Prognostic value of dipyridamole echocardiography early after uncomplicated myocardial infarction: a large-scale, multicenter trial. The EPIC Study Group

[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.

Quality control of B-lines analysis in stress Echo 2020

BACKGROUND

The effectiveness trial "Stress echo (SE) 2020" evaluates novel applications of SE in and beyond coronary artery disease. The core protocol also includes 4-site simplified scan of B-lines by lung ultrasound, useful to assess pulmonary congestion.

PURPOSE

To provide web-based upstream quality control and harmonization of B-lines reading criteria.

METHODS

60 readers (all previously accredited for regional wall motion, 53 B-lines naive) from 52 centers of 16 countries of SE 2020 network read a set of 20 lung ultrasound video-clips selected by the Pisa lab serving as reference standard, after taking an obligatory web-based learning 2-h module ( http://se2020.altervista.org ). Each test clip was scored for B-lines from 0 (black lung, A-lines, no B-lines) to 10 (white lung, coalescing B-lines). The diagnostic gold standard was the concordant assessment of two experienced readers of the Pisa lab. The answer of the reader was considered correct if concordant with reference standard reading ±1 (for instance, reference standard reading of 5 B-lines; correct answer 4, 5, or 6). The a priori determined pass threshold was 18/20 (≥ 90%) with R value (intra-class correlation coefficient) between reference standard and recruiting center) > 0.90. Inter-observer agreement was assessed with intra-class correlation coefficient statistics.

RESULTS

All 60 readers were successfully accredited: 26 (43%) on first, 24 (40%) on second, and 10 (17%) on third attempt. The average diagnostic accuracy of the 60 accredited readers was 95%, with R value of 0.95 compared to reference standard reading. The 53 B-lines naive scored similarly to the 7 B-lines expert on first attempt (90 versus 95%, p = NS). Compared to the step-1 of quality control for regional wall motion abnormalities, the mean reading time per attempt was shorter (17 ± 3 vs 29 ± 12 min, p < .01), the first attempt success rate was higher (43 vs 28%, p < 0.01), and the drop-out of readers smaller (0 vs 28%, p < .01).

CONCLUSIONS

Web-based learning is highly effective for teaching and harmonizing B-lines reading. Echocardiographers without previous experience with B-lines learn quickly.

Integrated quadruple stress echocardiography

Stress echocardiography (SE) is an established diagnostic technique. For 40 years, the cornerstone of the technique has been the detection of regional wall motion abnormalities (RWMA), due to the underlying physiologically-relevant epicardial coronary artery stenosis. In the last decade, three new parameters (more objective than RWMA) have shown the potential to integrate and complement RWMA: 1) B-lines, also known as ultrasound lung comets, as a marker of extravascular lung water, measured using lung ultrasound with the 4-site simplified scan symmetrically of the antero-lateral thorax on the third intercostal space, from mid-axillary to anterior axillary and mid-clavicular line; 2) left ventricular contractile reserve (LVCR), assessed as the peak stress/rest ratio of left ventricular force, also known as elastance (systolic arterial pressure by cuff sphygmomanometer/end-systolic volume from 2D echocardiography); 3) coronary flow velocity reserve (CFVR) on left anterior descending coronary artery, calculated as peak stress/rest ratio of diastolic peak flow velocity assessed using pulsed-wave Doppler. The 4 parameters (RWMA, B-lines, LVCR and CFVR) now converge conceptually, logistically, and methodologically in the Integrated Quadruple (IQ)-SE. IQ-SE optimizes the versatility of SE to include in a one-stop shop the core "ABCD" (asynergy+B-lines+contractile reserve+Doppler flowmetry) protocol. It allows a synoptic assessment of parameters mirroring the epicardial artery stenosis (RWMA), interstitial lung water (B-lines), myocardial function (LVCR) and small coronary vessels (CFVR). Each variable has a clear clinical correlate, different and complementary to all others: RWMA identify an ischemic vs. non-ischemic heart; B-lines a wet vs. dry lung; LVCR a strong vs. weak heart; CFVR a warm vs. cold heart. IQ-SE is highly feasible, with minimal increase in the imaging and analysis time, and obvious diagnostic and prognostic impact also beyond coronary artery disease - especially in heart failure. Large scale effectiveness studies with IQ-SE are now under way with the Stress Echo 2020 Study, and will provide the necessary evidence base prior to large scale acceptance of the technique.

Stress Echocardiography Positivity Predicts Cancer Death

BACKGROUND

Stress echocardiography (SE) predicts cardiac death, but an increasing share of cardiac patients eventually die of cancer. The aim of the study was to assess whether SE positivity predicts cancer death.

METHODS AND RESULTS

In a retrospective analysis of prospectively acquired single-center, observational data, we evaluated 4673 consecutive patients who underwent SE from 1983 to 2009. All patients were cancer-free at index SE and were followed up for a median of 131 months (interquartile range 134). We separately analyzed predetermined end points: cardiovascular, cancer, and noncardiovascular, noncancer death, with and without competing risk. SE was positive in 1757 and negative in 2916 patients; 869 cardiovascular, 418 cancer, and 625 noncardiovascular, noncancer deaths were registered. The 25-year mortality was higher in SE-positive than in SE-negative patients, considering cardiovascular (40% versus 31%; P<0.001) and cancer mortality (26% versus 17%; P<0.01). SE positivity was a strong predictor of cancer (cause-specific hazard ratio 1.19; 95% confidence interval, 1.16-1.73; P=0.05) and cardiovascular mortality (1.18; 95% confidence interval, 1.03-1.35; P=0.02). Fine-Gray analysis to account for competing risk gave similar results. Cancer risk diverged after 15 years, whereas differences were already significant at 5 years for cardiovascular risk.

CONCLUSIONS

SE results predict cardiovascular and cancer mortality. SE may act as a proxy of the shared risk factor milieu for cancer or cardiovascular death.

Simple six-item clinical score improves risk prediction capability of stress echocardiography

Objectives

To assess the value of a simple score integrating non-ischaemia-related variables in expanding the wall motion abnormalities risk power during stress echocardiography (SE).

Methods

Study includes 14 279 patients who underwent SE for evaluation of coronary artery disease. All-cause death was the end point. Patients were randomly divided into the modelling and validation group of equal size. In the modelling group, multivariate analysis was conducted using clinical, rest and SE data, and a score was obtained from the number of non-ischaemia-related independent prognostic predictors. The score prognostic capability was compared in both groups.

Results

During a median follow-up of 31 months, 1230 patients died: 622 (9%) in the modelling and 608 (9%) in the validation group (p=0.68). Independent predictors of mortality were ischaemia at SE (HR 1.77, 95% CI 1.49 to 2.12; p<0.0001) and six other parameters: age>65 years, wall motion at rest, diabetes, left bundle branch block, anti-ischaemic therapy and male sex. Risk score resulted prognostically effective in the modelling and validation groups, both with and without inducible ischaemia subset. When risk score was included in the multivariate analysis, besides ischaemia at SE it was the only independent predictor of mortality in the modelling (HR 1.70, 95% CI 1.60 to 1.82; p<0.0001), in the validation (HR 1.77, 95% CI 1.65 to 1.90; p<0.0001) and in the overall group (HR 1.73, 95% CI 1.66 to 1.82; p<0.0001).

Conclusions

Simple clinical variables may be able to optimise SE risk stratification.

Quality control of regional wall motion analysis in stress Echo 2020

BACKGROUND

The trial "Stress Echo (SE) 2020" evaluates novel applications of SE beyond coronary artery disease. The aim of the study was control quality and harmonize reading criteria.

METHODS

One reader from 78 centers of the SE 2020 network asked for credentials to read a set of 20 SE video-clips selected by the core lab. All aspiring centers met the pre-requisite of high-volume and the years of experience in SE ranged from 5 to 31years (mean value 18years). The diagnostic gold standard was a reading by the core lab. The a priori determined pass threshold was 18/20 (≥90%).

RESULTS

Of the initial 78 who started, 57 completed the first attempt: individual readers' score on first attempt ranged from 07/20 to 20/20 (accuracy from 35% to 100%, mean 78.7±13%) and 44 readers passed it. There was a very poor correlation between years of experience and the reader's score on first attempt (r=-0.161, p=0.231). Of the 13 readers who failed the first attempt, 12 took it again after the web-based session and their accuracy improved (74% vs. 96%, p<0.001). The kappa inter-observer agreement before and after web-based training was 0.59 on first attempt and rose to 0.91 on the last attempt.

CONCLUSIONS

In SE reading, the volume of activity or years of experience is not synonymous with diagnostic quality. Qualitative analysis and operator-dependence can become a limiting weakness in clinical practice, in the absence of strict pathways of learning, credentialing and audit.

Coronary flow reserve/diastolic function relationship in angina-suffering patients with normal coronary angiography

AIMS

Coronary blood flow and diastolic function are well known to interfere with each other through mechanical and metabolic mechanisms. We aimed to assess the relationship between coronary flow reserve (CFR) and diastolic dysfunction in patients suffering from angina but with normal coronary angiography.

METHODS

In 16 patients with chest pain and angiographically normal coronary arteries, CFR was measured using transthoracic echo-Doppler by inducing hyperemia through dipyridamole infusion. Diastolic function (E/A, deceleration time, isovolumetric relaxation time [IVRT], propagation velocity [Vp]) and left ventricular mass were evaluated by means of two-dimensional transthoracic echocardiography.

RESULTS

The patients were initially divided into two groups on the grounds of CFR only (ACFR: altered CFR, n = 9; NACFR: unaltered CFR, n = 7). Thereafter they were divided into four groups on the grounds of CFR and diastolic function (NN: normal; AA: altered CFR/diastole; AN: altered CFR/normal diastole; NA: normal CFR/altered diastole). Most of the subjects were scheduled in AA (n = 8) or NA (n = 5) groups, which were taken into consideration for further analysis. Patients were not different regarding various risk factors. ACFR and AA patients were older with normal body weight in comparison with NACFR and NA patients (P < 0.05). In the AA group, CFR and diastolic variables were found to be related to each other.

CONCLUSION

Diastolic dysfunction and reduced CFR were correlated in patients with concomitant alterations of those variables only. Because most risk factors were shared with patients with altered diastolic properties only, our findings could represent a direct relationship between altered CFR and diastole.

Association Between Elevated Pulse Pressure and High Resting Coronary Blood Flow Velocity in Patients With Angiographically Normal Epicardial Coronary Arteries

BACKGROUND

The aim of our study was to evaluate the relationship of pulse pressure (PP), a raw index of arterial stiffness, with noninvasively determined coronary flow reserve (CFR) and its components, in patients with angiographically normal epicardial coronary arteries.

METHODS AND RESULTS

The study population included 398 patients without angiographic evidence of coronary stenosis, who underwent high-dose dipyridamole stress echocardiography with transthoracic-derived CFR evaluation on the left anterior descending artery. CFR was calculated as the ratio between high-dose dipyridamole and resting coronary diastolic peak velocities. Patients were divided into 2 groups: the first group included the first and second PP tertiles (n=298, PP ≤60 mm Hg) and the second group included the highest PP tertile (n=100, PP >60 mm Hg). Mean blood pressure, systolic blood pressure (both P<0.0001), age (P<0.002), and left ventricular mass index (P=0.013) were higher in the highest PP tertile, which also showed higher resting coronary flow velocity (31.6±9.6 cm/s versus 27.7±6.4 cm/s, P<0.0001) and marginally lower CFR (2.5±0.6 versus 2.6±0.6, P=0.044). Hyperemic coronary flow velocity did not differ between the 2 groups. By separate multiple linear regression analyses, after adjusting for sex, age, the highest systolic blood pressure tertile (≥140 mm Hg), left ventricular mass index, and cardiovascular risk factors, the highest PP tertile was associated with resting coronary flow velocity (P=0.003) and only marginally with hyperemic coronary flow velocity (P<0.02), whereas its association with CFR was not significant.

CONCLUSIONS

In patients without epicardial coronary artery stenosis, the highest PP tertile is associated with an increased coronary flow velocity at rest.

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 echo 2020: the international stress echo study in ischemic and non-ischemic heart disease

BACKGROUND

Stress echocardiography (SE) has an established role in evidence-based guidelines, but recently its breadth and variety of applications have extended well beyond coronary artery disease (CAD). We lack a prospective research study of SE applications, in and beyond CAD, also considering a variety of signs in addition to regional wall motion abnormalities.

METHODS

In a prospective, multicenter, international, observational study design, > 100 certified high-volume SE labs (initially from Italy, Brazil, Hungary, and Serbia) will be networked with an organized system of clinical, laboratory and imaging data collection at the time of physical or pharmacological SE, with structured follow-up information. The study is endorsed by the Italian Society of Cardiovascular Echography and organized in 10 subprojects focusing on: contractile reserve for prediction of cardiac resynchronization or medical therapy response; stress B-lines in heart failure; hypertrophic cardiomyopathy; heart failure with preserved ejection fraction; mitral regurgitation after either transcatheter or surgical aortic valve replacement; outdoor SE in extreme physiology; right ventricular contractile reserve in repaired Tetralogy of Fallot; suspected or initial pulmonary arterial hypertension; coronary flow velocity, left ventricular elastance reserve and B-lines in known or suspected CAD; identification of subclinical familial disease in genotype-positive, phenotype- negative healthy relatives of inherited disease (such as hypertrophic cardiomyopathy).

RESULTS

We expect to recruit about 10,000 patients over a 5-year period (2016-2020), with sample sizes ranging from 5,000 for coronary flow velocity/ left ventricular elastance/ B-lines in CAD to around 250 for hypertrophic cardiomyopathy or repaired Tetralogy of Fallot. This data-base will allow to investigate technical questions such as feasibility and reproducibility of various SE parameters and to assess their prognostic value in different clinical scenarios.

CONCLUSIONS

The study will create the cultural, informatic and scientific infrastructure connecting high-volume, accredited SE labs, sharing common criteria of indication, execution, reporting and image storage of SE to obtain original safety, feasibility, and outcome data in evidence-poor diagnostic fields, also outside the established core application of SE in CAD based on regional wall motion abnormalities. The study will standardize procedures, validate emerging signs, and integrate the new information with established knowledge, helping to build a next-generation SE lab without inner walls.

Prognostic role of stress echocardiography in hypertrophic cardiomyopathy: The International Stress Echo Registry

BACKGROUND

Stress echo (SE) may have a role in the outcome in patients with hypertrophic cardiomyopathy (HCM).

OBJECTIVES

The aim was to assess the prognostic value of SE in a retrospective multicenter study in HCM.

METHODS

We enrolled 706 HCM patients. The employed stress was exercise (n=608) and/or vasodilator (n=146, dipyridamole in 98 and adenosine in 48). We defined SE positivity according to clinical/hemodynamic criteria including: symptoms (all stress modalities), exercise-induced hypotension (failure to increase or fall >20mmHg, exercise) and exercise-induced left ventricular outflow tract obstruction (left ventricular outflow tract obstruction >50mmHg); and ischemic criteria, such as new wall motion abnormalities (new wall motion abnormality) and/or reduction of coronary flow reserve velocity (CFVR≤2.0) on left anterior descending coronary artery with vasodilator stress assessed in 116 patients. All patients completed the clinical follow-up.

RESULTS

Positive SE showed more frequently CFVR reduction, exercise-induced hypotension, left ventricular outflow tract obstruction, and symptoms (38, 23, 20 and 15% respectively), but new wall motion abnormality only in 6%. During a median follow-up of 49months 180 events were observed, including 40 deaths. Clinical/hemodynamic criteria did not predict outcome (X2 0.599, p=0.598), whereas ischemia-related SE criteria (X2: 111.120, p<0.0001) was significantly related to outcome. Similarly, mortality was predicted with SE ischemic-criteria (X2 16.645, p<0.0001).

CONCLUSIONS

SE has an important prognostic significance in HCM patients, with ischemia-related end-points showing greater predictive accuracy than hemodynamic endpoints. New wall motion abnormalities and impairment of CFVR should be specifically included in SE protocols for HCM.

Prediction of mortality by stress echocardiography in 2835 diabetic and 11 305 nondiabetic patients

BACKGROUND

To compare the capability by stress echocardiography results to predict overall mortality in a large unselected cohort of diabetic and nondiabetic patients.

METHODS AND RESULTS

The study group comprised 14 140 patients (2835 diabetics and 11 305 nondiabetics) who underwent stress echocardiography for evaluation of known (n=5671) or suspected (n=8469) coronary artery disease. Ischemia at stress echocardiography was observed in 768 (27%) diabetics and 2644 (23%) nondiabetics. During a median follow-up of 30 months (first quartile, 9; third quartile, 63), 1213 patients died. In diabetics, multivariable indicators of mortality were age (hazard ratio [HR], 1.07, 95% confidence interval [CI], 1.06-1.09), rest wall motion abnormality (HR, 2.43; 95% CI, 1.83-3.22), and ischemia at stress echocardiography (HR, 1.71; 95% CI, 1.34-2.18). In nondiabetics, multivariable indicators of mortality were age (HR, 1.07; 95% CI, 1.06-1.08), rest wall motion abnormality (HR, 2.19; 95% CI, 1.86-2.57), male sex (HR, 1.65; 95% CI, 1.41-1.93), ischemia at stress echocardiography (HR, 1.54; 95% CI, 1.32-1.80), and antischemic therapy at the time of test (HR, 1.15; 95% CI, 1.00-1.32). In stress echo negative subjects for ischemia, antischemic therapy showed increased annual mortality in nondiabetic patients with (3.8% versus 3.1%; P=0.04) or without rest wall motion abnormality (1.6% versus 0.9%; P<0.0001); it failed to do so in diabetic patients with (5.7% versus 5.8%; P=0.89) or without rest wall motion abnormality (2.6% versus 1.9%; P=0.10).

CONCLUSIONS

Ischemia at stress echocardiography is a strong and independent predictor of total mortality in diabetic as well as nondiabetic patients. Antischemic therapy markedly affects the negative predictive value of stress echocardiography in nondiabetic patients, whereas it is prognostically neutral in the diabetic population.

Dual imaging stress echocardiography versus computed tomography coronary angiography for risk stratification of patients with chest pain of unknown origin

Background

Dual imaging stress echocardiography, combining the evaluation of wall motion and coronary flow reserve (CFR) on the left anterior descending artery (LAD), and computed tomography coronary angiography (CTCA) are established techniques for assessing prognosis in chest pain patients. In this study we compared the prognostic value of the two methods in a cohort of patients with chest pain having suspected coronary artery disease (CAD).

Methods

A total of 131 patients (76 men; age 68 ± 9 years) with chest pain of unknown origin underwent dipyridamole (up to 0.84 mg/kg over 6 min) stress echo with CFR assessment of LAD by Doppler and CTCA. A CFR ≤ 1.9 was considered abnormal, while > 50% lumen diameter reduction was the criterion for significant CAD at CTCA.

Results

Of 131 patients, 34 (26%) had ischemia at stress echo (new wall motion abnormalities), and 56 (43%) had reduced CFR on LAD. Significant coronary stenosis at CTCA was found in 69 (53%) patients. Forty-six patients (84%) with abnormal CFR on LAD showed significant CAD at CTCA (p < 0.001). Calcium score was higher in patients with reduced than in those with normal CFR (265 ± 404 vs 131 ± 336, p = 0.04). During a median follow-up of 7 months (1st to 3rd quartile: 5–13 months), there were 45 major cardiac events (4 deaths, 11 nonfatal myocardial infarctions, and 30 late [≥6 months] coronary revascularizations). At Cox analysis, independent prognostic indicators were calcium score > 100 (HR 2.84, 95% CI 1.33-6.07, p = 0.007), significant CAD at CTCA (HR 2.68, 95% CI 1.23-5.82, p = 0.013), and inducible ischemia or CFR <1.9R on LAD on dual imaging stress echo (HR 2.25, 95% CI 1.05-4.84, p = 0.038).

Conclusions

Functional and anatomical evaluation using, respectively, dual imaging stress echocardiography and CTCA are both effective modalities to risk stratify patients with chest pain of unknown origin, yielding independent and comparable prognostic value. Compared to CTCA, however, stress echocardiography has the advantage of lower cost and of being free of radiations.

Imaging techniques in coronary atherosclerotic disease: dobutamine stress echocardiography--evidence and perspectives

Dobutamine stress echocardiography is the most widely disseminated noninvasive technique for the assessment of coronary artery disease. Its results are important for clinical decisions. It is a versatile technique with high sensitivity and specificity for detecting viable myocardium at jeopardy. More recently, strain rate imaging has been applied to stress echocardiography. This approach relies on tissue Doppler or two-dimensional strain imaging to quantify myocardial deformation. The application of contrast echocardiographic techniques to stress echocardiography enables left ventricular opacification for border enhancement and myocardial perfusion imaging. Thus, this application is not limited to stress echocardiography, but has utility whenever image quality adversely affects wall motion assessment. Recently, three-dimensional stress echocardiography imaging has been proposed as an alternative approach to assess myocardial ischemia.

Long-term prognosis in stable angina; medical treatment or coronary revascularization in patients younger than 70 years?

BACKGROUND

Literature on the appropriateness of coronary revascularization in chronic angina is still scanty. The study aimed to compare long-term effects of revascularization with those of medical therapy in stable angina.

METHODS

In an observational single center study, we assessed 10 year follow-up of 1442 consecutive patients with chronic angina, at least one coronary vessel disease, no previous myocardial infarction, screened for inducible ischemia. Patients>70 years were excluded. The event-free probabilities were estimated by Kaplan-Meier curves; all cause death, cardiac death, non-fatal myocardial infarction were the considered end points.

RESULTS

Age was 56±8 yrs. Global left ventricular function was preserved in all. Myocardial ischemia was documented in 1190 patients. Coronary disease was more severe in patients with inducible ischemia as compared to those with negative stress test (p<0.001); 868 patients underwent one revascularization procedure, 511 coronary angioplasty. Median follow-up was 106 months; 13% all cause deaths, 8% cardiac deaths, 6% non-fatal myocardial infarction were registered. When provocative test was negative revascularization did not improve survival (1% per year mortality irrespective of type of treatment). Conversely survival was significantly improved by revascularization when ischemia was documented (0.7% vs 1.8% per year mortality for revascularization vs medical therapy, p<0.05). Incidence of non-fatal myocardial infarction was low and similar in both groups.

CONCLUSION

In low-risk chronic angina coronary revascularization does not improve long-term prognosis unless inducible myocardial ischemia is present. This suggests considering coronary revascularization as an effective tool in treating coronary artery disease only when myocardial ischemia has been documented.

Cardiac imaging after myocardial infarction

After myocardial infarction, optimal clinical management depends critically on cardiac imaging. Remodelling and heart failure, presence of inducible ischaemia, presence of dysfunctional viable myocardium, future risk of adverse events including risk of ventricular arrhythmias, need for anticoagulation, and other questions should be addressed by cardiac imaging. Strengths and weaknesses, recent developments, choice, and timing of the different non-invasive techniques are reviewed for this frequent clinical scenario.

Clinical and prognostic role of pressure-volume relationship in the identification of responders to cardiac resynchronization therapy

BACKGROUND

The identification of responders remains challenging in cardiac resynchronization therapy (CRT). Pressure-volume relationship (PVR) is a method to evaluate left ventricular myocardial contractility during stress. The aim of the study was to assess the role of PVR to identify responders to CRT.

METHODS

Seventy-two patients (57% with ischemic etiology) referred to CRT: ejection fraction ≤ 35%, New York Heart Association ≥ III and QRS duration ≥ 120 milliseconds, underwent dobutamine stress echocardiography (up to 40 μg/kg per minute). PVR was defined as systolic cuff pressure/end-systolic volume index difference between rest-peak dobutamine stress echocardiography. Responders were identified by clinical and/or echocardiographic (end-systolic volume decrease ≥ 15%) follow-up criteria. We divided retrospectively the patient population into 2 groups, accordingly to the presence of myocardial contractile reserve that was set at the value of PVR (0.72 mm Hg/mL per square meter) obtained by a receiver operating characteristic analysis.

RESULTS

During a median follow-up of 12 months, 8 patients (11%) died. Patients with lower PVR, showed higher brain natriuretic peptide levels (853 ± 1211 vs 342 ± 239, P = .044) larger left ventricular end-diastolic (196 ± 82 mL vs 152 ± 39 mL, P = .005) and end-systolic (147 ± 66 vs 112 ± 30 mL, P = .006) volumes. Intraventricular dyssynchrony was similar in the 2 groups (88 ± 45 vs 70 ± 32 milliseconds, P = .175). Patients with higher PVR presented a larger incidence of clinical (86% vs 46% P < .001), and echocardiographic responders to CRT (79% vs 40%, P = .002). Event-free survival was significantly better in patients with higher PVR (log rank = 5.78, P = .01).

CONCLUSION

Patients with preserved contractility, assessed by PVR during stress echocardiography show a favor clinical outcome and left ventricular reverse remodeling after CRT. In particular, PVR may have a significant clinical role in patients undergoing CRT, providing critical information for risk stratification.

Feasibility of real-time three-dimensional stress echocardiography: pharmacological and semi-supine exercise

Background

Real time three dimensional (RT3D) echocardiography is an accurate and reproducible method for assessing left ventricular shape and function.

Aim

assess the feasibility and reproducibility of RT3D stress echocardiography (SE) (exercise and pharmacological) in the evaluation of left ventricular function compared to 2D.

Methods and results

One hundred eleven patients with known or suspected coronary artery disease underwent 2D and RT3DSE. The agreement in WMSI, EDV, ESV measurements was made off-line.

The feasibility of RT-3DSE was 67%. The inter-observer variability for WMSI by RT3D echo was higher during exercise and with suboptimal quality images (good: k = 0.88; bad: k = 0.69); and with high heart rate both for pharmacological (HR < 100 bpm, k = 0.83; HR ≥ 100 bpm, k = 0.49) and exercise SE (HR < 120 bpm, k = 0.88; HR ≥ 120 bpm, k = 0.78). The RT3D reproducibility was high for ESV volumes (0.3 ± 14 ml; CI 95%: -27 to 27 ml; p = n.s.).

Conclusions

RT3DSE is more vulnerable than 2D due to tachycardia, signal quality, patient decubitus and suboptimal resting image quality, making exercise RT3DSE less attractive than pharmacological stress.

Implication of the continuous prognostic spectrum of Doppler echocardiographic derived coronary flow reserve on left anterior descending artery

The additive prognostic value of coronary flow reserve (CFR) over regional wall motion has been established, but there is more than a binary (normal-abnormal) response in CFR, which can be continuously titrated. We assessed the prognostic value of quartiles of CFR, evaluated by transthoracic Doppler of the left anterior descending coronary artery (LAD), in patients with known or suspected coronary artery disease (CAD). One thousand six hundred twenty patients (1,006 men, 64 +/- 11 years of age) underwent dipyridamole (up to 0.84 mg/kg over 6 minutes) stress echocardiography with CFR evaluation of LAD by Doppler and coronary angiography. Patients were followed up for a median of 19 months. Mean CFR in the entire population was 2.25 +/- 0.65. Stress echocardiogram was positive for ischemia in 480 patients (30%). Obstructive (>or=70% vessel stenosis) CAD at angiography was present in 650 patients (40%). During follow-up, there were 298 events (42 deaths, 73 ST-elevation myocardial infarctions, and 183 non-ST-elevation myocardial infarctions). Patients (n = 399) undergoing revascularization were censored. With the Kaplan-Meier method, the first quartile of CFR (<or=1.80) was associated with a worse (p <0.0001) event rate than other quartiles in the entire population and in patients with no ischemia at stress echocardiography. Furthermore, the second quartile of CFR (1.81 to 2.16) was predictive of increased (p <0.0001) risk compared to the higher quartiles. In conclusion, Doppler echocardiographically derived CFR in LAD is a strong and independent prognostic predictor in patients with known or suspected CAD, but the spectrum of prognostic stratifications is expanded if the response is titrated according to a continuous scale rather than artificially dichotomized.

Identification of responders to cardiac resynchronization therapy by contractile reserve during stress echocardiography

AIMS

The identification of responders to cardiac resynchronization therapy (CRT) remains a challenge. We assessed the role of dyssynchrony (DYS) and contractile reserve (CR) in identifying CRT responders.

METHODS AND RESULTS

Sixty-nine patients (55% with ischaemic aetiology) referred for CRT (ejection fraction < or =35%, New York Heart Association > or =III, and QRS duration > or =120 ms) underwent baseline evaluation of DYS and dobutamine stress-echo [up to 40 microg/kg/min: CR was defined as a wall motion score index (WMSI) variation > or =0.20]. CRT responders were identified by clinical and/or echocardiographic [end-systolic volume (ESV) decrease > or =15%] follow-up criteria. During a median follow-up of 11 months, 46 patients (66%) were classified as clinical responders. Reverse remodelling was found in 34 of the 59 patients (58%) with echocardiographic follow-up. CR was present in 78% of clinical responders (P = 0.001) and in 69% with reverse remodelling (P = 0.005). DYS was equally present in the two groups. Reverse remodelling was correlated with rest-stress changes in ESV (r = 0.439, P = 0.003) and in WMSI (r = 0.450, P = 0.001), but not with DYS. CR (OR = 6.2, 95% CI = 1.4-27.6, P = 0.015) was the best predictor of response to CRT.

CONCLUSION

Patients with CR show a favourable clinical and reverse LV remodelling response to CRT. This finding shifts the focus from electrical (dyssynchrony) to the myocardial substrate of functional response.

Impact of gender on risk stratification by stress echocardiography

OBJECTIVE

To compare the prognostic value of stress echocardiography results in men and women with known and suspected coronary artery disease.

METHODS

We analyzed the data of 8737 patients (5529 men and 3208 women) who underwent stress echocardiography (exercise in 523 patients, dipyridamole in 6227 patients, dobutamine in 1987) for evaluating known (n=3857) or suspected (n=4880) coronary artery disease. Patients were followed up for the occurrence of overall mortality or nonfatal myocardial infarction.

RESULTS

During a median follow-up of 25 months, 1218 cardiac events (693 deaths and 525 infarctions) occurred. Moreover, 2263 patients (1731 men [31%] and 532 women [17%]; P<.0001) underwent coronary revascularization and were censored. Stress echocardiography results added prognostic information to that of clinical findings and resting wall motion score index in men and women with both known and suspected coronary artery disease. In patients with known coronary artery disease, women had a higher (P=.01) event rate than men in the presence of ischemia. The annual event rate was worse for nondiabetic women (P=.007) but not diabetic women; age had a neutral prognostic effect in the 2 sexes. In patients with suspected coronary artery disease, men without ischemia had a higher (P<.0001) event rate than women. The annual event rate was worse in men aged less than 65 years (P<.0001) or more than 65 years (P=.04), and those with (P=.03) or without (P<.0001) diabetes.

CONCLUSION

Prognosis is at least comparable in men and women with ischemia and in those with coronary artery disease and no ischemia at stress echocardiography. In these clinical settings, availability for major procedures should be similar for both genders.

Depressed coronary flow reserve is associated with decreased myocardial capillary density in patients with heart failure due to idiopathic dilated cardiomyopathy

OBJECTIVES

We sought to examine the relationship between coronary flow reserve (CFR) and myocardial capillary density (MCD) in patients with idiopathic dilated cardiomyopathy, heart failure, and normal coronary arteries.

BACKGROUND

Coronary flow reserve is depressed in patients with idiopathic dilated cardiomyopathy, particularly in those with end-stage congestive heart failure.

METHODS

We studied 18 patients, 48 +/- 10 years of age, who had a mean New York Heart Association functional class of 2.9 +/- 1.3, mean left ventricular ejection fraction of 22 +/- 8%, and mean pulmonary capillary wedge pressure of 23 +/- 10 mm Hg. CFR measurements were made with a 0.014-inch pressure-temperature sensor-tipped guide wire placed in the distal left anterior descending coronary artery. Thermodilution curves were constructed in triplicate at baseline and during maximum hyperemia induced by intravenous adenosine. CFR was calculated from the ratio of mean transit times. Right heart endomyocardial biopsies were performed during the same procedure. Autopsied specimens from nonfailing hearts were used as controls. The tissue was histochemically stained with CD-34 for morphometric measurements of MCD.

RESULTS

We observed a close linear relationship between CFR and MCD (r = 0.756, p = 0.0001). The MCD in 7 patients with a CFR >or=2.5 (73.2 +/- 16) was similar to that measured in normal control patients, (85 +/- 11, p = NS). In contrast, the MCD in 11 patients with a CFR <2.5 was 33.2 +/- 14, which was significantly lower than in patients with heart failure and normal CFR (73.2 +/- 16, p = 0.001) or in controls (85 +/- 11, p < 0.0001).

CONCLUSIONS

A marked decrease in MCD was found in patients presenting with congestive heart failure as the result of idiopathic dilated cardiomyopathy and a depressed CFR.

Usefulness of stress echocardiography for risk stratification of patients after percutaneous coronary intervention

The prognostic value of stress echocardiography in patients with previous percutaneous coronary intervention (PCI) remains undefined. The aim of this study was to investigate the prognostic implication of stress echocardiography after PCI. The study group comprised 1,063 patients (794 men, 65 +/- 10 years of age) who underwent stress echocardiography with exercise (n = 105), dipyridamole (n = 780), or dobutamine (n = 178) after a median of 10 months from a successful PCI. Of these patients, 616 (58%) complained of chest pain and 447 (42%) were asymptomatic. Stress echocardiogram was positive for inducible ischemia in 328 patients (31%). During a median follow-up of 20 months, there were 167 events (61 deaths, 106 infarctions). Independent predictors of mortality were age (hazard ratio [HR] 1.06, 95% confidence interval [CI] 1.03 to 1.09, p <0.0001), wall motion score index at rest (HR 3.91, 95% CI 2.19 to 6.99, p <0.0001), and ischemia at stress echocardiography (HR 1.82, 95% CI 1.05 to 3.16, p = 0.03). Five-year mortalities were 20% in patients with and 9% in those without ischemia (p = 0.006). Independent predictors of hard events were ischemia at stress echocardiography (HR 3.82, 95% CI 2.75 to 5.29, p <0.0001), age (HR 1.02, 95% CI 1.01 to 1.04, p = 0.009), wall motion score index at rest (HR 1.98, 95% CI 1.30 to 3.02, p = 0.002), multivessel disease at time of PCI (HR 1.45, 95% CI 1.05 to 2.02, p = 0.02), and female gender (HR 1.44, 95% CI 1.03 to 2.01, p = 0.03). Five-year hard event rates were 53% in patients with and 16% in those without ischemia (p <0.0001). Stress echocardiographic positivity added prognostic information to clinical and at-rest echocardiographic parameters in symptomatic and asymptomatic patients. Moreover, it identified a subset of patients at higher risk of developing hard events independent of the subtending coronary anatomy (multivessel or single vessel disease). In conclusion, stress echocardiography is effective in risk-stratifying patients with previous PCI. In particular, inducible ischemia is a strong and independent predictor of mortality and hard events.

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.

Head to head comparison of 2D vs real time 3D dipyridamole stress echocardiography

Real-time three-dimensional (RT-3D) echocardiography has entered the clinical practice but true incremental value over standard two-dimensional echocardiography (2D) remains uncertain when applied to stress echo. The aim of the present study is to establish the additional value of RT-3D stress echo over standard 2D stress echocardiography. We evaluated 23 consecutive patients (age = 65 ± 10 years, 16 men) referred for dipyridamole stress echocardiography with Sonos 7500 (Philips Medical Systems, Palo, Alto, CA) equipped with a phased – array 1.6–2.5 MHz probe with second harmonic capability for 2D imaging and a 2–4 MHz matrix-phased array transducer producing 60 × 70 volumetric pyramidal data containing the entire left ventricle for RT-3D imaging. In all patients, images were digitally stored in 2D and 3D for baseline and peak stress with a delay between acquisitions of less than 60 seconds. Wall motion analysis was interpreted on-line for 2D and off-line for RT-3D by joint reading of two expert stress ecocardiographist. Segmental image quality was scored from 1 = excellent to 5 = uninterpretable. Interpretable images were obtained in all patients. Acquisition time for 2D images was 67 ± 21 sec vs 40 ± 22 sec for RT-3D (p = 0.5). Wall motion analysis time was 2.8 ± 0.5 min for 2D and 13 ± 7 min for 3D (p = 0.0001). Segmental image quality score was 1.4 ± 0.5 for 2D and 2.6 ± 0.7 for 3D (p = 0.0001). Positive test results was found in 5/23 patients. 2D and RT-3D were in agreement in 3 out of these 5 positive exams. Overall stress result (positive vs negative) concordance was 91% (Kappa = 0.80) between 2D and RT-3D. During dipyridamole stress echocardiography RT-3D imaging is highly feasible and shows a high concordance rate with standard 2D stress echo. 2D images take longer time to acquire and RT-3D is more time-consuming to analyze. At present, there is no clear clinical advantage justifying routine RT-3D stress echocardiography use.

Cardiac functional stress imaging: a sequential approach with stress echo and cardiovascular magnetic resonance

AIMS

The aim of the study was to assess the feasibility and accuracy of an integrated stress imaging algorithm with echo first and second-line Cardiac Magnetic Resonance (CMR) in selected cases. Stress echo (SE) is widely used for non-invasive diagnosis of coronary artery disease (CAD), but difficult patients and ambiguous responses may be met even with top-level technology and expertise. CMR might ideally complement SE in well-selected cases with unfeasible and/or ambiguous and/or submaximal results.

METHODS AND RESULTS

152 in-hospital patients with chest pain and normal baseline function were referred for SE and coronary angiography. Of the initial population, 33 were shunted to CMR due to poor acoustic window or ambiguous or submaximal SE test. The only criterion of positivity for both techniques was the presence of regional wall motion abnormalities in at least 2 contiguous segments. Coronary angiography was performed independently of test results. Significant CAD was identified by a >50% quantitatively assessed diameter reduction in at least 1 major coronary vessel.CAD was present in 88 patients. Interpretable and diagnostic stress test were obtained in 143 patients with the sequential algorithm. The sequential (SE in 110 + CMR in 33 patients) algorithm showed a sensitivity of 76% (95% CI 66% to 85%) specificity of 87% (95% CI 76% to 95%) and accuracy of 80% (95% CI 73% to 86%).

CONCLUSION

A sequential functional stress imaging algorithm with stress echo first and stress CMR in selected cases is feasible, clinically realistic and allows an efficient, radiation-free diagnosis of CAD.

Additional prognostic value of coronary flow reserve in diabetic and nondiabetic patients with negative dipyridamole stress echocardiography by wall motion criteria

OBJECTIVES

The aim of this prospective, multicenter, observational study was to compare the prognostic value of Doppler echocardiographic-derived coronary flow reserve (CFR) in diabetic and nondiabetic patients with known or suspected coronary artery disease and negative dipyridamole stress echocardiography.

BACKGROUND

The prognostic value of CFR in diabetic patients with negative stress echocardiography remains unknown.

METHODS

The study group consisted of 1,130 patients (207 diabetics) with known (n = 418) or suspected (n = 712) coronary artery disease and negative stress echocardiography by wall motion criteria. All underwent dipyridamole (up to 0.84 mg/kg over 6 min) echocardiography with CFR evaluation of left anterior descending artery by Doppler. A value of CFR < or =2.0 was considered abnormal.

RESULTS

Coronary flow reserve was abnormal in 309 (27%) patients. During a median follow-up of 16 months, 98 events (8 deaths, 24 ST-segment elevation myocardial infarctions, and 66 non-ST-segment elevation myocardial infarctions) occurred. In addition, 101 patients underwent revascularization and were censored. Multivariable prognostic indicators were abnormal CFR (p < 0.0001), anti-ischemic therapy at the time of testing (p = 0.002), age (p = 0.02), and resting wall motion abnormality (p = 0.05). The event rate was markedly higher (p < 0.0001) for both diabetic and nondiabetic patients with abnormal CFR as compared with diabetic and nondiabetic patients with normal CFR. Of note, a preserved CFR off therapy identified diabetic and nondiabetic patients with better survival and comparable yearly event rates (2.2% vs. 2.0%, p = 0.80).

CONCLUSIONS

Coronary flow reserve provides independent prognostic information in diabetic and nondiabetic patients with known or suspected coronary artery disease and negative dipyridamole stress echocardiography. In particular, a normal CFR off therapy is associated with better and similar survival in the 2 populations.

Predischarge exercise electrocardiogram and stress echocardiography can predict long-term clinically driven revascularization following acute myocardial infarction

BACKGROUND

Predischarge stress testing provides suboptimal prediction of spontaneous hard events following uncomplicated acute myocardial infarction (AMI).

HYPOTHESIS

This study was aimed at assessing whether soft cardiac ischemic events requiring late revascularization could be predicted more accurately.

METHODS

In all, 428 patients undergoing exercise electrocardiography (ECG) and stress echocardiography (SE, 345 dobutamine and 83 dypiridamole) within 15 days of uncomplicated AMI were followed up for 425 (range 20-2220) days. Soft ischemic events (effort angina>class II [Canadian Cardiovascular Society Classification] and unstable angina) driving late (>6 months) revascularization were regarded as endpoints.

RESULTS

A total of 58 events (29 effort and 29 unstable angina with subsequent 47 coronary artery bypass grafts and 11 percutaneous transluminal coronary angioplasties) occurred: 26 in patients with positive exercise ECG and 34 in patients with positive SE. Univariate predictors of revascularizations were positive exercise ECG (p = 0.0001), peak wall motion score index (WMSI) (p = 0.0009), low workload (p = 0.0018), rest WMSI (p = 0.02) and positive SE (p = 0.02). Cox multivariate analysis selected peak WMSI, positive exercise ECG, and low workload positive exercise ECG as independent predictors of late revascularizations.

CONCLUSIONS

Predischarge stress testing identifies the long-term occurrence of soft ischemic events driving late revascularization after uncomplicated AMI.

The prognostic impact of coronary flow-reserve assessed by Doppler echocardiography in non-ischaemic dilated cardiomyopathy

AIMS

Coronary flow-reserve (CFR) can be impaired in non-ischaemic dilated cardiomyopathy (DCM), unmasking a coronary microcirculatory dysfunction of potential prognostic impact. The aim of the present study is to evaluate the prognostic value of Doppler echocardiographic-derived CFR in patients with DCM.

METHODS AND RESULTS

We evaluated 129 DCM patients (85 male; age 62+/-11) by transthoracic dipyridamole (0.84 mg/kg in 10 min) stress echocardiography. All patients had an ejection fraction<40% (mean 32+/-7) and angiographically normal coronary arteries with NYHA class<or=3. CFR was assessed on left anterior descending artery using pulsed Doppler as the ratio of maximal peak vasodilation (dipyridamole) to rest diastolic flow velocity. All patients were followed-up for a median of 22 months. Mean CFR was 2.0+/-0.5. At individual patient analysis 46 patients had normal (CFR>2.0) and 83 had abnormal CFR. During follow-up, 18 patients died and 33 showed worsening of NYHA class. The worse event-free survival was observed in those patients with an abnormal CFR when compared with those having a normal CFR at high dose of dipyridamole (70 vs. 22%, at 75 months of follow-up, P<0.0001). In the multivariable analysis, severity of mitral insufficiency (HR=1.9, 95% CI=1.06-2.87), abnormal CFR (HR=4.0, 95% CI=1.1-15.6), resting wall motion score index (HR=6.9, 95% CI=1.5-30.7) were independent predictors of survival.

CONCLUSION

In DCM patients, CFR is often impaired. A reduced CFR during vasodilator stress is an independent prognostic marker of bad prognosis.

Clinical and functional determinants of coronary flow reserve in non-ischemic dilated cardiomyopathy

Coronary flow reserve (CFR) is impaired in non-ischemic dilated cardiomyopathy (DCM). Mechanisms by which such impairment occurs are still unknown, but cofactors such as diastolic compressive force, left ventricular hypertrophy, and microvascular disease have been implied. In order to characterize the determinants of CFR in non-ischemic DCM, we evaluated 110 non-ischemic DCM patients (58 men; age=61+/-12 years) and 21 age- and gender-matched control patients (14 men; age=59+/-13 years) by transthoracic (n=88) or transesophageal (n=22) dipyridamole (0.84 mg/ kg in 10') stress echocardiography. All patients showed angiographically normal coronary arteries. Non-ischemic DCM patients had an ejection fraction <45% while control patients had normal left ventricular systolic function. CFR was assessed on LAD by pulsed Doppler as the ratio of maximal vasodilation (dipyridamole) to rest peak diastolic coronary flow velocity. Mean CFR value was 2.0+/-0.6 for DCM patients and 3.2+/-0.5 for controls (p<0.01). At individual non-ischemic DCM patient analysis, 46 patients had normal CFR> or =2 (Group 1) and 64 patients had abnormal CFR<2 (Group 2). On univariate analysis, CFR reduction correlated with NYHA functional class (r=-0.33, p=0.001), left ventricular ejection fraction ( r=0.23, p=0.02), end-systolic volume (r=-0.23, p=0.02), systolic pulmonary artery pressure (r=-0.42, p=0.0001), deceleration time (r=0.24, p=0.02). Logistic multiregression analysis showed that only NYHA functional class significantly and negatively correlated with CFR (odds ratio=0.9; 95% confidence intervals: 0.03-.35, p=0.0001). In patients with non-ischemic DCM, CFR is reduced but with substantial individual variability, only partially accounted for by level of systolic and diastolic dysfunction. The clinical functional class is the strongest predictor of CFR reduction in these patients, with lowest flow reserve found in more advanced NYHA class.

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 value of a multiparametric risk score in patients undergoing dipyridamole stress echocardiography

To set up a prognostic score including clinical data and stress echocardiographic findings, the data of 3,969 patients who underwent dipyridamole stress were analyzed. Age (hazard ratio [HR] 3.21), peak wall motion score index (HR 2.62), diabetes mellitus (HR 2.36), and male gender (HR 1.69) were independent predictors of mortality and were incorporated into a prognostic score allowing us to estimate 1-, 3-, and 5-year survival in the patient cohort. The multiparametric risk score, immediately available at the bedside, can be used to predict the survival of patients undergoing dipyridamole stress echocardiography.

The additive prognostic value of restrictive pattern and dipyridamole-induced contractile reserve in idiopathic dilated cardiomyopathy

BACKGROUND

Diastolic dysfunction and lack of contractile reserve are unfavorable prognostic predictors in patients with dilated cardiomyopathy (DCM).

AIMS

This study aims to assess whether diastolic dysfunction and lack of dipyridamole-induced contractile reserve were additive predictors of poor outcome in patients with DCM.

METHODS

A total of 116 patients with DCM and ejection fraction (EF<35%) were studied by dipyridamole echo (0.84 mg/kg over 10 min). At rest, a restrictive filling pattern was defined as: E/A ratio >2 and an E-wave deceleration time of <140 ms on transmitral flow velocity profile.

RESULTS

Rest wall motion score index (WMSI) was 2.2+/-0.3 and decreased to 1.9+/-0.41 after dipyridamole (p<0.001). During follow-up (median 26.5 months), 22 cardiac deaths occurred. At multivariate analysis, dipyridamole-induced contractile reserve yielded significant incremental prognostic value (RR=0.275, p<0.006) over NYHA class (RR=1.971, p<0.03), angiotensin-converting enzyme inhibitor therapy (RR=0.173, p<0.001), and left ventricular end-diastolic diameter (RR=1.131, p<0.001). The worst prognostic combination was the presence of restrictive pattern at rest and the absence of contractile reserve (deltaWMSI<0.15).

CONCLUSION

In patients with DCM, the ominous combination of restrictive transmitral flow pattern and lack of contractile reserve during dipyridamole stress predicts an unfavourable outcome.

Long-term Prognostic Value of Transesophageal Atrial Pacing Stress Echocardiography

OBJECTIVE

The aim of our study was to evaluate the long-term prognostic value of transesophageal atrial pacing stress echocardiography (TAPSE) for the prediction of cardiovascular events (myocardial infarction) and mortality at 10-year follow-up.

METHODS

TAPSE was applied as a diagnostic modality in 93 consecutive patients (mean age 45 +/- 8 years) who were diagnosed for the cause of chest pain. Long-term follow-up data were obtained from 87 (94%) patients with a mean duration of follow-up of 92 +/- 4 months. Stress echocardiography was performed using TAPSE with a mean pacing rate of 142 +/- 18/min.

RESULTS

Predefined cardiac events occurred during the follow-up period in 45 (52%) patients, including 24 (28%) with hard end points: 10 (12%) with nonfatal myocardial infarction and 17 who died (events overlap). Positive result of TAPSE was found in 47 (54%) patients and among those with positive TAPSE result, 16 died (94% of total mortality) and 21 had a hard event (death or infarction-88% of total prevalence). Survival free from hard events was noted in 37 (92%) patients with negative TAPSE and only in 26 (55%) of those with positive TAPSE ( P = .001). Independent predictive factors for mortality were TAPSE positivity (relative risk with 95% confidence interval [RR/CI] = 39.6 [36.3-42.9], P = .0006) and diabetes (RR/CI = 10.2 [8.6-11.8], P = .0026). Independent predictive factors for myocardial infarction were diabetes (RR/CI = 8.1 [6.3-9.9], P = .0186) and significant coronary stenosis in angiography (RR/CI = 9.0 [6.8-11.2], P = .0479). Independent predictive factors for death or nonfatal myocardial infarction were TAPSE positivity (RR/CI = 12.3 [11.1-13.3], P = .0001) and diabetes (RR/CI = 7.0 [5.8-8.2], P = .0018).

CONCLUSIONS

Positive TAPSE result carries long-term prognostic information regarding mortality and risk of myocardial infarction that can be used to identify patients requiring more aggressive treatment. Negative TAPSE allows highly accurate definition of low-risk population with discriminating power maintained during the 10-year period. TAPSE result and diabetes are the strongest independent predictors for long-term mortality in multivariate analysis.

Pre-discharge stress echocardiography and exercise ECG for risk stratification after uncomplicated acute myocardial infarction: results of the COSTAMI-II (cost of strategies after myocardial infarction) trial

OBJECTIVE

To compare in a prospective, randomised, multicentre trial the relative merits of pre-discharge exercise ECG and early pharmacological stress echocardiography concerning risk stratification and costs of treating patients with uncomplicated acute myocardial infarction.

DESIGN

262 patients from six participating centres with a recent uncomplicated myocardial infarction were randomly assigned to early (day 3-5) pharmacological stress echocardiography (n = 132) or conventional pre-discharge (day 7-9) maximum symptom limited exercise ECG (n = 130).

RESULTS

No complication occurred during either stress echocardiography or exercise ECG. At one year follow up there were 26 events (1 death, 5 non-fatal reinfarctions, 20 patients with unstable angina requiring hospitalisation) in patients randomly assigned to early stress echocardiography and 18 events (2 reinfarctions, 16 unstable angina requiring hospitalisation) in the group randomly assigned to exercise ECG (not significant). The negative predictive value was 92% for stress echocardiography and 88% for exercise ECG (not significant). Total costs of the two strategies were similar (not significant).

CONCLUSION

Early pharmacological stress echocardiography and conventional pre-discharge symptom limited exercise ECG have similar clinical outcome and costs after uncomplicated infarction. Early pharmacological stress echocardiography should be considered a valid alternative even for patients with interpretable baseline ECG who can exercise.

Relevance of tissue Doppler in the quantification of stress echocardiography for the detection of myocardial ischemia in clinical practice

In the present article we review the main published data on the application of Tissue Doppler Imaging (TDI) to stress echocardiography for the detection of myocardial ischemia. TDI has been applied to stress echocardiography in order to overcome the limitations of visual analysis for myocardial ischemia. The introduction of a new technology for clinical routine use should pass through the different phases of scientific assessment from feasibility studies to large multicenter studies, from efficacy to effectiveness studies. Nonetheless the pro-technology bias plays a major role in medicine and expensive and sophisticated techniques are accepted before their real usefulness and incremental value to the available ones is assessed. Apparently, TDI is not exempted by this approach : its applications are not substantiated by strong and sound results. Nonetheless, conventional stress echocardiography for myocardial ischemia detection is heavily criticized on the basis of its subjectivity. Stress echocardiography has a long lasting history and the evidence collected over 20 years positioned it as an established tool for the detection and prognostication of coronary artery disease. The quantitative assessment of myocardial ischemia remains a scientific challenge and a clinical goal but time has not come for these newer ultrasonographic techniques which should be restricted to research laboratories.

[Predictive significance of residual ischemia detected by the dobutamine stress-echocardiography test soon after the first uncomplicated myocardial infarction]

BACKGROUND

To evaluate the long-term prognostic value of dobutamine stress-echocardiography (ECG) test for new coronary events (new episodes of angina pectoris, cardiac-related deaths, and reinfarctions) early after the first uncomplicated myocardial infarction.

METHODS

Dobutamine stress-echocardiography tests were performed in all of 104 patients 10-20 days after the first myocardial infarction. Patients were followed-up for 36 (29 +/- 7) months. Kaplan-Meier cumulative survival curves were tested by Breslow test (Log Rank).

RESULTS

Two cardiac deaths (1.92%), nine nonfatal myocardial infarctions (8.65%), and three cases of recurrent angina pectoris (2.88%) occurred during the prospective follow-up. Cumulative survival curves showed that in patients with negative findings of dobutamine stress-echocardiography test, survival time without significant events was 35.31 months, while in the group with positive findings of dobutamine stress-echocardiography test it was 30.91 months (log Rank 7.22; p<0.01). Prognostic value of dobutamine stress-echocardiography test was analyzed by Cox regression model and was 2.92, meaning that the risk of significant events was 2.92 times higher in the group of patients with positive findings of dobutamine stress-echocardiography test.

CONCLUSION

Patients with negative findings of dobutamine stress-echocardiography test were with significantly higher possibility of surviving without significant events in comparison with the patients in whom the findings of dobutamine stress-echocardiography test were positive. In combination with clinical signs and ECG results, the results of dobutamine stress-echocardiography test improved prognostic value in the patients with the first uncomplicated myocardial infarction, and in that way influenced the strategy of their further treatment.

Pharmacologic stress echocardiography predicts total mortality early after acute myocardial infarction

OBJECTIVE

The aim of this multicenter, prospective, observational study was to assess the value of inducible ischemia in a large population of survivors of a first uncomplicated myocardial infarction (MI).

METHODS AND RESULTS

Pharmacologic stress echocardiography either with high-dose dipyridamole (0.84 mg/kg over 10 minutes) or high-dose dobutamine (up to 40 microg/kg over 3 minutes) (DET) was performed 9 +/- 10 days after a first acute uncomplicated MI in 1681 patients (1499 males; 57 +/- 10 years) with technically satisfactory rest echocardiographic study. Patients were followed up for a mean of 16 +/- 18 months (range: 1-122). DET was positive for myocardial ischemia in 884 (52.5%) and negative in 797 (47.5%) patients. During the follow-up there were 49 deaths for all-cause mortality (2.9% of the total population), 22 of which were cardiac; 62 (3.6%) nonfatal MIs; and 164 (9.7%) hospital readmissions for unstable angina. In all, 376 patients (22%) underwent coronary revascularization (bypass operation or angioplasty).

RESULTS

Hard events occurred in 71 of the 884 patients with positive and in 40 of the 797 patients with negative DET (8% vs 5%, P =.014). Using the Cox proportional hazards model, age (relative risk [RR] 1.07, 95% confidence interval [CI] 1.03-1.1), history of angina (RR 3.8, 95% CI 1.6-8.6), peak wall-motion score index (RR 2.2, 95% CI 1.1-4.4), and pharmacologic dose at ischemia (RR 1.5, 95% CI 1.04-2.3) were independent predictors of all-cause death.

CONCLUSIONS

In survivors of a first acute uncomplicated MI DET allows effective risk stratification on the basis of the presence, severity, and extent the induced ischemia.

Prediction of mortality in patients with right bundle branch block referred for pharmacologic stress echocardiography

Right bundle branch block (RBBB) is independently associated with all-cause mortality in patients referred for noninvasive evaluation of coronary artery disease. However, further stratification of risk in these patients has not been specifically addressed. The aim of this study was to risk stratify patients with RBBB who were referred for stress echocardiography. The study population was comprised of 343 patients (267 men; age 66 +/- 9 years) with RBBB who underwent pharmacologic stress echocardiography (231 dipyridamole, 112 dobutamine) for evaluation of suspected or known coronary artery disease. Overall mortality was the only end point. Stress echocardiography was positive for ischemia in 109 patients (32%). During follow-up (38 +/- 32 months), 36 deaths occurred. Seventy-three patients underwent revascularization and were censored. Ischemia at stress echocardiography (hazard ratio [HR] 2.9, 95% confidence interval [CI] 1.5 to 5.5, p=0.002), left anterior fascicular block (LAFB) (HR 2.8, 95% CI 1.4 to 5.6, p = 0.002), age >65 years (HR 2.1, 95% CI 1.0 to 4.3, p=0.047), and wall motion score index at rest (HR 2.5, 95% CI 1.0 to 6.5, p=0.057) were multivariate predictors of mortality. On the basis of stress echocardiographic result and presence and/or absence of LAFB, 3 levels of risk were identified: (1) low-risk, in cases of no ischemia and no LAFB (49% of the entire study population); (2) intermediate-risk, in cases of ischemia or LAFB only; and (3) high-risk, in cases of ischemia and LAFB. Clinical data, electrocardiography at rest, and stress echocardiographic results can provide effective stratification of risk in patients with RBBB.

Diagnostic value of exercise electrocardiography and dipyridamole stress echocardiography in hypertensive and normotensive chest pain patients with right bundle branch block

OBJECTIVES

Studies on the diagnostic value of exercise electrocardiography in right bundle branch block produced controversial results, and data on the accuracy of stress echo are still lacking. The aim of the study was to compare the diagnostic value of exercise electrocardiography and dipyridamole stress echo in chest pain patients with right bundle branch block, and to verify whether stress testing accuracy is affected by history of hypertension.

METHODS

The study group was made up of 71 patients (56 men, aged 63 +/- 8 years) with chest pain of unknown origin and complete right bundle branch block. Of them, 35 were hypertensives and 36 normotensives. Patients performed, on different days and in random order, exercise electrocardiography and dipyridamole stress echo and underwent coronary angiography.

RESULTS

Significant (> or = 70% diameter stenosis) coronary artery disease was found in 34 patients (17 hypertensives and 17 normotensives). Positive exercise electrocardiography (ST-segment shift > 1 mm at 80 ms after the J point in leads V5 and V6 or leads II and Vf) and dipyridamole stress echo (new wall motion abnormalities) were observed in 38 and 30 patients, respectively. The result of tests was concordant in 69% of hypertensives and 92% of normotensives. The two tests shared the same sensitivity in hypertensives (82%) and normotensives (71%). Of 37 patients without coronary artery disease, 12 had a false-positive result during exercise electrocardiography and four during stress echo. The specificity was lower for exercise electrocardiography than for stress echo in hypertensives (50 versus 89%, P = 0.0006), while no difference was evidenced in normotensives (84 versus 89%, P = 0.4). In hypertensives, the accuracy, positive, and negative predictive values were 66, 61, and 75% for exercise electrocardiography, and 86, 87, and 84% for stress echo. Corresponding figures in normotensives were 78, 80, and 76% for exercise electrocardiography, and 81, 86, and 77% for stress echo.

CONCLUSIONS

In chest-pain patients with right bundle branch block, dipyridamole stress echo was effective to diagnose coronary artery disease in both normotensives and hypertensives. Moreover, it exhibited superior diagnostic information than exercise electrocardiography in hypertensives, due to significantly higher specificity. However, the two tests had similar diagnostic value in normotensives.

Value of echocardiography in predicting future cardiac events after acute myocardial infarction

Short- and long-term survival after acute myocardial infarction mainly depends on three factors: the amount of myocardium that had become necrotic, the area of myocardium at further risk of becoming necrotic, and the patency of the infarct-related artery. Echocardiography is a low-cost, safe, bedside, repeatable tool, particularly useful for prognostic stratification after myocardial injury. Two-dimensional echocardiography analyzes left ventricular function, the most powerful predictor of survival immediately after acute myocardial infarction. Myocardial contrast echocardiography measures the infarct size and detects viable myocardium. Stress echocardiography stratifies patients with viable myocardium and/or multivessel coronary artery disease who need further diagnostic and therapeutic interventions. Transthoracic coronary Doppler ultrasonography assesses effective recanalization and coronary flow reserve of the left anterior descending coronary artery. Further technologic advances are needed to allow direct noninvasive measurement of flow by transthoracic Doppler ultrasonography in other coronary arteries.

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.