Comparison of dobutamine and exercise echocardiography for detecting coronary artery disease

Diagnostic accuracy of exercise stress testing for coronary artery disease: a systematic review and meta-analysis of prospective studies

BACKGROUND

Exercise stress testing offers a non-invasive, less expensive way of risk stratification prior to coronary angiography, and a negative stress test may actually avoid angiography. However, previous meta-analyses have not included all exercise test modalities, or patients without known Coronary artery disease (CAD).

METHODS AND RESULTS

We systematically reviewed the literature to determine the diagnostic accuracy of exercise stress testing for CAD on angiography. MEDLINE (January 1966 to November 2009), MEDION (1966 to July 2009), CENTRAL (1966 to July 2009) and EMBASE (1980-2009) databases were searched for English language articles on diagnostic accuracy of exercise stress testing. We included prospective studies comparing exercise stress testing with a reference standard of coronary angiography in patients without known CAD. From 6,055 records, we included 34 studies with 3,352 participants. Overall, we found published studies regarding five different exercise testing modalities: treadmill ECG, treadmill echo, bicycle ECG, bicycle echo and myocardial perfusion imaging. The prevalence of CAD ranged from 12% to 83%. Positive and negative likelihood ratios of stress testing increased in low prevalence settings. Treadmill echo testing (LR+ = 7.94) performed better than treadmill ECG testing (LR+ = 3.57) for ruling in CAD and ruling out CAD (echo LR- = 0.19 vs. ECG LR- = 0.38). Bicycle echo testing (LR+ = 11.34) performed better than treadmill echo testing (LR+ = 7.94), which outperformed both treadmill ECG and bicycle ECG. A positive exercise test is more helpful in younger patients (LR+ = 4.74) than in older patients (LR+ = 2.8).

CONCLUSIONS

The diagnostic accuracy of exercise testing varies, depending upon the age, gender and clinical characteristics of the patient, prevalence of CAD and modality of test used. Exercise testing, whether by echocardiography or ECG, is more useful at excluding CAD than confirming it. Clinicians have concentrated on individualising the treatment of CAD, but there is great scope for individualising the diagnosis of CAD using exercise testing.

Clinical relevance of chest pain during dobutamine stress echocardiography in women

BACKGROUND

Dobutamine stress echocardiography (DSE) is commonly used for diagnosis and management of patients with known or suspected coronary artery disease. Chest pain occurring during DSE potentially provides additional diagnostic accuracy. Our experience suggests that chest pain occurs frequently in women undergoing DSE.

HYPOTHESIS

It was the purpose of this study to determine the frequency with which chest pain occurs in women undergoing DSE and the relation to inducible ischemia or coronary artery stenosis.

METHODS

To determine the prevalence and clinical significance or chest pain during DSE, we reviewed the records of 154 consecutive women undergoing DSE in our laboratory. Of these, 59 patients (37.5%) also underwent coronary angiography. The presence or absence of chest pain was correlated with ECG changes, left ventricular wall motion abnormalities during DSE, and coronary stenosis by angiography.

RESULTS

Forty-one women (26%) developed chest pain during DSE. Patients experiencing chest pain were older (58.5 +/- 9.3 vs. 54.9 +/- 12.6; p = 0.05), and had lower resting heart rates (71 +/- 12.2 vs. 77.9 +/- 14.9; p = 0.008), but received similar maximum doses of dobutamine and reached comparable peak heart rates (131.1 +/- 17.4 vs. 133.5 +/- 21.7; p = NS). Patients with chest pain more commonly exhibited ST-segment depression > or = 1 mm during dobutamine infusion (13/41, 32%, vs. 17/113, 15%; p = 0.02), but chest pain showed no statistically significant correlation with abnormal DSE or with coronary stenosis.

CONCLUSIONS

In women undergoing DSE, chest pain occurs in 26% and does not appear to be related to inducible myocardial ischemia. Electrocardiographic changes occur more frequently in patients who experience chest pain, but are also often unrelated to inducible myocardial ischemia.

Detection of coronary stenoses by stress echocardiography using a previously implanted pacemaker for ventricular pacing: preliminary report of a new method

BACKGROUND

The number of patients with pacemakers has been increasing and a large number of them will present with chest pain or symptoms suggesting angina pectoris. Myocardial ischemia and presence of coronary artery disease are difficult to detect and assess by noninvasive methods in patients with a pacemaker; the electrocardiogram (ECG) at rest and during exercise is usually very difficult to analyze in terms of ischemia or even presence of an acute myocardial infarction.

HYPOTHESIS

To detect significant coronary stenosis in patients with previously implanted pacemakers, we tested a new stress echocardiography method using incremental ventricular pacing by already implanted pacemakers.

METHODS

We studied prospectively 25 consecutive patients who underwent stress echocardiography with increasing ventricular pacing up to either 85% of the age-predicted maximal heart rate or chest pain. Positive tests were defined by new hypokinesia or worsening of a preexisting alteration in wall motion in at least two adjacent territories. All patients underwent coronary angiograms to define the presence and severity of coronary stenoses.

RESULTS

Among the 25 tests, 11 (44%) were stopped for chest pain. 1 (4%) for moderate discomfort, 1 (4%) for a drop in blood pressure, and the target pacing rate was achieved in the tests of the remaining 12 patients (48%). There were no complications. Thirteen patients had significant stenoses. In 10 cases, stress echocardiography was a true positive test with respect to coronary angiography. There were 11 true negative, 1 false positive, and 3 false negative tests. The sensitivity was 77%, specificity was 90%, the positive predictive value was 91%, and the negative predictive value 79%. The accuracy was 84%.

CONCLUSIONS

This new stress echocardiography method appears feasible, easy, safe, and effective for detection of significant coronary stenoses in patients with pacemakers.

Stress echocardiography expert consensus statement: European Association of Echocardiography (EAE) (a registered branch of the ESC)

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. Among different stresses of comparable diagnostic and prognostic accuracy, semisupine exercise is the most used, dobutamine the best test for viability, and dipyridamole the safest and simplest pharmacological stress and the most suitable for combined wall motion coronary flow reserve assessment. The additional clinical benefit of myocardial perfusion contrast echocardiography and myocardial velocity imaging has been inconsistent to date, whereas the potential of adding - coronary flow reserve evaluation of left anterior descending coronary artery by transthoracic Doppler echocardiography adds another potentially important dimension to stress echocardiography. New emerging fields of application taking advantage from the versatility of the technique are Doppler stress echo in valvular heart disease and in dilated cardiomyopathy. In spite of its dependence upon operator's training, stress echocardiography is today the best (most cost-effective and risk-effective) possible imaging choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.

Enhanced diagnosis of coronary artery disease in women by dobutamine thallium-201 ST-segment/heart rate slope and thallium-201 myocardial SPECT

BACKGROUND/PURPOSE

The diagnosis of coronary artery disease (CAD) in women presents a great challenge because of poor exercise capacity and inadequate heart rate response during stress test. The clinical significance of stress-related ST-segment/heart rate slope (ST/HR slope) value for evaluating CAD in women remains controversial. Therefore, we conducted the present study to assess the diagnostic performance of dobutamine ST/HR slope in women, compared with myocardial perfusion study using thallium-201 single-photon emission computed tomography (Tl-201 SPECT).

METHODS

A total of 51 female patients with suspected CAD underwent simultaneous 12-lead electrocardiographic recording during 3-minute stages of dobutamine infusion as well as Tl-201 SPECT, and coronary angiography was performed within 2 weeks post Tl-201 SPECT. The sensitivity, specificity, positive predictive value and negative predictive value of dobutamine ST/HR slope and Tl-201 SPECT were assessed, and the results of coronary angiography were used as a gold standard.

RESULTS

The sensitivity, specificity and accuracy of dobutamine ST/HR slope in detecting CAD were 43%, 83% and 61%, and those of Tl-201 SPECT were 71%, 87% and 78%, respectively. However, using both positive results of Tl-201 SPECT and ST/HR slope for detecting CAD, the diagnostic specificity increased from 87% to 96%. Using both negative results of Tl-201 SPECT and ST/HR slope to exclude CAD, the negative predictive value increased from 71% to 85%. The accuracy of dobutamine ST/HR slope in detecting CAD was not affected by the use of beta-blockers.

CONCLUSION

Dobutamine ST/HR slope is less sensitive and less accurate than Tl-201 SPECT for detecting CAD in women. However, it adds diagnostic benefit to Tl-201 SPECT with only a little extra calculation.

B-type Natriuretic Peptide Is Not a Marker of Ischemia During Dobutamine Stress Echocardiography

Elevated levels of B-type natriuretic peptide (BNP) have been reported in association with exercise-induced ischemia. Data regarding BNP as a marker of ischemia during dobutamine stress echocardiography (DSE) are not conclusive. This study was designed to evaluate changes in BNP during DSE. A total of 74 patients referred to rule out ischemia by DSE were enrolled in the study. All patients had DSE using standard protocol. Of 74 patients enrolled, 6 were excluded because of nondiagnostic tests. Of the remaining 68 patients, 15 had positive DSE and 53 were negative for ischemia. The BNP levels (mean +/- SD) in the patients without ischemia were 42.5 pg/mL (+/-SD 47.6) at baseline and 41.9 pg/mL (+/-SD 48.9) at peak, and the measurements in the patients with ischemia were 90 pg/mL (+/-SD 171.7) at baseline and 88 pg/mL (+/-SD 149.2) at peak. BNP levels do not change during DSE with or without evidence of ischemia.

A meta-analytic comparison of echocardiographic stressors

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Anginal Threshold between Stress Tests: Exercise versus Dobutamine Stress Echocardiography

PURPOSE

Dobutamine echocardiography (DOB) can be substituted to exercise testing when necessary for clinical reasons. Current literature suggests DOB is maximal when 85% of maximal predicted heart rate (%PHR) is achieved (similar to EX), but there is little evidence to determine whether this target has the same clinical significance as during EX. We therefore performed this study to compare the ischemic threshold between EX and DOB.

METHODS

Twenty men with stable angina underwent in a random order DOB and EX echocardiograms after being weaned off their cardiac medications. Electrocardiography, heart rate (HR), and systolic blood pressure were recorded every minute. Ischemic threshold was defined as the precise time at which clinical angina occurred.

RESULTS

Anginal threshold appeared consistently at a higher level for DOB than EX as evidenced by the higher rate-pressure product (RPP) values (22,492 +/- 4,300 vs 20,371 +/- 5,367 bpm x mm Hg, DOB vs EX, respectively, P = 0.02), HR (126 +/- 23 vs 119 +/- 15 bpm, P = 0.01), and %PHR (79 +/- 15% vs 74 +/- 10%, P < 0.01). Thirty-two percent of the subjects presented an ischemic HR above 85% of PHR and 60% had a higher ischemic HR during DOB versus EX.

CONCLUSIONS

This study shows that estimation of anginal threshold during DOB is feasible and is slightly higher (approximately 10%) than during EX. Extrapolation of a cut off target heart rate from an exercise modality to a pharmaceutical one may not be valid.

Variability of inotropic and chronotropic response during dobutamine stress echocardiography and possible implications for diagnostic accuracy

Chronotropic and inotropic response patterns were assessed during dobutamine stress echocardiography. Three heart rate response patterns were noted: nonresponders (48% of patients), slow responders (30% of patients), and fast responders (21% of patients). There was no relation between heart rate and contractile response.

Cardiovascular physiology during supine cycle ergometry and dobutamine stress

PURPOSE

This study compared cardiac hemodynamics during supine cycle ergometry and dobutamine stress.

METHODS

Thirty-two healthy volunteers (19 female, 13 male, 23.5 +/- 3.5 yr old) completed respective tests on separate days and in random order. Heart rate, blood pressure, and cardiac output were recorded at baseline and peak stress. Echocardiographic measures included left ventricular end-diastolic dimension, fractional shortening, heart rate corrected velocity of circumferential fiber shortening, end-systolic wall stress, and the difference between measured and predicted fiber shortening for measured wall stress.

RESULTS

Compared with peak exercise, dobutamine infusion resulted in lower cardiac output (12 +/- 2 vs 16 +/- 4 l x min(-1), P < 0.0001), heart rates (163 +/- 7 vs 175 +/- 12 beats x min(-1), P < 0.0001), and systolic blood pressure (160 +/- 22 vs 185 +/- 20 mm Hg, P < or = 0.0001). Echocardiography demonstrated smaller left ventricular end-diastolic dimension (4.2 +/- 0.7 vs 4.5 +/- 0.7 cm, P = 0.013), higher fractional shortening (0.55 +/- 0.07 vs 0.50 +/- 0.06%, P < 0.001), higher VCFc (2.07 +/- 0.36 vs 1.54 +/- 0.20 circs x s(-1), P < 0.001) higher VCFdiff (0.94 +/- 0.35 vs 0.48 +/- 0.20 circs x s(-1), P < 0.001), and lower end-systolic wall stress (25 +/- 11 vs 42 +/- 16 g x cm(-2), P < 0.001). The stress-velocity relationship during dobutamine demonstrated higher y-intercept and steeper slope, indicating greater load-independent contractility.

CONCLUSION

The cardiovascular adaptation to exercise and dobutamine stress differ significantly. Cardiac output during peak exercise is greater than during peak dobutamine secondary to increased heart rate and stroke volume. Despite a greater increase in contractility and decrease in afterload, a smaller increase in cardiac output during dobutamine stress may be secondary to limited ventricular preload.

Use of atropine to maintain higher heart rate after exercise during treadmill stress echocardiography

The sensitivity of treadmill stress echocardiography (SE), which is extensively used as a noninvasive test to detect myocardial ischemia, is contingent on the rapid acquisition of 2-dimensional echocardiographic (2D) images immediately after exercise, before a substantial decrease in heart rate (HR). This test is technically challenging and needs proficient sonographers to obtain the images rapidly. This study was designed to determine whether administration of atropine at peak exercise would maintain a higher HR longer after exercise, thereby facilitating acquisition of images. Two comparable groups of patients were randomized to receive either 0.5 mg atropine intravenously (i.v.) (n = 20), or no medication (n = 19) at peak exercise. HR was significantly higher in the atropine group compared with the control group (P <.05) at 60, 90, and 120 seconds after exercise. There were no serious complications in either group. Atropine can be safely used to maintain a higher HR after exercise during SE, thus reducing the technical challenge of obtaining postexercise 2D images while HR remains elevated.

Pharmacologic stress testing for coronary disease diagnosis: A meta-analysis

BACKGROUND

Although noninvasive pharmacologic stress tests are widely used, their relative performance is not clear. We compared the performance of pharmacologic stress tests combined with echocardiography or nuclear imaging for the diagnosis of coronary disease.

METHODS

We performed a regression meta-analysis of published data. We included studies published between January 1975 and June 1999 in which subjects underwent echocardiographic or single-photon emission computed tomography (SPECT) stress testing with adenosine, dipyridamole, or dobutamine for diagnosis of coronary artery disease. All subjects also underwent coronary angiography. Two independent reviewers abstracted population characteristics, technical factors, methodologic factors, and results and calculated test sensitivity and specificity.

RESULTS

Eighty-two studies met the inclusion criteria. The sensitivity of dipyridamole SPECT imaging, 89% (95% CI, 84%-93%), was higher than that of dipyridamole echocardiography, but the specificity of dipyridamole SPECT imaging, 65% (95% CI, 54%-74%), was lower than that of dipyridamole echocardiography. Dipyridamole and adenosine tests had similar sensitivities and specificities. The sensitivity of dobutamine echocardiography, 80% (95% CI, 77%-83%) was similar to that of dobutamine SPECT imaging, but dobutamine echocardiography had a higher specificity, 84% (95% CI, 80%-86%) than dobutamine SPECT imaging did.

CONCLUSIONS

The findings of our study can be used to guide the selection of the optimal pharmacologic stress test for each patient. Maximum sensitivity can be attained by use of a vasodilator combined with SPECT imaging. Maximum specificity can be attained by use of a vasodilator with echocardiography. The highest combination of sensitivity and specificity can be attained with dobutamine echocardiography.

Functional and prognostic significance of silent ischemia during dobutamine stress echocardiography in the elderly

BACKGROUND

The functional and prognostic significance of silent ischemia relative to symptomatic ischemia during non-invasive testing remains controversial.

DESIGN

The aim of this prospective study was to assess whether the presence of dobutamine-induced silent ischemia was associated with the amount of myocardial ischemic burden and to determine the prognostic significance of painless ischemia in elderly people with stable coronary artery disease.

METHODS

A cohort of 289 patients > or =70 years of age with positive dobutamine stress echocardiography result and significant coronary artery disease proven by coronary arteriography, were followed up during a 35 +/- 13 month period for the development of cardiac events.

RESULTS

The prevalence of silent ischemia during dobutamine infusion was 63%. Patients with painful ischemia were more likely to have lower peak heart rate (P < 0.01) and showed ST segment depression more frequently during the dobutamine stress test than did patients with painless ischemia (52 versus 31%, P < 0.05). There was no significant difference between the patients with and without angina according to wall motion score index at rest (1.35 +/- 0.29 versus 1.32 +/- 0.37) and at peak stress (1.61 +/- 0.35 versus 1.58 +/- 0.44), stress-rest wall motion index difference (0.27 +/- 0.09 versus 0.25 +/- 0.08), the presence of dyskinesia at peak stress (36 versus 31%), the number of segments with regional > or =2 point change from rest to peak stress (38 versus 29%) and the decrease of left ventricular end systolic volume at peak stress (89 versus 86%). During the follow-up period a total of 269 patients developed 153 (57%) cardiac events: 15 cardiac deaths, 19 non-fatal myocardial infarctions, 119 episodes of unstable angina. No significant difference in cardiac mortality and in total cardiac event rate was observed between patients with or without angina (6 versus 5% and 60 versus 55%, respectively).

CONCLUSIONS

Our data demonstrate that the magnitude of myocardial dysfunction assessed by dobutamine stress echocardiography is comparable in elderly patients with or without anginal chest pain. The presence of painful ischemia is not accompanied by an increased risk for subsequent cardiac events in this cohort of patients.

Stratification of single-vessel coronary stenosis by ischemic threshold at the onset of wall motion abnormality during continuous monitoring of left ventricular function by semisupine exercise echocardiography

We studied the relation between the ischemic threshold at the onset of wall motion abnormality on exercise echocardiography (EE) and the severity of coronary stenosis in patients with 1-vessel coronary artery disease (CAD). We screened 216 consecutive patients who underwent coronary angiography and EE for suspected CAD. Ninety-five (74 men; age, 56 +/- 12 years) satisfied the study criteria, that is, the presence of 1-vessel disease or no evidence of CAD on angiography and a normal baseline echocardiogram. Eighty-seven patients had 1-vessel CAD on angiography, and exercise-induced wall motion abnormality occurred in 73 (77%). Optimal cutoff values of percent diameter stenosis and minimal lumen diameter for predicting a positive EE were 61% (sensitivity and specificity of 76%) and 1.12 mm (sensitivity and specificity of 74%). Among patients with positive EE, heart rate-blood pressure product at ischemic threshold was correlated with quantitative coronary stenosis (r = -0.72, P <.001). The ischemic threshold from continuous monitoring of left ventricular function during semisupine EE is correlated with the severity of coronary stenosis among patients with 1-vessel disease and a normal resting echocardiogram.

Second harmonic imaging improves sensitivity of dobutamine stress echocardiography for the diagnosis of coronary artery disease

OBJECTIVE

Our purpose was to assess the value of second harmonic imaging compared with fundamental imaging for the diagnosis of coronary artery disease during dobutamine stress echocardiography.

PATIENTS AND METHODS

Sixty-four patients underwent dobutamine stress echocardiography with both fundamental imaging and second harmonic imaging. Coronary angiography was performed within 3 months. Ischemia was defined as new or worsening wall motion abnormalities in > or = 1 segment during dobutamine stress echocardiography. Coronary artery disease was defined as a > or = 70% luminal diameter stenosis in > or = 1 coronary artery by coronary angiography.

RESULTS

There was a higher prevalence of segments with invisible border with fundamental compared with second harmonic imaging both at rest (11% vs 8%, P < .05) and at peak stress (17% vs 10%, P < .001). Significant coronary artery disease was present in 49 (77%) patients. The sensitivity of dobutamine stress echocardiography for detection of coronary artery disease by fundamental and second harmonic imaging was, respectively, 78% and 94% (P < .05), whereas specificity was similar (73% vs 73%). Second harmonic imaging had a particularly higher sensitivity for the diagnosis of 1-vessel disease (93% vs 50%, P < .05).

CONCLUSION

The use of second harmonic imaging improves the sensitivity of dobutamine stress echocardiography for the diagnosis of coronary artery disease compared with fundamental imaging, particularly for 1-vessel coronary artery disease, whereas specificity remains unchanged.

Anatomy of a meta-analysis: a critical review of "exercise echocardiography or exercise SPECT imaging? A meta-analysis of diagnostic test performance"

BACKGROUND

Accurate diagnosis of coronary heart disease has the potential to contribute substantially to cost-effective delivery of health services. Recent work by Fleischmann et al (JAMA 1998;280:913-20) represents an effort to summarize the accuracy of exercise echocardiography and exercise single photon emission computed tomography (SPECT).

METHODS AND RESULTS

A critique of the previous work was constructed, obtaining the 44 articles used. These articles were reviewed and summarized with established techniques for meta-analysis. The studies summarized by Fleischmann et al were found to be significantly heterogeneous (echocardiography and SPECT, both P<.001). In the SPECT cohort, combination of different radioisotopes and reading techniques, and inclusion of reports using experimental techniques, were sources of heterogeneity. In the echocardiography cohort, experimental techniques and an individual series were identified. When the sample was stratified for sources of heterogeneity, it was found that there was no significant difference in diagnostic accuracy between the echocardiography and SPECT techniques used in current clinical practice. Meta-regression with summary receiver operating characteristic curve techniques, after adjustment of the model for multicolinearity and outliers, revealed that there were no significant differences between SPECT as used in current clinical practice and echocardiography.

CONCLUSION

The report by Fleischmann et al contains serious flaws that limit its validity and generalizability.

Dobutamine-atropine stress echocardiography and dipyridamole sestamibi scintigraphy for the detection of coronary artery disease: limitations and concordance

OBJECTIVES

We sought to compare dobutamine-atropine stress echocardiography (DASE) and dipyridamole Technetium 99-m (Tc-99m) sestamibi single photon emission computed tomography (SPECT) scintigraphy (DMIBI) for detecting coronary artery disease (CAD).

BACKGROUND

Both DASE and DMIBI are effective for evaluating patients for CAD, but their concordance and limitations have not been directly compared.

METHODS

To investigate these aims, patients underwent multistage DASE, DMIBI and coronary angiography within three months. Dobutamine-atropine stress echocardiography and stress-rest DMIBI were performed according to standard techniques and analyzed for their accuracy in predicting the extent of CAD. Segments were assigned to vascular territories according to standard models. Angiography was performed using the Judkin's technique.

RESULTS

The 183 patients (mean age: 60 +/- 11 years, including 50 women) consisted of 64 patients with no coronary disease and 61 with single-, 40 with two- and 18 with three-vessel coronary disease. Dobutamine-atropine stress echocardiography and DMIBI were similarly sensitive (87%, 104/119 and 80%, 95/119, respectively) for the detection of CAD, but DASE was more specific (91%, 58/64 vs. 73%, 47/64, p < 0.01). Sensitivity was similar for the detection of CAD in patients with single-vessel disease (84%, 51/61 vs. 74%, 45/61, respectively) and multivessel disease (91%, 53/58 vs. 86%, 50/58, respectively). Multiple wall motion abnormalities and perfusion defects were similarly sensitive for multivessel disease (72%, 42/58 vs. 66%, 38/53, respectively), but, again, DASE was more specific than DMIBI (95%, 119/125 vs. 76%, 95/125, respectively, p < 0.01). Dobutamine-atropine stress echocardiography and DMIBI were moderately concordant for the detection and extent of CAD (Kappa 0.47, p < 0.0001) but were only fairly (Kappa 0.35, p < 0.001) concordant for the type of abnormalities (normal, fixed, ischemia or mixed).

CONCLUSIONS

Dobutamine-atropine stress echocardiography and DMIBI were comparable tests for the detection of CAD. Both were very sensitive for the detection of CAD and moderately sensitive for the extent of disease. The only advantage of DASE was greater specificity, especially for multivessel disease. Dobutamine-atropine stress echocardiography may be advantageous in patients with lower probabilities of CAD.

Evaluation of regional wall motion and quantitative measures of ventricular function during dobutamine stress echocardiography in pediatric cardiac transplantation patients

BACKGROUND

Graft coronary disease is a leading cause of death in patients who have undergone cardiac transplantation. The purpose of this study was to evaluate regional wall motion response and quantitative measures of ventricular function during dobutamine stress echocardiography (DSE) in pediatric transplantation patients.

METHODS

Eleven patients were evaluated the first year after transplantation (10/11 no rejection). Ten of the 11 were reevaluated 1.2 +/- 0.3 years later (9/10 no rejection).

RESULTS

Dobutamine stress echocardiography revealed the following: (1) baseline regional wall motion abnormalities in 80% that resolved in all, (2) increased heart rate and blood pressure, (3) no change in left ventricular end-diastolic diameter, (4) decreased end-systolic diameter, (5) decreased wall stress and increased velocity of circumferential fiber shortening, (6) increased VCFcZ score (representing systolic left ventricular function), and (7) a decreased mitral passive-to-active filling ratio. Patients with rejection had abnormal VCFcZ scores at rest.

CONCLUSIONS

Pediatric transplantation patients without rejection have baseline regional wall motion abnormalities. With DSE, the following are present: (1) resolution of wall motion abnormalities, (2) increased contractility independent of load, and (3) changes in diastolic parameters that reflect increased heart rate. Patients with rejection may have abnormal contractility at rest.

Diagnostic and prognostic use of stress echocardiography in stable patients

Stress echocardiography is an effective diagnostic and prognostic technique in stable patients with known or suspected coronary artery disease (CAD), myocardial infarction, or chronic left ventricular dysfunction and those undergoing noncardiac surgery. Stress echocardiography is sensitive and specific for the detection and extent of CAD. Negative tests confer a high negative predictive value for cardiac events regardless of the clinical risk. Positive studies confer a high positive predictive value for ischemic events in patients with intermediate to high clinical risk. Stress echocardiography provides incremental 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 to that from 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 one-vessel disease. Sensitivities are similar for the detection and extent of disease in patients with multivessel CAD.

The comparable diagnostic accuracies of dobutamine-stress and dipyridamole-stress echocardiographies: a meta-analysis

BACKGROUND

Dobutamine-stress and dipyridamole-stress echocardiographies are widely used for pharmacological stress echocardiography, with wide geographical variations.

OBJECTIVE

To assess whether evidence derived from the literature indicates or disapproves that either stress modality confers diagnostic superiority.

METHODS

We performed a meta-analysis of peer-reviewed literature of published trials with head-to-head comparison, on the same population, of high-dose (0.84 mg/kg) dipyridamole-stress versus high-dose (up to 40 micrograms/kg per min) dobutamine-stress echocardiography. Data from 12 studies performed in 12 institutions in seven countries were analysed. Angiographic information about 818 patients was considered.

RESULTS

The diagnostic accuracies of the two tests were similar (631 of 818, 77%, for dipyridamole versus 654 of 818, 80%, for dobutamine, NS). Overall sensitivities were 403 of 568 (71%) for dipyridamole and 437 of 568 (77%) for dobutamine (P < 0.05). Sensitivities for patients with single-vessel disease were 177 of 275 (64%) for dipyridamole and 203 of 275 (74%) for dobutamine (P < 0.05). Sensitivities for patients with multivessel disease were 162 of 203 (80%) for dipyridamole and 163 of 203 (80%) for dobutamine (NS). Specificities were 232 of 250 (93%) for dipyridamole and 217 of 250 (87%) for dobutamine (P < 0.05). Data from an additional 26 studies with dipyridamole alone and 47 studies with dobutamine alone were analysed. The diagnostic accuracies were 80% for dipyridamole (n = 2038 patients; 95% confidence interval 75-82%) and 82% for dobutamine (n = 4264 patients; 95% confidence interval 79-84%).

CONCLUSION

High-dose dobutamine-stress and high-dose dipyridamole-stress echocardiographies have comparable diagnostic accuracies, with a slightly higher sensitivity with dobutamine and a slightly higher specificity with dipyridamole.

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.

Relation between exercise and dobutamine stress-induced wall motion abnormalities and severity and location of stenosis in single-vessel coronary artery disease

BACKGROUND

Quantitative coronary angiography has been shown to allow accurate assessment of coronary stenosis. Exercise and dobutamine stress echocardiography both are established methods for assessing the functional importance of coronary stenosis. The relation, however, between exercise and dobutamine stress-induced wall motion abnormalities and the severity and location of stenosis remains controversial.

METHODS AND RESULTS

Thirty patients with single-vessel coronary artery disease with >/=50% minimal luminal reduction and stable angina participated in the study. Severity of coronary artery stenosis was assessed by means of computed angiography. During peak exercise echocardiography 23 patients had wall motion abnormalities and 7 did not. A positive test result was associated with severity of stenosis >/=80% for 65% of stenoses (P <.05 versus severity of stenosis <80%) and with a proximal location of 94% of stenoses (P <.01 versus middle and distal stenoses). A significant correlation was found between area of stenosis and difference in wall motion score between rest and peak exercise (r = 0.53, P <.01). The proportion of positive exercise stress was greater among stenoses with severity <80% (62% versus 46% dobutamine stress, P <.05). During dobutamine stress echocardiography 18 patients had wall motion abnormalities and 12 patients did not. A positive test result was associated with severity of stenosis >/=80% in 72% of stenoses (P <.05 versus severity of stenosis <80%) and with a proximal location in 81% of stenoses (P <.01 versus middle and distal stenoses). A weak correlation was found between area of stenosis and difference in wall motion score between rest and peak dobutamine stress (r = 0.37, P <.05).

CONCLUSIONS

Among patients with single-vessel coronary artery disease, positive stress echocardiographic test results usually are associated with proximal >/=80% stenosis. Patients with <80% stenoses are more likely to have a positive exercise stress test result than a positive dobutamine stress test result.

Influence of dobutamine or exercise stress on the results of pulsed-wave Doppler assessment of myocardial velocity

BACKGROUND

Pulsed-wave Doppler assessment of myocardial velocity (MDV) may permit a more quantitative interpretation of stress echocardiography. This technique has been used with dobutamine echo (DbE), but exercise echo (ExE) may be preferred in patients who are able to exercise maximally. The influence of these stressors on the results of MDV are undefined.

PURPOSE

This study sought to determine whether differences between the physiology of DbE and ExE could influence the MDV responses to stress and whether interpretative criteria should be different with exercise or dobutamine stress.

METHODS

DbE or ExE was performed in 105 patients tested for known or suspected coronary artery disease. Pulsed-wave MDV was obtained in basal segments of anteroseptal, septal, anterior, posterior, lateral, and inferior walls in the apical views at rest and at peak doses of dobutamine or immediately after exercise. Segments were classified as normal or abnormal (ischemia or scar) according to results of 2-dimensional echocardiography, and MDV obtained at rest and stress was compared by using analysis of variance.

RESULTS

Resting heart rate was similar before both dobutamine and exercise, but heart rate at peak dobutamine exceeded that after exercise (137 +/- 10 vs 115 +/- 22, P <.01). For both ExE and DbE, MDV was significantly greater at rest and stress in normal than in abnormal segments. Stress MDV in both normal and abnormal segments was greater with DbE than with ExE (17.0 +/- 4.8 cm/s vs 10. 3 +/- 3.4 cm/s, P <.001 for normal segments and 10.7 +/- 4.4 cm/s vs 7.9 +/- 3.3 cm/s, P <.001 for abnormal segments. Increase in MDV/Deltaheart rate induced by DbE was greater than by ExE in normal (0.14 +/- 0.07 cm/s. beat for DbE and 0.09 +/- 0.08 cm/s. beat for ExE; P <.05) but similar in abnormal segments (0.06 +/- 0.07 cm/s. beat for DbE and 0.05 +/- 0.09 cm/s. beat for ExE). MDV correlated better with peak heart rate at ExE (r = 0.56, P <.01) than at DbE (r = 0.28, P <.01).

CONCLUSIONS

MDV responses to exercise and pharmacologic stress appear to be different, reflecting differences in inotropy, loading, and the timing of imaging. These findings may influence the ability of MDV to differentiate normal from abnormal stress echocardiography responses.

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.

Effects of dobutamine on coronary stenosis physiology and morphology: comparison with intracoronary adenosine

BACKGROUND

The mechanisms leading to dobutamine-induced ischemia are not fully understood. In the present study, we investigated the effects of high-dose intravenous dobutamine on morphological and physiological indexes of coronary stenoses.

METHODS AND RESULTS

Twenty-two patients with normal left ventricular function and isolated coronary stenoses were studied. At catheterization, mean aortic pressure (P(a)), mean distal coronary pressure (P(d)), and P(d)/P(a) as an index of myocardial resistance were recorded at rest, after intracoronary adenosine, and during intravenous infusion of dobutamine (10 to 40 micrograms . kg(-1). min(-1)). Reference vessel diameter and minimal luminal diameter, as assessed by coronary angiography, did not change during dobutamine infusion compared with baseline (2.84+/-0.49 versus 2.77+/-0.41 mm and 1.35+/-0.38 versus 1. 27+/-0.31 mm, respectively; both P=NS). During peak dobutamine infusion, P(d) and P(d)/P(a) reached similar levels as during adenosine infusion (60+/-18 versus 59+/-18 mm Hg and 0.68+/-0.18 versus 0.68+/-0.17, respectively; all P=NS). In 9 patients, an additional bolus of intracoronary adenosine given at the peak dose of dobutamine failed to further decrease P(d)/P(a). Furthermore, in patients with dobutamine-induced wall motion abnormalities, the maximal decrease in P(d)/P(a) was similar during dobutamine and adenosine infusions.

CONCLUSIONS

High-dose intravenous infusion of dobutamine does not modify the dimensions of the epicardial coronary stenosis. However, much like the direct coronary vasodilator adenosine, dobutamine fully exhausts myocardial resistance regardless of the presence of mechanical dysfunction.

Dobutamine stress echocardiography in women with chest pain. Pilot phase data from the National Heart, Lung and Blood Institute Women's Ischemia Syndrome Evaluation (WISE)

OBJECTIVES

The aim of this project was to assess the utility of dobutamine stress echocardiography (DSE) for evaluation of women with suspected ischemic heart disease.

BACKGROUND

Most investigations addressing efficacy of diagnosis and treatment of coronary artery disease (CAD) have been performed in predominantly male populations. As part of the Women's Ischemia Syndrome Evaluation (WISE) study, DSE was assessed in women participating at the University of Florida clinical site.

METHODS

Women with chest pain or other symptoms suggestive of myocardial ischemia and clinically indicated coronary angiography were eligible for the WISE study. Enrolled subjects underwent DSE using a modified protocol. Coronary stenosis was assessed by core laboratory quantitative coronary angiography (QCA).

RESULTS

The 92 women studied ranged in age from 34 to 82 years (mean 57.5). All women had > or = 1 major risk for CAD, and most (89, 97%) had > or = 2 risk factors. In 78 women (85%), left ventricular wall motion was normal at baseline and during peak infusion. The remaining 14 women had wall motion abnormalities during DSE. By QCA, 25 women (27%) had > or = 50% coronary stenosis, including 10 with single-vessel obstruction. Dobutamine stress echocardiography was abnormal in 10 of these 25 women, yielding overall sensitivity of 40%, and 60% for multivessel stenosis. Exclusion of women with inadequate heart rate response yielded overall sensitivity of 50%, and 81.8% for multivessel stenosis. Dobutamine stress echocardiography was normal in 54 of the 67 women with < 50% coronary narrowing, specificity 80.6%.

CONCLUSIONS

Dobutamine stress echocardiography reliably detects multivessel stenosis in women with suspected CAD. However, DSE is usually negative in women with single-vessel stenosis, and in the larger subset without coronary stenosis. Ongoing protocols of the WISE study are expected to improve diagnostic accuracy in women with single-vessel disease, as well as provide important data in the substantial number of women with chest pain but without epicardial coronary artery stenosis.

Long-term prognosis in women with normal dobutamine stress echocardiography

Although the long-term prognosis for patients with a normal dobutamine stress echocardiographic result is good, most studies have focused on men. We assessed the long-term cardiac prognosis for women by reviewing the cases of 100 women who underwent dobutamine stress echocardiography for suspected coronary artery disease and found that women with a normal result have an excellent long-term cardiac prognosis.

Impact of Age on the Safety and the Hemodynamic Response Pattern During High Dose Dobutamine Echocardiography

BACKGROUND: The purpose of the present study was to assess the safety and hemodynamic response of high dose dobutamine echocardiography (DE) in different age groups. DE is frequently used in the diagnosis of coronary artery disease; its safety in very elderly patients is not established, and there are no standards for blood pressure and heart rate response. METHODS AND RESULTS: The test was performed using up to 50 µg/kg/min in 400 patients: 164 middle-aged (age < 65 years), 187 elderly (age, 65-79 years), and 49 very elderly (age >/= 80 years). It was stopped because of side effects in 91 (23%) patients. Serious side effects occurred in 1.5% of the patients. There was a significant (60% +/- 35%) increase in heart rate, and a modest (10% +/- 19%) increase in the blood pressure (P <.001). The change in heart rate was similar in the three age groups, but there was a blunting of the blood pressure response with age. Hypotension was related to ischemia only in the very old. CONCLUSIONS: High-dose dobutamine is safe in all age groups. Dobutamine induces mainly a chronotropic and less a hypertensive response. The chronotropic response of the very old is similar with that of younger patients, but the hypertensive response is blunted in this group.

Hemodynamic effects of arbutamine

This study examined the hemodynamic effects of arbutamine, a synthetic catecholamine, in 12 patients with and 7 patients without coronary artery disease. Arbutamine produced a balanced positive inotropic (increase in left ventricular dp/dt) and chronotropic effect (increase in heart rate).

Dobutamine stress echocardiography for assessing coronary artery disease after transplantation in children

OBJECTIVES

The purpose of this study was to determine the feasibility, safety and diagnostic accuracy of dobutamine stress echocardiography (DSE) for evaluating posttransplant coronary artery disease (TxCAD) in children, and to determine the frequency of selected cardiac events after normal or abnormal DSE.

BACKGROUND

Posttransplant coronary artery disease is the most common cause of graft loss (late death or retransplantation) after cardiac transplantation (CTx) in children. Coronary angiography, routinely performed to screen for TxCAD, is an invasive procedure with limited sensitivity. The efficacy of DSE for detecting atherosclerotic coronary artery disease is established, but is unknown in children after CTx.

METHODS

Of the 78 children (median age 5.7 years, range 3 to 18) entered into the study, 72 (92%) underwent diagnostic DSE by means of a standard protocol, 4.6 +/- 1.9 years after CTx. The results of coronary angiography performed in 70 patients were compared with DSE findings. After DSE, subjects were monitored for TxCAD-related cardiac events, including death, retransplantation and new angiographic diagnosis of TxCAD.

RESULTS

No major complications occurred. Minor complications, most often hypertension, occurred in 11% of the 72 subjects. The sensitivity and specificity of DSE were 72% and 80%, respectively, when compared with coronary angiography. At follow-up (21 +/- 8 months), TxCAD-related cardiac events occurred in 2 of 50 children (4%) with negative DSE, versus 6 of 22 children (27%) with positive DSE (p < 0.01).

CONCLUSIONS

DSE is a feasible, safe and accurate screening method for TxCAD in children. Positive DSE identifies patients at increased risk of TxCAD-related cardiac events. Negative DSE predicts short-term freedom from such events.

Pathophysiologic mechanisms underlying dobutamine- and exercise-induced wall motion abnormalities

BACKGROUND

Dobutamine and exercise echocardiography are accepted as tests of comparable efficacy for the diagnosis of coronary artery disease. Although dobutamine has been classified as "exercise simulating," the mechanisms of ischemia with dobutamine and exercise have not been well studied. This study sought to compare the determinants of myocardial oxygen consumption.

METHODS AND RESULTS

We studied 54 patients with coronary artery disease undergoing dobutamine and exercise stress. A subgroup of 13 patients with comparable degrees of wall motion abnormalities and ST-segment changes during both stresses were selected to compare the determinants of ischemia in comparable circumstances. Dobutamine was infused to a mean maximal dose of 32+/-8 microg/kg/min, and exercise was stopped at an average of 135+/-25 W. The mean regional wall motion score was not statistically different between the two protocols (p = 0.27). At the onset of wall motion abnormalities and peak stress, the heart rate increased significantly less during dobutamine than during exercise (106+/-23 vs 126+/-19 beats/min, p < 0.001). The same was true of systolic blood pressure (155+/-21 vs 205+/-24 mm Hg, p < 0.001) and the rate-pressure product (16.5+/-4.6 vs 25.9+/-5, p < 0.001). Cardiac volumes were similar during both tests.

CONCLUSIONS

Ischemia occurs at a lower level of external cardiac work during dobutamine than during exercise stress. We suspect that additional mechanisms, such as the oxygen wasting effect of dobutamine, may be responsible for this observation.

Diagnostic and prognostic implications of left ventricular cavity obliteration response to dobutamine echocardiography

Left ventricular (LV) cavity obliteration during dobutamine echocardiography (DE) indicates a vigorous inotropic response to stress. Such a response may suggest the absence of coronary artery disease (CAD), but a small LV cavity may also preclude recognition of wall motion abnormalities. We sought to determine the frequency, correlates, accuracy, and prognostic value of the LV cavity obliteration response in 336 consecutive patients who underwent coronary angiography within 1 year of DE. Cavity obliteration was defined by contact of the opposite walls in the apical views during DE, and ischemia by detection of a new or worsening wall motion abnormality. Sensitivity was based on comparison with coronary anatomy in 220 patients without prior revascularization. The prognostic implications of cavity obliteration were examined by follow-up of 324 patients (96%) over 23 +/- 9 months for death, myocardial infarction, and late revascularization. Cavity obliteration was present in 86 of the 336 DE studies (26%). Baseline and stress hemodynamics were not predictive of cavity obliteration, which was associated with LV hypertrophy and female gender (p <0.0001), and inversely related to LV systolic dysfunction and use of angiotensin-converting enzyme inhibitors or diuretics (p <0.02). The sensitivity of DE was less in patients with cavity obliteration than the remainder, especially in single vessel (46% vs 92%, p <0.001) but also in multivessel CAD (73% vs 95%, p = 0.01). Irrespective of DE and angiographic results, cavity obliteration was a negative predictor for cardiac events (RR 0.42, 95% confidence interval [CI] 0.21 to 0.87, p = 0.02) and death (RR 0.14, 95% CI 0.02 to 1.09, p = 0.06). Even after exclusion of patients with LV dysfunction, cavity obliteration was an independent predictor of freedom from events (RR 0.41, 95% CI 0.19 to 0.88, p = 0.02). Thus, LV cavity obliteration is a frequent response to DE, which compromises the sensitivity of DE but is correlated paradoxically with a favorable clinical outcome.

Assessment of myocardial perfusion and contractile function by inotropic stress Tc-99m sestamibi SPECT imaging and echocardiography for optimal detection of multivessel coronary artery disease

OBJECTIVE

To assess whether inotropic stress myocardial perfusion imaging, echocardiography, or a combination of the two could enhance the detection of multivessel disease, over and above clinical and exercise electrocardiographic data.

DESIGN

100 consecutive patients investigated by exercise electrocardiography and diagnostic coronary arteriography underwent simultaneous inotropic stress Tc-99m sestamibi SPECT (MIBI) imaging and echocardiography. MIBI imaging and echocardiographic data were analysed using a 12 segment left ventricular model, and each segment was ascribed to a particular coronary artery territory. The presence of perfusion defects with MIBI imaging or of wall thickening abnormality with echocardiography in at least two coronary artery territories at peak stress was taken as diagnostic of multivessel disease. Arteriographic evidence of > or = 50% stenosis was considered significant.

RESULTS

56 patients had multivessel disease. The sensitivity of the combination of MIBI imaging and echocardiography for detecting this was greater than either MIBI imaging or echocardiography alone (82%, 68%, and 68%, respectively; p = 0.005). Clinical and exercise electrocardiographic variables gave an R2 value of 18.2% for predicting multivessel disease. The addition of either MIBI imaging (R2 = 29.2%; p = 0.002) or echocardiography (R2 = 28.8%; p < 0.001) enhanced the detection of multivessel disease, and the inclusion of both had further incremental value (R2 = 34.8%; p = 0.003). Age (p = 0.03), MIBI imaging (p = 0.007), and echocardiography (p = 0.001) were independent predictors of multivessel disease.

CONCLUSIONS

The assessment of both myocardial perfusion and contractile function by simultaneous inotropic stress MIBI imaging and echocardiography optimises the non-invasive detection of multivessel disease.

Comparison of dobutamine and treadmill exercise echocardiography in inducing ischemia in patients with coronary artery disease

OBJECTIVES

We sought to compare the magnitude of ischemia precipitated by both treadmill exercise and dobutamine stress echocardiography.

BACKGROUND

Although it is alleged that dobutamine stress produces ischemia similar in degree and extent to that produced during treadmill exercise, a direct comparison with treadmill exercise, the most common form of exercise, has not been performed.

METHODS

Eighty-five consecutive patients with known coronary artery disease underwent both stress tests on the same day, in random order.

RESULTS

Sixty-two patients (73%) had positive results on exercise echocardiography compared with 53 (62%) who had positive results on dobutamine stress (p = NS). Of the 53 patients with positive dobutamine test results, wall motion abnormalities appeared after the addition of atropine in 35 patients (66%). During dobutamine infusion, 22 patients (26%) had a hypotensive response that was reversed in 16 by prompt administration of atropine. At peak dobutamine-atropine stress, heart rate was higher than that at peak exercise (p < 0.001), whereas systolic blood pressure and rate-pressure product were higher at peak exercise than at peak dobutamine-atropine stress (p = 0.0001). In the 53 patients with positive results on both tests, peak wall motion score index was greater with treadmill exercise than with dobutamine-atropine infusion ([mean +/- SD] 1.73 +/- 0.45 vs. 1.57 +/- 0.44, p < 0.001).

CONCLUSIONS

Echocardiography immediately after treadmill exercise induces a greater ischemic burden than dobutamine-atropine infusion. In the clinical setting, exercise echocardiography should therefore be chosen over dobutamine echocardiography for diagnosing ischemia, when possible. When dobutamine echocardiography is used as an alternative modality, maximal heart rate should always be achieved by the addition of atropine.

[The predictive signs of multivessel coronary disease in echocardiography with dobutamine]

AIMS

To assess the ability of dobutamine echocardiography to detect multivessel coronary artery disease and to determine predictive factors for multivessel disease with or without beta-blockers.

PATIENTS AND METHODS

A total of 101 patients underwent dobutamine stress echocardiography and coronary angiography (evaluation of chest pain 76, extent of coronary disease after myocardial infarction 19, other indications 6).

RESULTS

Ten patients in whom the test was prematurely terminated were excluded. Out of 91 patients who underwent dobutamine echocardiography, 54 patients had multivessel disease (sensitivity of dobutamine test 93%, specificity 46%). Heart rate at the maximum dose of dobutamine or atropine was 88 +/- 21 beats/min for multivessel diseases and 104 +/- 21 beats/min without multivessel disease (p < 0.001). A cut-off value < 94 beats/min discriminated patients at risk for multivessel disease. After adjusting for treatment with beta-blockers, heart rate < 94 beats/min, ECG signs of ischemia, and abnormalities on baseline echocardiogram with remote asynergies during dobutamine testing were independent predictors of multivessel disease in the multivariate analysis (probability > 90% when at least two factors were present).

CONCLUSION

A heart rate < 94 beats/min at peak dose of dobutamine or after atropine, ECG signs of ischemia, and the presence of abnormalities on echocardiogram at rest with remote asynergies during dobutamine stress testing were independent predictive factors of multivessel coronary artery disease.

Methodology, feasibility, safety and diagnostic accuracy of dobutamine stress echocardiography

Large numbers of patients referred for evaluation of chest pain are unable to perform adequate, diagnostic exercise testing. In these patients, dobutamine stress echocardiography (DSE) represents an alternative, exercise-independent stress modality. Apart from the approximately 5% of patients with an inadequate acoustic window, 10% of patients referred for this test have nondiagnostic (submaximal negative) test results. Serious side effects during or shortly after DSE are uncommon, with ventricular fibrillation or myocardial infarction occurring in approximately 1 of 2,000 studies. No deaths have been reported. On the basis of a total number of 2,246 patients, reported in 28 studies, the sensitivity, specificity and accuracy of the test for the detection of coronary artery disease (CAD) were 80%, 84% and 81%, respectively. Mean sensitivities for one-, two- and three-vessel disease were 74%, 86% and 92%, respectively. The sensitivity for detection of disease in the left circumflex coronary artery (55%) was lower, both compared with that for left anterior descending (72%) and right coronary artery disease (76%). The sensitivity of predicting multivessel disease by multiregion echocardiographic abnormalities varied widely, from 8% to 71%. In direct comparisons, DSE was superior to exercise electrocardiography and dipyridamole echocardiography and comparable to exercise echocardiography and radionuclide imaging. DSE is a useful, feasible and safe exercise-independent stress modality for assessing the presence, localization and extent of CAD.

Dobutamine stress tele-echocardiography for evaluation of emergency department patients with chest pain

OBJECTIVES

The practically and accuracy of dobutamine stress tele-echocardiography (DSTE) were assessed in patients presenting to the emergency department with chest pain.

BACKGROUND

Many patients evaluated for chest pain in the emergency department (ED) are admitted to the hospital needlessly because of the difficulty in differentiating noncardiac chest pain from myocardial ischemia.

METHODS

One hundred sixty-three patients with no evidence of myocardial infarction on initial blood studies or the electrocardiogram who were recommended for hospital admission to rule out myocardial infarction or myocardial ischemia were enrolled in this four-phase study. Rest echocardiography was performed in the ED, and the images were transmitted to a cardiologist for interpretation. If the results were normal, DSTE was then administered by a trained nurse. In the first three phases, all patients were admitted for observation regardless of the results of DSTE. In the fourth phase, those having normal DSTE results were able to be released.

RESULTS

The test was completed within an average of 5.4 h of presentation to the ED. The sensitivity and specificity of DSTE versus clinical and cardiac catheterization findings were 89.5% and 88.9%, respectively, with a negative predictive value for DSTE of 98.5%. Patients experienced frequent mild side effects (54.7%), but few (6.3%) caused the test to be discontinued prematurely. In phase 4 of the study, 72% of those slated for hospital admission because of cardiac risk factors and chest pain suggesting myocardial ischemia were discharged after normal DSTE results.

CONCLUSIONS

The use of DSTE in the evaluation of patients presenting with chest pain may improve screening for those who can be safely released from the ED.

Long-term prognostic significance of dobutamine echocardiography in patients with suspected coronary artery disease: results of a 5-year follow-up study

OBJECTIVES

This study sought to assess the long-term prognostic utility of dobutamine stress echocardiography in predicting fatal and nonfatal cardiac events.

BACKGROUND

Although dobutamine stress echocardiography has improved sensitivity and specificity for detection of coronary artery disease, little is known of its predictive value for long-term cardiac events. Therefore, we followed up 120 consecutive patients who underwent dobutamine echocardiography for suspected coronary disease from March 1989 to August 1991.

METHODS

All patients presenting for coronary angiography for chest pain were eligible for recruitment. Follow-up was 100% complete at 5 years (range 3.0 to 6.1). Cardiac events were defined as cardiac death or nonfatal myocardial infarction or the need for coronary revascularization (coronary angioplasty or bypass surgery).

RESULTS

Positive (n = 78) and negative (n = 42) dobutamine test groups differed in their rates of coronary artery bypass graft surgery (37.2% vs. 9.5%, p < 0.001, respectively) and mortality. Of 26 total deaths, 22 occurred in the group with positive dobutamine test results (28% vs. 9.5%, p < 0.018); all 7 cardiac deaths occurred in this group as well (9% vs. 0%, p < 0.045). By multivariate regression analysis, positive results on dobutamine echocardiography remained independently predictive of future cardiac death after left ventricular ejection fraction and other clinical variables were accounted for.

CONCLUSIONS

A positive finding on dobutamine echocardiography is an independent predictor of long-term cardiac mortality, whereas a negative finding confers a significantly reduced likelihood of cardiac death as much as 5 years from initial testing. We conclude that dobutamine stress echocardiography can be used to predict which patients with suspected coronary artery disease are at low risk for cardiac death and do not require concurrent nuclear or invasive testing.

On-line quantitative assessment of left ventricular filling during dobutamine stress echocardiography: a useful addition to conventional wall motion scoring

In order to determine whether the diastolic rate of ventricular volume change obtained on-line with an automatic border detection (ABD) system during dobutamine stress echocardiography (DSE) would provide an interpretation of the diastolic ventricular response to the drug in quantitative terms in the assessment of coronary artery disease, we studied, with ABD and DSE, 59 patients who underwent coronary arteriography within 2 months of the stress test. Eleven patients had normal coronary findings or non-significant coronary lesions. Significant (> or =70% diameter stenosis) coronary artery disease (CAD) was present in 48 patients (81%). Dobutamine stress echocardiography (DSE) to a maximal dose of 50 microg/kg per min was performed in all patients. ABD images were acquired at rest and at the peak of infusion along with conventional two-dimensional images. The following measurements were evaluated: left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), slope of rapid filling segment (RFS), peak filling rate (PFR), rapid filling phase fractional change (RFFC). Patients with non-significant coronary artery lesions exhibited a hyperdynamic response with an LVEF increment of at least 20% from baseline to peak drug infusion. In these patients the effect of dobutamine produced an increase of RFS from 35.5+/-5.6 to 86.5+/-10.5 ml/s, an increase of PFR from 4.4+/-0.6 to 6.8+/-0.6 EDV/s, and an increase of RFFC from 74+/-8 to 92+/-5% (P<0.001). Of the 48 patients with coronary artery disease, 27 had <20% LVEF increase at peak dobutamine infusion. Four of 22 patients with single vessel disease and 23 of 26 patients with multivessel disease had an abnormal systolic response. After dobutamine infusion single vessel CAD patients showed a decrease of RFS from 33.4+/-5.3 to 26.7+/-5.9 ml/s, a decrease of PFR from 3.8+/-0.7 to 3.0+/-0.7 EDV/s, and a decrease of RFFC from 73+/-6 to 59+/-4% (P<0.001). Multivessel CAD patients showed a decrease of RFS from 32.0+/-5.9 to 23.1+/-4.1 ml/s, a decrease of PFR form 3.8+/-0.6 to 2.8+/-0.6 EDV/s, and a decrease of RFFC from 71+/-5 to 54+/-8% (P<0.001). The overall sensitivity of detecting CAD was 85% for conventional DSE and 90% for ABD-DSE (P=NS). The sensitivities of detecting patients with single vessel and multivessel CAD with conventional DSE were 68 and 92%, respectively, and with ABD-DSE were 91% (P<0.01) and 96% (P=NS), respectively. Our results show that an abnormal diastolic as well as systolic response during on-line quantitative assessment of dobutamine stress echocardiography is a sensitive marker of coronary artery disease and is predictive for the detection of extensive lesions. The described measurements can be utilized to improve the DSE sensitivity in identifying coronary artery disease. On-line quantitation of diastolic indexes with ABD can represent another step toward obtaining uniform results after stress echocardiography.

Advantages and disadvantages of dobutamine stress echocardiography compared with treadmill exercise electrocardiography in detecting ischemia

We compared the effectiveness and practicability of dobutamine stress echocardiography (DSE) and treadmill exercise electrocardiographic testing (TMT) for detecting coronary artery disease. Ninety-six patients (mean age 58.8 +/- 9.0 years) who presented for coronary angiography underwent both DSE and symptom-limited TMT. Two-dimensional echocardiography was performed to detect ischemia-induced wall motion abnormalities during incremental dobutamine infusion (5-40 micrograms/kg per min administered in 5 min steps). The sensitivity of detecting ischemia was 63% for TMT and 79% for DSE (p < 0.05); the specificity was 61% for TMT and 88% for DSE (p < 0.05). The accuracy of TMT was 63% and of DSE 82% (p < 0.01). In patients in whom both tests gave true-positive results, the maximum ST depression was evaluated during DSE and TMT (n = 31). The ST segment depressions detected by DSE were significantly smaller than those detected by TMT (0.04 +/- 0.04 mV vs 0.17 +/- 0.07 mV, p < 0.01), and 10 patients had no evidence of ST segment depression despite the presence of new wall motion abnormalities. DSE took significantly longer to perform than TMT (26.0 +/- 5.0 min vs 5.5 +/- 2.0 min, p < 0.01). Thus, DSE is more sensitive, specific and accurate than TMT in detecting coronary artery disease and can detect ischemia at an earlier stage. However, it takes longer to perform than TMT and thus may be less suitable for routine clinical use.

Dobutamine stress testing in the cardiac catheterization laboratory

Dobutamine stress ventriculography is a safe test that appears to separate groups of patients with and without significant coronary artery stenoses. In this study, all 7 patients with significant coronary artery stenoses who reached a heart rate > or = 110 beats/min had a positive stress test, whereas 9 of 10 control patients had a negative stress test.