Stress echocardiography in elderly patients with coronary artery disease: applicability, safety and prognostic value of dobutamine and adenosine echocardiography in elderly patients

Stress CMR Perfusion Imaging in the Medicare-Eligible Population: Insights From the SPINS Study

BACKGROUND

Patients aged ≥65 years account for a disproportionately large portion of cardiovascular (CV) events and pose a challenge for noninvasive detection of coronary artery disease.

OBJECTIVES

This study sought to determine the prognostic value of stress cardiac magnetic resonance (CMR) in a Medicare-eligible group of patients in a multicenter setting in the United States.

METHODS

From a multicenter U.S. registry, the study identified patients aged ≥65 years who were referred for stress CMR for evaluation of myocardial inducible ischemia. The primary outcome was defined as CV death or nonfatal myocardial infarction, whereas the secondary outcome was defined as any primary outcome, hospitalization for unstable angina, hospitalization for congestive heart failure, and unplanned late coronary artery bypass grafting. The associations of CMR findings with CV outcomes adjusted to clinical risk markers and health care cost spending were determined.

RESULTS

Among 1,780 patients (aged 73 ± 5.7 years; 46% female), study investigators observed 144 primary events and 323 secondary events, over a median follow-up of 4.8 years. The presence of inducible ischemia and late gadolinium enhancement (LGE) was associated with incrementally higher event rates. Patients with neither inducible ischemia nor LGE experienced a <1% annualized rate of primary outcome. In a multivariable model adjusted for CV risk factors, inducible ischemia and LGE maintained an independent association with primary (HR: 2.80 [95% CI: 1.93-4.05]; P < 0.001; and HR: 1.85 [95% CI: 1.21-2.82]; P = 0.004, respectively) and secondary (HR: 2.46 [95% CI: 1.90-3.19]; P < 0.001; and HR: 1.72 [95% CI: 1.30-2.27]; P < 0.001, respectively) outcomes. Rates of revascularization, as well as downstream costs for patients without CMR-detected inducible ischemia, remained low throughout the follow-up period.

CONCLUSIONS

In a multicenter cohort of Medicare-eligible older patients, stress CMR was effective in providing risk stratification. (Stress CMR Perfusion Imaging in the United States [SPINS] study; NCT03192891).

Adenosine stress myocardial perfusion imaging in octogenarians: Safety, tolerability, and long-term prognostic implications of hemodynamic response and SPECT-related variables

BACKGROUND

Evaluation of tolerability, safety, and prognostic implications of adenosine stress myocardial perfusion imaging (MPI) in octogenarians.

METHODS

370 octogenarians (49% known coronary artery disease) were studied. Hemodynamic response, MPI-related data, and rest-left ventricular ejection fraction (LVEF) based on echocardiography were registered per patient, and prospective follow-up was performed to document all-cause death (ACD), cardiac death (CD), myocardial infarction (MI), and late revascularization.

RESULTS

No deaths or MIs were observed during adenosine infusion or the short-term post-infusion period. 86% of patients were able to tolerate a 6-minute infusion. All side effects terminated spontaneously after infusion cessation, except for one case of pulmonary oedema. After 9.3 years, there were 124 ACDs, 62 CDs, 16 MIs, and 35 revascularizations. Differences between survival curves of summed stress score (SSS)-based risk groups were significant for all end points (P < .001). SSS and LVEF were independent predictors of all end points (P ≤ .01) and lung uptake of cardiac end points. ΔHR <10 bpm (OR = 1.78, P = .004) and inability to increase HR by >10 bpm and decrease systolic blood pressure by >10 mmHg (OR = 2, P = .02) during adenosine infusion were independent predictors of ACD and CD, respectively. Hemodynamic response variables, SSS, and lung uptake provided incremental prognostic value over pre-test data for ACD and CD.

CONCLUSIONS

In octogenarians, adenosine stress MPI is well tolerated and provides effective long-term risk stratification.

Prognostic usefulness of contemporary stress echocardiography in patients with left bundle branch block and impact of contrast use in improving prediction of outcome

Aims

Patients with symptomatic left bundle branch block (LBBB) may have myocardial ischaemia due to both coronary artery disease and/or cardiomyopathy (microcirculatory abnormalities) and may have concomitant left ventricular (LV) dysfunction. We aimed to assess the feasibility and prognostic value of contemporary stress echocardiography (SE), which can uncover both pathophysiologies in LBBB patients in routine clinical practice, and also aimed to assess the additive value of contrast SE.

Methods and results

Accordingly, 190 consecutive patients (age 70.5 ± 11.3 years, LV ejection fraction = 50.1 ± 10%) with symptomatic LBBB who underwent SE over 6 years were assessed, of which 142 (75%) underwent contrast SE and 176 (92.6%) had diagnostic SE. Inducible ischaemia was present in 25 (14.2%) patients. During follow-up (35.4 ± 20.2 months) there were 32 deaths (18%) and 18 (10.2%) first cardiovascular (CV) events (acute myocardial infarction/mortality) in the 176 patients with diagnostic studies. Wall thickening score index at peak stress (WTSIpeak), which measures combined LV function and inducible ischaemia, was an independent predictor of mortality (HR = 3.78, 95% CI = 1.39-10.31, P = 0.01) and CV events (HR = 3.96, 95% CI = 1.1-14.3, P = 0.036). An abnormal SE (myocardial ischaemia and/or abnormal LV function) predicted an almost three-fold increase in all-cause mortality and CV events compared with normal SE. Amongst the confounders affecting assessment of wall thickening in LBBB and conventional prognostic variables, use of contrast was an independent predictor (P = 0.034) of WTSI1.16 (optimal predictor of mortality/CV outcome).

Conclusion

SE in patients with LBBB demonstrated high feasibility and the combination of LV systolic function and myocardial ischaemia provided important prognostic information. Contrast-enhanced SE improved the prediction of outcome.

Temporal analysis of regional strain rate during adenosine triphosphate stress before and after percutaneous coronary interventions

Regional myocardial ischemia is thought to be characterized by diastolic dysfunction. We aimed to clarify whether temporal analysis of strain rate (SR) index derived from two-dimensional speckle-tracking echocardiography (2DTE) can assess the regional myocardial ischemia or not. Forty-two patients with significant coronary stenoses were referred for percutaneous coronary intervention (PCI). 2DTE was performed before and a day after PCI. Time from aortic valve closure to peak early diastolic longitudinal SR ∆(TAVC-E SR) was measured both at baseline and during adenosine triphosphate (ATP) infusion. TAVC-E SR was calculated as TAVC-E SR during ATP infusion subtracted by TAVC-E SR at baseline. In forty-five target ischemic regions, TAVC-E SR at baseline was significantly longer than that of control regions (166 ± 28 vs. 136 ± 32 ms, P < 0.0001). TAVC-E SR in target ischemic regions significantly prolonged during ATP stress to 221 ± 37 ms (P < 0.0001), while it did not change in control regions. Immediately after PCI, TAVC-E SR in target regions significantly decreased to 135 ± 27 ms, P < 0.0001 without prolongation during ATP stress. Receiver operating characteristic curves demonstrated that ∆TAVC-E SR could assess regional myocardial ischemia by a cutoff criterion of 14 ms with sensitivity of 93% and specificity of 95%. 2DTE-derived TAVC-E SR significantly increased during ATP stress only in ischemic myocardium. This phenomenon disappeared immediately after PCI. Temporal analysis of TAVC-E SR appeared to be useful to assess the regional myocardial ischemia.

Meta-analysis of optimal risk stratification in patients >65 years of age

This meta-analysis evaluated the optimal noninvasive strategy for cardiac risk assessment of patients >65 years of age with known or suspected coronary artery disease using the available literature. Patients >65 years of age constitute a growing proportion of the population and have higher cardiovascular morbidity and mortality, but an optimal strategy to predict the risk of cardiac events in this group is unknown. A systematic search of MEDLINE was performed for cohort studies of ≥100 patients >65 years old with ≥12 months of follow-up that reported cardiac death and/or nonfatal myocardial infarction after any of stress myocardial perfusion imaging (MPI), stress echocardiography, or exercise tolerance testing (ETT) for known or suspected coronary artery disease. Pooled annualized event rates were calculated for each technique. Summary odds ratios (ORs) between normal and abnormal test results were calculated using a random-effects model. Seventeen studies (MPI 7, stress echocardiography 7, ETT 3) in 13,304 patients (mean age 75.5 years) were included. Abnormal compared to normal stress MPI (OR 11.8, 95% confidence interval [CI] 7.5 to 18.7) and stress echocardiography (OR 3.2, 95% CI 2.6 to 3.9) accurately stratified risk in patients. However, patients with abnormal and normal ETT results had similar cardiac event rates (OR 3.1, 95% CI 0.8 to 11.5). In conclusion, stress imaging with MPI or stress echocardiography effectively stratified risk in patients, whereas ETT alone did not.

Value of exercise echocardiography for predicting mortality in elderly patients

BACKGROUND

Elderly patients with suspected or known coronary artery disease are often referred for pharmacological stress testing. Data on the value of exercise echocardiography (ExEcho) for predicting outcome (particularly all-cause mortality) in these patients are scarce.

METHODS

Peak treadmill ExEcho was performed in 2159 patients ≥ 70 years of age with known or suspected coronary artery disease. Left ventricular wall motion was evaluated at baseline and with exercise, and the increase in wall motion score index from rest to peak exercise (ΔWMSI) was calculated. Ischaemia was diagnosed when new or worsening wall motion abnormalities developed with exercise. The end points were all-cause mortality and major cardiac events (cardiac death or myocardial infarction).

RESULTS

Ischaemia developed in 844 patients (38·6%) during exercise. Over a mean follow-up of 3·5 ± 3·1 years, 439 deaths occurred. The cumulative 5-year mortality rate was 29·3% in patients with ischaemia versus 16·8% in those without ischaemia (P < 0·001). After covariate adjustment, ΔWMSI remained an independent predictor of mortality [hazard ratio (HR) 2·37, 95% confidence interval (CI) 1·66-3·39, P < 0·001] and major cardiac events (HR 3·48, 95% CI 2·11-5·74, P < 0·001). These results remained significant even in patients with chronotropic incompetence. When added to a model with clinical, resting echocardiographic and exercise electrocardiogram variables, ExEcho results provided incremental value for the prediction of both end points (P < 0·001).

CONCLUSIONS

ExEcho is feasible in elderly patients with suspected or known coronary artery disease and provides useful information for risk stratification in these patients.

Strain measurements during adenosine triphosphate infusion before and after percutaneous coronary intervention

BACKGROUND

In regional myocardial ischemia, contractile delay develops, which can be assessed by measuring time to peak strain (TPS) on tissue Doppler imaging. The aims of the present study were to clarify the usefulness of TPS measurements during adenosine triphosphate (ATP) stress in assessing myocardial ischemia and to evaluate whether prolongation of TPS disappears immediately after percutaneous coronary intervention (PCI) or not.

METHODS AND RESULTS

A total of 26 patients underwent strain measurements before and after PCI. Corrected TPS for heart rate (TPSc) in target regions and in control regions were measured both at baseline and during ATP infusion. TPSc ratio was calculated as a ratio of TPSc during ATP stress to TPSc at baseline. TPSc in the target region significantly increased during ATP infusion before PCI, which was significantly longer than hyperemic TPSc in control regions. Accordingly, TPSc ratio in the target regions before PCI was significantly greater than that in control regions (1.22+/-0.17 vs 0.96+/-0.09, respectively, P<0.0001). Following PCI, the TPSc ratio in the target regions significantly decreased to 0.98+/-0.05 (P<0.0001). Receiver operating characteristic curve analysis provided a cut-off of 1.04 in TPSc ratio for detecting myocardial ischemia with a sensitivity of 93% and specificity of 93%.

CONCLUSIONS

TPS measurements during ATP stress differentiated target from control myocardium before PCI. The prolongation of TPSc disappeared immediately after PCI.

Methodological Analysis of Diagnostic Dobutamine Stress Echocardiography Studies

BACKGROUND

Dobutamine stress echocardiography (DSE) is an accepted test for the diagnosis of coronary artery disease (CAD), despite its wide diagnostic accuracy.

AIM

Which factors cause test variability of DSE for the diagnosis of CAD.

METHODS

In a retrospective analysis of 46 studies in 5,353 patients, the potential causes of diagnostic variability were systematically analyzed, including patient selection, definition of CAD, chest pain characteristics, confounding factors for DSE (left ventricular hypertrophy, left bundle branch block, female gender), work-up bias (present when patient's chance to undergo coronary angiography is influenced by the result of DSE), review bias (present when DSE is interpreted in relation to CAG), DSE protocol and definition of a positive DSE.

RESULTS

Diagnostic variability was related to definition of a positive test, but not related to the definition of CAD or DSE protocol. However, only three of eight methodological standards for research design found general compliance. Differences in the selection of the study population (quality of echocardiographic window, angina pectoris), handling of confounding factors and analysis of disease in individual coronary arteries were observed. Lack of data on analysis of relevant chest pain syndromes and handling of nondiagnostic test results hampered further evaluation of these standards.

CONCLUSION

Methodological problems may explain the wide range in diagnostic variability of DSE. An improvement of clinical relevance of DSE testing is possible by stronger adherence to common and new methodological standards.

Factors affecting sensitivity and specificity of diagnostic testing: dobutamine stress echocardiography

BACKGROUND

Clinical characteristics of patients, angiographic referral bias, and several technical factors may all affect the reported diagnostic accuracy of tests. The aim of this study was to assess their influence on the diagnostic accuracy of dobutamine stress echocardiography (DSE).

METHODS

The medical literature from 1991 to 2006 was searched for diagnostic studies using DSE and meta-analysis was applied to the 62 studies thus retrieved, including 6881 patients. These studies were analyzed for patient characteristics, angiographic referral bias, and several technical factors.

RESULTS

The sensitivity of DSE was significantly related to the inclusion of patients with prior myocardial infarctions (0.834 vs 0.740, P < .01) and defining the results of DSE as already positive in case of resting wall motion abnormalities rather than obligatory myocardial ischemia (0.786 vs 0.864, P < .01). Specificity tended to be lower when patients with resting wall motion abnormalities were included in a study (0.812 vs 0.877, P < .10). The presence of referral bias adversely affected the specificity of DSE (0.771 vs 0.842, P < .01).

CONCLUSION

This analysis suggests that the reported sensitivity of DSE is likely higher and the specificity lower than expected in routine clinical practice because of the inappropriate inclusion of patients with prior myocardial infarctions, the definition of positive results on DSE, and the negative influence of referral bias. However, in the patient subset that will be sent to coronary angiography, the opposite results can be expected.

Recent advances in dobutamine stress echocardiography

Dobutamine stress echocardiography (DSE) is a reliable cardiac risk stratifier that has widespread applicability because of its clinical accuracy and cost effectiveness. Dobutamine has positive inotropic and chronotropic effects and is commonly used in patients who cannot exercise or achieve an adequate heart rate response with exercise. Recently available long-term results from several independent clinical trials, combined with enhancements in image quality, have improved the ability to detect significant coronary artery disease and determine myocardial viability. Dobutamine stress echocardiography has an excellent safety profile with clinical results superior to regular exercise electrocardiography and comparable with exercise echocardiography and radionucleotide perfusion stress imaging. Low-dose dobutamine response can accurately predict dysfunctional yet viable myocardial regions that may improve with revascularization. Clinical studies are now available refining the common use of DSE preoperatively in female patients with valvular disease, as well as in the emergency department. Dobutamine stress echocardiography does have some limitations in discriminating particular regions of ischemia when multiple ventricular segments are involved and when the imaging is suboptimal. It can be applied using minimal additional resources in an otherwise functioning echocardiography laboratory and, with appropriate training, can result in clinical results comparable with those of large-scale multicenter trials. Ongoing improvements in technology and the development of new reagents such as myocardial contrast agents hold promise for further advancement in the near future.

Prognostic value of exercise stress test and dobutamine stress echo in patients with known coronary artery disease

BACKGROUND

The aim of this study was to compare the feasibility of dobutamine stress echocardiography (DSE) and exercise stress test (EST) between patients in different age groups and to evaluate their proportional prognostic value in a population with established coronary artery disease (CAD).

METHODS

The study sample included 323 subjects, subdivided in group 1 (G1), comprising 246 patients aged <75 years, and group 2 (G2), with 77 subjects aged >or=75 years. DSE and EST were performed before enrollment in a cardiac rehabilitation program; for prognostic assessment, end points were all-cause mortality and hard cardiac events (cardiac death or nonfatal myocardial infarction).

RESULTS

During DSE, G2 patients showed worse wall motion score index (WMSI), but the test was stopped for complications in a comparable proportion of cases (54 G1 and 19 G2 patients, P = NS). EST was inconclusive in similarly high proportion of patients in both groups (76% in G1 vs. 84% in G2, P = NS); G2 patients reached a significantly lower total workload (6 +/- 1.6 METs in G1 vs. 5 +/- 1.2 METs in G2, P < 0.001). At multivariate analysis, a lower peak exercise capacity (HR 0.566, CI 0.351-0.914, P = 0.020) was associated with higher mortality, while a high-dose WMSI >2 (HR 5.123, CI 1.559-16.833, P = 0.007), viability (HR 3.354, CI 1.162-9.678, P = 0.025), and nonprescription of beta-blockers (HR 0.328, CI 0.114-0.945, P = 0.039) predicted hard cardiac events.

CONCLUSION

In patients with known CAD, EST and DSE maintain a significant prognostic role in terms of peak exercise capacity for EST and of presence of viability and an extensive wall motion abnormalities at peak DSE.

Prognostic value of ankle-brachial index and dobutamine stress echocardiography for cardiovascular morbidity and all-cause mortality in patients with peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) is associated with an excessive risk for cardiovascular events and mortality. To determine measures prognostic of adverse events, ankle-brachial index (ABI) was compared with dobutamine stress echocardiography (DSE) in patients referred to our vascular center for the evaluation of PAD.

METHODS

The medical records of consecutive patients referred for the concurrent evaluation of PAD and coronary artery disease (CAD) between 1992 and 1995 were reviewed for subsequent cardiovascular events and death.

RESULTS

Among 395 patients (mean age, 69.7 +/- 9.6 years; 40% women), 341 had abnormal ABI and 268 had abnormal DSE (95 fixed and 173 stress-induced wall motion abnormalities). During a mean follow-up of 4.7 years, 27.3% of patients experienced a cardiovascular event, and 39.4% died. By multivariate analysis, ABI provided the strongest prediction of all-cause mortality (hazard ratio [HR], 2.34; 95% confidence interval [CI], 1.36 to 4.05; P = .002). Conversely, DSE with inducible or fixed wall motion abnormalities showed no association with cardiovascular events or increased mortality in multivariate analysis. The only DSE variable independently predictive of mortality was decreased left ventricular ejection fraction (<50%) at peak stress (HR, 1.70; 95% CI, 1.22 to 2.36; P = .002). Statin and aspirin therapy, but not beta-blockers, were protective. There was no relation between ABI and wall motion index score at rest or after stress.

CONCLUSIONS

In high-risk patients referred to our vascular center for the evaluation of PAD, the assessment of ABI provided a strong independent prediction of all-cause mortality. Therefore, proper interpretation of this simple, affordable, and reproducible measure extends beyond the assessment of PAD severity. Although a poor left ventricular response to dobutamine was also predictive, other echo variables were not.

Preoperative Exercise Echocardiography and Perioperative Cardiovascular Outcomes in Elderly Patients Undergoing Cancer Surgery

Limited information is available on the value of exercise echocardiography (EE) for identifying operative risk in elderly patients undergoing noncardiac surgery. The authors investigated the outcome in 221 consecutive patients 75 years and older who had EE before intermediate- or high-risk cancer surgery. Baseline clinical data, postoperative adverse cardiovascular events (PACE), and 30-day mortality were collected from the medical records and the Social Security Death Index. The mean age +/- SD of the group was 78.9+/-3.5 years; 57% were men. Significant cardiovascular abnormalities (by echocardiography) were present in 71.5%. Mean metabolic equivalents +/- SD achieved during exercise was 4.9+/-1.9. EE identified 50 (22.6%) patients with ischemia and/or infarction. Perioperative beta-blockers were used in 80% of patients with coronary artery disease vs 48.5% without coronary artery disease (P<.0001). There were 31 PACE in 26 (11.8%) patients. Atrial fibrillation was the most common PACE, seen in 18 (8.1%) patients, followed by congestive heart failure in 8 (3.6%), acute coronary syndrome in 2 (0.9%), and cardiac arrest in 1 (0.5%). Thirty-day mortality was only 0.9%. Hospital lengths of stay for patients with and without PACE were 16.8+/-14.9 and 8.5+/-4.8 days (P< or =.0001), respectively. An abnormal EE predicted PACE (22% vs 8.8%; P< .025). Perioperative beta-blockers reduced the incidence of postoperative atrial fibrillation (4.9% vs 12.2%; P=.052). In conclusion, EE is feasible in very elderly patients. There is a high prevalence of cardiac abnormalities in the elderly. An abnormal EE predicts PACE, which, in turn, is associated with increased length of stay.

Stress Echocardiography in Octogenarians: Transesophageal Atrial Pacing is Accurate, Safe, and Well Tolerated

The feasibility and diagnostic accuracy of transesophageal pacing stress echocardiography for detection of inducible myocardial ischemia were evaluated in 161 patients 80 years of age or older (mean 84 +/- 3.9, range 80-97). The pacing time was 5.5 +/- 2.5 minutes with a total test time of 37 +/- 7 minutes. The mean achieved heart rate was 96 +/- 7% (83%-121%) of maximum predicted with an average rate pressure product of 21,560 +/- 5175 beats/min x mm Hg. There were minor adverse events in 8% of cases and no major complications occurred. Patient acceptance was high. When compared with myocardial single photon emission computed tomography, pacing stress echocardiography had a sensitivity of 89% and a specificity of 93% for the detection of myocardial ischemia, and 91% agreement (kappa = 0.80, P < .001). We demonstrate that pacing stress echocardiography is safe and accurate for detection of myocardial ischemia and, thus, a reliable substitute to exercise and pharmacologic stress testing in octogenarians.

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.

Long-Term Prediction of Mortality in Elderly Persons by Dobutamine Stress Echocardiography

BACKGROUND

Dobutamine stress echocardiography (DSE) was shown to provide incremental prognostic information. However, its role in the prediction of mortality in elderly persons is not well defined. We assessed the value of DSE in the prediction of mortality and hard cardiac events during long-term follow-up in patients older than 65 years.

METHODS

We studied 1434 patients >65 years old (mean age 72 +/- 3 years) who underwent DSE for evaluation of coronary artery disease. Ischemia was defined as new or worsening wall motion abnormalities. Follow-up events were total mortality and hard cardiac events (cardiac mortality and nonfatal myocardial infarction). Multivariable Cox regression analysis was used to identify the independent predictors of follow-up events.

RESULTS

Ischemia was detected in 675 patients (47%). Five hundred six patients (35%) had a normal study, and 253 (18%) had fixed wall motion abnormalities. During a mean follow-up of 6.5 years, 532 (37%) deaths occurred, of which 249 (17%) were due to cardiac causes. A nonfatal myocardial infarction occurred in 45 patients (3%). Independent predictors of all-cause mortality in a multivariate analysis model were age (hazard ratio [HR] 1.06; 95% confidence interval [CI], 1.05-1.08), male sex (HR 1.5; 95% CI, 1.2-1.8), hypertension (HR 1.2; 95% CI, 1.1-1.4), smoking (HR 1.3; 95% CI, 1.1-1.6), diabetes (HR 1.4; 95% CI, 1.1-1.8), rest wall motion abnormalities (HR 1.07; 95% CI, 1.06-1.09), and ischemia (HR 1.3; 95% CI, 1.1-1.6). Independent predictors of hard cardiac events were age (HR 1.07; 95% CI, 1.05-1.09), male sex (HR 1.3; 95% CI, 1.1-1.7), smoking (HR 1.3; 95% CI, 1.1-1.6), diabetes (HR 1.6; 95% CI, 1.2-2.2), rest wall motion abnormalities (HR 1.13; 95% CI, 1.12-1.16), and ischemia (HR 2.1; 95% CI, 1.5-2.8).

CONCLUSION

DSE provides independent prognostic information to predict all-cause mortality and hard cardiac events in elderly patients.

The use of stress echocardiography for prognostication in coronary artery disease: an overview

PURPOSE OF REVIEW

Stress echocardiography has a high accuracy for the detection of coronary artery disease. Additionally, it provides clinically useful prognostic information, such as resting left ventricular function, myocardial viability, stress-induced ischemia, vascular extent of wall motion abnormalities, and changes in end-systolic volume and ejection fraction with stress.

RECENT DEVELOPMENTS

The timing, extent, and severity of the stress-induced wall motion abnormalities are important determinants of long-term prognosis. Previous studies have shown the efficacy of stress echocardiography in predicting long-term cardiac events in mixed patient groups and the value of this test in selected patient subsets.

SUMMARY

This review attempts to define the role of stress echocardiography for prognostication in coronary artery disease, pointing out the ability of this technique to identify low-risk and high-risk subsets among patients with known or suspected coronary artery disease and thus guide patient management decisions.

Atrial fibrillation in dobutamine stress echocardiography

OBJECTIVES

To describe the incidence of atrial fibrillation induced by dobutamine stress echocardiography and characterize patients at risk of developing atrial fibrillation, by constructing a simple validated risk score index.

DESIGN

An observational study using prospectively collected data.

METHODS

3800 consecutive patients in sinus rhythm undergoing dobutamine stress echocardiography were randomly divided to a case (2/3) and test group (1/3). Associations of predetermined demographic, clinical, electrocardiographic and echocardiographic variables were calculated in patients with and without atrial fibrillation induced by dobutamine stress echocardiography in the case group. Logistic regression analysis determined significant independent risk predictors, a scoring index was constructed and validated on the test group.

RESULTS

There was a 2% incidence of dobutamine stress echocardiography-induced atrial fibrillation in the study population. Risk predictors of atrial fibrillation included: a history of atrial fibrillation (2 points), increased left atrial diameter, right bundle branch block, decreased rest heart rate and hypertension (1 point each). The case subgroup low-risk patients (score 0-2) had a 1% risk, moderate-risk patients (score 3) a 2.7% and high-risk patients (score 4-6) a 14.5% risk of developing atrial fibrillation during dobutamine stress echocardiography. The rates in the test subgroup were 1%, 3.8% and 15.3%, respectively.

CONCLUSION

Atrial fibrillation during dobutamine stress echocardiography is not common, the risk of developing atrial fibrillation during dobutamine stress echocardiography can be predicted by using a simple risk score system comprised of clinical, electrocardiographic and rest echocardiographic variables, which may be of help when planning a dobutamine stress echocardiography test in selected cases.

Safety and cardiac chronotropic responsiveness to the early injection of atropine during dobutamine stress echocardiography in the elderly

OBJECTIVE

To determine the safety and cardiac chronotropic responsiveness to early atropine dobutamine stress echocardiography (DSE) in the elderly.

DESIGN

Retrospective study of 258 patients >or= 70 years who underwent early atropine DSE and 290 patients >or= 70 years who underwent conventional DSE. In the early atropine protocol, atropine was started at 20 microg/kg/min of dobutamine if heart rate was < 100 beats/min, up to 2 mg. The cardiac chronotropic responsiveness in the elderly was compared with a control group of patients < 70 years matched for sex, myocardial infarction, diabetes, and treatment with beta blockers and calcium channel blockers.

RESULTS

The dose of dobutamine given to elderly patients was lower during early atropine than during conventional DSE (mean (SD) 29 (7) v 38 (4) microg/kg/min, p = 0.001). Early atropine DSE resulted in diminished incidence of ventricular extrasystoles, non-sustained ventricular tachycardia, bradycardia, and hypotension compared with conventional DSE. In comparison with patients < 70 years, elderly patients required lower doses of dobutamine and atropine and achieved a higher percentage of predicted maximum heart rate (92 (9)% v 88 (10)%, p = 0.0001). Except for more common hypotension (16% v 10%, p = 0.004), no other difference in adverse effects was observed between patients >or= 70 and < 70 years.

CONCLUSIONS

Early atropine DSE is a safe strategy in the elderly resulting in lower incidence of minor adverse effects than with the conventional protocol. Elderly patients presented adequate cardiac chronotropic responsiveness to early injections of atropine, requiring lower doses of drugs to reach test end points.

Adenosine stress myocardial perfusion tomographic imaging in patients with significant aortic stenosis

BACKGROUND

Myocardial perfusion scintigraphy has been used by some investigators for the diagnosis of coronary artery disease (CAD) in patients with mild, moderate, and moderate to severe aortic stenosis, with various results. The aim of this study was to assess the safety and diagnostic accuracy of adenosine stress myocardial perfusion scintigraphy (adenosine single photon emission computed tomography [Ad-SPECT]) for the detection of CAD in patients with significant aortic stenosis.

METHODS AND RESULT

The study included 75 patients with significant aortic stenosis (maximal instantaneous aortic valve gradient >80 mm Hg [range, 81-149 mm Hg] and aortic valve area <0.75 cm2). All patients underwent Ad-SPECT after a 6-minute infusion of adenosine (140 microg/kg body weight per minute). At the third minute of adenosine infusion, a bolus of 3 mCi thallium 201 was injected, and SPECT acquisition was obtained immediately after completion of adenosine infusion. Coronary angiography was performed in all patients. No major complications during adenosine infusion were observed. All unpleasant symptoms lasted for only a few seconds and did not necessitate cessation of the test. Concerning the angiographically diagnosed CAD, we found that Ad-SPECT showed a sensitivity of 88.6%, a specificity of 72.5%, a positive predictive value of 73.8%, a negative predictive value of 87.8%, and a diagnostic accuracy of 80%.

CONCLUSIONS

Ad-SPECT is a moderately accurate method for detecting the presence or absence of CAD in patients with severe aortic stenosis. However, further modification of this method is required before it can supplant cardiac catheterization in the preoperative evaluation of patients with severe aortic stenosis.

Use of pharmaceuticals in noninvasive cardiovascular diagnosis

A number of pharmaceuticals are employed as diagnostic agents for cardiovascular diseases. Four groups of agents are reviewed here: 1) vasoactive substances employed as adjuncts to physical maneuvers in diagnosis of structural heart disease; 2) vasodilators used to produce heterogeneity of coronary flow; 3) sympathomimetic agents simulating the effects of exercise on the heart for the purpose of detection of coronary artery stenosis; and 4) ultrasonic contrast agents used to enhance myocardial imaging for the assessment of segmental wall motion. In the first group are amyl nitrate, a vasodilator, and methoxamine and phenylephrine, both vasopressors. The vasodilators of the second group are dipyridamole and adenosine. When combined with scintigraphic perfusion imaging or with echocardiographic assessment of segmental wall motion, these agents can detect single- or multiple-vessel coronary artery disease with sensitivity and specificity comparable to submaximal exercise. They are especially useful for preoperative risk assessment before noncardiac surgery. The sympathomimetic agents of the third group, dobutamine and arbutamine, increase myocardial contractility and heart rate, and dilate the peripheral vasculature. As with the vasodilators, when combined with nuclear or echocardiographic techniques they are equivalent to exercise in detection of coronary disease. They are especially useful in patients with bronchospastic disease and for assessment of myocardial viability. Agents from groups 2 and 3 have acceptable side-effect and safety profiles. The last group reviewed includes echocardiographic contrast agents that, in this investigative setting, are employed to enhance detection of segmental wall motion when used with agents from groups 2 and 3.

Age-related determinants of outcome after acute myocardial infarction: a dobutamine-atropine stress echocardiographic study

OBJECTIVES

To investigate the cause of worse survival in older patients after myocardial infarction (MI).

DESIGN

Prospective 18-month and longer follow-up study of a cohort of 167 patients (mean age +/- standard deviation 58 +/- 12, including 71 aged >or=65) with acute MI for cardiac events, defined as cardiac death, recurrent MI, or resuscitated ventricular tachycardia or fibrillation (VT/VF).

SETTING

Milwaukee County Medical Complex and the Zablocki Veterans Affairs Medical Center, Milwaukee, WI.

PARTICIPANTS

One hundred sixty-seven patients who underwent dobutamine-atropine stress echocardiography (DASE) in the first week (2-7 days) after acute MI and were medically managed.

MEASUREMENTS

Comparison of event rates in older (>or=65 years) and younger (<65 years) patients and of clinical, resting echocardiographic, DASE, and angiographic findings in patients with and without events. Coronary angiography was performed in 141.

RESULTS

Older and younger patients tolerated DASE well. During follow-up, there were 29 cardiac events (cardiac death in 17, nonfatal MI in 10, and VT/VF in 2). Events were more common in older patients (26% vs 12%, P <.05), especially death (19% vs 5%, P <.05). Scar size in the infarct zone by DASE was larger (4.0 +/- 2.8 vs 3.0 +/- 2.7 segments, P <.05) and remote wall motion abnormalities more common (47 vs 29%, P <.05) in older patients. Univariate determinants of outcome (P <.05) in older patients were diabetes mellitus; remote wall motion abnormalities; angiographic multivessel disease; scar size; ejection fraction; and resting, low-, and peak-dose wall motion score. Univariate determinants in younger patients were similar, but diabetes mellitus was not. Multivariate analysis revealed that remote wall motion abnormalities and scar size by DASE were independently predictive of outcome in older and younger patients and diabetes mellitus only in older patients. Low- and peak-dose DASE data enhanced (P <.01) the prediction of outcome in all patients with acute MI relative to clinical data and resting echocardiography.

CONCLUSION

DASE was more predictive of outcome than clinical data and resting echocardiography in both age groups. Scar size and remote wall motion abnormalities were the primary determinants of outcome irrespective of age. The worse prognosis of older patients correlated with diabetes mellitus, greater scar size, and higher incidence of remote inducible ischemia.

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.

Stress testing in the elderly

The ever-increasing number of older patients requiring diagnostic and prognostic assessment for coronary artery disease has necessitated accurate, noninvasive techniques applicable to this age group. Exercise testing, either alone or with radionuclide or echocardiographic imaging, remains a useful tool in elderly patients capable of performing vigorous treadmill or cycle exercise. Fortunately, for the large elderly subset incapable of such exercise, pharmacologic stress testing with dipyridamole, adenosine, or dobutamine offers an excellent alternative. Choosing the most appropriate stress testing modality for a given patient from among the many choices available remains the clinician's challenge.

Prognostic power of dobutamine echocardiography after uncomplicated acute myocardial infarction in the elderly

STUDY OBJECTIVES

To assess the prognostic value of dobutamine-atropine stress echocardiography (DSE) after uncomplicated acute myocardial infarction (AMI) in elderly patients.

DESIGN

We analyzed 59 consecutive patients (42 men) aged > or = 70 years (mean +/- SD age, 75 +/- 4 years) who underwent DSE within 10 days after uncomplicated AMI. DSE was carried out following the standard protocol. Five myocardial responses were considered: (1) negative, (2) sustained improvement of contractility, (3) biphasic response (initial improvement followed by worsening), (4) worsening of contractility in the infarcted area, and (5) worsening at a distance.

RESULTS

Mean follow-up duration was 13 +/- 8 months. Twenty-one patients had an event: cardiac death (n = 5), myocardial infarction (n = 1), heart failure (n = 1), unstable angina (n = 10), and revascularization (n = 4). Clinical and stress echocardiographic variables previously related to adverse prognosis were entered in Cox regression analysis, and the predictors of impaired outcome were inducible ischemia during DSE (hazard ratio [HR], 2.97; 95% confidence interval [CI], 1.77 to 4.99; p < 0.001) and resting wall motion score index (WMSI) > 1.6 (HR, 1.68; 95% CI, 1.02 to 2.77; p = 0.04). After excluding revascularization procedures and considering only spontaneous events, the following predictors were found: ischemia during DSE (HR, 2.95; 95% CI, 2.78 to 3.12; p < 0.001) and resting WMSI > 1.6 (HR, 2.53; 95% CI, 1.30 to 4.93; p = 0.006).

CONCLUSIONS

Inducible ischemia during DSE within 10 days after uncomplicated AMI predicts an impaired outcome in the elderly.

Dobutamine stress echocardiography: safety in diagnosing coronary artery disease

Dobutamine stress echocardiography is considered a relatively well-tolerated diagnostic modality, effective in the management of patients with known or suspected coronary artery disease. Adverse effects during testing are relatively frequent, precluding the achievement of a diagnostic end-point in about 5 to 10% of tests. These adverse effects, mostly tachyarrhythmias and arterial hypotension, are usually minor and self limiting. However, severe life-threatening complications, as well as death, also occur. By analysing Medline-quoted literature up to March 1999, we found 35 original studies from a single institution with more than 100 patients, as well as 2 multicentre studies, concerning the feasibility and safety of dobutamine stress echocardiography. In a cumulative total of 26438 tests performed, 79 life-threatening complications (such as acute myocardial infarction, asystole, ventricular fibrillation, sustained ventricular tachycardia or severe symptomatic hypotension) have been reported, giving an incidence of 1 severe adverse reaction per every 335 examinations. In addition, 29 isolated case reports have been published describing life-threatening complications during dobutamine echocardiography. In case reports, 2 deaths have been described, both due to acute cardiac rupture in patients with recent inferior myocardial infarction. Severe adverse reactions during dobutamine echocardiography can be ischaemia independent, and are independent of operator experience and are unpredictable; some complications can be late occurring and long lasting. As a consequence, the procedure must be clearly indicated, written informed consent has to be obtained from the patient, an attending physician must be present during testing, and long term observation of outpatients is useful in order to manage late complications. In conclusion, while the safety of dobutamine stress echocardiography was reported to be outstanding in early reports, further experience presents a substantially more worrying picture. This must be taken into account by both physicians and patients when assessing the risk-benefit profile of the procedure.

Safety, hemodynamic profile, and feasibility of dobutamine stress technetium myocardial perfusion single-photon emission CT imaging for evaluation of coronary artery disease in the elderly

OBJECTIVES

Cardiovascular disease is the leading cause of morbidity and mortality in the elderly. The evaluation of coronary artery disease by exercise stress testing is frequently limited by the patient's inability to exercise. Although pharmacologic stress testing with dobutamine is an alternative, the safety of dobutamine myocardial perfusion scintigraphy in the elderly has not been previously studied.

PATIENTS AND METHODS

We studied the safety and feasibility of dobutamine (up to 40 microg/kg/min)-atropine (up to 1 mg) stress myocardial perfusion scintigraphy using technetium single-photon emission CT imaging in 227 patients > or = 70 years old (mean +/- SD age, 75 +/- 4 years). A control group of 227 patients < 70 years old (mean age, 55 +/- 11 years; matched for gender, prevalence of previous infarction, beta-blocker therapy, and severity of resting perfusion abnormalities) was studied to assess age-related differences in the safety and the hemodynamic response. A feasible test was defined as the achievement of the target heart rate and/or an ischemic end point (angina, ST-segment depression, or reversible perfusion abnormalities).

RESULTS

No myocardial infarction or death occurred during the test. The target heart rate was achieved more frequently in the elderly patients (87% vs 79%; p < 0.05). The elderly patients had a higher prevalence of supraventricular tachycardia (7% vs 1%; p < 0.005) and premature ventricular contraction (74% vs 32%; p < 0.005) during the test, as compared to the younger patients. There was a trend to a higher prevalence of ventricular tachycardia (5% vs 2%) and atrial fibrillation (3% vs 0.4%) in the elderly patients. Arrhythmias were terminated spontaneously by termination of dobutamine infusion or by administration of metoprolol. Independent predictors of supraventricular tachyarrhythmias and ventricular tachycardia were older age (p < 0.001; chi(2), 9.8) and myocardial perfusion defect score at rest (p < 0.01; chi(2), 6.8) respectively, by using a multivariate analysis of clinical and stress test variables. Elderly patients had a higher prevalence of systolic BP drop > 20 mm Hg during the test (37% vs 12%; p < 0.05). The test was terminated due to hypotension in 2% of the elderly patients and in 1% of the control group. Age was the most powerful predictor of hypotension (p < 0.005; chi(2), 10.3). The test was considered feasible in 216 elderly patients (95%) and in 209 patients of the control group (92%).

CONCLUSION

Dobutamine-atropine stress myocardial perfusion scintigraphy is a highly feasible method for the evaluation of coronary artery disease in the elderly. Elderly patients have a higher risk for developing hypotension and supraventricular tachyarrhythmias during a dobutamine stress test. However, dobutamine-induced hypotension is often asymptomatic and rarely necessitates the termination of the test.

Detection of coronary artery disease in patients with severe aortic stenosis with noninvasive methods

Exercise stress ECG testing is not generally recommended in patients with severe aortic stenosis. Analysis of the utility of exercise testing, both with and without the use of myocardial thallium-201 scintigraphy for the diagnosis of coronary artery disease (CAD), yielded low specificity. A noninvasive, safe, and accurate diagnostic modality to ascertain the presence of CAD is not available to date for patients with severe aortic stenosis. The aim of this study was to assess the safety and diagnostic accuracy of adenosine stress echocardiography (A-Stress-Echo) and of adenosine stress myocardial perfusion scintigraphy (A-SPECT), for the detection of CAD in patients with severe aortic stenosis. The study included 50 patients with severe aortic stenosis (maximal instantaneous aortic valve gradient >80 mmHg, range 81 to 144 mmHg, and aortic valve area <0.75 cm2). All patients were submitted to A-Stress-Echo, after a 6-minute infusion of adenosine (140 microg/kg body weight/min), and then (>3 days later) A-SPECT with the same dosage of adenosine as above. Coronary angiography was performed in all patients. No major complications were observed. The unpleasant symptoms were brief and did not necessitate cessation of the test. Both modalities showed the same sensitivity (85% for A-SPECT and 85% for A-Stress-Echo) angiographically diagnosed CAD while A-Stress-Echo yielded much higher specificity (96.7% vs 76.7%). Concordance of the two methods was found in 40 cases and the specificity for those patients was 100%. A-Stress-Echo and A-SPECT, either separately or in combination, constitute excellent and safe noninvasive diagnostic methods in detecting CAD in patients with severe aortic stenosis.

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

BACKGROUND AND PURPOSE

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

RESULTS

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

CONCLUSIONS

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