Low-dose Dobutamine Stress Research Articles

A "Hibernating-Like" Viable State Induced by Lentiviral Vector-Mediated Pigment Epithelium-Derived Factor Overexpression in Rat Acute Ischemic Myocardium.

The failure to maintain the viability of ischemic myocardium is one of the mechanisms that causes ischemic heart dysfunction after revascularization. Hibernating myocardium is considered to be able to maintain long-term viability during chronic hypoperfusion. Pigment epithelium-derived factor (PEDF) decreases the contractility of hypoxic cardiomyocytes and protects cardiomyocytes against ischemic injury, which is strikingly similar to the pathophysiologic characteristics of hibernating myocardium. It was therefore postulated that PEDF may induce acute ischemic myocardium into a "hibernating-like" state to maintain its viability. Adult Sprague-Dawley rat models of acute myocardial infarction were surgically established. Lentiviral vectors carrying the PEDF gene (PEDF-LVs) were delivered into myocardium with infarction to overexpress PEDF locally. It was found that PEDF local overexpression significantly reduced myocardial infarct size and cardiomyocytes necrosis but did not improve cardiac function at rest. The contractile reserve assessed by low-dose dobutamine stress echocardiography and "perfusion-metabolism mismatch" assessed by positron emission tomography, which are the characteristics of viable myocardium in hibernation, were observed in the PEDF overexpressed ischemic heart. Ultrastructural changes observed by electron microscopy and glycogen deposition explored by Periodic acid-Schiff staining were similar to the histological characteristics of hibernating myocardium. Moreover, PEDF overexpression protected the cardiomyocytes against anoxic injury and retained their functional recovery potential after reoxygenation in vitro. PEDF local overexpression may induce acute ischemic myocardium into a "hibernating-like" state and maintain its viability. This novel effect of PEDF presents an important clinical approach to enhance functional recovery after revascularization therapy in acute myocardial infarction.

Stress Echocardiography in Aortic Stenosis

In apparently asymptomatic severe aortic stenosis (AS) group, stress echocardiography objectively identifies symptomatic, high-risk AS patients requiring early aortic valve replacement (AVR). The low-flow, low-gradient AS is well-characterized clinical entity with distinct diagnostic, management, and clinical outcome challenges. A comprehensive two-dimensional transthoracic echocardiography (2D echo) and Doppler and low-dose dobutamine stress echocardiography are of paramount importance for accurate diagnosis and timely decision of AVR. However, clinicians and imaging experts should be aware of the pitfalls and inaccuracies inherent in 2D echo/Doppler measurements and the effects of pathophysiological factors which impact the stroke volume and transvalvular gradient measurements. In appropriate clinical situations, clinicians should take additional help of cardiac computational tomography, cardiac magnetic resonance imaging, and biomarkers.

Stress echocardiography in aortic stenosis

In apparently asymptomatic severe aortic stenosis (AS) group, stress echocardiography objectively identifies symptomatic, high-risk AS patients requiring early aortic valve replacement (AVR). The low-flow, low-gradient AS is well-characterized clinical entity with distinct diagnostic, management, and clinical outcome challenges. A comprehensive two-dimensional transthoracic echocardiography (2D echo) and Doppler and low-dose dobutamine stress echocardiography are of paramount importance for accurate diagnosis and timely decision of AVR. However, clinicians and imaging experts should be aware of the pitfalls and inaccuracies inherent in 2D echo/Doppler measurements and the effects of pathophysiological factors which impact the stroke volume and transvalvular gradient measurements. In appropriate clinical situations, clinicians should take additional help of cardiac computational tomography, cardiac magnetic resonance imaging, and biomarkers.

Poster Session - Poster session 2

Background: Preliminary studies suggest that myocardial scar can be visualised by transthoracic echocardiography (TTE) using a low mechanical index (MI). Data describing the usefulness of scar imaging by TTE to predict myocardial viability are limited. Purpose: We investigated the association between myocardial scar, as imaged by low MI TTE, and viability as assessed by low-dose dobutamine stress echocardiography (DSE). Methods: We analysed 59 patients who had rest echocardiography including low MI (0.4-0.5) scans and DSEs, performed for myocardial viability between 29/04/2015 to 16/05/2018. Median age was 64 years (interquartile range 57-71), 55 (93%) were male. Left ventricular contrast opacification SonoVue (Braco) was used according to American Society of Echocardiography (ASE) standards (n = 39). Two experienced cardiologists blindly and independently performed 16-segment scar assessment at rest. Viability by DSE was used to represent the ‘gold standard’, from which sensitivity, specificity, negative and positive predictive values of viability assessed by scar at rest were calculated. Results: 42 (71%) of studies had evidence of scar at rest identified by low MI imaging. Presence of scar at rest has a sensitivity of 42%, specificity of 92%, positive and negative predictive values of 82 and 64%, respectively (Table 1). Specificity was higher in non-contrast compared to contrast images, at 97 and 90 %, respectively. The right coronary artery territory had a lower specificity compared to left anterior descending and circumflex territories. Conclusions: Presence of scar at rest has a low sensitivity but high specificity to predict non-viability on low-dose DSE. The presence of scar at rest TTE has the potential to reduce the need for low-dose DSE as these patients are unlikely to have viable myocardium in this region.

Dobutamine stress echocardiography unmasks early left ventricular dysfunction in asymptomatic patients with uncomplicated Type 2 diabetes: A comprehensive 2D speckle-tracking imaging Study

Discrepancies are present in the literature on resting myocardial mechanics in patients with uncomplicated type 2 diabetes mellitus (T2DM). Data are noticeably sparse regarding circumferential function and torsional mechanics. Resting deformation imaging may not be sensitive enough to detect subtle dysfunctions. The aim of this study was thus to comprehensively evaluate myocardial mechanics in patients with T2DM at rest and to investigate whether dobutamine stress echocardiography could unmask functional alterations that would remain otherwise subtle at rest. Forty-four patients with T2DM and 35 healthy control subjects of similar age and sex were prospectively recruited. After conventional echocardiography, myocardial mechanics was evaluated at rest and during low-dose dobutamine stress echocardiography (target heart rate, 110 beats/min). Patients with T2DM presented with altered global diastolic function but preserved systolic function. Deformation imaging indexes were similar between groups at rest, but significant differences were noticed under dobutamine infusion ( Table 1 ). Multivariate analysis identified epicardial fat, dyslipidemia, and fasting glycaemia as significant contributors to the changes from rest to dobutamine. These findings demonstrate the usefulness of dobutamine stress echocardiography in establishing impairments in myocardial mechanics in patients with uncomplicated T2DM. Systemic metabolic disturbances and epicardial fat act as the main contributors to the blunted response to dobutamine stress in these patients.

Value of low-dose dobutamine stress echocardiography on defining true severe low gradient aortic stenosis in patients with preserved left ventricular ejection fraction

Low-dose dobutamine stress echocardiography (DSE) is a valuable tool to distinguish true-severe (TS) from pseudo-severe (PS) low gradient aortic valve stenosis (LGAS) in patients with reduced left ventricular ejection fraction (LVEF). However, only scanty studies reported the clinical utility of DSE in differentiating TS-LGAS patients with preserved LVEF. We investigated the clinical utility of DSE in LGAS patients with preserved LVEF and the echocardiographic determinants suggestive of TS-LGAS. 130 consecutive LGAS patients [indexed aortic valve area (AVA) ≤ 0.6cm2/m2 and mean trans-aortic pressure gradient (PGmean) < 40mmHg] with preserved (≥ 50%, n = 63) and reduced (< 50%, n = 67) LVEF were included. DSE defined TS-LGAS (projected AVA ≤ 1 cm2) in 61.2% patients with reduced LVEF and in 68.3% patients with preserved LVEF. Multivariate logistic regression analysis showed that baseline AVA was an independent determinant of TS-LGAS both in LVEF ≥ 50% (OR 0.45, P = 0.004) and LVEF < 50% groups (OR 0.55, P = 0.005). Reduced septal and lateral mitral annular plane systolic excursion (MAPSE, OR 0.72 and 0.75, P = 0.013 and 0.016) and septal TDI-s´ were significantly associated with TS-LGAS in patients with LVEF ≥ 50%. Higher systolic pulmonary artery pressure (SPAP, OR 1.43, P = 0.045) was associated with TS-LGAS in patients with LVEF < 50%. DSE is useful to define TS-LGAS also in patients with preserved LVEF. Lower baseline AVA values are linked with TS-LGAS in both patients with reduced and preserved LVEF. Reduced MAPSE and septal TDI-s´ are suggestive of TS-LGAS in patients with preserved LVEF, while higher SPAP is associated with TS-LGAS in patients with reduced LVEF.

Dobutamine Stress Echocardiography Unmasks Early Left Ventricular Dysfunction in Asymptomatic Patients with Uncomplicated Type 2 Diabetes: A Comprehensive Two-Dimensional Speckle-Tracking Imaging Study

Discrepancies are present in the literature on resting myocardial mechanics in patients with uncomplicated type 2 diabetes mellitus (T2DM). Data are noticeably sparse regarding circumferential function and torsional mechanics. Resting deformation imaging may not be sensitive enough to detect subtle dysfunctions. The aim of this study was thus to comprehensively evaluate myocardial mechanics in patients with T2DM at rest and to investigate whether dobutamine stress echocardiography could unmask functional alterations that would remain otherwise subtle at rest. Forty-four patients with T2DM and 35 healthy control subjects of similar age and sex were prospectively recruited. After conventional echocardiography, myocardial mechanics was evaluated at rest and during low-dose dobutamine stress echocardiography (target heart rate, 110 beats/min). Patients with T2DM presented with altered global diastolic function but preserved systolic function. Deformation imaging indexes were similar between groups at rest, but significant differences were noticed under dobutamine infusion for longitudinal strain (-21.2±2.4% vs -24.2±2.5%, P<.001), circumferential strain (apex, -32.3±5.3% vs -36.3±5.3%, P=.002; papillary muscle, -25.6±3.2% vs -28.0±3.6%, P=.001; base, -23.2±3.6% vs -25.3±3.8%, P=.03), apical (11.2±4.4° vs 14.1±6.3°, P=.020) and basal (-12.2±3.3° vs -14.3±3.9°, P=.021) rotation, and twist (21.9±5.9° vs 26.8±8.3°, P=.007). Multivariate analysis identified epicardial fat, dyslipidemia, and fasting glycaemia as significant contributors to the changes from rest to dobutamine. These findings demonstrate the usefulness of dobutamine stress echocardiography in establishing impairments in myocardial mechanics in patients with uncomplicated T2DM. Systemic metabolic disturbances and epicardial fat act as the main contributors to the blunted response to dobutamine stress in these patients.

UTILIZATION OF DOBUTAMINE STRESS STUDIES IN PATIENTS WITH SYMPTOMATIC, SEVERE LOW-FLOW/LOW-GRADIENT AORTIC STENOSIS UNDERGOING TRANSCATHETER AORTIC VALVE REPLACEMENT

Patients with severe low-flow/low gradient aortic stenosis (LFLGAS) and reduced left ventricular ejection fraction (LVEF) [group D2] pose a diagnostic dilemma. Current guidelines recommend low-dose dobutamine stress testing (DST) for these patients. Left ventricular (LV) recovery after transcatheter

FLOW RATE NOT STROKE VOLUME IS A SUPERIOR PROGNOSTIC MARKER OF TRANSORTIC FLOW AND FLOW RESERVE IN PATIENTS WITH LOW-FLOW LOW-GRADIENT AORTIC STENOSIS UNDERGOING LOW-DOSE DOBUTAMINE ECHOCARDIOGRAPHY

The objectives of low-dose dobutamine stress echocardiography (LDDSE) in low-flow low-gradient aortic stenosis (LFLG AS) are both to normalise transvalvular flow, at which juncture the aortic valve area informs the true AS severity, and to assess flow reserve. Conventionally, these assessments are

SY2-1 - Assessment and Treatment for Secondary Mitral Regurgitation

The assessment and treatment for secondary mitral regurgitation (MR) are based on the concepts different from those for primary MR. The main etiology of traditional secondary MR is mitral leaflet tethering-tenting occurring from left ventricular dilatation and systolic dysfunction. The origin of secondary MR usually takes a transverse direction along the mitral leaflets' coaptation. Consequently, the Doppler-derived volumetric method should be selected for the echocardiographic quantitative analysis of the secondary MR rather than the proximal isovelocity surface area method. In general, the strong medical therapies are required in heart failure patients with significant secondary MR. Mitral valve surgery may be also considered for patients with severe secondary MR with heart failure symptoms despite the optimal medical therapies. Concomitant mitral valve surgery is more reasonable in patients with coronary artery disease and severe secondary MR at the time of coronary artery bypass grafting (CABG). It is still controversial whether concomitant mitral valve surgery should be performed in patients with coronary artery disease and moderate secondary MR at the time of CABG. Low-dose dobutamine stress echocardiography or exercise stress echocardiography may be helpful to address this issue. For secondary MR seen in patients with atrial fibrillation and left atrial dilatation despite havinf preserved left ventricular ejection fraction, mitral annuloplasty would be the primary treatment.

The relationship between myocardial perfusion and left ventricular longitudinal systolic function in patients with coronary slow flow

Objective To investigate whether myocardial perfusion impairment and left ventricular(LV) longituadinal systolic dysfunction had happened in patients with coronary slow flow(CSF), and to assess the relationship between them by myocardial contrast echocardiography(MCE) and speckle tracking imaging(STI). Methods A total of 55 patients underwent coronary angiography for angina were enrolled, of those 35 with coronary slow flow phenomenon as CSF group, 20 patients with normal coronary angiography as control group. STI and MCE were performed from the apical 4-, 3-and 2-chamber views at baseline and after low-dose dobutamine stress echocardiography (LDDSE) in CSF group and control group. STI derived LV global longitudinal strain(GLS) and GLS amplitude of variation(ΔGLS), and MCE derived myocardial blood flow(MBF), and myocardial flow reserve(MFR) were obtained. And the correlation between GLS/ΔGLS and MBF/MFR was analyzed. Results At baseline, the GLS and MBF were similar between CSF group and control group(P>0.05). After LDDSE, both GLS and MBF were significantly increased in two groups(P<0.05). The GLS, ΔGLS, MBF, and MFR in CSF group were significantly lower than those in control group(P<0.05). There was no significant correlation between GLS and MBF at baseline in the CSF group(r=-0.274, P=0.111). However, after LDDSE significant correlation existed between GLS and MBF(r=-0.630, P=0.000). Conclusions LV longituadinal systolic function is impaired in patients with CSF under dobutamine stress test, the impairment of MBF and MFR could be an important contributor to the decrease of LV longituadinal systolic function. Key words: Echocardiography; Microbubbles; Dobutamine; Coronary disease; Ventricular function, left; Speckle tracking imaging

P6133Blood pressure during low dose dobutamine stress echo as a predictor of mortality after cardiac resynchronization in ViaCRT study

P6133Blood pressure during low dose dobutamine stress echo as a predictor of mortality after cardiac resynchronization in ViaCRT study

P3351Cardiac magnetic resonance deformation analysis and low-dose dobutamine stress echocardiography for assessment of myocardial viability

P3351Cardiac magnetic resonance deformation analysis and low-dose dobutamine stress echocardiography for assessment of myocardial viability

124 Stroke volume determined flow reserve does not predict the true severity of low-flow low-gradient aortic stenosis and is not a robust marker of contractile reserve in patients undergoing low-dose dobutamine echocardiography

BackgroundDuring low-dose dobutamine stress echocardiography (LDDSE) in low-flow low-gradient aortic stenosis (LFLGAS), both the aortic stenosis (AS) severity and the presence of contractile reserve (CR) are conventionally assessed based on...

Low-flow/low-gradient aortic stenosis-Still a diagnostic and therapeutic challenge.

Aortic stenosis (AS) is the most frequently observed valvular heart disease. During the symptomatic stage, the rate of death increases dramatically, so that a precise diagnostic approach is taken to guide therapeutic options. Of patients with severe AS, 30% to 50% present with low-flow/low-gradient AS (LF/LGAS) status. This review focuses on LF/LGAS and the best diagnostic and therapeutic management in either classic LF/LGAS with reduced left ventricular ejection fraction (LVEF) or paradoxical LF/LGAS with preserved LVEF. Current literature demonstrates that in classic LF/LGAS it is crucial to rule out a pseudo-severe AS, because reduced LVEF may result in an incomplete opening of the valve. This can be done by low-dose dobutamine stress echocardiography. Classic LF/LGAS has poor clinical outcomes when managed conservatively; therefore, surgical or interventional aortic valve replacement should be performed. In paradoxical LF/LGAS, the LVEF is preserved (>50%), but impaired filling of the concentric hypertrophied ventricle leads to reduced stroke volume. Therefore, diagnostic and therapeutic decisions in paradoxical LF/LGAS are even more challenging. It is a heterogeneous disease entity, and it is crucial to rule out any diagnostic errors because numerous potential confounders might lead to misdiagnosis. As in classic stenosis, pseudo-severe stenosis must be ruled out as well. Evaluation via multidetector computed tomography or transesophageal echocardiography can help to evaluate the morphologic alterations of the valve (eg, calcification). Further studies are necessary to understand this disease entity and to evaluate the optimal diagnostic and therapeutic approach for these patients.

Value of Low-Dose Dobutamine Stress Real-Time Myocardial Contrast Echocardiography in the Diagnosis of Coronary Heart Disease.

To investigate the value of low-dose dobutamine stress real-time myocardial contrast echocardiography (RT-MCE) in the diagnosis of coronary heart disease (CHD). A total of 65 hospitalized patients with suspected or confirmed CHD were detected by RT-MCE combined with low-dose dobutamine stress (0.84 mg/kg). Perfusion curves were quantitatively analyzed using QLAB software. Peak intensity (A), slope of curves (β), and perfusion (A × β) were also calculated. Based on the results of coronary angiography, patients were divided into no obvious stenosis group (<50%), mild stenosis group (50%-74%), moderate stenosis group (75%-89%), and severe stenosis group (≥90%). The A, β, and A × β values before and after low-dose dobutamine stress of each group were compared. In the basal state and after low-dose dobutamine stress, the A, β, and A × β values significantly decreased as the stenosis degree of the myocardial segments increased. The same variation tendency was also found in the A, β, and A × β reserve values, and there was significant difference in these reserve values between moderate and severe stenosis groups and no obvious stenosis and mild stenosis groups. Collateral circulation had marked effects on the values of myocardial perfusion parameters and their reserve values, especially in the segments with severe stenosis. Low-dose dobutamine stress RT-MCE can be a sensitive method for clinical diagnosis and risk assessment of CHD and may provide a basis for further treatment of CHD.

STROKE VOLUME DETERMINED FLOW RESERVE DOES NOT PREDICT THE TRUE SEVERITY OF LOW-FLOW LOW-GRADIENT AORTIC STENOSIS AND IS NOT A ROBUST MARKER OF CONTRACTILE RESERVE IN PATIENTS UNDERGOING LOW-DOSE DOBUTAMINE ECHOCARDIOGRAPHY

Background: During low-dose dobutamine stress echocardiography in low-flow low-gradient aortic stenosis (LFLGAS), both the aortic stenosis severity and the presence of contractile reserve are conventionally assessed based on stroke volume flow reserve (SVFR) (stroke volume increase ≥20%). However

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

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. 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.

Prediction of left ventricular contractile recovery using tissue Doppler strain and strain rate measurements at rest in patients undergoing percutaneous coronary intervention.

The aim of the study was to assess the ability of tissue Doppler (TD) deformation analysis at rest to predict left ventricular contractile recovery in patients undergoing percutaneous coronary intervention (PCI). This prospective cohort enrolled 67 patients with segmental wall motion abnormality. Assessment of each segment was performed at rest and during low dose Dobutamine stress echocardiography (DSE) using a 4 point scoring system, TD peak systolic strain (PSS) and peak systolic strain rate (PSSR). The study followed up the patients for contractile improvement after 6months of successful PCI by echocardiography. Of a 319 dysfunctional segments, 155 (49%) showed contractile recovery and 164 (51%) did not. PSS and PSSR at rest were significantly higher in recovered segments compared to segments without recovery (PSS: -7.27 ± 0.8 Vs. -6.14 ± 0.7%, PSSR: -0.34 ± 0.13 Vs. -0.24 ± 0.1/s. p < 0.0001 both). Similarly, both parameters were significantly higher in the contractile recovery group at follow up (p 0.001). Resting PSSR as well as PSS and PSSR during DSE were significant independent predictors of contractile recovery (p < 0.001 each). For predicting segmental contractile recovery, resting PSSR with a -0.31/s cut-off point had 76% sensitivity and 59% specificity (AUC 0.74), DSE qualitative viability assessment had asensitivity of 75% and specificity of 77%, DSE PSS with a cut-off point of -9.1% had 74% sensitivity and 63% specificity (AUC 0.77) and DSE PSSR with a cut-off point of-0.72/s had 78% sensitivity and 77% specificity (AUC 0.81). Resting PSSR is a modest predictor of segmental contractile recovery after PCI while PSSR during DSE has a comparable diagnostic performance to subjective wall motion scoring. Recovered segments show improvement of deformation parameters after PCI.

The detection of viable myocardium by low-dose dobutamine stress speckle tracking echocardiography in patients with old myocardial infarction.

To explore the significance and value of speckle-tracking echocardiography (STE) associated with low-dose dobutamine stress echocardiography (LDDSE) for the detection of viable myocardium (VM) in patients with old myocardial infarction (OMI). We performed STE with LDDSE in 33 hospitalized patients with OMI and left ventricular systolic dysfunction. QLAB software was used to analyze strain (S) and strain rate (Sr). Percutaneous coronary intervention (PCI) was subsequently performed. The movement of each wall segment was observed by routine echocardiography before and after 1, 3, and 6 months of PCI, and improvement was regarded as the gold standard for diagnosing VM. Compared with semi-quantitative wall-motion analysis combined with LDDSE, the sensitivity, specificity, and accuracy of c-STE (combining the three directions of S and Sr) at LDDSE were 91.6%, 79.5%, and 87.5%, respectively (p < 0.02). Among the deformation parameters, longitudinal strain (LS) and longitudinal strain rate (LSr) had the highest sensitivity, specificity, and accuracy. Upon combining LS and LSr at LDDSE to parallel tests, the sensitivity, specificity, and accuracy were 91.7%, 90%, and 90.6%, respectively. Compared with baseline, LVEF after PCI increased from 43.3% ± 2.6% to 47.3% ± 2.9% (p < 0.001). Global strain at LDDSE is superior to semi-quantitative wall-motion analysis with LDDSE for the assessment of VM. When the multivariable analysis and the parallel tests are combined, LS combined with LSr can be considered an independent predictor of VM. LVEF is improved after PCI in patients with VM and OMI. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:545-554, 2016.