Identification of multivessel coronary artery disease by exercise echocardiography

Clinical outcomes of discordant exercise electrocardiographic and echocardiographic findings compared with concordant findings in patients with chest pain and no history of coronary artery disease: An observational study

The aim of this study was to evaluate comparative clinical outcomes of discordant electrocardiographic (ECG) and echocardiographic (Echo) findings compared with concordant findings during treadmill exercise echocardiography in patients with chest pain and no history of coronary artery disease (CAD).A total of 1725 consecutive patients who underwent treadmill echocardiography with chest pain and no history of CAD were screened. The patients were classified into 4 groups: ECG-/Echo- (negative ECG and Echo), ECG+/Echo- (positive ECG and negative Echo), ECG-/Echo+, and ECG+/Echo+. Concomitant CAD was determined using coronary angiography or coronary computed tomography. Major adverse cardiac events (MACEs) were defined as a composite of coronary revascularization, acute myocardial infarction, and death.MACEs were similar between ECG-/Echo- and ECG+/Echo- groups. Compared with ECG+/Echo- group, ECG-/Echo+ group had more MACEs (adjusted hazard ratio [HR] adjusted by clinical risk factors [95% confidence interval {CI}], 3.57 [1.75-7.29], P < .001). Compared with ECG+/Echo+ group, ECG-/Echo+ group had lower prevalence of concomitant CAD and fewer MACEs (HR, 0.49 [0.29-0.81], P = .006).Positive exercise Echo alone during treadmill exercise echocardiography had worse clinical outcomes than positive ECG alone, and the latter had similar outcomes to both negative ECG and Echo. Positive exercise Echo alone also had better clinical outcomes than both positive ECG and Echo. Therefore, exercise Echo findings might be superior for predicting clinical outcomes compared with exercise ECG findings. Additional consideration of ECG findings on positive exercise Echo will also facilitate better prediction of clinical outcomes.

Comparison of Heart Rate Blood Pressure Product Versus Age-Predicted Maximum Heart Rate as Predictors of Cardiovascular Events During Exercise Stress Echocardiography

Exercise stress echocardiograms (ESEs) are a functional cardiovascular (CV) test typically used for the investigation of coronary artery disease. ESEs are often terminated at a predetermined age-predicted maximum heart rate (APMHR) to facilitate timely acquisition of ultrasound images at peak exercise. Although an APMHR of 85% is often used, this has not been validated as a suitable termination end point. Heart rate blood pressure product (HRBPP) as an established measure of myocardial work may provide a more reliable assessment of cardiac workload. The aim of this study was to assess maximal HRBPP (MHRBPP) and APMHR as markers of cardiac workload during ESE, using CV events at mean follow-up as the outcome variable. After exclusions, 712 patients being investigated for ischemic heart disease, performed an ESE to volitional fatigue using the standard Bruce protocol. Patient demographics and test data were collected and patients followed for 4.4 ± 2.1 years. Cut-points for MHRBPP (25,060; area under curve 0.77) and APMHR (93.8% and 97.9%; area under curve 0.71; p = 0.12 for difference) were established from receiver operating characteristic analysis. Those achieving an APMHR >85% but MHRBPP <25,060 had significantly more CV events than achieving an MHRBPP >25,060 regardless of APMHR (p <0.05). In conclusion, the current study demonstrates the superior prognostic power of MHRBPP over APMHR alone for the prediction of future CV events in patients performing an otherwise negative ESE for the detection of myocardial ischemia.

Assessment of Diastolic Function During Exercise Echocardiography: Annulus Mitral Velocity or Transmitral Flow Pattern?

OBJECTIVES

We hypothesize that the change in the left ventricular (LV) diastolic pattern (DP) may be measured with high reproducibility and correlates with exercise echocardiography (EE) better than the ratio of early LV inflow velocity to early diastolic annulus velocity (E/e' index).

BACKGROUND

The E/e' index has been related to LV filling pressures but has not been compared with DP.

METHODS

We selected 179 consecutive patients who were referred for EE. Early (E) and late (A) LV inflow velocities by conventional pulsed Doppler, and septal annulus e' velocity by pulsed Doppler myocardial imaging were measured at rest (R) and post-exercise (PE).

RESULTS

Four LV-DPs were found: abnormal relaxation (AR) at R and PE (E < A) in 110 patients; AR at PE (E > A at R; E < A at PE) in 22 patients; restrictive pattern (RP) at R and PE (E > A) in 18 patients; and RP at PE (E < A at R; E > A at PE) in 29 patients. The more accurate PE cutoff E/e' values to predict abnormal EE, ischemic response, poor functional capacity (< 8 Mets in men; < 6 Mets in women), and lack of increase in left ventricular ejection fraction (LVEF) were 12, 12, 11, and 11 (areas under the curve were 0.53, 0.53, 0.63, and 0.57, respectively). Corresponding areas under the curve for an RP at R + PE or only at PE were 0.57, 0.55, 0.54, and 0.56 (P = not significant). The sensitivity of an RP at R + PE or only at PE was lower and the specificity was higher than those of the different E/e' cutoff values for predicting abnormal EE, functional capacity, ischemic response, and lack of increase in LVEF. Achieved Mets were lower in patients with an RP at R + PE or only at PE irrespectively of the E/e' values, whereas achieved Mets in patients with AR at R + PE or only at PE were lower if the E/e' was > or = 11 (8.2 +/- 2.9 vs. 9.8 +/- 3.1, P = .01). Interobserver and intraobserver concordance were 95% (kappa = 0.86) and 100% (kappa = 1.0) for an RP, and 86% (kappa = 0.73) and 92% (kappa = 0.78) for a PE-E/e' value of > or = 11.

CONCLUSIONS

E/e' does not allow further stratification in patients with exercise RP. We propose both measurement of E/e' and determination of the LV-DP (a quickly assessable variable) for the assessment of diastolic function during EE. However, when an RP persists or develops with exercise, further assessment may not be more informative.

Stress echocardiography from 1979 to present

Stress echocardiography was initially developed in 1979 and has seen substantial success in the evaluation of patients with known or suspected coronary artery disease. It has proven applicable to clinical questions of diagnosis, prognosis and follow-up. It has been heavily dependent on technologic advancements, initially digital capturing for side-by-side visualization and, more recently, developments in detailed methods of evaluating myocardial mechanics and contrast echocardiography for perfusion.

Global left ventricular systolic function based on the sum of regional myocardial velocities during exercise echocardiography

OBJECTIVES

We sought to assess the relationship between global Doppler myocardial imaging (DMI) and left ventricular (LV) ejection fraction (LVEF) at both rest and exercise.

BACKGROUND

We have previously demonstrated that global DMI correlates with LVEF at rest with low variability.

METHODS

LVEF by 2-dimensional echocardiography, systolic global tissue Doppler velocity (s-TDV), strain (S) rate (SR), and S were assessed in 122 patients. LVEF was measured at rest and at peak exercise, whereas DMI was performed at rest and immediately postexercise. The region of interest by color DMI was set to enclose the external myocardial border when the LV achieved its maximal dimension. The means of the DMI assessments in the 4- and 2-chamber apical views at rest and postexercise were measured to correlate with LVEF.

RESULTS

Significant correlations were found between the LVEF and global s-TDV, SR, and S either at rest (r = 0.32, r = 0.50, and r = 0.33, all P < .001) or at exercise (r = 0.47, r = 0.63, and r = 0.40, all P < .001). The best differentiation of an abnormal from a normal LVEF (>or=50%) at rest was provided by s-TDV less than 1.8 cm/s (sensitivity 63%, specificity 78%, area under the curve [AUC] 0.76, confidence interval [CI] 0.63-0.90), SR greater than -0.50/s (sensitivity 90%, specificity 76%, AUC 0.86, CI 0.76-0.97), and S greater than -9% (sensitivity 83%, specificity 75%, AUC 0.81, CI 0.70-0.91); whereas at exercise it was provided by s-TDV less than 3.5 cm/s (sensitivity 75%, specificity 74%, AUC 0.79, CI 0.69-0.89), SR greater than -0.80/s (sensitivity 83%, specificity 81%, AUC 0.91, CI 0.86-0.96), and S greater than -11% (sensitivity 67%, specificity 69%, AUC 0.74, CI 0.63-0.85).

CONCLUSIONS

Global DMI is a valuable tool to assess global LV function during exercise.

Risk Stratification by Treadmill Exercise Echocardiography in Patients with Excellent Exercise Capacity

BACKGROUND

The incremental value of exercise echocardiography (EE) has been demonstrated to be maximal in patients with moderate pretest probability for coronary artery disease, but there is a lack of data in patients with low pretest probability or patients with good functional capacity.

METHODS

To investigate whether such incremental value is maintained in patients with excellent exercise capacity, we studied 1,433 patients who had excellent exercise capacity (>or=8 METs for women, >or=10 METs for men).

RESULTS

During a follow-up of 2.3 +/- 1.5 years, 42 hard events occurred (cardiac death or nonfatal myocardial infarction). Variables independently associated to hard events were male gender (P = 0.04), % of the age-predicted maximum heart rate (P = 0.02), chronotropic reserve (P = 0.002), and abnormal EE (P = 0.03; incremental P value of EE = 0.03).

CONCLUSIONS

EE has incremental value over clinical variables, resting echocardiography, and exercise testing variables in patients with excellent exercise capacity. EE may be preferable to ECG exercise testing even in patients expected to have good exercise capacity.

Usefulness of a novel ultrasound transducer for continuous monitoring treadmill exercise echocardiography to assess coronary artery disease

BACKGROUND

The feasibility of a novel ultrasound probe, which can be attached to the left ventricular (LV) apex chest wall and allows free rotation around its long axis direction for the continuous monitoring of LV wall motion, was tested.

METHODS AND RESULTS

There were 36 subjects who had coronary artery disease (CAD). By attaching a novel ultrasound probe to the chest wall, the LV apical views were recorded during treadmill exercise stress echocardiography (Echo). The continuous monitoring of LV wall motion was satisfactorily feasible in 30 of 36 patients. The visualization rate of the overall LV segments was higher at rest (90%) compared to that during peak exercise (77%). The segments were better visualized in apical portions (90-100%) than in mid (77-96%) or basal portions (68-87%). The sensitivity, specificity, and accuracy for detecting CAD were 61, 100 and 77%, respectively. The wall motion score index 3 and 6 min after exercise decreased significantly compared to those at peak exercise. The number of segments with dyssynergy was highest at the peak exercise. Ischemic ST-T depression on electrocardiography was observed only at peak stress periods.

CONCLUSIONS

Continuous monitoring treadmill exercise Echo using a novel ultrasound probe seems feasible for the non-invasive and physiological assessment of CAD.

Risk stratification by treadmill exercise echocardiography

BACKGROUND

Although exercise echocardiography (EE) has value for the diagnosis of coronary artery disease (CAD), it's not clear whether it may be useful for risk assessment in all categories of patients. To determine whether: 1) there is an incremental value of EE over clinical, exercise and resting echocardiographic variables for the prediction of events according to the pre-test probability of CAD; and 2) the number, location of the diseased territories, and nature of the disease affect the risk stratification, we studied 2436 patients referred for EE that were followed for 2.1 +/- 1.5 years.

METHODS

Based on a pre-test score, previous myocardial infarction (MI) or revascularizations, 1242 patients were considered as having high, 1038 moderate, and 156 low pre-test probability.

RESULTS

There were 89 hard events (myocardial infarction or cardiovascular death) in the 1203 patients with abnormal EE vs. 31 events in the 1233 with normal EE (p < 0.0001). Gender, Mets, heart rate x blood pressure, resting wall motion score index and number of involved territories at exercise were independently associated to hard events (final Chi-square = 170, incremental p value of exercise echo <0.0001). The incremental value of exercise echo over other variables was found in patients with the different pre-test probabilities.

CONCLUSIONS

Exercise echocardiography has incremental value over clinical, exercise and resting echocardiographic variables in patients with different pre-test probabilities of CAD.

Role of Biplane and Biplane Echocardiographically Guided 3-Dimensional Echocardiography During Dobutamine Stress Echocardiography

Image acquisition time and wall-motion score of conventional 2-dimensional (2D) dobutamine stress echocardiography (DSE) were compared with those of biplane and 3-dimensional (3D) DSE in 50 patients (age 67 +/- 13 years) with regular rhythms during clinically indicated DSE. Commercially available systems were used for the study. We used a conventional transducer for 2D and a matrix-array transducer (x4 or x3-1) for two biplane (60- and 120-degree) images and one 3D full-volume image. Image quality was scored as 1 = good; 2 = adequate; and 3 = inadequate. Segmental wall-motion scores for each method were analyzed in blinded fashion. Acquisition times of biplane (9.3 +/- 2.8 seconds) and biplane-guided 3D (additional 2.6 +/- 1.0 seconds) echocardiography were significantly shorter than those of conventional 2D DSE (60.0 +/- 26.7 seconds) (P < .001). Image quality was adequate or good in 94% for biplane and 96% for 3D echocardiography. Agreement of segmental wall-motion score was present in 87.6% of segments for 2D versus biplane and 85.9% for 2D versus 3D at baseline and in 88.0% for 2D versus biplane and 87.4% for 2D versus 3D at peak stress. Acquisition of biplane or biplane-guided 3D volumetric data during DSE with use of a new matrix-array transducer was feasible and shortened image acquisition time without affecting the diagnostic yield compared with conventional 2D imaging.

Comparison of exercise echocardiography and the Duke treadmill score for risk stratification in patients with known or suspected coronary artery disease and normal resting electrocardiogram

BACKGROUND

Although exercise echocardiography (EE) is not clearly indicated in patients with normal electrocardiogram (ECG) as the first evaluation, there is a lack of data regarding its superiority over the Duke score for prognosis. We investigate whether EE has incremental value over the Duke score for predicting outcome in patients with normal ECG.

METHODS

One thousand six hundred forty-seven patients with interpretable ECG referred for EE were followed up for 2.5 +/- 1.4 years. There were 58 hard events (myocardial infarction or cardiovascular death).

RESULTS

There were 38 events in 735 patients with abnormal EE versus 20 events in 912 with normal EE (P < .0001). The Duke score, resting wall motion score index, and ischemia were independently associated to events (incremental P value of EE = .03). The Duke score allowed stratification of patients with abnormal EE (P = .001) or ischemia (P = .01) into different risk categories but did not stratify patients without these characteristics. Exercise echocardiography variables stratified patients with the low Duke score (left anterior descending artery territory P = .04, left anterior descending artery ischemia P = .03) and with the intermediate Duke score (abnormal EE P = .005, necrosis P = .0009, ischemia P = .004, resting ejection fraction P < .00001, resting wall motion score index P < .00001, peak ejection fraction P < .00001, peak wall motion score index P < .0001, number of territories P = .002, left anterior descending artery territory P = .001, and left anterior descending artery ischemia P = .002) but did not with the high Duke score.

CONCLUSIONS

Exercise echocardiography has incremental value over clinical variables, the Duke score, and resting echocardiography for the prediction of hard cardiovascular events in patients with normal resting ECG.

Doppler Tissue Imaging During Supine and Upright Exercise in Healthy Adults

Doppler tissue imaging variables were measured in 18 healthy men and women during supine bicycle stress exercise and upright exercise treadmill testing. From a color Doppler tissue imaging cineloop, tissue velocities in basal and mid segments of the standard 3 apical views during rest and peak exercise were assessed. Compared segments were adjusted for double product, and peak variables were compared using the paired t test. Peak systolic velocity and strain rate increased with both forms of exercise (P < .03). Time to compression-expansion crossover shortened in all segments with exercise and at peak exercise treadmill testing versus peak supine bicycle stress exercise (P < .03). Of all segments, 81% were analyzable for peak systolic velocity, 79% for strain rate. Doppler tissue imaging is a feasible tool for quantitatively assessing left ventricular response to supine and upright exercise.

Stress Echocardiography

Stress echocardiography is commonly employed for the clinical management of known or suspected coronary artery disease. This review discusses the accuracy of the technique, which is equivalent to that of competing imaging techniques, as well as its overall role in patient management. The utilization of stress echocardiographic modalities in clinical presentations, such as chest pain, congestive heart failure, and valvular heart disease, and preoperative risk assessment, as well as determining myocardial viability, are discussed.

Stress echocardiography for the diagnosis and risk stratification of patients with suspected or known coronary artery disease: a critical appraisal. Supported by the British Society of Echocardiography

Stress echocardiography today has matured into a robust and reliable technique not only for the diagnosis of suspected coronary artery disease (CAD) but also for the accurate risk stratification of patients with suspected and established CAD. This is mainly because of rapid advances in image acquisition, digital display, and the development of harmonic and contrast imaging. Stress echocardiography today is also utilised in patients with heart failure both for assessing the cause of heart failure and determining the extent of hibernating myocardium. With advances in myocardial perfusion imaging, stress echocardiography now allows simultaneous assessment of myocardial function and perfusion. Tissue Doppler imaging allows quantitation of wall motion. Ready availability and reliability makes stress echocardiography a cost effective technique for the assessment of CAD.

Comparison of peak and postexercise treadmill echocardiography with the use of continuous harmonic imaging acquisition

OBJECTIVES

We sought to compare the feasibility and accuracy of peak and postexercise treadmill echocardiography with the use of continuous harmonic imaging capture.

BACKGROUND

Previous work has demonstrated the superiority of peak exercise echocardiography (EE) as compared with post-EE for the diagnosis of coronary artery disease (CAD). However, most of these studies used fundamental imaging and view-per-view acquisition systems. Technical advantages in stress echocardiography include harmonic imaging and continuous imaging capture.

METHODS

The study group included 650 patients (423 men; 60 +/- 12 years) who were submitted to peak and postexercise treadmill echocardiography.

RESULTS

Postexercise images were acquired within 55 seconds after exercise (28 +/- 10). The number of segments visualized in each view were similar at peak and post-EE except for the parasternal short-axis view, which was better qualified at postexercise. For analysis of diagnostic capability we included 312 patients: 195 were included on the basis of having had an EE and a coronary angiography, whereas 117 patients with pretest probability of CAD < 10% who had atypical chest pain or were asymptomatic were also included and considered as having no CAD. CAD (>/=50% stenosis) was confirmed in 159 patients. Positive EE was defined as ischemia or necrosis. Sensitivity for CAD was higher with peak imaging (92% vs 77%, P <.001), with similar specificity (78% vs 87%, P = not significant) and accuracy (85% vs 82%, P = not significant).

CONCLUSION

Peak treadmill EE is technically feasible and has higher sensitivity for CAD than posttreadmill EE. Therefore, in the clinical setting, peak EE should be performed for diagnostic purposes.

Exercise echocardiography with addition of atropine

Exercise echocardiography with the addition of atropine was performed in 31 patients who had a very small probability of achieving submaximal heart rate. Conclusive tests were obtained in 77% of the patients with this protocol.

Prognostic value of contrast stress echocardiography in patients with image quality too limited for traditional noncontrast harmonic echocardiography

Clinical data and contrast stress echocardiography (CSE) results were analyzed in 283 patients to establish the prognostic value of CSE for patients with limited echocardiogram image quality at baseline. The mean follow-up period was 736 +/- 337 days. Only 7 patients (2.5%) had nondiagnostic image quality with contrast enhancement. During follow-up, 24 cardiac events (8.5%) occurred (5 cardiac-related deaths, 2 nonfatal myocardial infarction, 17 coronary revascularizations). Overall sensitivity, specificity, and positive and negative predictive values were 60.9%, 76.8%, 19.7%, and 95.5%, respectively. Kaplan-Meier event-free survival was higher for patients with a negative CSE result as compared with those with a positive CSE finding (P <.0001). In a multivariate Cox proportional hazards model, positive CSE was the strongest predictor of cardiac events (risk ratio 3.7; 95% confidence interval 1.6-8.7). CSE can successfully predict cardiac events for patients with limited noncontrast echocardiographic image quality. A negative CSE result conferred a good prognosis.

Interpretation of Left Ventricular Wall Motion During Stress Testing

This article describes the obstacles to stress echocardiographic interpretation, and reviews the techniques currently available that offer a more objective approach to stress wall motion analysis than the conventional visual methodology. These techniques include Doppler-based methods, such as myocardial Doppler velocity and strain rate imaging, as well as automated border detection techniques, such as acoustic quantification and color kinesis.

Myocardial time intervals preceding left ventricular filling in chronic coronary artery disease: value of a decreased septal ejection time

The aim was to assess the capabilities of a two-segment myocardial recording to recognize patients with an underlying chronic ischemic process as a fast screening from controls, prior to the usual segment-to-segment tissue Doppler echocardiographic assessment of ischemia. Ischemia generates systolic and relaxation abnormalities. A flow Doppler index of global systolic and diastolic myocardial performance was recently drawn from time durations studied by coupling isovolumic relaxation (IR) to preejection (PEP)/ejection (ET) ratio (PEP/ET). We derived a similar tissue Doppler approach to the period preceding the left ventricular filling: PEP', the ejectional inward wall motion representing ET' and the prefilling (PreFg) period ranging from the end of ET' to the onset of the outward wall motion approximating IR, were measured and ratios calculated between variables. Spectral tissue Doppler was applied to septal and posterior walls of 28 patients with proven chronic coronary artery disease and preserved left ventricular function and of 12 age-matched controls. Data were compared with global flow data. Global information did not differentiate both groups, save for IR (sensitivity 32%, specificity 57%). In patients, tissue Doppler mean values of single variables (P=0.004-0.0006) and ratios (P=0.03-0.002) significantly differed from controls. Moreover, septal ET' differentiated 13 patients with one-vessel (219+/-34 ms) from 10 with two-vessel disease (158+/-70 ms, P=0.01). Sensitivity and specificity of a septal ET'<190 ms for a two-vessel disease were 80%. The two-segment tissue Doppler echocardiographic study provided a rapid screening of patients versus controls and helped to predict the number of diseased vessels.

[Exercise echocardiography to differentiate dilated cardiomyopathy from ischemic left ventricular dysfunction]

OBJECTIVES

Previous studies have shown the usefulness of dobutamine echocardiography to differentiate dilated cardiomyopathy (DC) from ischemic left ventricular dysfunction (ILVD), but no studies have been made using exercise echocardiography (EE). We hypothesized that most patients with DC have some contractile reserve and experience an increase in left ventricular ejection fraction (LVEF) during exercise, as opposed to patients with ILVD. Differences in response to EE may be useful to clinically differentiate between these two entities.

PATIENTS AND METHOD

Between 1 March 1995 and 1 March 2001, we performed 4,133 EE studies on 3,830 patients. Of 289 patients (8%) with moderate or severe LV dysfunction (biplane LVEF < 41% and left ventricular end-diastolic diameter > 5.2 cm), 207 were excluded: 111 for a history of myocardial infarction; 28 for scarring on echocardiography (regional akinesia/dyskinesia with thinning and/or increased brightness); 13 for previous revascularization procedures; 9 for aortic valve disease; 11 for a known cause of cardiomyopathy; and 35 for not undergoing angiography. The study group was therefore composed of 82 patients who were encouraged to perform maximal treadmill EE. EE criteria for ILVD were either impaired regional wall motion (RWM) or a decrease/no change in LVEF from baseline to peak exercise, while criteria for DC were RWM improvement/no change and LVEF increase. The ILVD group was formed by 39 patients with stenosis >/= 70% diameter stenosis of a major epicardial coronary artery or major branch vessel. The remaining 43 patients constituted the DC group.

RESULTS

The number of coronary risk factors (ILVD 2.0 1.1; DC 1.9 1.1), baseline LVEF (ILVD 30 7; DC 30 8), and exercise-induced angina (ILVD 23%; DC 14%) did not differ between groups (p = NS). ILVD patients achieved less Mets (6.6 3.1 vs 8.3 2.8; p < 0.05), had a lower heart rate x systolic blood pressure product (22 5 vs 27 7; p < 0.001), and developed regional and/or global LV dysfunction more frequently (79 vs 28%; p < 0.001). Sensitivity, specificity, positive and negative predictive values and global accuracy for ILVD detection were 79% (95% CI: 70-88), 72% (95% CI: 63-81), 72% (95% CI: 63-81), 79% (95% CI: 67-85), and 76% (95% CI: 69-83), respectively.

CONCLUSION

Global and/or regional LV function impairment with exercise is accurate in identifying patients with ILVD. This method could reduce the need for invasive procedures.

Contribution of stress echocardiography to clinical decision making in unselected ambulatory patients with known or suspected coronary artery disease

BACKGROUND

Due to its higher diagnostic accuracy stress echocardiography (SE) has been advocated as a substitute for stress ECG to detect coronary heart disease (CAD). However, its contribution to clinical decision-making in unselected patients presenting to the ambulatory care centre for known or suspected coronary artery disease is unclear.

METHODS

To evaluate the clinical value of SE in unselected patients, we prospectively obtained SE and stress ECG in 221 consecutive patients (142 males; mean age 58+/-12 years) presenting to the ambulatory care centre with known or suspected CAD. Patients with acute coronary syndrome were not included.

RESULTS

Results of stress ECG and SE were concordant in 181 (82%) and discordant in 40 patients (18%). The clinical decision to recommend or to currently withhold coronary angiography was possible solely on the basis of clinical criteria and stress ECG findings in 191 (86.4%) patients but was guided by the results of SE in 30 patients (13.6%). Left heart catheterization and coronary angiography were conducted in 61 patients. In this population SE was more accurate (82.6%) than stress ECG (65.6%) in indicating significant coronary artery stenosis.

CONCLUSION

Despite its higher accuracy, SE adds little to the information derived from dynamic stress ECG and symptom evaluation in unselected outpatients with known or suspected CAD. Thus, SE should not in general replace stress ECG as a screening method for detecting significant coronary artery disease, for both clinical and economic reasons.

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

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

Stress echocardiography in the diagnosis of coronary artery disease

Stress echocardiography (SE) is currently a widely accepted method for the diagnostic and prognostic assessment of coronary artery disease. This article reviews new concepts in SE, such as new stress techniques, new methods of endocardial border detection, strain, tissue Doppler velocities, and others. Although some of these techniques are in their infancy, we believe that they will become widely accepted.

Stress echocardiography: technical considerations

Stress echocardiography has evolved into a widely practiced and accepted method for the noninvasive assessment of the status of the coronary anatomy. Furthermore, this modality incorporates the ability to assess left ventricular function, valvular structure and function, intracardiac masses, the pericardium, and hemodynamics. The extent to which this tool can reliably provide useful clinical information is dependent, in part, on optimal performance. The purpose of this report is to provide an overview of those technical considerations that can contribute to the successful operation of a stress echocardiography laboratory. Consideration is given to personnel qualifications, functional requirements of the digital acquisition/storage/replay system, functional integration of the various hardware components, characteristics of the software, physical layout of the facility, and alternatives to treadmill exercise as the stressor. A thorough understanding of the physiologic basis of stress echocardiography, coupled with optimization of resources used in its performance, enable this tool to be an extraordinarily useful and cost-efficient method for comprehensive cardiovascular assessment.

Pacing stress echocardiography: an alternative to pharmacologic stress testing

OBJECTIVES

We sought to evaluate the diagnostic accuracy and feasibility of bedside pacing stress echocardiography (PASE) as a potential substitute for pharmacologic stress echocardiography in patients admitted to the hospital with new-onset chest pain or worsening angina pectoris.

BACKGROUND

Accurate and rapid noninvasive identification and evaluation of the extent of coronary artery disease (CAD) is essential for optimal management of these patients.

METHODS

Bedside transthoracic stress echocardiography was performed in 54 consecutive patients admitted to a community hospital with new-onset chest pain, after acute myocardial infarction had been excluded. We used 10F transesophageal pacing catheters and a rapid and modified pacing protocol. The PASE results were validated in all patients by coronary angiography performed within 24 h of the test. Significant CAD was defined as > or =75% stenosis in at least one major epicardial coronary artery.

RESULTS

The sensitivity of PASE for identifying patients with significant CAD was 95%, specificity was 87% and accuracy was 92%. The extent of significant CAD (single- or multivessel disease) was highly concordant with coronary angiography (kappa = 0.73, p<0.001). Pacing stress echocardiography was well tolerated, and only 4% of the patients had minor adverse events. The mean rate-pressure product at peak pacing was 22,313+/-5,357 beats/min per mm Hg, and heart rate >85% of the age-predicted target was achieved in 94% of patients. The average duration of the bedside PASE test, including image interpretation, was 38+/-6 min.

CONCLUSIONS

Bedside PASE is rapid, tolerable and accurate for identification of significant CAD in patients admitted to the hospital with new-onset chest pain or worsening angina pectoris.

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.

A rapid stress-testing protocol for the detection of coronary artery disease: comparison of two-stage transesophageal atrial pacing stress echocardiography with dobutamine stress echocardiography

OBJECTIVES

We compared a new two-stage transesophageal atrial pacing stress echocardiography (TAPSE) protocol with a standard dobutamine stress echocardiography (DSE) protocol.

BACKGROUND

Transesophageal atrial pacing stress echocardiography has been proposed as an efficient alternative to DSE.

METHODS

Two-stage TAPSE (85% and 100% of age-predicted maximum heart rate) and DSE (5 to 40 microg/kg/min at 3-min stages with or without atropine) were both performed, in random sequence, in each patient of a study group of 36 patients. Regional wall-motion analysis, patient acceptance (1 = low, 5 = high), hemodynamics and duration for performing and interpreting tests were compared.

RESULTS

Transesophageal atrial pacing stress echocardiography was successful in 35 of the 36 patients (feasibility 97%). More TAPSE than DSE studies were called "ischemic" (37% vs. 14%; p = 0.005). Peak heart rate was higher with TAPSE (144 +/- 18 vs. 129 +/- 15 beats/min, p = 0.0001). Peak cardiac index (4.6 +/- 2.1 vs. 5.1 +/- 1.9 liters/min/m2, p = 0.14), patient acceptance score (4.2 +/- 0.7 vs. 3.8 +/- 1.3, p = 0.17) and study duration (14.2 +/- 9.3 vs. 13.3 +/- 3.3 min, p = 0.59) were similar. Recovery time (7.1 +/- 7.6 vs. 16.2 +/- 15.9 min, p = 0.0003) and interpretation time (9.1 +/- 2.8 vs. 13.5 +/- 4.4 min, p = 0.0001) were shorter for TAPSE than for DSE.

CONCLUSIONS

Two-stage TAPSE permits rapid evaluation of cardiac patients. Peak cardiac index and patient acceptance scores were similar for TAPSE and DSE. Ischemia was detected more often with TAPSE; this result was attributed to the higher peak heart rate obtained with this protocol.

Assessment of regional left ventricular function during exercise test with pulsed tissue Doppler imaging

To investigate whether mitral annular velocity, measured by tissue Doppler imaging (TDI), is able to get a feasible quantitative evaluation of global and regional left-ventricular function during exercise test, 29 patients with previous uncomplicated myocardial infarction were studied by exercise echocardiography. All patients underwent coronary arteriography within 10 days of stress echocardiography. All of them were in sinus rhythm and had no right or left bundle branch block or significant mitral regurgitation as observed by left ventriculography. A total of 12 patients had anteroseptal and/or posteroseptal wall asynergies and left anterior descending involvement; 9 patients had lateral and/or posteroinferior asynergies and left circumflex coronary artery involvement; 8 patients had inferior and posteroseptal wall asynergies and right coronary artery involvement. Twelve subjects of same age and sex with normal cardiovascular findings were selected as a control group. TDI sample volumes were set on the mitral annuli corresponding to anteroseptal, posterior, posteroseptal, lateral, anterior, and inferior wall in 4-chamber, 2-chamber, and long-axis views. There was a significant correlation between the left-ventricular ejection fraction (0.41 +/- 0.8) and the means of the systolic (S) values (6.1 +/- 0.9 cm/sec, r = 0.83, p < 0.01). The mean S at the sites corresponding to the infarct regions (5.5 +/- 0.4 cm/sec) was significantly lower than the control group (11 +/- 0.8 cm/sec, p < 0.001). After stress, in patients with multivessel disease, S values corresponding to remote regions were significantly lower (p < 0.01) compared with control subjects. Thus, the parameters obtained from mitral annular velocities with pulsed TDI in patients with previous myocardial infarction reflect left ventricular asynergy corresponding to the infarct regions and reversible regional dysfunction after exercise.

Accuracy of exercise echocardiography to detect coronary artery disease in left bundle branch block unassociated with either acute or healed myocardial infarction

To search for the value of treadmill exercise echocardiography in the detection of coronary artery disease in noninfarcted patients with left bundle branch block, we studied 35 patients (17 with coronary artery disease). We found high sensitivity, specificity, and accuracy (76%, 83%, and 80%, respectively).

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

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Overall and Segmental Agreement of Stress Echocardiography

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

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.

An algorithm for noninvasive identification of angiographic three-vessel and/or left main coronary artery disease in symptomatic patients on the basis of cardiac risk and electron-beam computed tomographic calcium scores

OBJECTIVES

We sought to model an algorithm for noninvasive identification of angiographically obstructive three-vessel and/or left main disease based on conventional cardiac risk assessment and site and extent of coronary calcium determined by electron-beam computed tomography (EBCT).

BACKGROUND

Such an algorithm would greatly facilitate clinical triage in symptomatic patients with no previous diagnosis of coronary artery disease (CAD).

METHODS

We examined 291 patients with suspected, but not previously diagnosed, CAD who underwent coronary angiography for clinical indications. Cardiac risk factors were determined as defined by the National Cholesterol Education Program. An EBCT scan was performed in all patients, and a coronary calcium score (Agatston method) was computed. Total per-patient calcium scores and separate scores for the major coronary arteries were generated. These scores were also analyzed for localization of coronary calcium in the more distal versus proximal tomographic sections. These parameters and the risk factors were considered for the model described in the following section.

RESULTS

Sixty-eight patients (23%) had angiographic three-vessel and/or left main CAD. Multiple logistic regression analysis determined male sex, presence of diabetes and left anterior descending (LAD) and circumflex (LCx) coronary calcium scores, independent from more distal calcium localization, as independent predictors for identification of three-vessel and/or left main CAD. Based on this four variable model, a simple noninvasive index (NI) was constructed as the following: loge(LAD score) + log(e)(LCx score) + 2[if diabetic] + 3[if male]. Receiver operating characteristic curve analysis for this NI yielded an area under the curve of 0.88+/-0.03 (p < 0.0001) for separating patients with, versus without, angiographic three-vessel and/or left main CAD. Various NI cutpoints demonstrated sensitivities from 87-97% and specificities from 46-74%. The NI values >14 increased the probability of angiographic three-vessel and/or left main CAD from 23% (pretest) to 65-100% (posttest), and NI values <10 increased the probability of no three-vessel and/or left main CAD from 77% (pretest) to 95-100% (posttest).

CONCLUSIONS

On the basis of a simple algorithm ("noninvasive index"), EBCT calcium scanning in conjunction with risk factor analysis can rule in or rule out angiographically severe disease, i.e., three-vessel and/or left main CAD, in symptomatic patients.

Nonexercise stress transthoracic echocardiography: transesophageal atrial pacing versus dobutamine stress

OBJECTIVES

To compare transesophageal atrial pacing stress echocardiography with dobutamine stress echocardiography for feasibility, safety, duration, patient acceptance and concordance in inducing wall motion abnormalities.

BACKGROUND

Transesophageal atrial pacing is an effective method of increasing heart rate and has been used in the assessment of coronary artery disease.

METHODS

Both tests were performed in sequence on the same patients in random order. Transesophageal atrial pacing stress echocardiography began at a heart rate of 10 beats/min above the baseline value and was increased by 20 beats/min every two min until 85% of the age-predicted maximum heart rate or another end point was reached. Dobutamine echocardiography was performed using three-min stages and a maximum dose of 40 microg/kg per min. Atropine (total dose < or =2 mg) was administered at the start of the 40 microg/kg per min stage if needed to augment heart rate or during pacing if Wenckebach heart block occurred.

RESULTS

Transesophageal atrial pacing stress echocardiography was feasible in 100 of 104 patients (96%); the duration (8.6+/-3.6 min) was significantly shorter than that of dobutamine stress echocardiography (15.1+/-3.9 min) (p = 0.0001). With transesophageal atrial pacing stress echocardiography, the recovery period was shorter, symptoms and dysrhythmias were fewer, hypertension and hypotension were less common and target heart rate was more frequently achieved. No complications occurred with either test. Patient acceptance was satisfactory. Agreement between results of both tests was good for segmental wall motion scoring with a 16-segment model, scores 1 to 5 (kappa: rest, 0.79; peak, 0.57) and test interpretation (normal, ischemia, infarction or resting wall motion abnormality with ischemia) (kappa: 0.77).

CONCLUSIONS

Transesophageal atrial pacing stress echocardiography is a feasible, well-tolerated alternative to dobutamine stress echocardiography. It can be performed rapidly and shows good agreement with dobutamine stress echocardiography in the induction of myocardial ischemia.