Prognostic Value of Dobutamine Stress Echocardiography in Patients Undergoing Diagnostic Coronary Arteriography

There are only a few studies addressing the prognostic value of dobutamine stress echocardiography in patients with suspected coronary artery disease and none have assessed its value compared with coronary arteriography. Accordingly, graded dobutamine stress echocardiography was performed in 121 patients who underwent coronary arteriography based on symptoms and the findings of treadmill exercise electrocardiography. During the follow-up period of mean (SD) months (15 ± 9) there were 41 cardiac events (death [n = 5], acute myocardial infarction [n = 2], unstable angina [n = 29], and congestive heart failure [n = 5]). There were a greater number of patients with inducible wall motion abnormality (88%) on dobutamine stress with cardiac events compared with those without (55%, p <0.001). The wall motion score indexes at rest (1.6 ± 0.6) and at peak stress (2.1 ± 0.8) were worse in patients with cardiac events compared with those without (1.2 ± 0.3, p <0.001 and 1.5 ± 0.6, p <0.001, respectively). When multivariate analysis was performed using clinical, exercise, echocardiographic, and coronary arteriographic data the independent predictors of cardiac events were exercise duration (p = 0.01), presence of inducible wall motion abnormality (p = 0.03), and wall motion score index at peak stress (p <0.001). Thus, dobutamine stress echocardiography is a powerful predictor of future cardiac events in patients undergoing exercise testing and coronary arteriography for evaluation of chest pain and is superior to both exercise electrocardiography and coronary arteriography for the prediction of subsequent cardiac events.

Graded dobutamine stress echocardiography was performed in 121 patients undergoing diagnostic coronary arteriography for suspected coronary artery disease based on symptoms and findings of exercise electrocardiography. Stepwise Cox regression analysis using clinical, exercise electrocardiographic, echocardiographic, and coronary arteriography variables revealed that wall motion score index at peak stress (p <0.001), inducible ischemia (p = 0.03), and exercise duration (p = 0.04) were the only independent predictors of cardiac events.     

Effects of Beta-Blockade and Atropine on Ischemic Responses in Left Ventricular Regions Subtending Coronary Stenosis During Dobutamine Stress Echocardiography

Objectives. This study was designed to examine the effects of a beta-adrenergic blocking agent on the ischemic response to dobutamine stress and to determine the degree to which these effects can be abolished by the addition of atropine.

Background. Whether beta-blockade affects the sensitivity of dobutamine stress echocardiography for the diagnosis of coronary artery disease has been controversial.

Methods. In nine pigs, a left anterior descending coronary artery stenosis was created to reduce flow reserve (maximal/rest flow) to 1.1 to 1.9 without baseline regional wall motion abnormalities. This corresponded to a 50% to 90% diameter stenosis. Wall thickening was measured using epicardial echocardiography. Regional lactate production and coronary venous pH were monitored from an adjacent cardiac vein. A standard protocol of dobutamine stress echocardiography was first performed. After normalization of the ischemic abnormalities elicited with this infusion, esmolol was infused at 50 μg/kg body weight per min and the dobutamine test was repeated, with 1.0 mg of atropine added at the maximal dobutamine dose.

Results. Without esmolol, dobutamine stress induced myocardial ischemia with a reduction in regional wall thickening and lactate production in all nine pigs. Multiple regression analysis revealed that coronary flow per heartbeat (p < 0.01) and lactate production (p < 0.05) independently correlated with regional wall thickening during dobutamine stress. The beta-blocker significantly reduced heart rate and regional oxygen consumption and altered the relation between coronary flow per heartbeat and regional wall thickening (p < 0.05) during dobutamine stress. Esmolol prevented dobutamine-induced ischemia (lactate production and wall motion abnormalities) in seven of nine pigs. The addition of atropine induced lactate production and a reduction in wall thickening in five of seven pigs in which ischemia had been prevented by beta-blockade. However, lactate production was higher and regional venous pH was lower with the baseline dobutamine infusion than with that performed after esmolol with atropine added at the maximal dobutamine dose (p < 0.05).

Conclusions. A correlation between regional wall thickening and coronary flow per heartbeat was demonstrated during baseline dobutamine stress. Beta-blockade shifted this relation so that dobutamine stress-induced myocardial ischemia was attenuated. The mechanisms by which beta-blockade prevents dobutamine-induced ischemia appeared to be mainly through decreases in heart rate and rate of rise in left ventricular pressure, improvement of regional coronary flow per heartbeat and attenuation of regional ischemic lactate production. Adding atropine in conventional doses enhanced the ability of dobutamine stress to induce myocardial ischemia but did not completely abolish the effects of beta-blockade on either the severity of dobutamine-induced wall thickening abnormalities or regional metabolic disturbances.

(J Am Coll Cardiol 1996;28:1866–76)>     

The echo-dobutamine test for the diagnosis of myocardial ischemia. Study on 20 patients with normal kinetics at rest

We have assessed the value of dobutamine stress echocardiography for the diagnosis of myocardial ischemia in 20 consecutive patients referred for chest pain, without a previous myocardial infarction and with a normal left ventricular wall motion at rest. The test was considered positive when wall motion abnormalities appeared during dobutamine infusion (from 5 to a maximum of 40 micrograms/Kg/min). The results were compared to the % diameter stenosis (%DS) quantitatively measured on coronary arteriography. "Significant" coronary artery disease was defined as greater than or equal to 50% DS. No significant side effects occurred in any patients during the test. Transient wall motion abnormalities were detected in 8 of the 12 patients with significant coronary artery disease (sensitivity = 66%) and in 1 of the 8 patients without significant coronary artery disease (specificity = 88%). All the patients with false-negative dobutamine stress echocardiography had distal stenosis or stenosis in a collateral vessel; moreover, all the patients with true-positive dobutamine stress echocardiography had proximal (7 patients) or middle (1 patient) stenosis. The results of this study show that dobutamine stress echocardiography is a safe and feasible test for the noninvasive diagnosis of myocardial ischemia.     

Catecholamine stress echocardiography

Two-dimensional echocardiographic monitoring during catecholamine infusion has shown promise as a safe and accurate method for detection of coronary artery disease. The clinical application of catecholamine stress echocardiography has been facilitated by the development of digital image processing techniques. The sensitivity of this method of stress testing has been improved by drug infusion protocols that are designed to maximize myocardial stress. Recent investigations have demonstrated the value of dobutamine stress echocardiography for detection of multivessel disease following myocardial infarction and for assessment of cardiac risk before noncardiac surgery. Evaluation of changes in wall motion and thickening that occur during low dose dobutamine infusion may enable detection of viable myocardium after thrombolytic treatment of acute myocardial infarction. Compared to alternative noninvasive diagnostic methods, catecholamine stress echocardiography permits continuous acquisition of high-quality information on regional and global systolic function. This and other advantages have prompted the search for broader applications of this technique.     

Stress echocardiography for the diagnosis of coronary artery disease: progress towards quantification

PURPOSE OF REVIEW: This review highlights recent progress in the quantitative approach to the interpretation of stress echocardiograms. Recent literature regarding the application of tissue Doppler and strain rate imaging for the diagnosis of coronary artery disease is summarized. RECENT FINDINGS: The high temporal and spatial resolution of tissue Doppler and strain rate imaging permit recognition of regional myocardial dysfunction. These techniques have been performed during low- and high-dose dobutamine stress echocardiography and have been applied to exercise echocardiography. During stress, the peak systolic velocity and early diastolic velocity increased to a greater degree in normal segments compared to ischemic segments. With tissue Doppler imaging, viable segments show increases in systolic velocities in contrast to infarcted segments. Presently, the feasibility of strain rate imaging is slightly less than that of conventional wall motion assessment. However, in preliminary studies, tissue Doppler parameters and especially strain rate parameters appear to offer advantages in accuracy compared to conventional wall motion assessment. SUMMARY: Tissue Doppler and strain rate imaging offer great promise for the accurate, reproducible quantification of regional myocardial function. Further studies are indicated to prove their accuracy, efficiency, and superiority over existing methods.     

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 (²⁰¹Tl) 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 ²⁰¹Tl scintigraphy showed a sensitivity of 71%. For detection of lesions of ≥75% diameter stenosis, dobutamine echocardiography showed a sensitivity of 52% and ²⁰¹Tl 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.     

New developments in pharmacologic stress imaging.

The clinical usefulness of cardiac imaging modalities that rely upon the detection of perfusion defects and wall motion disturbances requires conditions that provoke a heterogeneity of coronary flow and a myocardial oxygen imbalance, respectively. Traditionally, this has been achieved by exercise stress testing. Many patients cannot perform dynamic exercise sufficiently for various reasons. Pharmacologic stress has been proven to be an attractive alternative for physical exercise. Currently, several stressing agents are used in conjunction with thallium-201 scintigraphy, 2-D echocardiography and, recently, MRI. The most employed agents include vasodilators, such as dipyridamole and adenosine, and catecholamines, such as dobutamine (Table VI). The predominant rationale of thallium-201 perfusion scintigraphy is based on the creation of a flow maldistribution between territories supplied by normal arteries and those supplied by stenotic arteries that does not necessarily require ischemia. Dipyridamole and adenosine, as rather selective coronary vasodilators, are well suited to provoke such a condition and may be classified as the ideal markers of myocardial perfusion. 2-D echocardiography and MRI have the potential to provide noninvasively derived information of cardiac dynamics and regional myocardial function. To assess the functional significance of coronary artery disease, detection of wall motion abnormalities and alterations in ejection fraction require the presence of myocardial ischemia. Dobutamine, as a widely applied inotropic agent in the management of severely depressed left ventricular contractile function, seems to be an appropriate pharmacologic stressor when heart failure is absent. By increasing contractility, heart rate, and systolic arterial pressure, it is capable of inducing an imbalance between myocardial oxygen demand and supply, leading to ischemia in patients with coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular systolic dysfunction during exercise and dobutamine stress in patients with hypertrophic cardiomyopathy

OBJECTIVES: We sought to characterize stress-induced left ventricular systolic dysfunction in patients with hypertrophic cardiomyopathy (HCM). BACKGROUND: Myocardial ischemia and diastolic dysfunction occur in patients with HCM. We hypothesized that, in the setting of transient myocardial ischemia, left ventricular systolic dysfunction occurs during exercise and dobutamine stress. METHODS: We studied 39 patients with HCM but without obstructive symptoms at rest or coronary artery disease. A continuous ventricular function monitor equipped with cadmium telluride detectors (VEST) was used to evaluate left ventricular function during supine bicycle ergometer exercise. Dobutamine stress echocardiography (DSE) was also performed. The left ventricular ejection fraction (LVEF) and regional wall motion were determined from echocardiographic images. RESULTS: Changes in the LVEF correlated between exercise and dobutamine stress (r = 0.643, p < 0.0001). The LVEF decreased more than 5% at peak exercise in 17 of patients (group II), while the other patients had normal responses (group I). New regional wall motion abnormalities during dobutamine infusion were detected in 18 of 110 (16.4%) segments in group I and 42 of 85 (49.4%) segments in group II. Decreased or unchanged regional wall motion occurred more frequently in hypertrophied segments than in nonhypertrophied segments (p < 0.0001). There were significant inverse correlations between the LVEF responses during both stresses and the number of abnormal segments noted during dobutamine stress in all patients (VEST: p < 0.005; DSE: p < 0.0005). Signs of left ventricular obstruction were observed in 11 of 39 patients during DSE. However, there was no significant correlation between the LVEF response and the dobutamine-induced left ventricular pressure gradient. CONCLUSIONS: Exercise-induced systolic dysfunction occurred in 50% of patients with HCM. In these patients, regional wall motion abnormalities were present in hypertrophied segments.     

Regional response of myocardial acceleration during isovolumic contraction during dobutamine stress echocardiography: a color tissue Doppler study and comparison with angiocardiographic findings

BACKGROUND: Color tissue Doppler imaging permits noninvasive quantitation of regional wall motion. In experimental studies, a new marker, the slope of the isovolumic contraction wave, isovolumic acceleration (IVA) was more insensitive to ventricular loading conditions than myocardial velocities. This study compared the regional response IVA to dobutamine stress echocardiography to angiographic findings. METHODS: The Myocardial Doppler in Stress Echocardiography (MYDISE) study prospectively recruited 149 consecutive patients with chest pain for dobutamine stress tissue Doppler echocardiography prior to coronary angiography. This color tissue Doppler database was analyzed for IVA in 1,192 basal and mid segments at rest and again at peak stress. Angiographic findings were compared to IVA and peak systolic velocities (PSV) in corresponding cardiac segments. The diagnostic accuracy of IVA to predict coronary artery stenosis was determined using cut-off values for three representative segments and with the MYDISE diagnostic model including eight segments. RESULTS: Regional IVA increased in a dose-dependent manner during dobutamine infusion. The response was blunted in the supply territory of stenosed coronary artery branches. IVA performed slightly better than PSV as single marker for coronary artery stenosis. A diagnostic model incorporating IVA and PSV was 85-95% accurate (area under receiver operating characterstic curves). CONCLUSIONS: Regional changes of isovolumic acceleration during dobutamine stress echocardiography reflect regional wall motion and can be used to predict coronary artery stenosis with similar accuracy as a model based on systolic myocardial velocities. As a single marker, IVA performed better than myocardial velocities.     

Integrated evaluation of relation between coronary lesion features and stress echocardiography results: the importance of coronary lesion morphology

OBJECTIVES: The aim of this study was to analyze, in the same group of patients, the relationship between multiple variables of coronary lesion and results of exercise, dobutamine and dipyridamole stress echocardiography tests. BACKGROUND: Integrated evaluation of the relation between stress echocardiography results and angiographic variables should include not only the assessment of stenosis severity but also evaluation of other quantitative and qualitative features of coronary stenosis. METHODS: Study population consisted of 168 (138 male, 30 female, mean age 51+/-9 years) patients, on whom exercise (Bruce treadmill protocol), dobutamine (up to 40 mcg/kg/min) and dipyridamole (0.84 mg/kg over 10 min) stress echocardiography tests were performed. Stress echocardiography test was considered positive for myocardial ischemia when a new wall motion abnormality was observed. One-vessel coronary stenosis ranging from mild stenosis to complete obstruction of the vessel was present in 153 patients, and 15 patients had normal coronary arteries. The observed angiographic variables included particular coronary vessel, stenosis location, the presence of collaterals, plaque morphology according to Ambrose classification, percent diameter stenosis and obstruction diameter as assessed by quantitative coronary arteriography. RESULTS: Covariates significantly associated with the results of physical and pharmacological stress tests included for all three stress modalities presence of collateral circulation, percent diameter stenosis and obstruction diameter, as well as lesion morphology (p < 0.05 for all, except collaterals for dobutamine stress test, p = 0.06). By stepwise multiple logistic regression analysis, the strongest predictor of the outcome of exercise echocardiography test was only percent diameter stenosis (p = 0.0002). However, both dobutamine and particularly dipyridamole stress echocardiography results were associated not only with stenosis severity - percent diameter stenosis (dobutamine, p = 0.04; dipyridamole, p = 0.003) - but also, and even more strongly, with lesion morphology (dobutamine, p = 0.006; dipyridamole, p = 0.0009). As all of stress echocardiography results were significantly associated with percent diameter stenosis, the best angiographic cutoff in relation to the results of stress echocardiography test was: exercise, 54%; dobutamine, 58% and dipyridamole, 60% (p < 0.05 vs. exercise). CONCLUSIONS: Integrated evaluation of angiographic variables have shown that the results of dobutamine and dipyridamole stress echocardiography are not only influenced by stenosis severity but also, and even more importantly, by plaque morphology. The results of exercise stress echocardiography, although separately influenced by plaque morphology, are predominantly influenced by stenosis severity, due to a stronger exercise capacity in provoking myocardial ischemia in milder forms of coronary stenosis.     

Dobutamine stress echocardiography: its role in the diagnosis of coronary artery disease.

We have assessed the usefulness of dobutamine infusion for the diagnosis of coronary artery disease by using two-dimensional echocardiography and 12-lead electrocardiogram. Dobutamine was infused at incremental doses (up to a maximum of 40 micrograms kg-1 min-1) in 52 patients with chest pain; all the patients underwent coronary angiography; significant coronary artery disease was quantitatively defined as greater than or equal to 50% diameter stenosis. Thirty-six patients were on betablockers. The test was considered positive when new regional wall motion abnormalities appeared during dobutamine infusion. No significant side effects occurred in any patient during the test. Transient wall motion abnormalities were detected in 20 of 37 patients with coronary artery disease (sensitivity = 54%); ischaemic ST segment changes were present on ECG in nine patients (sensitivity = 24%). Dobutamine stress echocardiography was negative in 12 of 15 patients with coronary artery diameter stenosis less than 50% (specificity = 80%). Exercise electrocardiography (ECG) was performed in 35 of these 52 patients. Maximum heart rate and systolic blood pressure were significantly higher during exercise than during dobutamine stress test (127 +/- 23 vs 99 +/- 24 beats min-1, P less than 0.0001; 179 +/- 25 vs 152 +/- 30 mmHg, P less than 0.0001). The exercise ECG test was positive in 12 of the 26 patients with significant coronary artery disease (sensitivity = 46%), and dobutamine stress echocardiography in 16 (sensitivity = 62%). Dobutamine stress echocardiography test is a safe and feasible diagnostic test for the noninvasive diagnosis of coronary artery disease and can be performed in patients unable to exercise.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hypotension during dobutamine stress echocardiography: initial description and clinical relevance.

Hypotension during exercise treadmill testing is correlated with the presence of coronary artery disease, its severity, and prognosis. The importance of hypotension during dobutamine stress testing has not been previously reported to our knowledge. We reviewed 43 cases of hypotension occurring in 42 patients out of a total of 116 consecutive stress dobutamine echocardiographic procedures performed in a total of 112 patients. Of the 42 patients with hypotension, 20 underwent cardiac catheterization. Regional wall motion abnormalities induced by dobutamine infusion were found in 13 of these patients, all of whom had significant (greater than or equal to 70% diameter reduction) coronary artery disease. The remaining seven patients without regional wall motion abnormalities did not have significant coronary artery disease at catheterization. Of the remaining 22 patients with dobutamine-induced hypotension, 20 had no induced regional wall motion abnormalities, were not catheterized, and were followed clinically. None of these patients had a cardiac event during a mean follow-up period of 11.5 months. We conclude that hypotension during dobutamine stress echocardiography in the absence of regional wall motion abnormalities does not indicate significant coronary artery disease or portend an adverse prognosis.     

Exercise echocardiography

Exercise echocardiography is a versatile, noninvasive diagnostic test that involves the recording and interpretation of 2-dimensional echocardiograms prior to, during, and after exercise. By analyzing and comparing wall motion at each stage, a prediction about the presence or absence of coronary artery disease can be made. The development of a wall motion abnormality is both sensitive and specific for the presence of a significant coronary stenosis. Changes in regional systolic function during exercise enable the clinician to distinguish between infarction and ischemia. Thus, the test yields information on the presence, extent, severity, and location of coronary artery disease. Echocardiography can be adapted to almost any form of stress, although treadmill or bicycle exercise are most commonly employed. An advantage of bicycle stress echocardiography is the opportunity to image during exercise, rather than relying on postexercise recording. This contributes to enhanced sensitivity, although false-positive results may increase due to the difficulties of analyzing wall motion during strenuous exercise. Exercise echocardiography increases the diagnostic accuracy of stress testing in a manner similar to radionuclide perfusion imaging. It is particularly useful in the setting of an ambiguous stress electrocardiography (ECG) or when a false-negative or false-positive result is suspected. It has been successfully applied to patients following revascularization and yields useful prognostic data in a variety of clinical situations. Exercise echocardiography is being increasingly utilized as a safe and accurate test in patients with known or suspected coronary artery disease.     

Dobutamine stress echocardiography: Detection of coronary artery disease in patients with dilated cardiomyopathy

Objectives. This study attempted to determine the safety and accuracy of dobutamine stress echocardiograpby for detection of coronary artery disease in patients with dilated cardiomyopathy.Background. Detection of regional wall motion abnormalities at rest does not reliably distinguish ischemic front nonischemic cardiomyopathy. Previous studies have shown that dobutamine stress echocardiography safely and accurately identifies coronary artery disease in patients without dilated cardiomyopathy.Methods. Seventy patients with dilated cardiomyopathy under-went dobutamine stress echocardiography. Echocardiograms were obtained at baseline and at low (5 to 10 μg/kg body weight per min) and peak doses of dobutamine. Rest and stress left ventricular wall motion scores were derived from analysis of regional wall motion. Fifty-four subjects underwent coronary angiography.Results. Dobutamine infusion was terminated after achievement of the target heart rate or maximal protocol dose in 49 patients (70%), ischemia in 12 (17%), arrhythmia in 4 (6%) and side efects in 5 (7%). No patient had prolonged ischemia or sustained arrhythmia. Of those with angiographic studies, 40 had significant coronary artery disease (≥50% diameter stenosis). Use of the change in global wall motion score index from low to peak dose resulted in a sensitivity of 83% for dobutamine stress echocardiography and a specificity of 71% for detection of coronary artery disease. Sensitivity for detection of triple-,double-and single-vessel disease was 100%, 83% and 69%, respectively.Conclusions. Dobutamine stress echocardiography safely provides diagnostic information in patients with dilated cardiomyopathy. This technique has high sensitivity for multivessel coronary artery disease but only moderate specificity.     

Echocardiographic detection of coronary artery disease during dobutamine infusion.

BACKGROUND. Two-dimensional echocardiography performed during dobutamine infusion has been proposed as a potentially useful method for detecting coronary artery disease. However, the safety and diagnostic value of dobutamine stress echocardiography has not been established. METHODS AND RESULTS. In this study, echocardiograms were recorded during step-wise infusion of dobutamine to a maximum dose of 30 micrograms/kg/min in 103 patients who also underwent quantitative coronary angiography. The echocardiograms were digitally stored and displayed in a format that allowed simultaneous analysis of rest and stress images. Development of a new abnormality in regional function was used as an early end point for the dobutamine infusion. No patient had a symptomatic arrhythmia or complications from stress-induced ischemia. Significant coronary artery disease (greater than or equal to 50% diameter stenosis) was present in 35 of 55 patients who had normal echocardiograms at rest. The sensitivity and specificity of dobutamine-induced wall motion abnormalities for coronary artery disease was 89% (31 of 35) and 85% (17 of 20), respectively. The sensitivity was 81% (17 of 21) in those with one-vessel disease and 100% (14 of 14) in those with multivessel or left main disease. Forty-one of 48 patients with abnormal echocardiograms at baseline had localized rest wall motion abnormalities. Fifteen had coronary artery disease confined to regions that had abnormal rest wall motion, and 26 had disease remote from these regions. Thirteen of 15 patients (87%) without remote disease did not develop remote stress-induced abnormalities, and 21 of 26 (81%) who had remote disease developed corresponding abnormalities. CONCLUSIONS. Echocardiography combined with dobutamine infusion is a safe and accurate method for detecting coronary artery disease and for predicting the extent of disease in those who have localized rest wall motion abnormalities.     

Pharmacological stress echocardiography in the diagnosis of coronary artery disease and myocardial ischaemia: a comparison between dobutamine and dipyridamole.

The objective of this study was to relate regional wall motion abnormalities assessed by dobutamine and dipyridamole stress echocardiography to quantitative measurements of coronary artery stenoses in consecutive patients referred for coronary angiography, and to compare haemodynamic effects of and complications related to the two agents. Patients underwent stress echoes on separate days in random sequence and had coronary angiography within 3 days of stress echocardiography. Echocardiograms were assessed by two investigators unaware of the patients' coronary anatomy. Coronary angiograms were also assessed quantitatively using the computer-assisted Cardiovascular Angiography Analysis System. There were 46 consecutive patients referred for coronary angiography; 28 were using beta-antagonists. Main outcome measures were sensitivity and specificity for dobutamine and dipyridamole stress echocardiography for detection of coronary artery disease (wall motion abnormalities at rest or stress) and myocardial ischaemia (stress induced new wall motion abnormalities). Sensitivity for the detection of myocardial ischaemia was found to be 57% for dobutamine and 64% for dipyridamole. Specificities were 78% and 89% respectively. Sensitivities for detection of coronary artery disease (lesion > or = 50% diameter stenosis) was 79% for dobutamine and 82% for dipyridamole; specificities were 78% and 89% respectively. These differences between the two agents are not significant. There were no severe side effects with either agent. Mean heart rate rose significantly with both tests but was higher with dobutamine; mean systolic blood pressure rose with dobutamine and fell with dipyridamole. It was concluded that dobutamine and dipyridamole stress echocardiography have similar sensitivities and specificities for detection of myocardial ischaemia and coronary artery disease although the haemodynamic effects of the two agents are different. Both are free from serious complications.     

Detection of angiographically significant coronary artery disease with accelerated intermittent imaging after intravenous administration of ultrasound contrast material

BACKGROUND: Accelerated intermittent harmonic imaging (AII) is used to detect myocardial perfusion abnormalities after intravenous injection of ultrasound contrast medium. A low mechanical index and frame rates of 10 to 20 Hz are used to allow simultaneous wall motion analysis. The purpose of this study was to determine whether the myocardial contrast enhancement achieved with AII can be used to detect angiographically significant coronary artery disease during stress echocardiography. METHODS: We gave intravenous perfluorocarbon containing microbubbles to 45 patients (total of 270 regions) during dobutamine (n = 27) or exercise (n = 18) stress testing with AII. Quantitative angiography was performed on all patients after the stress echocardiograms were interpreted. RESULTS: Quantitative angiography showed >50% diameter stenosis of at least 1 vessel in 32 patients (total of 118 regions). There were visually evident contrast defects in 100 (85%) of these regions, and wall motion was abnormal in 64 (54%). Overall, there was agreement between regional perfusion and quantitative angiographic findings in 217 of the 270 regions (kappa = 0.61; 80% agreement). Agreement with findings at quantitative angiography was good for both dobutamine stress (kappa = 0.66; 83% agreement) and exercise (kappa = 0.53; 77% agreement). The greatest incremental benefit of AII versus wall motion was gained during dobutamine stress. The contrast studies depicted 90% of the regions supplied by a vessel with >50% stenosis, whereas wall motion depicted only 32% (P =.001). CONCLUSIONS: The results of this study indicated that accelerated intermittent perfusion imaging during stress echocardiography can improve the sensitivity of the study in detecting angiographically significant coronary artery disease, especially during dobutamine stress.     

Detection of viable myocardium by dobutamine stress tagging magnetic resonance imaging with three-dimensional analysis by automatic trace method

The present study attempted to detect the viability of myocardium by quantitative automatic 3-dimensional analysis of the improvement of regional wall motion using an magnetic resonance imaging (MRI) tagging method. Twenty-two subjects with ischemic heart disease who had abnormal wall motion on echocardiography at rest were enrolled. All patients underwent dobutamine stress echocardiography (DSE), coronary arteriography and left ventriculography. The results were compared with those of 7 normal volunteers. MRI studies were done with myocardial tagging using the spatial modulation of magnetization technique. Automatic tracing with an original program was performed, and wall motion was compared before and during dobutamine infusion. The evaluation of myocardial viability with MRI and echocardiography had similar results in 19 (86.4%) of the 22 patients; 20 were studied by positron emission tomography or thallium-201 single photon emission computed tomography for myocardial viability, or studied for improvement of wall motion following coronary intervention. The sensitivity of dobutamine stress MRI (DSMRI) with tagging was 75.9% whereas that of DSE was 65.5%. The specificity of DSMRI was 85.7% (6/7) and that of DSE was 100% (7/7). The accuracy of DSMRI was 77.8% (28/36) and that of DSE 72.2% (26/36). DSMRI was shown to be superior to DSE in terms of evaluation of myocardial viability.     

Intravenous myocardial contrast echocardiography for the diagnosis of coronary artery disease

PURPOSE OF REVIEW: Myocardial contrast echocardiography is a recently developed technique that permits the noninvasive assessment of myocardial perfusion. Myocardial contrast enhancement from microbubbles characteristically reflects the myocardial blood volume. The analysis of microbubble kinetics using quantitative myocardial contrast echocardiography permits the evaluation of myocardial blood flow both at rest and during pharmacological stress. RECENT FINDINGS: Myocardial contrast echocardiography has been shown to have good concordance with single photon emission computed tomography for the localization of perfusion abnormalities. As a result of its better spatial resolution and the fact that it tracks myocardial blood flow changes, it seems to have higher sensitivity for the detection of angiographically significant coronary artery disease, while maintaining similar specificity to single photon emission computed tomography. Low mechanical index imaging techniques (real-time myocardial contrast echocardiography) have the advantage of permitting simultaneous analysis of wall motion and perfusion, which is particularly important during dobutamine stress. Myocardial perfusion analysis using real-time myocardial contrast echocardiography has been shown to have higher sensitivity and diagnostic accuracy than wall motion analysis for the detection of coronary artery disease. Quantitative myocardial contrast echocardiography seems to overcome the expertise requirements for appropriate interpretation of myocardial perfusion images, and may have been demonstrated to be an accurate supplemental technique for estimating the severity of coronary artery disease. SUMMARY: Recent technological advances have positioned myocardial contrast echocardiography as a safe and feasible technique for the evaluation of myocardial perfusion. The analysis of myocardial perfusion using myocardial contrast echocardiography has higher diagnostic accuracy than wall motion analysis for detecting coronary artery disease.     

Dipyridamole echocardiography

Intravenous dipyridamole is a potent coronary vasodilator that has been extensively investigated over the past several years in the noninvasive assessment of patients with suspected coronary artery disease when exercise cannot be performed or is suboptimal. As an alternative to exercise studies, dipyridamole has been used in combination with different cardiac imaging techniques such as echocardiography, thallium scintigraphy, and radionuclide ventriculography. Extensive experience has been obtained with dipyridamole thallium-201 imaging for coronary artery disease screening, risk stratification, and prognosis after an acute coronary event. However, experience with the use of dipyridamole in combination with two-dimensional echocardiography has been limited. Dipyridamole increases coronary blood flow in nondiseased coronary vessels relative to coronary vessels with significant luminal narrowings. These provide the basis for detecting regional differences in flow by using different cardiac imaging techniques. Two-dimensional echocardiography would show regional wall-motion abnormalities in response to those regional differences in coronary blood flow. In this article, the most commonly used protocols, safety, and practicability of dipyridamole echocardiography are reviewed. As an alternative to exercise, dipyridamole echocardiography shares all the indications of a standard exercise test. Clinical applications of dipyridamole echocardiography include coronary artery disease screening, suspected coronary artery spasm, postmyocardial infarction risk stratification, evaluation of percutaneous transluminal coronary angioplasty results, and prognosis following an acute coronary event. Compared to conventional (ECG) exercise testing, dipyridamole echocardiography appears to be equally sensitive but more specific. Compared to atrial pacing, dipyridamole provokes ischemia at a lower rate pressure product and results in a greater ST segment depression suggesting that dipyridamole induces more profound myocardial ischemia than atrial pacing. Dipyridamole thallium and exercise thallium have shown to be equally sensitive and specific in the assessment of coronary artery disease. High dose dipyridamole echocardiography appeared to be equally sensitive and more specific. Experimental studies have demonstrated that dobutamine appears to be a more powerful pharmacological agent in inducing wall-motion abnormalities. Dipyridamole echocardiography as compared to stress echocardiography offers the advantage of obtaining better quality postintervention images. With regard to sensitivity and for coronary artery disease diagnosis, both techniques appear to render similar results. Although further studies are needed, the available data indicates that cardiac ultrasound imaging prior to and following the intravenous administration of dipyridamole may be an attractive alternative to thallium perfusion imaging in the clinical setting, particularly when radionuclide capabilities are not present.