of CAD, whereas radionuclide scintigraphy may be more sensitive for single-vessel disease. Sensitivities are similar for the detection and extent of disease in patients with multivessel CAD.

Advances in Exercise Echocardiography Can This Technique Still Thrive in the Era of Pharmacologic Stress Testing?

In the current literature, pharmacologic stress techniques are the focus of interest and excitement regarding new technologies and new indications such as the diagnosis of viable myocardium. In contrast, exercise echocardiography has evolved less and is less amenable to the introduction of new technologies. This article reviews the indications for exercise echocardiography (especially in contrast to pharmacologic stress), its accuracy relative to other testing, and application to clinical decision making. Exercise echocardiography remains to be well accepted as a diagnostic and risk-assessment technique, and in some clinical situations it provides valuable data that are not available during pharmacologic stress testing.

Overall and Segmental Agreement of Stress Echocardiography

Several stress echocardiography (SE) modalities have been introduced for diagnosing coronary artery disease (CAD). Exercise and dobutamine SE are commonly considered to have a better diagnostic accuracy than vasodilator SE. The purpose of this study was to assess the agreement between the test results and the segmental concordance between three SE tests in patients with chest pain. A total of 60 patients (mean age, 55.1 years; SD, 2.1) were tested by symptom-limited bicycle (BSE), dipyridamole-atropine (DiASE), and dobutamine (DSE) tests. CAD (50% stenosis) was present in 44 patients, and 26 patients had one-vessel disease. In BSE and DSE, the double product at peak stress (26.5 and 16.1 vs 13.3 x 10(3), respectively, P < 0.005 vs DiASE) and the peak wall motion score index were higher than in DiASE (1.40 and 1.35 vs 1.26, respectively, P < 0.05 vs DiASE). BSE, DiASE, and DSE did not differ in sensitivity in diagnosing CAD (90%, 93%, and 95%, respectively). Similarly, there were no statistically significant differences in the diagnostic accuracy of BSE, DiASE, and DSE (78%, 88%, and 87%, respectively). The intermethod agreement was moderate between BSE and DiASE (kappa = 0.51), good between BSE and DSE (kappa = 0.62), and moderate between DiASE and DSE (kappa = 0.57). The segmental agreement between BSE, DiASE, and DSE was mostly moderate. Agreement was best between the pharmacologic tests due to test protocols, especially the anterior wall (kappa > 0.60). Also, the basal segments showed good agreement. In conclusion, BSE, DiASE, and DSE have a similar diagnostic accuracy in detecting CAD. The overall agreement between the tests was good, and the assessment of wall motion was variable. Nevertheless, concordant diagnosis of a patient can be obtained by BSE, DiASE, and DSE without loss of diagnostic power.

Stress echocardiography in women

The diagnosis of coronary heart disease in women has been thought to be more difficult than in men, owing to the overall lower prevalence and severity of disease in women, as well as more subtle clinical presentations. Exercise electrocardiography is associated with a high rate of false-positive results. In contrast, exercise and pharmacologic stress echocardiography have been shown to have high sensitivity, specificity, and prognostic value in women, comparable to that obtained in a male population. Although exercise thallium provides high f disease accuracy, due to its cost, availability, and radiation exposure, it may not be the ideal initial test in women. Thus, compared with other modalities, the advantages of stress echocardiography include its lower cost, availability, and high diagnostic accuracy. In the evaluation of women with chest pain, the initial step should involve clinical stratification into low, moderate, or high-probability groups based on symptoms, age, and cardiovascular risk factors. In women with atypical chest pain and a low probability of coronary heart disease, further testing should be avoided because any positive result is likely to be falsely positive. In those women with a moderate likelihood of disease, the most efficient and cost-effective strategy includes stress echocardiography as the initial test. This approach avoids the high rate of false-positive results with subsequent unnecessary angiography generated by exercise electrocardiography, as well as minimalizing false-negative results, which would lead to delays and potential increase in morbidity and mortality from untreated coronary heart disease. The optimal strategy for women at high clinical risk may be either exercise echocardiography or cardiac catheterization as the initial test. Although the diagnosis of CAD in women is different than in men, it is not necessarily more difficult. Astute clinical evaluation, in conjunction with judicious use of diagnostic testing, yields excellent results.

Objective evaluation of regional left ventricular wall motion during dobutamine stress echocardiographic studies using segmental analysis of color kinesis images

OBJECTIVES

To test the feasibility of objective and automated evaluation of echocardiographic stress tests, we studied the ability of segmental analysis of color kinesis (CK) images to detect dobutamine-induced wall motion abnormalities and compared this technique with inexperienced reviewers of conventional gray-scale images.

BACKGROUND

Conventional interpretation of stress echocardiographic studies is subjective and experience dependent.

METHODS

CK images were obtained in 89 of 104 consecutive patients undergoing clinical dobutamine stress studies and were analyzed using custom software to calculate regional fractional area change in 22 segments in four standard views. Each patient's data obtained at rest was used as a control for automated detection of dobutamine-induced wall motion abnormalities. Independently, studies were reviewed without CK overlays by two inexperienced readers who classified each segment's response to dobutamine. A consensus reading of two experienced reviewers was used as the gold standard for comparisons. In a subgroup of 16 patients, these consensus readings and CK detection of wall motion abnormalities were compared with coronary angiography.

RESULTS

The consensus reading detected ischemic response to dobutamine in 43 of 1958 segments in 23 of 89 patients. Automated detection of stress-induced wall motion abnormalities correlated more closely with the standard technique than the inexperienced reviewers (sensitivity 0.76 vs. 0.55, specificity 0.98 vs. 0.94 and accuracy 0.97 vs. 0.92). When compared with coronary angiography in a subgroup of patients, analysis of CK images differentiated between normal and abnormal wall motion more accurately than expert readers of gray-scale images (accuracy of 0.93 vs. 0.82).

CONCLUSIONS

Analysis of CK images allows fast, objective and automated evaluation of regional wall motion, sensitive enough for clinical dobutamine stress data and more accurate than inexperienced readers. This method may result in a valuable adjunct to conventional visual interpretation of dobutamine stress echocardiography.

Exercise echocardiography. Principles, methods, and clinical use

Stress echocardiography is composed of a family of examinations in which various forms of cardiovascular stress are combined with echocardiographic imaging to assist in the diagnosis of coronary artery disease. Exercise cardiography has evolved over the past 20 years into a routinely available clinical tool employed in both university and community hospital settings. This article discusses advantages and disadvantages of using exercise echocardiography.

Supine bicycle versus post-treadmill exercise echocardiography in the detection of myocardial ischemia: a randomized single-blind crossover trial

OBJECTIVES

We sought to determine the comparative accuracy of supine bicycle exercise echocardiography (SBE) and posttreadmill exercise echocardiography (TME) in detecting myocardial ischemia in patients with known or suspected coronary artery disease (CAD).

BACKGROUND

Supine bicycle echocardiography and TME have been used for evaluation of CAD. However, the comparative accuracy of these modalities in the detection of ischemia in the same patients is not known.

METHODS

Seventy-four patients (age 59 +/- 9 years [mean +/- SD]) referred for evaluation of coronary disease underwent SBE (starting at 25 to 50 W with 25-W increment every 3 min) and post-TME (Bruce protocol) in a random sequence. Digitized images at baseline and maximal exercise were interpreted in a random and blinded fashion.

RESULTS

Maximal heart rate was higher during TME, whereas systolic blood pressure was higher during SBE, resulting in a similar double product. At quantitative angiography (n = 67), 57 patients had coronary stenosis (>50%). During SBE, ischemia was detected in 47 patients compared with 38 patients by TME (p < 0.001). Wall motion score index at maximal exercise was higher with SBE than with TME (1.48 +/- 0.51 vs. 1.38 +/- 0.43; p < 0.001). The extent of myocardial ischemia (number of ischemic segments) was higher during SBE compared with TME (3.3 +/- 3.4 vs. 2.3 +/- 2.9 segments; p = 0.004), whereas severity of abnormal wall motion was similar. The sensitivity of SBE and TME for CAD was 82% and 75% with a specificity of 80% and 90%, respectively. Image quality was similar with both techniques. Patients and sonographers favored SBE over TME.

CONCLUSIONS

During SBE and TME exercise, patients achieve a similar double product. During SBE, however, the detection of ischemia is more frequent and more extensive which, along with patient and sonographer preference, makes supine bicycle exercise a valuable stress echocardiographic modality.

Long-Term Value of Stress Echocardiography in the Triage of Patients with Atypical Chest Pain Presenting to the Emergency Department

The purpose of this study was to assess the use of stress echocardiography in the triage of patients presenting to the emergency department with atypical chest pain. We hypothesized that a negative stress echocardiogram would identify patients with a very low risk for future cardiac events, thus reducing the requirement for unnecessary hospitalizations. Stress testing was performed in 105 patients presenting with atypical chest pain, no prior history of coronary artery disease, a nondiagnostic electrocardiogram (ECG), negative serial creatine phosphokinase level at 0 and 4 hours, and baseline normal echocardiograms. Cardiac stress was invoked using an exercise protocol in 75 (71%) patients and intravenous dobutamine in 30 (29%) patients, with ECG and echocardiography results analyzed separately. Cardiac events (myocardial infarction, coronary revascularization, and cardiac death) were noted in 7 (7%) patients with a mean follow-up of 2.8 +/- 1.3 years. Univariate analysis identified five predictors of future cardiac events, but only stress-induced wall motion abnormalities were found to be predictive with multivariate analysis. Kaplan-Meier estimate of cumulative event-free survival for cardiac events at 3 years was 99% for a negative stress echocardiogram (no stress-induced wall motion abnormalities) compared with 95% for stress ECG (< 1-mm ST segment depression). The event-free rate of a positive stress echocardiogram and stress ECG was 25% and 63%, respectively. We conclude that stress echocardiography can be performed safely in patients presenting with atypical chest pain. A negative stress echocardiogram carries an excellent 3-year prognosis and thus identifies patients who may forgo hospital admission and further cardiovascular workup.

Utility of stress echocardiography in the triage of patients with atypical chest pain from the emergency department

We followed 108 patients presenting to the emergency department with atypical chest pain and triaged with stress echocardiography. One-year cardiac event-free survival was 100% with a negative stress echocardiogram and 25% with a positive study.

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.

Risk stratification of patients with medically treated unstable angina using exercise echocardiography

Functional testing is recommended for risk stratification of medically treated patients with unstable angina. Exercise echocardiography is used in this situation, but its safety and prognostic value are not well defined. The objective of this study was to assess the incremental prognostic value of exercise echocardiography in 226 consecutive patients (128 men, age 59+/-13 years) with medically treated unstable angina, who underwent exercise echocardiography from 1991 to 1996. Clinical risk was designated as low in 108 patients, intermediate in 116, and high in 2 patients according to the unstable angina practice guidelines. There were no major complications from the stress tests. The exercise electrocardiogram was nondiagnostic in 57 patients (25%). Ischemia was identified by exercise electrocardiography in 33 patients and exercise echocardiography in 55 patients. Patients were followed for 29+/-18 months. After exclusion of 38 patients who underwent early revascularization, 28 patients had cardiac death, nonfatal infarction, and late (>3 months) revascularization. Ischemia at exercise echocardiography was associated with a 24-month event-free survival of 81%, compared to 95% with negative exercise echocardiography (p=0.02). A positive exercise electrocardiogram was associated with a 24-month event-free survival of 84%, compared to 93% with negative exercise electrocardiograms (p=0.08). In a Cox regression model, event-free survival was predicted by ischemia at exercise echocardiography (relative risk 2.8, confidence interval: 1.3 to 6.3, p=0.05), but not at exercise electrocardiography (relative risk 2.1, confidence interval 0.7 to 5.8, p=0.16).

Usefulness of exercise echocardiography in predicting cardiac events in an outpatient population

The prognostic value of exercise echocardiography in an outpatient population is not well defined. A total of 1,020 consecutive patients referred for exercise echocardiography in an ambulatory care setting were studied by reviewing their medical records and exercise echocardiographic data. Of these, 71 (7%) were excluded due to technically inadequate tests, leaving 949 patients who were included in the analysis. A positive exercise echocardiogram (EE) was defined as an appearance of a new wall motion abnormality or worsening of a baseline abnormality. Cardiac events, defined as myocardial infarction, coronary angioplasty, coronary bypass surgery, and death, were documented during a 12-month follow-up period. Cardiac events occurred in 17% of patients (26 of 152) with a positive exercise echocardiogram (EE) and in 2.5% (20 of 797) with a negative EE (p <0.001). The incidence of myocardial infarction (2.6% vs 0.4%, p <0.02), coronary angioplasty (7% vs 1%, p <0.001), and coronary bypass surgery (9% vs 1%, p <0.001) were higher in patients with a positive versus a negative EE. There was 1 death in the positive study group and none in the negative group. Significant independent variables (p <0.05) that predicted cardiac events included a positive exercise electrocardiogram, history of coronary angioplasty, nonspecific ST-T changes on the baseline electrocardiogram, double product <25,000, men, chest pain on exercise test, and a positive exercise electrocardiogram. On a stepwise logistic regression model, exercise echocardiography emerged as an independent predictor of future cardiac events in an outpatient population. This predictive value was enhanced in the presence of a positive exercise electrocardiogram compared with a negative exercise electrocardiogram (24.2% vs 7.9%, p <0.03). Our study suggests that exercise echocardiography is an independent predictor of future cardiac events in an outpatient population.

The Sensitivity of Exercise Echocardiography Can Be Improved by Taking the Delayed Myocardial Contraction into Account

The purpose of this study was to test whether the systolic myocardial wall motion abnormalities at the early stages of ischemia are applicable to the diagnosis of coronary artery disease. Forty-four patients with suspected coronary artery disease were studied with the use of low-level exercise echocardiography. Exercise was stopped at the onset of first cardiac symptoms, and no patient exceeded 70% of the age-predicted maximal heart rate level. Forty patients had significant stenosis in at least one coronary artery on coronary angiography. Ten control subjects with a low probability of ischemic heart disease also were studied with exercise echocardiography. The first ischemic wall motion abnormality in systole, defined as delayed onset of the contraction (a regional delay of at least 100 milliseconds in a frame-by-frame analysis of echocardiograms) without any reduction in systolic movement, was regarded separately from hypokinesis (systolic wall motion excursion of less than 5 mm). When the delayed onset of the contraction also was taken into account, 37 of the 40 patients with coronary artery disease had an ischemic response after exercise. The sensitivity of the test thus was 93%. The reduction in systolic wall movement was detected in only 18 of these patients at the exercise level attained (70% or less of age-predicted maximal heart rate). There were two false-positive echocardiograms, but when the control group also was considered, the specificity of the test remained high at 86%. The sensitivity of exercise echocardiography can be increased by paying attention to the delayed onset of the systolic contraction, which occurs at the early stages of ischemia.

Prognostic value of stress echocardiography in the evaluation of atypical chest pain patients without known coronary artery disease

Patients with atypical chest pain frequently lack significant coronary artery disease (CAD) and are, therefore, at low risk for future adverse cardiovascular events. We hypothesized that in this group of patients, stress echocardiography could identify those at risk for cardiac events. We retrospectively reviewed (mean follow-up 23.0 +/- 7.2 months) the prognostic value of stress echocardiography for major (cardiac death, myocardial infarction, congestive heart failure, and unstable angina) and total (major events plus coronary revascularization) cardiac events in 661 patients with atypical chest pain, normal global left ventricular (LV) systolic function, and no history of CAD. A positive stress echocardiogram was defined as the development of new or worsening wall motion abnormalities with exercise stress (80%) or dobutamine (20%). A total of 41 cardiac and 16 major events were noted. The event-free survival for total cardiac events was 97% for a normal stress echocardiogram and 93% for a normal stress electrocardiogram (ECG) at 30 months. A positive stress ECG predicted an event-free rate of 86% compared with 74% for stress-induced wall motion abnormalities and 42% if stress-induced LV dysfunction accompanied the wall motion abnormalities. A strategy recommending invasive studies based on positive stress echocardiogram results increased the per-patient cost, but led to greater savings per cardiac event predicted and provided incremental prognostic value for future cardiac events beyond clinical and stress electrocardiographic data. Thus, stress echocardiography in low-risk patients for CAD appears to be more cost effective than a stress ECG.

Color Doppler imaging of the myocardium: current status and potential clinical applications

Doppler myocardial imaging (DMI) is a new technique with potential clinical and research applications. It applies traditional pulsed and color Doppler techniques to the analysis of myocardial contractile velocity. A major area of focus is in the quantitation of regional and global myocardial function and evaluation of myocardial perfusion in conjunction with myocardial contrast studies. DMI may also provide a direct, relatively load-independent assessment of diastolic function. Further work is required to identify its role in clinical and research studies.

Stress echocardiography: recommendations for performance and interpretation of stress echocardiography. Stress Echocardiography Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography

Cardiovascular stress testing remains the mainstay of provocative evaluation for patients with known or suspected coronary artery disease. Stress echocardiography has become a valuable means of cardiovascular stress testing. It plays a crucial role in the initial detection of coronary disease, in determining prognosis, and in therapeutic decision making. The purpose of this document is to outline the recommended methodology for stress echocardiography with respect to personnel and equipment as well as the clinical use of this recently developed technique. Specific limitations will also be discussed.

Stress echocardiography for assessing myocardial ischaemia and viable myocardium

Images

The Five View Technique for Stress Echocardiography: A Description and Evaluation of Segmental Imaging and Reported Angiographic Data

Stress echocardiography is an accurate means of evaluating ischemic heart disease with sensitivities and specificities equivalent to alternate modalities. The sensitivities to disease of vessels with posterior wall distribution are, however, significantly lower. Studies establishing these figures have used a 4 view digital imaging technique as standard. This study aimed to determine if the use of a 5 view template (4 views plus an apical 3 chamber (3ch) view) significantly improved stress echo results. One hundred consecutive stress echocardiograms using a 5 view format were analyzed by two independent observers. Nine thousand regional wall segments were graded quantitatively and qualitatively and comparisons were made between the 4 and 5 view techniques. Reported angiographic sensitivities of the two techniques were analyzed and compared to the segmental imaging data. The 5 view template was found to increase overall segmental imaging by 30% and imaging of lateral and posterior walls was increased by 50% while the additional poststress cycle was acquired in under 13 seconds. Five view studies reported increased mean sensitivities to left anterior descending coronary artery (LAD) disease of 29.7%, right coronary artery (RCA) disease of 25.7%, and circumflex coronary artery (Cx) disease of 51.6%. This study found that the 5 view technique significantly increased left ventricular segmental imaging, particularly of the posterior and lateral walls, and is associated with increased angiographically determined sensitivity, particularly for vessels with posterior wall distribution when compared to the 4 view technique.

How does computer-assisted digital wall motion analysis influence observer agreement and diagnostic accuracy during stress echocardiography?

This study assessed interobserver and intraobserver variation and diagnostic accuracy during 25 dipyridamole stress echocardiography tests interpreted with different analysis systems: a) computer display of high frame rate digital cineloops (47 frames/s); b) computer display of lower frame rate digital cineloops (24 frames/s); and c) videotape recordings. The majority of the patients (84%) had documented coronary artery disease with baseline wall motion abnormalities due to previous myocardial infarctions and/or coronary bypass surgery, thus comprising a population with difficult interpretation of stress echocardiography. Diagnostic accuracy was assessed using coronary angiography as reference method. Interobserver and intraobserver agreement was highest when analysis was performed from computer-displayed cineloops, 96 and 92%, respectively, compared to 84 and 80% respectively, using videotape recordings. Sensitivity for identification of coronary artery stenosis was similar using digital cineloops with high frame rate or videotape recordings (67% to 80% for both systems), and tended to be lower using cineloops with lower frame rate for analysis (53%). Inter- and intraobserver differences for wall motion score index were not significantly influenced by the analysis system. We conclude that computer assisted analysis with high frame rate of the displayed cineloops provides optimal observer agreement and diagnostic accuracy in the same range as videotape analysis in patients undergoing stress echocardiography.

Comparison between dobutamine echocardiography and thallium-201 scintigraphy in detecting residual stenosis, ischemia, and necrosis in patients with prior myocardial infarction

BACKGROUND

Following the first attempts to detect myocardial ischemia with two-dimensional echocardiography stress testing, pharmacologic stress using dobutamine infusion has become an alternative to echocardiography exercise testing for evaluation of coronary artery disease. It has been shown that stress echocardiography has a diagnostic accuracy similar to that of an exercise thallium test. Other studies, however, indicated that radionuclide myocardial perfusion imaging was more sensitive than exercise or pharmacologic stress echocardiography for detection of ischemia or jeopardized myocardium.

HYPOTHESIS

The aim of the present study was to determine the ability of dobutamine stress echocardiography in comparison with thallium-201 scintigraphy to identify multivessel disease and the presence of myocardial scar and ischemia in 60 consecutive patients who suffered a first myocardial infarction (MI).

METHODS

Patients were evaluated by coronary angiography and ventriculography, thallium-201 (201TI) tomographic scintigraphy, and dobutamine echocardiography within 3 months of a first MI. Forty-seven had Q-wave MI and 13 had non-Q-wave MI. Eleven patients were excluded from final analysis-7 because of failure to achieve target heart rate in spite of the use of atropine, and 4 because of high blood pressure following the infusion of dobutamine.

RESULTS

Dobutamine echocardiography showed an overall sensitivity of 43% for detection of coronary artery lesions of 50-74% diameter stenosis and 201TI scintigraphy showed a sensitivity of 71%. For detection of lesions of > or = 75% diameter stenosis, dobutamine echocardiography showed a sensitivity of 52% and 201TI a sensitivity of 70%. Overall agreement between wall motion and myocardial perfusion for detection of necrosis and/or ischemia in the infarct area was 40.4% with a kappa coefficient of 0.09 (p = 0.13). For detection of ischemic myocardium outside the infarct zone, overall agreement was 78.6% with a kappa coefficient of 0.49 (p < 0.0001).

CONCLUSION

Dobutamine echocardiography results showed a lower sensitivity than myocardial perfusion images in predicting multivessel coronary artery disease, and there was poor agreement between both methods in identifying necrosis or ischemia.

Is review of videotape necessary after review of digitized cine-loop images in stress echocardiography? A prospective study in 306 patients

The interpretation of stress echocardiography has been made easier by the comparison of digitized prestress and poststress frame-grabbed images (cine-loops), each representing a portion of a single cardiac cycle. Often, review of these digitized images is substituted for review of the complete videotape record of the examination. An alternative is to review both the digitized images as well as the videotape record of the rest and stress images. To date, there has been insufficient documentation of whether these options (cine-loop images alone versus cine-loop images plus videotape) provide comparable or additive information. Therefore, we prospectively evaluated information obtained from review of cine-loop images versus combined review of cine-loop images and videotape records in 306 consecutive patients undergoing treadmill (213 patients, 70%) or dobutamine (93 patients, 30%) stress echocardiography. An experienced echocardiologist first reviewed the cine-loop images and scored the wall motion in 16 segments at rest and with stress. Next, the complete videotape record was reviewed with repeated wall motion scoring. A questionnaire comparing cine-loop and videotape images was completed at the end of each review. Digitization of images was technically inadequate in 14 patients (4%). In 116 (40%) of the other 292 patients, the regional wall motion assessment, after relying solely on cine-loop images, was modified with subsequent videotape review. In 40 patients (14%), these modifications resulted in a change in the final impression regarding whether the study result was normal or abnormal. In a multivariate analysis, age, gender, and type of stress echocardiography had no significant influence on discordance of the cine-loop image and combined cine-loop and video information. Stepwise logistic regression analysis identified poorer image quality (p < 0.0001) and regional wall motion abnormalities (p < 0.0001) as predictors of discordance between cine-loop and combined review. We conclude that relying solely on digitized cine-loop images representing a single cardiac cycle is not optimal, especially if the quality of the digitized images is suboptimal and if regional wall motion abnormalities are present. Thus we recommend a combined review of both cine-loop images and videotape images in the interpretation of stress echocardiography.

Sex and test verification bias. Impact on the diagnostic value of exercise echocardiography

BACKGROUND

The use of exercise echocardiography for the diagnosis of coronary artery disease (CAD) has been validated in pilot studies but is not documented in clinical practice and in women comparatively with men. The objectives of this study were to determine the effects of sex and of test verification bias on the diagnostic performance of exercise echocardiography.

METHODS AND RESULTS

Three thousand six hundred seventy-nine consecutive patients (1714 women, 1965 men) who underwent an exercise echocardiographic study were studied; the observed sensitivity, specificity, and correct classification rate were calculated among 340 patients (244 men, 96 women) who underwent angiography; to study the effect of test verification bias, sensitivity and specificity were estimated for all patients who underwent exercise echocardiography including those not referred to angiography. In the angiographic group, the prevalence of CAD was 60% in women and 80% in men. The observed sensitivity and specificity of exercise echocardiography was 78% and 44% in men and 79% and 37% in women. After adjustment for test verification bias, the estimated sensitivity was lower in women (32% versus 42% in men), whereas specificity was similar in both sexes. The positive predictive value was lower in women (66%) compared with men (84%).

CONCLUSIONS

In clinical practice, test verification bias results in a lower observed specificity and a higher sensitivity of exercise echocardiography. In women, positive predictive value and adjusted sensitivity are lower compared with that in men.

[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.

Detection of coronary artery disease in the presence of left ventricular atrophy

To evaluate the accuracy of exercise echocardiography for the recognition of coronary artery disease in the presence of left ventricular hypertrophy 70 patients were studied. Significant coronary artery disease was present in 25 patients and left ventricular hypertrophy had 29 patients. All patients underwent an exercise ECG and echocardiographic test during which cine-loop digitized echocardiography was obtained. Wall motion was analyzed and a regional wall motion score index was calculated. The overall sensitivities of exercise ECG and echocardiography for detecting coronary artery disease were 60% and 64%, respectively, and the specificities were 49% and 78%, respectively. In patients with left ventricular hypertrophy the specificity of exercise echocardiography was higher (71%) compared to exercise ECG (21%) while in patients without hypertrophy the sensitivity was higher (70% vs. 40%, respectively). Of the 19 patients with a non-diagnostic stress ECG, echocardiography correctly identified 100% of those with coronary artery disease but only 53% of those without disease. It is concluded that exercise digital echocardiography represents a good diagnostic alternative to the exercise ECG for identifying coronary artery disease in the presence of left ventricular hypertrophy and should be useful in patients with a non-diagnostic exercise ECG.

Arbutamine vs. exercise stress testing in patients with coronary artery disease: evaluation by echocardiography and electrocardiography

Arbutamine is a new beta-adrenergic agonist with potent chronotropic and inotropic properties developed to pharmacologically induce stress. A prospective trial was conducted in five centers with a total enrolment of 45 patients with angiographically documented coronary artery disease. The primary purpose of the trial was to compare the efficacy of arbutamine with symptom-limited exercise in provoking clinical (angina), electrocardiographic (> or = 0.1 mV ST depression) and echocardiographic (induced wall motion abnormality) evidence of transient stress-induced ischemia. The secondary purpose was to assess the safety of arbutamine in patients with coronary artery disease. Ischemia was induced at a lower heart rate, systolic blood pressure and pressure-rate product during arbutamine infusion than during exercise. Using angina and/or electrocardiographic evidence of ischemia, arbutamine was more sensitive than exercise in detecting myocardial ischemia (77 vs. 58%, P = 0.021). Using echocardiography, the sensitivity for inducing wall motion abnormalities was 88% with arbutamine and 79% with exercise (P = not significant). Echocardiography in combination with angina and/or electrocardiographic evidence increased the sensitivity to 94% using arbutamine and to 88% with exercise. For the patients with multivessel disease, the sensitivity was 97% and 91%, respectively. No serious adverse events, either cardiac or noncardiac, were associated with arbutamine, and no patient had prolonged ischemia. Although exercise is the preferred method of stress for patients who are able to exercise adequately, arbutamine is at least as sensitive as exercise for the diagnosis of myocardial ischemia, and appears to be a safe and effective alternative to exercise testing in patients unable to exercise adequately.

Use of exercise echocardiography to evaluate patients after coronary angioplasty

Exercise echocardiography is a sensitive, specific, and highly accurate method for detecting coronary restenosis and progressive compromise of untreated arterial segments in patients who have undergone percutaneous transluminal coronary angioplasty. It is far more reliable in predicting the status of the coronary anatomy in such patients than exercise electrocardiography or symptomatic status.

The importance of work-up (verification) bias correction in assessing the accuracy of SPECT thallium-201 testing for the diagnosis of coronary artery disease

Noninvasive testing is often evaluated by the sensitivity and specificity in comparison with a more invasive, but more definitive "gold" standard. However, work-up or verification bias, which occurs when the results of a noninvasive test impact the decision to perform the gold standard invasive test, increases the "observed" sensitivity and decreases the "observed" specificity of the noninvasive test. Most large clinical studies utilizing a noninvasive technique to diagnose coronary artery disease have biases, particularly work-up bias. To obtain more accurate measurements of sensitivity and specificity, we determined the observed sensitivity and specificity of stress (exercise and dipyridamole) single photon emission computed tomographic (SPECT) thallium testing for the detection of coronary artery disease by angiography, and then applied previously published equations to correct for work-up bias. From a computerized data base, reports of 4354 stress SPECT thallium studies from January 1, 1986 through December 31, 1992 were reviewed. All patients with a known history of myocardial infarction or prior coronary angiography were excluded, leaving 2688 patients. From this total, 471 patients underwent coronary angiography within 90 days following stress SPECT thallium testing. Coronary artery disease was defined as a visually assessed stenosis of a coronary artery or a major branch > 50%. Of the 2688 stress SPECT thallium studies, 1265 were normal and 1423 were abnormal. For the 471 patients who underwent catheterization within 90 days following stress SPECT thallium testing. the "observed" sensitivity and specificity were 98 and 14%, respectively. After correction for work-up bias, the corrected sensitivity and specificity were 82 +/- 6% and 59 +/- 2%, respectively. Most studies utilizing noninvasive technologies for the detection of coronary artery disease include patients with known coronary artery disease and have work-up bias as well. By knowing the thallium results of patients with and without catheterization, we were able to correct for work-up bias. These data provide better estimate of the sensitivity and specificity of stress SPECT thallium testing.

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.

Exercise echocardiography, angiography, and intracoronary ultrasound after cardiac transplantation

Fifty-one consecutive patients underwent exercise echocardiography, angiography, and intracoronary ultrasound (ICUS) 2.5 years (range from 1 to 6) after cardiac transplantation. The average age of the donor was 29 years (range 13 to 50), and the average age of the recipient was 49 +/- 12 years. In total, 78 studies were performed, as 25 patients had >1 annual evaluation and 2 patients had 3 consecutive annual evaluations. Of the 78 angiographic studies, 40 (26 patients) had evidence of coronary artery disease, defined as a focal stenosis (>20%, n=4) or luminal irregularities (n=36). However, by ICUS all 51 patients had intimal thickening at some point, with 34 patients possessing diffuse disease and 17 focal intimal thickening only. Of the 25 serial studies, 12 progressed by at least 1 Stanford class. The sensitivity of angiography for determination of class III to IV intimal thickening was 64% and the specificity was 76%. On exercise echocardiography, 6 examinations revealed resting wall motions abnormalities, whereas 6 had inducible wall motion abnormalities with exercise. The sensitivity of exercise echocardiography to determine class III to IV intimal thickening was 15%, and the specificity was 85%. In conclusion, exercise echocardiography is an insensitive method for predicting transplant-mediated coronary artery disease, whereas luminal irregularities on angiography may predict the presence of Stanford grade III to IV intimal thickening.

Interobserver and intraobserver variation for analysis of left ventricular wall motion at baseline and during low- and high-dose dobutamine stress echocardiography in patients with high prevalence of wall motion abnormalities at rest

Interobserver and intraobserver variation for analysis of left ventricular regional wall motion during dobutamine stress echocardiography was assessed. Computer-displayed cineloops from 33 patients, 25 with baseline wall motion abnormalities, were analyzed by two observers blinded for patient data. Assessment included (1) baseline wall motion abnormalities, (2) evidence of myocardial viability at 10 micrograms/kg/min dobutamine, and (3) evidence of myocardial ischemia at 30 to 40 micrograms/kg/min. Wall motion score index was calculated at each stage. Interobserver and intraobserver agreement for baseline wall motion abnormalities was 100%. Interobserver agreement for viability and ischemia was 84% and 82%, respectively; intraobserver agreement was 92% and 85%, respectively. Mean interobserver differences in wall motion score index ranged from 0.06 +/- 0.14 at baseline to 0.09 +/- 0.20 at high doses (p < 0.05 at all levels); mean intraobserver differences ranged from 0.001 +/- 0.14 to 0.01 +/- 0.15 (difference not significant at all levels).

Comparison of ischemic response during exercise and dobutamine echocardiography in patients with left main coronary artery disease

OBJECTIVES

This study sought to compare manifestations of myocardial ischemia evoked by exercise and dobutamine echocardiography in patients with left main coronary artery disease.

BACKGROUND

During exercise testing, left ventricular cavity dilation, marked ST segment depression and blood pressure decrease indicate severe coronary artery disease. Whether these signs are comparably evoked by dobutamine echocardiography has not been described.

METHODS

Fifty-four patients who underwent stress echocardiography (36 exercise, 18 dobutamine) and coronary angiography showing > or = 50% left main stenosis were analyzed. Electrocardiographic and blood pressure changes, symptoms, wall motion score indexes and sensitivity for coronary artery disease were compared. In 47 patients, the left ventricular endocardium was traced to quantify volumes and ejection fraction.

RESULTS

Stress-induced regional wall motion abnormalities developed in 91% of patients; this was not different on exercise (89%) or dobutamine echocardiography (94%). Rate-pressure product and wall motion score index, similar at rest, tended to be higher after exercise than after dobutamine stress (p = 0.07 and p = 0.05, respectively). ST segment depression > or = 1 mm was more common with exercise (p = 0.005). Ejection fraction and end-systolic and end-diastolic volume indexes were comparable at rest in both groups. With exercise, ejection fraction decreased in 87% of patients, and end-systolic and end-diastolic volume indexes increased in 80%. In contrast, with dobutamine, decreased ejection fraction and increased volume indexes were infrequent. Ejection fraction was lower ([mean +/- SD] 45 +/- 19% vs. 54 +/- 12%, p = 0.007) and end-diastolic (69 +/- 26 vs. 50 +/- 17 ml/m2, p =0.02) and end-systolic (39 +/- 20 vs. 24 +/- 13 ml/m2, p = 0.02) volume indexes were higher after exercise than after dobutamine stress.

CONCLUSIONS

On the basis of changes in regional wall motion both dobutamine and exercise echocardiography have a comparable high sensitivity in diagnosing myocardial ischemia in left main coronary artery disease. However, conventional signs of severe myocardial ischemia, including left ventricular cavity dilation and marked ST segment depression, occur more often with exercise than with dobutamine echocardiography.

Exercise echocardiography in the diagnosis of coronary artery disease

The purpose of this study was to test the applicability of exercise echocardiography in the diagnosis of coronary artery disease. The results were compared to findings of coronary angiography. 118 patients, 100 males and 18 females, who were all referred to coronary angiography for suspected ischaemic heart disease, underwent exercise echocardiography using a cycle ergometer. At coronary angiography 108 patients had significant stenosis in at least one coronary artery. Ten patients had angiographically normal coronary arteries. A new or increased wall motion abnormality detected by echocardiography after the exercise was considered an ischaemic response. Of the 108 patients with coronary artery disease, 101 had abnormal exercise echocardiograms, and the overall sensitivity of exercise echocardiography in detecting ischaemic heart disease was 94%. Among the 10 patients without coronary artery disease, seven had normal and three had abnormal exercise echocardiograms, and the specificity of the test was 70%. In conclusion, exercise echocardiography is a reliable diagnostic method in screening of ischaemic heart disease, and it can be combined relatively easily with the exercise examinations.

Safety and efficacy of computerized closed-loop delivery of arbutamine: a new pharmacologic myocardial stress modality for the assessment of coronary artery disease. The European Arbutamine Study Group

This study evaluated the efficacy of computer-controlled closed-loop delivery of a new synthetic catecholamine, arbutamine, when given to induce myocardial ischemia detected by electrocardiography and echocardiography with a high (10 beats/min/min) and low (6 beats/min/min) rate of increase in heart rate (heart rate slope) in 70 patients with coronary artery disease. The electrocardiographic sensitivity for the detection of myocardial ischemia was 52% for the low slope and 51% for the high slope. The corresponding figures for echocardiographic sensitivity were 83% and 79% for the low and high slopes, respectively. There were no significant differences in changes from baseline to maximum in pharmacodynamic variables, although the mean times to reach maximum heart rate and systolic blood pressure were 1.4 minutes shorter (p = 0.001) and 3.7 minutes shorter (p < 0.05), respectively, for the high-slope regimen. The duration of the infusion was shorter (p < 0.001) for the high slope. In this study, closed-loop arbutamine administration was effective and safe in the detection of coronary artery disease for both heart rate slope regimens.

Influence of left ventricular hypertrophy on detection of coronary artery disease using exercise echocardiography

OBJECTIVES

This study examined the influence of left ventricular hypertrophy on the accuracy of exercise electrocardiography and echocardiography for detection of coronary artery disease.

BACKGROUND

Electrocardiographic repolarization abnormalities caused by left ventricular hypertrophy compromise the diagnostic accuracy of exercise electrocardiography but not of exercise echocardiography. The relative merits of these investigations are less well defined in patients with hypertrophy but without electrocardiographic (ECG) changes.

METHODS

We prospectively evaluated 147 consecutive patients without prior myocardial infarction undergoing both exercise echocardiography and coronary arteriography. Coronary stenoses > 50% diameter were present in 62 patients (42%). Positive test results were defined by a new or worsening wall motion abnormality or > 0.1 mV of ST depression. Echocardiographic left ventricular hypertrophy (mass > 131 g/m2 in men, > 100 g/m2 in women) was identified in 68 patients. A subgroup with clinically suspected hypertrophy was defined according to the presence of ECG evidence of hypertrophy, hypertension or aortic stenosis.

RESULTS

The overall sensitivity of exercise echocardiography exceeded that of exercise electrocardiography (71% vs. 54%, p = 0.06). Echocardiographic hypertrophy had no significant effect on the sensitivity of either test. The specificity of exercise echocardiography exceeded that of exercise electrocardiography (91 vs. 74%, p = 0.01). In patients with hypertrophy, the specificity of exercise echocardiography exceeded that of exercise electrocardiography (95% vs. 69%, p < 0.01), whereas among patients without hypertrophy, the specificities (respectively, 87% and 78%) were more comparable. The accuracy of exercise echocardiography exceeded that of the exercise ECG in the overall group (82% vs. 65%, p = 0.002) and in patients with hypertrophy (85% vs. 60%, p = 0.004), but this difference was less prominent in patients without hypertrophy (80% vs. 69%, p = NS). In patients with clinically suspected hypertrophy, exercise echocardiography demonstrated a higher sensitivity, specificity and accuracy than exercise electrocardiography. The cost incurred in the identification of coronary disease was least with a strategy involving use of the exercise echocardiogram instead of routine exercise testing in patients with known or clinically suspected left ventricular hypertrophy.

CONCLUSIONS

Exercise echocardiography is more accurate than exercise electrocardiography for the detection of coronary artery disease in patients with known or clinically suspected left ventricular hypertrophy.

Digital high frame rate stress echocardiography for detection of coronary artery stenosis by high dose dipyridamole stress testing

Diagnostic accuracy of high dose dipyridamole stress echocardiography (0.84 mg i.v./kg) for detecting coronary artery stenosis was assessed in 94 patients undergoing coronary angiography, and adverse effects were registered in the total study population of 120 patients. Echocardiographic analysis was performed with digital systolic cineloops with high frame-rate (47 frames/sec) for optimal left ventricular wall motion display. Results showed sensitivity of 73% for detection of arterial luminal stenosis > or = 75% or retrograde collateral flow to an occluded coronary artery. Sensitivity for detection of 1-vessel stenosis was 43% (6 of 14 patients), and for 2- and 3-vessel disease 79% (19 of 24) and 88% (16 of 18), respectively. Specificity was 92% (35 of 38), diagnostic accuracy 81%. The stenosed coronary artery was correctly localized in 85% of positive tests. Dipyridamole-induced increase in wall motion score index differed significantly between patients with 1-, 2-, and 3-vessel disease (0.02 +/- 0.17, 0.15 +/- 0.17, and 0.27 +/- 0.24, respectively), and early positive tests (dipyridamole dose of 0.56 mg/kg) were almost exclusively seen in patients with multivessel disease. Six patients (5%) developed symptomatic bradycardia and hypotension during the test. In conclusion, dipyridamole stress echocardiography is useful for detection and localization of coronary artery stenosis, particularly in patients with multivessel disease.

Stress imaging. Current clinical options for the diagnosis, localization, and evaluation of coronary artery disease

As technology advances, new methods evolve. In this article, the methods of stress testing and related imaging in coronary disease are addressed, and dynamic and pharmacologic stress, direct and indirect methods, are defined and evaluated. The stress imaging methods related to the modalities of scintigraphy and ultrasound are reviewed and their advantages and disadvantages assessed in view of scientific and economic factors.

Exercise echocardiography is an accurate and cost-efficient technique for detection of coronary artery disease in women

OBJECTIVES

This study compared the accuracy and cost implications of using exercise echocardiography and exercise electrocardiography for detection of coronary artery disease in women.

BACKGROUND

The specificity of exercise electrocardiography in women is lower than in men. Exercise echocardiography accurately identifies coronary artery disease in women, but its utility in place of exercise electrocardiography is unclear.

METHODS

One hundred sixty-one women without a previous Q wave infarction underwent exercise echocardiography and coronary angiography. Positive findings were a new or worsening wall motion abnormality on the exercise echocardiogram and ST segment depression > 0.1 mV at 0.08 s after the J point on the exercise electrocardiogram (ECG).

RESULTS

Coronary artery stenosis > 50% diameter narrowing was present in 59 patients; the sensitivity (mean +/- SD) of exercise echocardiography was 80 +/- 3%. In 48 patients with an interpretable ECG, the sensitivity of exercise echocardiography was 81 +/- 4%, and that of the exercise ECG was 77 +/- 3% (p = 0.50). In 102 patients without coronary artery disease, the overall specificity of exercise echocardiography was 81 +/- 4%. In 70 patients with an interpretable ECG, the specificity of exercise echocardiography (80 +/- 3%) exceeded that of the exercise ECG (56 +/- 4%, p < 0.0004). The accuracy of exercise echocardiography was also greater than exercise electrocardiography (81 +/- 5% vs. 64 +/- 6%, p < 0.005). Exercise echocardiography stratified significantly more patients of intermediate (20% to 80%) pretest disease probability into the high (> 80%) or low (< 20%) posttest probability group. In women without a previous exercise ECG, the specificity of exercise echocardiography continued to exceed that of exercise electrocardiography (80 +/- 3% vs. 64 +/- 3%, p = 0.05). Exercise echocardiography had the best balance between accuracy and cost for the diagnosis of coronary artery disease in women.

CONCLUSIONS

Exercise echocardiography is more specific than exercise electrocardiography for diagnosis of coronary artery disease in women and is a cost-effective approach to the diagnosis of coronary artery disease because of the avoidance of inappropriate angiography.

Application and perspectives of transesophageal stress echocardiography using monoplane and biplane instruments

Transesophageal stress echocardiography has been reported to have a high sensitivity and specificity for noninvasive identification and assessment of coronary artery disease. Its advantage is the virtually never obstructed acoustic window on the heart yielding superior image quality in almost all patients. Pharmacological stress as well as simultaneous atrial pacing--attaching electrodes to the echoscope--have been applied as stress modalities. Both transesophageal stress echocardiography modalities have been shown to be well tolerated, safe, and feasible in most patients. These promising initial experiences led to clinical application of this method for preoperative risk evaluation, for detection of restenosis after PTCA, and for evaluation of hibernating myocardium. This technique was also successful for evaluation of stress induced changes of transmitral and pulmonary venous flow in patients with left ventricular hypertrophy and coronary artery disease. Although all studies published so far were performed with monoplane technique, the sensitivity for detection of one-vessel and, even more so, multivessel disease was high. However, apical and basal wall-motion abnormalities may go undetected using monoplane equipment. The advent of biplane transesophageal imaging enables the visualization of more ventricular segments. Future studies will show to which degree biplane transesophageal stress echocardiography improves the diagnostic accuracy.

The influence of angiographically demonstrated coronary collaterals on the results of stress echocardiography

Previous studies using thallium-201 scintigraphy have suggested that angiographic coronary collaterals can protect against the development of stress-induced perfusion abnormalities, but the effect of collaterals on stress echocardiography (SECHO) has not been determined. In this study, 21 consecutive patients referred for cardiac catheterization underwent SECHO and coronary angiography. Of the 21 study patients, there was a total of 16 significantly obstructed coronary arteries (> or = 70% stenosis) in 14 patients. SECHO revealed stress-induced wall motion abnormalities in the distribution of seven of nine obstructed coronary vessels without angiographic collaterals, but in only one of seven vessels with collaterals (p < 0.05). Six of eight obstructed vessels not associated with a stress-induced wall motion abnormality had collaterals, whereas only one of eight obstructed vessels associated with a stress-induced wall motion abnormality had collaterals. We conclude that (1) angiographically demonstrated coronary collaterals can protect against the development of stress-induced wall motion abnormalities despite the presence of a high-grade coronary artery obstruction, and (2) the lack of a stress-induced wall motion abnormality on SECHO in the perfusion territory of an obstructed vessel may suggest the presence of adequate collateral perfusion.

Exercise echocardiography after coronary artery bypass surgery: correlation with coronary angiography

OBJECTIVES

Our aim was to assess, in patients after coronary artery bypass surgery, how well exercise echocardiography predicts the presence of vascular compromise on angiography.

BACKGROUND

Because late graft failure frequently occurs after bypass surgery, a reliable noninvasive technique is needed to identify those patients who would benefit from angiographic study.

METHODS

In 182 patients, a total of 213 symptom-limited treadmill exercise electrocardiograms (ECGs) and exercise echocardiograms were performed in association with coronary and bypass angiography 2 weeks to 21 years after bypass surgery.

RESULTS

There were more inconclusive exercise ECGs (28%) than exercise echocardiograms (9%). The positive predictive value was 85% for the exercise echocardiogram versus 62% for the exercise ECG; the corresponding negative predictive values were 81% versus 52%. The accuracy of the exercise echocardiogram was linked to the degree of underlying vascular compromise. After excluding cases with nondiagnostic results, due to either submaximal stress or poor image quality, the exercise echocardiogram detected 46 of the 60 cases with vascular compromise in one region (sensitivity 77%) and 47 of the 49 cases with compromise in two or three regions (sensitivity 96%). Similarly, an abnormal exercise echocardiogram had a positive predictive value of 71% for vascular compromise in one region and 98% for compromise in two or three regions. Most false negative exercise echocardiographic results were associated with posterolateral single-region vascular compromise on angiography.

CONCLUSIONS

This study confirms a high positive and negative predictive value of exercise echocardiography in the detection of vascular compromise in patients after bypass surgery. It is clearly superior to exercise electrocardiography in predicting which patients will have angiographically significant graft or arterial lesions, and it can be used to obtain a better selection of patients for angiographic study.