Stress echocardiography in heart failure

Usefulness of exercise stress echocardiography for predicting cardiovascular events and atrial fibrillation in hypertrophic cardiomyopathy

BACKGROUND

In hypertrophic cardiomyopathy (HCM), the determinants of exercise tolerance and the usefulness of exercise stress echocardiography (ESE) for predicting hard endpoints have not been fully investigated. We aimed to assess the key parameters of ESE for exercise tolerance and the factors predictive of cardiovascular events and new-onset atrial fibrillation (AF) in patients with HCM.

METHODS

Seventy-four consecutive patients with HCM who underwent ESE and with an ejection fraction ≥50 % were enrolled. The primary endpoint was a composite of cardiovascular death, heart failure hospitalization, ventricular fibrillation or tachycardia, and ventricular assist device implantation. The secondary endpoint was new-onset AF.

RESULTS

The primary endpoint occurred in 13 patients. The left and right ventricular functions during exercise were responsible for decreased exercise tolerance. Peak exercise e' and tricuspid annular plane systolic excursion (TAPSE) significantly predicted increased primary outcome risk (hazard ratio 1.35, 95 % confidence interval 1.10-1.76, p = 0.003; hazard ratio 1.19, 95 % confidence interval 1.07-1.32, p = 0.002, respectively), and the results were consistent even after adjustment by maximum workload. These ESE parameters improved the prognostic model containing estimated glomerular filtration rate (eGFR) and left atrial (LA) volume index. In AF-naive patients (n = 58), LA volume, peak exercise LA reservoir strain, and left ventricular outflow tract (LVOT) pressure gradient predicted new-onset AF.

CONCLUSIONS

In patients with HCM, ESE parameters related to left and right ventricular function were responsible for low exercise tolerance. Furthermore, e' and TAPSE at peak workload could be useful for predicting cardiovascular events in addition to eGFR and LA volume index. LVOT pressure gradient and LA function during exercise predicted new-onset AF.

Programmatic approach to patients with advanced ischemic cardiomyopathy: Integrating microaxial support into strategies for the modern era

Patients with advanced ischemic cardiomyopathy manifesting as left ventricular dysfunction exist along a spectrum of severity and risk, and thus decision-making surrounding optimal management is challenging. Treatment pathways can include medical therapy as well as revascularization through percutaneous coronary intervention or coronary artery bypass grafting. Additionally, temporary and durable mechanical circulatory support, as well as heart transplantation, may be optimal for select patients. Given this spectrum of risk and the complexity of treatment pathways, patients may not receive appropriate therapy given their perceived risk, which can lead to sub-satisfactory outcomes. In this review, we discuss the identification of high-risk ischemic cardiomyopathy patients, along with our programmatic approach to patient evaluation and perioperative optimization. We also discuss our strategies for therapeutic decision-making designed to optimize both short- and long-term patient outcomes.

Exercise stress echocardiography: Where are we now?

Exercise stress echocardiography (ESE) is a widely used diagnostic test in cardiology departments. ESE is mainly used to study patients with coronary artery disease; however, it has increasingly been used in other clinical scenarios including valve pathology, congenital heart disease, hypertrophic and dilated cardiomyopathies, athlete evaluations, diastolic function evaluation, and pulmonary circulation study. In our laboratories, we use an established methodology in which cardiac function is evaluated while exercising on a treadmill. After completing the exercise regimen, patients remain in a standing position or lie down on the left lateral decubitus, depending on the clinical questions to be answered for further evaluation. This method increases the quality and quantity of information obtained. Here, we present the various methods of exercise stress echocardiography and our experience in many clinical arenas in detail. We also present alternatives to ESE that may be used and their advantages and disadvantages. We review recent advances in ESE and future directions for this established method in the study of cardiac patients and underline the advantage of using a diagnostic tool that is radiation-free.

Global Longitudinal Strain at Rest as an Independent Predictor of Mortality in Liver Transplant Candidates: A Retrospective Clinical Study

Speckle tracking echocardiography enables the detection of subclinical left ventricular dysfunction at rest in many heart diseases and potentially in severe liver diseases. It could also possibly serve as a predictor for survival. In this study, 117 patients evaluated for liver transplantation in a single center between May 2010 and April 2016 with normal left ventricular ejection fraction were included according to clinical characteristics of their liver disease: (1) compensated (n = 29), (2) clinically significant portal hypertension (n = 49), and (3) decompensated (n = 39). Standard echocardiography and speckle tracking echocardiography were performed at rest and during dobutamine stress. Follow-up amounted to three years to evaluate survival and major cardiac events. Altogether 67% (78/117) of the patients were transplanted and 32% (31/96 patients) died during the three-year follow-up period. Global longitudinal strain (GLS) at rest was significantly increased (became more negative) with the severity of liver disease (p < 0.001), but reached comparable values in all groups during peak stress. Low (less negative) GLS values at rest (male: >−17/female: >−18%) could predict patient survival in a multivariate Cox regression analysis (p = 0.002). GLS proved valuable in identifying transplant candidates with latent systolic dysfunction.

Cardiopulmonary exercise testing and echocardiographic exam: an useful interaction

Cardiopulmonary exercise test (CPET) is a functional assessment that helps to detect disorders affecting the system involved in oxygen transport and utilization through the analysis of the gas exchange during exercise. The clinical application of CPET is various, it including training prescription, evaluation of treatment efficacy and outcome prediction in a broad spectrum of conditions. Furthermore, in patients with shortness of breath it provides pivotal information to bring out an accurate differential diagnosis between physical deconditioning, cardiopulmonary disease and muscular diseases. Modern software allows the breath-by-breath analysis of the volume of oxygen intake (VO₂), volume of carbon dioxide output (VCO₂) and expired air (VE). Through this analysis, CPET provides a series of additional parameters (peak VO₂, ventilatory threshold, VE/VCO₂ slope, end-tidal carbon dioxide exhaled) that characterize different patterns, helping in diagnosis process. Limitations to the routine use of CPET are mainly represented from the lack of measurement standardization and limited data from randomized multicentric studies. The integration of CPET with exercise stress echocardiography has been recently introduced in the clinical practice by integrating the diagnostic power offered by both the tools. This combined approach has been demonstrated to be valuable for diagnosing several cardiac diseases, including heart failure with preserved or reduced ejection fraction, cardiomyopathies, pulmonary arterial hypertension, valvular heart disease and coronary artery disease. Future investigations are needed to further promote this intriguing combination in the clinical and research setting.

Does stress echocardiography add incremental value to baseline ejection fraction for the early identification of candidates for implantable defibrillators?

Objective

A reduction in left ventricular ejection fraction (EF) remains the strongest indicator of increased risk of sudden cardiac death after an acute myocardial infarction (AMI). Guidelines recommend that patients with an EF ≤35%, 6–12 weeks after AMI should be considered for implantable cardioverter defibrillator (ICD) therapy. Stress echocardiography is a safe method to detect viability in a stunned myocardium. The purpose of this study was to investigate if stress echocardiography early after AMI could identify ICD candidates before discharge.

Methods

Ninety-six patients with EF ≤40% early after AMI were prospectively included in a cohort study, and investigated by baseline and stress echocardiography before discharge. Follow-up echocardiography was performed after 3 months. EF, mitral annular plane systolic excursion (MAPSE) and peak systolic velocity (PSV) were determined for each examination.

Results

There were 80 (83%) patients who completed the baseline, stress and follow-up echocardiography. Among them there were 32 (40%) patients who met the ICD criteria of EF ≤35% at 3 months. For these patients, EF, MAPSE and PSV were significantly lower than for those patients who recovered. The area under the receiver operating characteristic curve (AUC) was 85% (95% CI 0.74 to 0.94) for baseline EF to predict non-recovery. None of the other variables had a higher AUC.

Conclusion

Patients who met the ICD criteria of EF ≤35% at 3 months after myocardial infarction had lower EF, MAPSE and PSV on baseline and stress echocardiograph before discharge. Stress echocardiography did not add additional value in predicting non-recovery.

Haemodynamic effects of pharmacologic stress with adenosine in patients with left ventricular systolic dysfunction

BACKGROUND

In patients with heart failure, downregulation of adenosine receptor gene expression and impaired adenosine-related signal transduction may result in a diminished response to adenosine. This may have implications for cardiac stress testing. We evaluated the haemodynamic response to intravenous adenosine in patients with left ventricular systolic dysfunction (LVSD) undergoing stress cardiovascular magnetic resonance imaging (CMR).

METHODS AND RESULTS

We retrospectively examined 497 consecutive patients referred for clinical stress CMR. Blood pressure and heart rate responses with intravenous adenosine were compared in patients with normal, mild-moderately impaired and severely impaired LV systolic function (ejection fraction [EF] > 55%, 36-55% and < 35%, respectively). Following 2 min of adenosine infusion, there was a significant difference between the groups in the heart rate change from baseline, with a diminished heart rate response in patients with LVSD (p < 0.001). An increase in the dose of adenosine (up to 210 μg/kg/min) was required to achieve a sufficient haemodynamic response in more patients with severe LVSD (41%) than those with mild-moderately impaired and normal LV systolic function (24% and 19%, respectively, p < 0.001). Even with increased doses of adenosine in subjects with severe LVSD, peak haemodynamic response remained blunted. With multivariate analysis age (p < 0.001) and LVEF (p = 0.031) were independent predictors of heart rate response to adenosine.

CONCLUSION

Patients with reduced LVEF referred for stress CMR may have a blunted heart rate response to adenosine. Further study is warranted to determine whether this may be associated with reduced diagnostic accuracy and also the potential utility of further dose increases or alternative stressors.

Multidimensional contractile reserve predicts adverse outcome in patients with severe systolic heart failure: a 4-year follow-up study

AIMS

Left ventricular contractile reserve is a prognostic indicator for adverse outcome in patients with severe chronic heart failure with reduced ejection fraction (HFrEF). We investigated the dobutamine-induced changes of LV multidimensional deformation and their predictive value for cardiac mortality of patients with severe chronic HFrEF.

METHODS AND RESULTS

In this prospective study, out of 130 patients with severe HFrEF who underwent a low-dose dobutamine stress echocardiography (LDSE) study using speckle tracking imaging, 100 patients were followed up for the occurrence of cardiac death over a period of 4 years. Compared with survivors, non-survivors (n = 32) had lower radial strain (RS) and strain rate (RSR) (10.7 ± 5.9 vs. 20.1 ± 8% and 0.5 ± 0.2 vs. 0.8 ± 0.3 L/s, P < 0.001), a smaller increase of global longitudinal strain (GLS) and strain rate after LDSE (0.9 ± 1.5 vs. -3.3 ± 3.5% and -0.1 ± 0.1 vs. -0.3 ± 0.3 L/s, P < 0.001), and a lack of change in the circumferential and radial deformation. The dobutamine-induced changes of all speckle tracking indices predicted cardiac mortality, while, among resting echocardiographic parameters, only RS and RSR predicted survival, after adjusting for age, sex, cardiomyopathy aetiology, NYHA class, AF, BNP levels, resting LVED, and LV outflow tract velocity-time integral, and their respective changes produced by dobutamine (P < 0.05). The dobutamine-induced change of GLS and resting RS were the best additive predictors of mortality with a net reclassification improvement of 0.518 (P = 0.022) CONCLUSION: In severe chronic HFrEF, resting RS and the dobutamine-induced change of GLS are independent predictors of cardiac mortality.

Prognostic importance of tissue velocity imaging during exercise echocardiography in patients with systolic heart failure

Resting echocardiography measurements are poor predictors of exercise capacity and symptoms in patients with heart failure (HF). Stress echocardiography may provide additional information and can be expressed using left ventricular ejection fraction (LVEF), or diastolic parameters (E/E'), but LVEF has some major limitations. Systolic annular velocity (S') provides a measure of longitudinal systolic function, which is relatively easy to obtain and shows a good relationship with exercise capacity. The objective of this study was to investigate the relationship among S', E/E' and LVEF obtained during stress echocardiography and both mortality and hospitalisation. A secondary objective was to compare S' measured using a simplified two-wall model. A total of 80 patients with stable HF underwent exercise stress echocardiography and simultaneous cardiopulmonary exercise testing. Volumetric and tissue velocity imaging (TVI) measurements were obtained, as was peak oxygen uptake (VO2 peak). Of the total number of patients, 11 died and 22 required cardiac hospitalisation. S' at peak exertion was a powerful predictor for death and hospitalisation. Cut-off points of 5.3 cm/s for death and 5.7 cm/s for hospitalisation provided optimum sensitivity and specificity. This study suggests that, in patients with systolic HF, S' at peak exertion calculated from the averaged spectral TVI systolic velocity of six myocardial segments, or using a simplified measure of two myocardial segments, is a powerful predictor of future events and stronger than LVEF, diastolic velocities at rest or exercise and VO2 peak. Results indicate that measuring S' during exercise echocardiography might play an important role in understanding the likelihood of adverse clinical outcomes in patients with HF.

Quantitative assessment of left ventricular function by 3-dimensional speckle-tracking echocardiography in patients with chronic heart failure: a meta-analysis

OBJECTIVES

To provide a comprehensive analysis of the clinical utility of 3-dimensional (3D) speckle-tracking echocardiography for left ventricular (LV) function in patients with chronic heart failure (CHF).

METHODS

Literature searches were conducted in the PubMed, Embase, Web of Science, and China BioMedicine databases on relevant articles published before October 1, 2012. Crude standardized mean differences with 95% confidence intervals (CIs) were calculated.

RESULTS

Seven case-control studies were included with a total of 375 patients with CHF and 181 healthy control participants. Meta-analysis results showed that the LV ejection fraction in the patients was significantly lower than in the controls (standardized mean difference, -4.62; 95% CI, -6.19 to -3.04), whereas the LV end-diastolic volume (LVEDV) and LV end-systolic volume (LVESV) in the patients were higher than in the controls (LVEDV: standardized mean difference, 1.76; 95% CI, 1.09 to 2.44; LVESV: standardized mean difference, 2.04, 95% CI, 1.30 to 2.78). The results also indicated that the patients had a greater delay in the standard deviation of the time to peak area tracking and the maximum difference in the time to peak area tracking in the 16 LV segments than the controls (standard deviation of the time to peak area tracking: standardized mean difference, 3.01; 95% CI, 1.73 to 4.29; maximum difference in the time to peak area tracking: standardized mean difference, 3.26; 95% CI, 1.58 to 4.93). Furthermore, global longitudinal, circumferential, and radial strain were also significantly impaired in the patients compared to the controls (longitudinal strain: standardized mean difference, 2.75; 95% CI, 1.11 to 4.39; circumferential strain: standardized mean difference, 2.71; 95% CI, 1.15 to 4.27; radial strain: standardized mean difference, 1.80; 95% CI, 0.45 to 3.14).

CONCLUSIONS

This meta-analysis suggests that LV function in patients with CHF can be noninvasively and objectively measured by 3D speckle-tracking echocardiography.

Clinical applications of exercise stress echocardiography in the treadmill with upright evaluation during and after exercise

Exercise stress echocardiography is the most frequently used stress test in our laboratory. Exercise echocardiography is used mainly in the study of patients with coronary artery disease. However, the technique is increasingly being used to study other diseases. In our centre, we use an original methodology, published by us in 2000, in which we evaluate heart function during exercise in the treadmill. After the exercise, patients are maintained in orthostatic position when appropriate or lying down in left lateral decubitus for further evaluation. Since this method seems to increase the quality and the quantity of information obtained in so many clinical arenas, we now present a detailed review of this methodology and its applications.

The pressure/volume relationship during dobutamine stress echocardiography in transplanted heart: comparison with quality of life and coronary anatomy

Background

Cardiac allograft vasculopathy (CAV) is a major late complication in cardiac transplant recipients and has a relevant impact on outcome of these patients. Aims of this study: to compare, in cardiac transplant recipients patients, the diagnostic value of pressure/volume relationship (ESPVR) during dobutamine stress echocardiography (DSE) for coronary artery disease, assessed by Multislice Computed Tomography (MSCT), and by coronary angiography (CA). We also analyzed any possible relationship between ESPVR and the Health Related Quality of Life of the patients (HRQoL), evaluated by SF–36 questionnaire.

Methods

25 consecutive patients underwent DSE within 24 hours after MSCT coronary angiogram and then they underwent CA. The HRQoL questionnaire was administered to the patients in the settings of DSE. They were followed-up for 6 months.

Results

DSE has a sensitivity in detecting CAV of 67%, specificity of 95%, positive predictive value of 67% and negative predictive value of 95%; DSE with ESPVR has a sensitivity of 100%, specificity of 95%, positive predictive value of 75%, negative predictive value of 100%; MSCT has a sensitivity of 100%; specificity of 82%; positive predictive value of 43%; negative predictive value of 100%. Htx recipients with a flat-biphasic ESPVR, although asymptomatic, perceived a worst HRQoL compared with the up-sloping ESPVR population, and this is statistically significant for the general health (p 0.0004), the vitality (p 0.0013) and the mental health (p 0.021) SF-36 subscale.

Conclusions

Evaluation with DSE and ESPVR is accurate in the clinical control of heart transplant recipients reserving invasive evaluation only for patients with abnormal contractility indexes.

Low-dose dobutamine test associated with interventricular dyssynchrony: a useful tool to identify cardiac resynchronization therapy responders: data from the LOw dose DObutamine stress-echo test in Cardiac Resynchronization Therapy (LODO-CRT) phase 2 study

BACKGROUND

Cardiac resynchronization therapy (CRT) is effective in patients with heart failure, but 30% to 50% of subjects are classified as nonresponders. Identifying responders remains a challenging task.

AIMS

The LODO-CRT trial investigated the association between left ventricular contractile reserve (LVCR) and clinical and echocardiographic long-term CRT response.

METHODS

This is a multicenter, prospective, observational study. Left ventricular contractile reserve was detected using a dobutamine stress echocardiography test, defined as an ejection fraction increase of >5 points. Clinical CRT response was defined as the absence of major cardiovascular events (ie, cardiovascular death or heart failure hospitalization). Echocardiographic response was defined as a left ventricle end-systolic volume reduction of >10%.

RESULTS

A total of 221 CRT-indicated patients were studied (80% presented LVCR). During a mean follow-up of 15 ± 5 months, 17 patients died and 16 were hospitalized due to heart failure. The proportion of clinical responders was 155 (88%) of 177 and 33 (75%) of 44 (P = .036) in the groups with and without LVCR, respectively. Kaplan-Meier analysis showed a significant difference in cardiac survival/hospitalization between patients with and without LVCR. The proportion of echocardiographic responders was 144 (87%) of 166 and 16 (42%) of 38 in the groups with and without LVCR (P < .001), respectively; LVCR showed 90% sensitivity and 87% positive predictive value to prefigure echocardiographic CRT responders. Multivariable analysis identified LVCR and interventricular dyssynchrony as independent predictors of CRT response. The concomitant presence of both factors showed 99% specificity and 83% sensitivity in detecting responders.

CONCLUSION

The presence of LVCR helps in predicting a clinical and echocardiographic CRT response. Concomitant assessment of LVCR and interventricular dyssynchrony accurately stratifies responder and nonresponder patients.

Prognostic significance of right ventricular dimension on acute decompensation in chronic left-sided heart failure

Right ventricular (RV) dysfunction has been discussed in relation to an adverse outcome in heart failure (HF). The aim of this study was to analyze the relationship between RV function with HF exacerbation and its subsequent long-term outcome in patients with chronic left-sided HF.We studied 122 consecutive patients who were admitted for dyspnea due to exacerbated left-sided HF with a left ventricular (LV) ejection fraction of less than 40%. Conventional echocardiography was performed in the study subjects on admission and at discharge. Cox proportional hazards analysis revealed that RV end-diastolic dimension (RVDd) (hazard ratio 1.131, P = 0.005, 95% confidence interval 1.039-1.231) and the serum level of creatinine on admission were independent predictors of subsequent cardiac-related death, but RVDd at discharge and other LV parameters were not. Thus, patients were divided into tertiles on the basis of RVDd on admission: < 32 mm (n = 37), 32-40 mm (n = 43), and ≥ 40 mm (n = 42). According to the increase in the RVDd category, the cardiac-related death-free rate significantly decreased. Among the 3 groups, the pulse pressure and serum total bilirubin levels that demonstrated low cardiac output syndrome (LOS) parameters had significant differences.RVDd on admission could be measured noninvasively and easily to predict a worse long-term prognosis of chronic left-sided HF on admission, and showed correlations with LOS parameters.

Efficacy of LOw-dose DObutamine stress-echocardiography to predict cardiac resynchronization therapy response (LODO-CRT) multicenter prospective study: design and rationale

BACKGROUND

Although cardiac resynchronization therapy (CRT) has a well-demonstrated therapeutic effect in selected patients with advanced heart failure on optimized drug therapy, nonresponder rate remains high. The LODO-CRT is designed to improve patient selection for CRT. Design and rationale of this study are presented herein.

METHODS

LODO-CRT is a multicenter prospective study, started in late 2006, that enrolls patients with conventional indications for CRT (symptomatic stable New York Heart Association class III-IV on optimized drug therapy, QRS > or =120 milliseconds, left ventricular [LV] dilatation, LV ejection fraction < or =35%). This study is designed to assess the predictive value of LV contractile reserve (LVCR), determined through dobutamine stress echocardiography (defined as an LV ejection fraction increase >5 units), in predicting CRT response during follow-up. Assessment of CRT effects will follow 2 sequential phases: in phase 1, CRT response end point is defined as LV end-systolic volume reduction > or =10% at 6 months; in phase 2, both LV end-systolic volume reduction and clinical status via a clinical composite score will be evaluated at 12 months follow-up. Predictive value of LVCR will be compared to other measures, such as LV dyssynchrony measures, through adjusted multivariable analysis. For the purpose of the study, target patient number is 270 (with 95% confidence, 80% power, alpha < or = .05). Enrollment should be complete by the end of 2008.

CONCLUSIONS

The LODO-CRT trial is testing the hypothesis that LVCR assessment, using low-dose dobutamine stress echocardiography test, should effectively predict positive response to CRT both in terms of the reverse remodeling process as well as favorable long-term clinical outcome. Moreover, the predictive value of LVCR will be compared to that of conventional intra-LV dyssynchrony measures.

Role of echocardiography in diagnosis and risk stratification in heart failure with left ventricular systolic dysfunction

Heart failure (HF) is a complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood. Echocardiography represents the "gold standard" in the assessment of LV systolic dysfunction and in the recognition of systolic heart failure, since dilatation of the LV results in alteration of intracardiac geometry and hemodynamics leading to increased morbidity and mortality. The functional mitral regurgitation is a consequence of adverse LV remodelling that occurs with a structurally normal valve and it is a marker of adverse prognosis. Diastolic dysfunction plays a major role in signs and symptoms of HF and in the risk stratification, and provides prognostic information independently in HF patients and impaired systolic function. Ultrasound lung comets are a simple echographic sign of extravascular lung water, more frequently associated with left ventricular diastolic and/or systolic dysfunction, which can integrate the clinical and pathophysiological information provided by conventional echocardiography and provide a useful information for prognostic stratification of HF patients. Contractile reserve is defined as the difference between values of an index of left ventricular contractility during peak stress and its baseline values and the presence of myocardial viability predicts a favorable outcome. A non-invasive echocardiographic method for the evaluation of force-frequency relationship has been proposed to assess the changes in contractility during stress echo. In conclusion, in HF patients, the evaluation of systolic, diastolic function and myocardial contractile reserve plays a fundamental role in the risk stratification. The highest risk is present in HF patients with a heart that is weak, big, noisy, stiff and wet.

The independent prognostic value of contractile and coronary flow reserve determined by dipyridamole stress echocardiography in patients with idiopathic dilated cardiomyopathy

The aim of this study was to evaluate the prognostic value of Doppler echocardiographically derived coronary flow reserve (CFR) in assessing inotropic response in patients with idiopathic dilated cardiomyopathy (IDC). One hundred thirty-two patients with IDC (90 men; mean age 62 +/- 11 years) were evaluated by transthoracic dipyridamole (0.84 mg/kg in 10 minutes) stress echocardiography. All patients had ejection fractions <40% (mean 33 +/- 7%) and angiographically normal coronary arteries, with New York Heart Association class <or=III. CFR was assessed in the left anterior descending coronary artery by pulsed Doppler as the ratio of maximal peak vasodilation (dipyridamole) to rest diastolic flow velocity. Inotropic reserve was identified as rest-stress variation in wall motion score index >0.25. All patients were followed for a median of 24 months. Mean CFR was 2.0 +/- 0.5. On individual patient analysis, 48 patients had normal CFR (>2), and 84 had abnormal CFR. The mean wall motion score index at rest was 2.0 +/- 0.33 and decreased to 1.8 +/- 0.4 at peak dipyridamole dose (p <0.000). Forty-two patients (32%) had inotropic reserve. During follow-up, 19 patients died, and 34 showed worsening of New York Heart Association class. The worst outcomes were observed in those patients with abnormal CFR and no inotropic reserve with high-dose dipyridamole. In a Cox model, mitral insufficiency (hazard ratio [HR] 1.7, 95% confidence interval [CI] 1.1 to 2.8), New York Heart Association class (HR 2.0, 95% CI 1.1 to 3.7), abnormal CFR (HR 2.8, 95% CI 1.0 to 8.5), wall motion score index at rest (HR 3.5, 95% CI 1.3 to 9.8), and the absence of inotropic reserve with high-dose dipyridamole (HR 2.3, 95% CI 1.06 to 5.1) were independent predictors of survival. In conclusion, in patients with IDC, CFR is often impaired. Reduced CFR and the absence of an inotropic response during vasodilator stress are additive in predicting a worse prognosis.

Assessment of stress-induced pulmonary interstitial edema by chest ultrasound during exercise echocardiography and its correlation with left ventricular function

Ultrasound lung comet images (ULC) are useful for the noninvasive assessment of extravascular lung water (EVLW). We investigated the modification of EVLW, its relation to indices of left ventricular systolic and diastolic function, and noninvasively determined pulmonary capillary wedge pressure (PCWP) (PCWP = 1.24 ratio of early diastolic mitral inflow velocity to early diastolic velocity of the mitral annulus [E/Em] + 1.9) at rest and its variation during exercise echocardiography. A total of 72 patients (mean age 66.4 +/- 8.4 years) with mean ejection fraction of 41.2 +/- 14.4% underwent symptoms-limited exercise echocardiography. The sum of the ULC yielded a score of EVLW. The ULC increased significantly from baseline to postexercise (5.9 +/- 14.9 vs 11 +/- 20.7, P = .0001). Positive linear correlations were found between baseline ULC score and baseline ejection fraction (r = -0.37, P = .002), systolic pulmonary artery pressure (r = 0.69, P = .0001), E/Em (r = 0.70, P = .0001), and estimated PCWP (r = 0.69, P = .0001). The variation between postexercise and baseline ULC score correlated significantly with the variation between peak stress and rest PCWP (r = 0.62, P = .0001), systolic pulmonary artery pressure (r = 0.44, P = .0001), wall-motion score index (r = 0.30, P = .01), and peak stress E/Em (r = 0.71, P = .0001), whereas no significant correlations were found between variations of ULC score and ejection fraction. This study shows that ULC represents a simple way to assess the presence of excess EVLW. Increased EVLW is associated with estimated PCWP and indices of left ventricular systolic and diastolic dysfunction. The additional exercise-induced increase of PCWP, the worsening of left ventricular diastolic function, and extensive wall-motion abnormalities correlate with variations of EVLW.

End-systolic pressure/volume relationship during dobutamine stress echo: a prognostically useful non-invasive index of left ventricular contractility

AIMS

Left ventricular end-systolic pressure-volume relationship (PVR) provides a robust, relatively load-insensitive evaluation of contractility and can be assessed non-invasively during exercise echo. Dobutamine might provide an exercise-independent alternative approach to assess inotropic reserve. The feasibility of a non-invasive estimation of PVR during dobutamine stress in the echo lab and its relationship with subsequent clinical events was assessed.

METHODS AND RESULTS

We enrolled 137 consecutive patients referred for dobutamine stress echo. To build the PVR, the force was determined at different heart rate increments during stepwise dobutamine infusion as the ratio of the systolic pressure/end-systolic volume index. The PVR at increasing heart rate was flat-biphasic in 65 and up-sloping in 72 patients: 42 patients underwent surgery and 95 patients were treated medically (median follow-up, 18 months; interquartile range, 12-24). Events occurred in 18 patients (death in eight, acute heart failure in 10); a flat-biphasic PVR was independent predictor of events (RR=10.16, P<0.01).

CONCLUSION

PVR is feasible during dobutamine stress. This index of global contractility is reasonably simple, does not affect the imaging time, and only minimally prolongs the off-line analysis time. It allows unmasking quite different, and heterogeneous, contractility reserve patterns underlying a given ejection fraction at rest. The best survival is observed in patients with up-sloping PVR, whereas flat-biphasic pattern is a strong predictor of cardiac events.