Prognostic value of pharmacologic stress echocardiography in patients with left bundle branch block

Updated knowledge and practical implementations of stress echocardiography in ischemic and non-ischemic cardiac diseases: an expert consensus of the Working Group of Echocardiography of the Hellenic Society of Cardiology

Stress echocardiography (SE) is a well-established and valid technique, widely-used for the diagnostic evaluation of patients with ischemic and non-ischemic cardiac diseases. This statement of the Echocardiography Working Group of the Hellenic Society of Cardiology summarizes the consensus of the writing group regarding the applications of SE, based on the expertise of their members and on a critical review of current medical literature. The main objectives of the consensus document include a comprehensive review of SE methodology and training, focusing on the preparation, the protocols used and the analysis of the SE images and an updated, evidence-based knowledge about SE applications on ischemic and non-ischemic heart diseases, such as in cardiomyopathies, heart failure and valvular heart disease.

[The Clinical use of Stress Echocardiography in Ischemic Heart Disease Cardiovascular Ultrasound (2017)15:7. Translation authors: Arystan A.Zh., Fettser D.V.]

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows detecting myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependence on operator expertise, the lack of outcome data (a widespread problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

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.

The clinical use of stress echocardiography in ischemic heart disease

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows to detect myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician.

The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependance on operator expertise, the lack of outcome data (a widesperad problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

Stress echocardiography in the district hospital setting: a cost-saving analysis

AIMS

Accurate and cost-effective techniques are required for investigating patients experiencing chest pain, given the significant workload this patient cohort represents. We determined the cost impact of stress echocardiography compared with myocardial perfusion scintigraphy and coronary angiography in the investigation of patients with chest pain deemed unsuitable for exercise treadmill testing.

METHODS AND RESULTS

A total of 200 patients with chest pain-with a low-intermediate probability of coronary artery disease-consecutively referred for stress echocardiography were recruited. Referring clinicians were asked which management strategy they would have chosen were the stress echocardiography service unavailable. The cost saving of stress echocardiography, an accuracy analysis, and adverse outcomes at 6 and 24 months follow-up were determined. The total cost attributable to the stress echocardiography service was Pound Sterling 58 368. If unavailable, 78 (39%) patients would have been referred for angiography and 122 (61%) for perfusion scintigraphy at a cost of Pound Sterling 56 316 and Pound Sterling 42 090, respectively, with a total cost of Pound Sterling 98 406. This represents a cost saving of Pound Sterling 40 038.

CONCLUSION

Stress echocardiography is a cost saving method for the investigation of chest pain in patients with low-intermediate risk of flow limiting coronary artery disease in the district hospital setting.

Stress-induced QTc-interval shortening as an ancillary marker of ischemia in patients with complete left bundle branch block

BACKGROUND

In patients with left bundle branch block (LBBB), ischemia-induced repolarization changes associated with QTc-interval shortening may be recorded during coronary angioplasty. We aimed to assess whether these repolarization changes may be predictive of severe coronary artery disease in patients with LBBB.

METHODS

Fifty noninfarcted LBBB patients underwent dipyridamole stress test and coronary angiography for chest pain. To localize the site of ischemia, we considered four groups of conventional ECG leads (V1-V2-V3; V4-V5-V6; aVL-I; III-aVF-II), exploring the anteroseptal, lateral, high-lateral, and inferior left ventricular walls. ST-T changes and QTc intervals were estimated at rest and peak stress, lead by lead, in each group of leads and the fractional percentage difference between rest-stress QTc intervals ([DELTA]QTc) was calculated. A [DELTA]QTc greater than -10% was used to define significant QTc-interval shortening. Coronary stenosis of more than 70% and more than 90% were considered 'significant' and 'severe'.

RESULTS

According to dipyridamole stress test response, two groups were identified: group I (35 patients) with dipyridamole-induced ischemia and group II (15 patients) without dipyridamole-induced ischemia. The wall motion score index at peak stress (compared with resting wall motion score index) was significantly higher in group I (1.98 +/- 0.13 vs. 1.28 +/- 0.08, P < 0.0001) than in group II (1.36 +/- 0.18 vs. 1.25 +/- 0.08, P = 0.296). The patients of group I showed a significant QTc-interval shortening ([DELTA]QTc = -16.9 +/- 3.9%), whereas this did not happen in patients of group II ([DELTA]QTc = +8.8 +/- 2.4%, P < 0.0001). The patients of group I also had a more severe stenosis in the vessel related to the stress-induced dyssynergic area (I = 90.5 +/- 9.5 vs. II = 34.3 +/- 31.1%; P < 0.0001).

CONCLUSION

In patients with LBBB, stress-induced pseudonormalization pattern, associated with QTc-interval shortening, allows the identification of cardiac areas supplied by severely stenosed coronary arteries.

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

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

Utility of stress echocardiography in identifying significant coronary artery disease in patients with left bundle-branch block

HYPOTHESIS

The aim of the study was to determine the utility of stress echocardiography for identification of significant coronary artery disease (CAD) in higher-risk patients with an underlying left bundle-branch block (LBBB).

METHODS

Patients with LBBB undergoing stress echocardiography were divided into 2 groups: group 1 (no history MI), group 2 (history MI). Positive stress echocardiograms were compared with the presence of >50% luminal-diameter stenosis during coronary angiography. During the follow-up (FU) period, cardiac events were determined for hard and soft endpoints.

RESULTS

Sixty consecutive patients with LBBB underwent stress echocardiography. Twenty-eight patients had a positive stress echocardiogram (20 group 1; 8 group 2). Nineteen of these patients underwent coronary angiography (14 group 1; 5 group 2). In group 1, regional wall motion abnormality (RWMA) correlated with coronary anatomy in only 5 patients, while in group 2, RWMA correlated with coronary anatomy in only 2 patients. There were 12 false positives, with echocardiographic abnormalities identified. The positive predictive values in groups 1 and 2 were 35.7% and 40%, respectively. During the FU period, there was 1 mortality, 2 MI, 2 coronary revascularizations, and 6 hospitalizations (2 chest pain, 1 CHF, 3 coronary angiography). The negative predictive value for hard endpoints was 83%.

CONCLUSION

Stress echocardiography has a poor positive predictive value to identify significant angiographic CAD in higher-risk patients with LBBB; however, the negative predictive value for hard ischemic events is similar to patients without LBBB.

Accuracy of non-invasive techniques for diagnosis of coronary artery disease and prediction of cardiac events in patients with left bundle branch block: a meta-analysis

PURPOSE

Non-invasive evaluation of coronary artery disease (CAD) in patients with left bundle branch block (LBBB) has limitations inherent to different tests, and the relative merits of these tests are unclear. This meta-analysis assessed the accuracy of the frequently used non-invasive techniques, including exercise electrocardiography (ECG), myocardial perfusion imaging (MPI) and stress echocardiography (SE), for detection of CAD and prediction of cardiac events in patients with LBBB.

METHODS

A review was conducted of all reports on detection of CAD and prediction of cardiac events in patients with LBBB (published between January 1970 and December 2004), and revealed 55 diagnostic and nine prognostic reports with sufficient details to calculate test accuracy. Weighted (by sample size) sensitivity and specificity were calculated. Summary relative risk ratios (95% confidence intervals) were calculated.

RESULTS

Overall sensitivity was higher for exercise ECG and (quantitatively analysed) MPI than for SE (83.4% and 88.5% versus 74.6% respectively, p<0.0001). SE had a higher specificity (88.7%) than MPI (41.2%) and exercise ECG (60.1%) (p<0.0001). Based on analysis of eight reports, the relative risk of cardiac death or myocardial infarction in patients with an abnormal SE and MPI was elevated more than sevenfold, but it did not differ by imaging modality (p=0.9).

CONCLUSION

Meta-analysis of non-invasive CAD assessment in LBBB patients revealed that exercise ECG and MPI had the highest sensitivity, while SE had the highest specificity. The prognostic accuracy of MPI and SE appeared similar.

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.

Prognostic significance of chronotropic response to dobutamine stress echocardiography in patients with peripheral arterial disease

Chronotropic response is important during exercise stress testing. Less is known about its role after dobutamine stress echocardiography. In addition, limited information exists regarding the long-term prognostic value of dobutamine stress echocardiography in patients who have peripheral arterial disease. We studied 2,138 patients who had peripheral arterial disease (1,317 men, 70 +/- 10 years old) and who underwent dobutamine stress echocardiography. Follow-up was completed for all-cause mortality and cardiovascular morbidity (nonfatal myocardial infarction and coronary revascularization). Death and cardiovascular morbidity occurred in 961 patients (45%) and 348 patients (16%), respectively, during a follow-up of 6.1 +/- 2.7 years. Failure to achieve 85% of age-predicted maximal heart rate (hazard ratio [HR] 1.34, 95% confidence interval [CI] 1.16 to 1.54, p = 0.0001) and percent of abnormal segments at peak stress (HR/10% increment 1.04, 95% CI 1.01 to 1.07, p = 0.02) were independent predictors of mortality and morbidity (HR 1.35, 95% CI 1.06 to 1.71, p = 0.01 and HR 1.14, 95% CI 1.08 to 1.20, p <0.0001, respectively). The effect of not achieving the target heart rate during normal dobutamine stress echocardiography on 1-, 3-, 5-, and 10-year survival probabilities was comparable to that of ischemia (86% vs 88%, 75% vs 71%, 62% vs 59%, and 33% vs 32%, respectively; p = 0.8). In a stepwise multivariate model, dobutamine stress echocardiography had incremental value over clinical data and echocardiographic data at rest for predicting rates of mortality (model chi-square increase from 301 to 322, p <0.0001) and morbidity (model chi-square increase from 37 to 118, p <0.0001). In conclusion, chronotropic response and extent of abnormal segments at peak dobutamine stress provide incremental prognostic information in patients who have peripheral arterial disease.

Prognostic implications of intraventricular conduction defects in patients undergoing stress echocardiography for suspected coronary artery disease

PURPOSE

To investigate the prognostic implications of conduction defects in subjects without proven coronary artery disease who had been referred for stress echocardiography.

METHODS

The study sample consisted of 1230 patients (574 men and 656 women; mean [+/- SD] age, 63 +/- 10 years) who underwent stress echocardiography with dipyridamole (n = 780) or dobutamine (n = 450) to evaluate suspected coronary artery disease. A summary wall motion score (on a 1 to 4 scale) was calculated. Patients were followed for a mean of 41 +/- 27 months; mortality was the only endpoint.

RESULTS

Four hundred and twenty patients (34%) had intraventricular conduction defects on a resting electrocardiogram (173 with complete left bundle branch block, 98 with isolated right bundle branch block, 43 with right bundle branch block with left anterior hemiblock, and 106 with left anterior hemiblock). Ischemia at stress echo (new or worsening of preexisting wall motion abnormality) was found in 250 patients (20%). There were 56 deaths during follow-up; 138 patients underwent revascularization and were censored. Multivariate predictors of mortality were resting wall motion score index (hazard ratio [HR] = 6.0 per unit increase; 95% confidence interval [CI]: 2.3 to 16; P <0.0001), ischemia at stress echo (HR = 3.9; 95% CI: 2.2 to 6.7; P <0.0001), age >65 years (HR = 3.2; 95% CI: 1.7 to 5.9; P <0.0001), hypertension (HR = 1.8; 95% CI: 1.1 to 3.2; P = 0.03), and right bundle branch block with left anterior hemiblock (HR = 3.7; 95% CI: 1.8 to 7.5; P <0.0001). The other three forms of intraventricular conduction defects (left bundle branch block, isolated complete right bundle branch block, and left anterior hemiblock) were not associated with mortality in multivariate analyses, or among the 980 patients who did not have ischemia.

CONCLUSION

Right bundle branch block with left anterior hemiblock is an independent predictor of mortality in patients with suspected coronary artery disease undergoing stress echocardiography, whereas isolated right bundle branch block is associated with outcomes similar to those observed in patients with no conduction defects.

Stress echo results predict mortality: a large-scale multicenter prospective international study

OBJECTIVES

The purpose of this study was to assess the long-term value of pharmacologic stress echocardiography with either dipyridamole or dobutamine (DET) for prediction of cardiac death in patients with proven or suspected coronary artery disease (CAD).

BACKGROUND

Stress echocardiography is an established, cost-effective technique for the detection of CAD.

METHODS

From the Echo Persantine International Cooperative-Echo Dobutamine International Cooperative data bank, 7,333 patients (5,452 males; 59 +/- 10 years) underwent pharmacologic stress echocardiography with either high-dose dipyridamole (0.84 mg/kg over 10 min) (n = 4,984) or high-dose dobutamine (up to 40 microg/kg/3 min) (n = 2,349) for diagnostic purposes. Patients were followed up for a mean of 2.6 years (range 1 to 206 months).

RESULTS

The DET was positive for myocardial ischemia in 2,854 (35%) patients and negative in 4,479 (61%) patients. During the follow-up there were 161 cardiac deaths (sudden death and fatal myocardial infarction) (2.1% of the total population). Kaplan-Meier survival estimates showed a significantly better outcome for those patients with a negative pharmacologic stress echocardiography test compared with those with a positive test (92 vs. 71.2%, p = 0.0000).

CONCLUSIONS

Pharmacologic stress echocardiography with either dipyridamole or dobutamine is effective in predicting cardiac death during a long-term follow-up. A negative stress echocardiography test result is related to a favorable outcome.

Stress echocardiography: a historical perspective

Stress echocardiography is a popular cardiac imaging technique that provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging. Similar accuracy, however, should not be synonymous with being "clinically interchangeable." Because of economic cost, environmental impact, and individual biohazard exposure, a nuclear examination should be performed only when it cannot be replaced by other techniques that do not employ ionizing radiation. Nuclear medical imaging procedures, of which cardiological procedures are an important part, account for 4% of the annual effective radiation dose received by the average person in the United States. At the individual level, the radiological exposure of a single nuclear cardiology procedure conveys a low, but measurable, risk of fatal cancer, which varies from 1 in 1000 to 1 in 10,000, depending on the type of examination (higher for thallium scans; lower for technetium 99m methoxyisobutylisonitrile scans). Because the information provided by stress echocardiography and stress radionuclide perfusion imaging are similar, the choice of test should be made in the context of the environmental, biological, and economic effects of that choice.

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.

Safety, feasibility, and prognostic implications of pharmacologic stress echocardiography in 1482 patients evaluated in an ambulatory setting

BACKGROUND

The outpatient prognostic assessment of coronary artery disease (CAD) by exercise electrocardiography has limitations, including the feasibility of the test and its low positive predictive value in several clinical conditions. In the current study we investigated the safety, feasibility, and prognostic value of pharmacologic stress echocardiography in a large cohort of ambulatory patients.

METHODS

The study group was made of 1482 ambulatory patients (969 men, aged 60 +/- 10 years) who underwent stress echocardiography with either dipyridamole (n = 846) or dobutamine (n = 636) for evaluation of suspected or known stable CAD. The pretest likelihood of CAD was intermediate (<70%) in 709 patients and high (> or =70%) in 773 patients.

RESULTS

There was no complication during the dipyridamole test, whereas 2 ischemia-dependent, sustained ventricular tachycardias occurred during the dobutamine test. Limiting side effects were observed in 2% of dipyridamole and in 3% of dobutamine stresses. The echocardiogram was positive in 459 patients. During a mean follow-up of 28 +/- 24 months, 58 patients died, 33 had a nonfatal myocardial infarction, and 158 underwent early (< or =3 months) and 64 late (>3 months) revascularization. Multivariate predictors of hard events (death, infarction) were positive echocardiographic results (hazard ratio [HR] 2.9) and resting wall motion score index (WMSI) (HR 2.3). In considering major events (death, infarction, late revascularization) as end points, positive echocardiographic result (HR 4.3), scar (HR 2.2), and resting WMSI (HR 1.7) were independent prognostic predictors. The 5-year survival rates for the ischemic and nonischemic groups were, respectively, 80% and 91% (HR 3.6, 95% confidence interval [CI] 3.8-8.4; P <.0001) considering hard cardiac events and 65% and 88% (HR 2.6, 95% CI 2.1-5.9; P <.0001) considering major events. Multivariate predictors of major events were positive echocardiographic results (HR 8.2) and male sex (HR 2.5) for the intermediate-risk group and positive echocardiographic results (HR 2.9), resting WMSI (HR 1.8), and prior Q-wave myocardial infarction (HR 1.8) for the high-risk group.

CONCLUSIONS

Pharmacologic stress echocardiography is safe, highly feasible, and effective in prognostic assessment of ambulatory patients when both a general population and groups selected on the basis of pretest likelihood of CAD are analyzed. It represents a valid complementary tool to exercise electrocardiography for prognostic purposes in outpatients.