Real-time Contrast Echocardiography Research Articles

The myocardial ischemia evaluated by real-time contrast echocardiography may predict the response to cardiac resynchronization therapy: a large animal study.

Evidence-based criteria for applying cardiac resynchronization therapy (CRT) in patients with ischemic cardiomyopathy are still scarce. The aim of the present study was to evaluate the predictive value of real-time myocardial contrast echocardiography (RT-MCE) in a preclinical canine model of ischemic cardiomyopathy who received CRT. Ischemic cardiomyopathy was produced by ligating the first diagonal branch in 20 beagles. Dogs were subsequently divided into two groups that were either treated with bi-ventricular pacing (CRT group) or left untreated (control group). RT-MCE was performed at baseline, before CRT, and 4 weeks after CRT. Two-dimensional speckle tracking imaging was used to evaluate the standard deviation of circumferential (Cir12SD), radial (R12SD), and longitudinal (L12SD) strains of left ventricular segments at basal as well as middle levels. Four weeks later, the Cir12SD, R12SD, and myocardial blood flow (MBF) of the treated group were significantly improved compared to their non-CRT counterparts. Furthermore, MBF values measured before CRT were significantly higher in responders than in non-responders to bi-ventricular pacing. Meanwhile, no significant differences were observed between the responder and non-responder groups in terms of Cir12SD, R12SD, and L12SD. A high degree of correlation was found between MBF values before CRT and LVEF after CRT. When MBF value>24.9 dB/s was defined as a cut-off point before CRT, the sensitivity and specificity of RT-MCE in predicting the response to CRT were 83.3% and 100%, respectively. Besides, MBF values increased significantly in the CRT group compared with the control group after 4 weeks of pacing (49.8±15.5 dB/s vs. 28.5±4.6 dB/s, p<0.05). Therefore, we considered that myocardial perfusion may be superior to standard metrics of LV synchrony in selecting appropriate candidates for CRT. In addition, CRT can improve myocardial perfusion in addition to cardiac synchrony, especially in the setting of ischemic cardiomyopathy.

Abstract 15541: Effect of Stress Perfusion and Wall Motion Response on Outcome of Obese versus Non-Obese Subjects Without Known Coronary Artery Disease

Background: Although several studies have demonstrated a protective effect of obesity in coronary artery disease (CAD), it is unclear whether this protective effect is evident in patients referred for stress imaging. Real time contrast echocardiography (RTCE) permits the simultaneous analysis of perfusion and wall motion during different forms of stress echocardiography.The objective of this study was to determine whether a protective effect of obesity is evident in subjects referred for pharmacologic stress RTCE. Methods and Results: Wall motion (WM) and myocardial perfusion (MP) with RTCE (using SonoVue and Definity ultrasound contrast) were assessed in 2106 consecutive patients without known CAD referred for either dobutamine (n=1209) or dipyridamole (n=897) stress echocardiography. Of these, 481 (23%) were obese (body mass index&gt;30 kg/m2). Outcome (death/non-fatal infarction) was determined over a median follow-up of 1022 days. Multivariate Cox Models were created from significant univariate variables to assess hazard ratios (HR) and 95% confidence intervals (CI). Abnormal MP and/ or WM were seen in 246 dobutamine and 169 dipyridamole studies (equally distributed between obese and non-obese). Although event free survival (EFS) was significantly better for obese versus non-obese subjects with normal tests (p=0.01) and in obese patients with abnormal dobutamine stress perfusion/wall motion responses (p=0.009), obesity was not an independent clinical predictor of outcome, while age (HR 1.04 (95% CI 1.03-1.06) and male gender (HR 2.26;(95% CI 1.59-3.21) did independently predict outcome (both p&lt;0.001). Furthermore, abnormal responses to stress (either dobutamine or dipyridamole) were associated with significantly worse prognosis, independent of age, gender, or obesity (HR 2.67;95% CI 1.91-3.77). Conclusions: Although obese subjects with both normal and abnormal responses to pharmacologic stress have improved EFS when compared to non-obese with the same test result, this trait is not independently associated with outcome. Perfusion and wall motion responses determined with RTCE add significant predictive value in this setting irrespective of age, gender, or obesity status.

Is real time contrast echocardiography useful for assessment of the right ventricular morphology, function, and perfusion?

Contrast-enhanced echocardiography (CE) is recommended to assess left ventricular function and perfusion but is rarely used to assess the right ventricle (RV). We used CE to assess RV function and perfusion and evaluated whether RV perfusion defects varied in different patient groups with RV failure due to pressure overload. We studied 17 patients with acute pulmonary embolism (PE), 19 patients with chronic pulmonary arterial hypertension (CPH), and 7 healthy volunteers. The examination included RV opacification (RVO) and myocardial CE. RV end-diastolic area (RVEDA), RV end-systolic area (RVESA), fractional area change (FAC), and wall-motion score index (WMSI) were assessed before and after contrast agent administration. Perfusion was evaluated qualitatively and quantitatively. RVEDA, RVESA, FAC, and regional contractility were comparable before and after contrast agent injection. Significant perfusion defects were seen in PE and CPH (18/39 segments and 37/51 segments, respectively, vs. 0/21 segments in healthy volunteers; P < 0.0001). Wall-perfusion score index (WPSI) was higher in PE and CPH compared to healthy volunteers (1.5 ± 0.3 and 1.8 ± 0.4 vs. 1.0 ± 0.0; P = 0.02 and P = 0.0003, respectively). Linear correlations were noted between WMSI, FAC and WPSI (r = 0.5, P = 0.014 and r = -0.55, P = 0.005, respectively). Quantitative perfusion assessment revealed perfusion defects in the apical segment in the PE group. The mean region of interest value was insignificantly reduced in PE and CPH groups. Contrast-enhanced echocardiography is feasible and may be useful for RVO and perfusion assessment in patients with RV dysfunction due to systolic overload. The SonoVue contrast agent was well tolerated by stable patients with PE and CPH.

Prognostic Value of High-Dose Dipyridamole Stress Myocardial Contrast Perfusion Echocardiography

The addition of myocardial perfusion (MP) imaging during dipyridamole real-time contrast echocardiography improves the sensitivity to detect coronary artery disease, but its prognostic value to predict hard cardiac events in large numbers of patients with known or suspected coronary artery disease remains unknown. We studied 1252 patients with the use of dipyridamole real-time contrast echocardiography and followed them for a median of 25 months. The prognostic value of MP imaging regarding death and nonfatal myocardial infarction was determined and related to wall motion (WM), clinical risk factors, and rest ejection fraction by the use of Cox proportional-hazards models, C index, and risk reclassification analysis. A total of 59 hard events (4.7%) occurred during the follow-up (24 deaths, 35 myocardial infarctions). The 2-year event-free survival was 97.9% in patients with normal MP and WM, 91.9% with isolated reversible MP defects but normal WM, and 67.4% with both reversible MP and WM abnormalities (P<0.001). By multivariate analysis the independent predictors of events were age (hazard ratio 1.05, 95% confidence interval [CI], 1.02-1.08), sex (hazard ratio, 2.36; 95% CI, 1.32-4.23), reversible MP defects (hazard ratio, 3.88; 95% CI, 1.83-8.21), and reversible WM abnormalities with reversible MP defects (hazard ratio, 4.51; 95% CI, 2.25-9.07). Reversible MP defects added incremental predictive value and reclassification benefit over WM response and clinical factors (P=0.001). MP imaging using real-time perfusion echocardiography during dipyridamole real-time contrast echocardiography provides independent, incremental prognostic information regarding hard cardiac events in patients with known or suspected coronary artery disease. Patients with normal MP responses have better outcome than patients with normal WM; patients with both reversible WM and MP abnormalities have the worst outcome.

Experimental evaluation of different microembolization on cardiac systolic synchronism in pigs using realtime contrast echocardiography and speckle tracking imaging

Objective To study the influence of different microembolism on left ventricular systolic synchronism in pigs by detecting the real-time dypyridamole stress contrast echocardiography (RT-MCE).Methods Eighteen miniature pigs were randomly divided into three groups and underwent microembolization injection procedure through the middle of anterior descending coronary artery with different numbers of microsphere injection,as:group A(dosage 50 thousands,3 pigs),group B (dosage 120 thousands,8 pigs) and group C (dosage 150 thousands,7 pigs).The peak values and the time-to-peak circumferential strain(Circ.Strain),radial velocity (Radial Vel.) and radial strain (Radial Strain) were obtained both at mitral valve level and papillary muscle level at left ventricle short axis views using two-dimensional speckle tracking imaging(STI)analyzed by Philips Q-Lab 8.1 workshop,respectively.Results No significant difference in the presence of contraction synchrony was observed using RT-MCE.The time-to-peak Circ.Strain of microembolism related segments were prolonged at 1 week after microembolism detecting with dypyridamole stress RT-MCE (P＜0.05,both intro-group and inter-group).While time-to-peak radial strain were extended since 6 hours after the intervention to 1 week after the procedure.Conclusions Dypyridamole stress RT-MCE can be used to measure the myocardial perfusion accurately.The elongation of time-to-peak circ.strain and radial strain were developed with time in microembolism related segments. Key words: Cardiac resynchronization therapy ; Two-dimentional speckle tracking imaging ; Circumferential strain ; Radial velocity ; Radial strain ;

Left ventricular morphology and function in diabetic and nondiabetic hemodialyzed patients

Morbidity in end-stage renal disease (ESRD) diabetic patients is worse than in patients without diabetes mellitus (DM). This study aims to compare clinical, laboratory, and echocardiographic features between the ESRD patients with and without DM. Fifty-eight ESRD patients on dialysis were prospectively divided into two groups according to the presence of DM. Demographic, clinical, laboratory, and echocardiographic features (ejection fraction and wall motion score index) were compared between the two groups. Overall, 20 out of 58 patients (37.8%) with ESRD had DM. There were no significant differences between the patients with DM and those without DM when it comes to age (60.6 ± 10.6 vs. 59.0 ± 10.6 years, P = 0.665), ejection fraction (52.6% ± 12.8% vs. 54.2% ± 12.8%, P = 0.59), and wall motion score index (1.21 ± 0.3 vs.1.15 ± 0.3, P = 0.37). In multivariant analysis of the interventricular septum, posterior wall thickness and left atrium size correlated positively with DM. There was also no statistical difference in myocardial perfusion disturbances on real-time contrast echocardiography between the groups with and without DM (12 (60%) patients vs. 14 patients (36.8%), P = 0.079). Among diabetics 77.8% had significant atherosclerotic changes, while in the group without DM, only 38.1%, P = 0.01. From the laboratory parameters ferritin and high-sensitivity C-reactive protein levels were significantly higher in the group with DM, P = 0.014 and P = 0.026, respectively. Patients with ESRD and DM have significantly bigger left atrial size, thicker left ventricular walls, and higher serum ferritin and high-sensitivity C-reactive protein levels than the patients without DM. The aforementioned features may be possible risk factors for the development of adverse cardiac events in patients on hemodialysis.

Value of real-time three-dimensional adenosine stress contrast echocardiography in patients with known or suspected coronary artery disease

The aim of this study was to evaluate the feasibility of myocardial wall-motion and perfusion assessment using contrast echocardiography during real-time three-dimensional (RT3D) adenosine stress test, and compare its diagnostic accuracy with the two-dimensional (2D) method using coronary angiography as reference. Patients with known or suspected coronary artery disease (CAD) have been submitted to adenosine stress contrast echocardiography and coronary angiography, within a 1-month period. Two-dimensional apical four, two, and three chamber, as well as three-dimensional (3D) pyramidal full-volume data sets were acquired at rest and at peak stress. The 17-segment division of the left ventricle was used and each segment was evaluated based on wall motion and perfusion. Sixty patients (age: 60.1 ± 8.5 years, 38 men) were enrolled, i.e. 1020 segments were evaluated at rest and at peak stress. Wall-motion analysis per patient revealed that the sensitivity and specificity of 2D to detect CAD were 80 and 82% and of RT3D echocardiography were 82 and 64%, respectively, whereas in the per patient perfusion analysis the respective percentages were 88, 64% for 2D and 90, 73% for RT3D. Regarding left anterior descending artery and right coronary system, there seems to be no statistical significant difference in terms of wall-motion and perfusion evaluation between the two modalities. Real-time 3D adenosine stress echocardiography is a feasible and valuable technique to evaluate myocardial wall motion and perfusion in patients with suspected CAD, despite existing problems concerning lower spatial and temporal resolution when compared with 2D echocardiography.

Original research Perfusion assessed by real-time contrast echocardiography correlates with clinical and echocardiographic parameters in patients with first STEMI treated with PCI – 6-month follow-up

IntroductionAngiographic flow in an epicardial artery does not define perfusion at a microvascular level in patients with acute myocardial infarction (AMI). The aim of the study was assessing microvascular reperfusion by myocardial contrast echocardiography (MCE) and left ventricular (LV) functional recovery by echocardiographic methods in patients treated with primary PTCA.Material and methods100 consecutive patients with first ST-elevation AMI with single vessel disease treated successfully with primary PCI were enrolled. Regional contrast score index (RCSI), ejection fraction (EF), wall motion score index (WMSI), and end-systolic and end-diastolic volume (ESV, EDV) were evaluated during hospitalization and at 6-month follow-up. The patients were divided into 2 groups according to the absence (Group 1) or presence (Group 2) of perfusion defects on MCE.ResultsGroup 1 had lower WMSI (p = 0.0009), higher EF than Group 2 (44.7 and 55.9% respectively, p = 0.000067), and lower ESV (66.0 and 52.6 ml respectively, p = 0.003185). In Group 1 LVEF increased significantly on 6-month follow-up (p = 0.026), while in Group 2 it decreased (p = 0.0175). Both EDV and ESV were significantly lower in Group 1 (p = 0.0106 and p = 0.002882, respectively). There was a correlation between the presence of perfusion defects in the initial contrast echo and unfavourable change in ejection fraction during the follow-up (ANOVA for repeated measures, F[1.91] = 5.85, p = 0.0175). The combined clinical end-point (death and reinfarction) was significantly lower in patients without perfusion defect (p = 0.039).ConclusionsMyocardial contrast echocardiography results correlated with clinical outcome and recovery of systolic left ventricular function at 6-month follow-up.

Real-time myocardial perfusion contrast echocardiography and regional wall motion abnormalities after aneurysmal subarachnoid hemorrhage

The pathophysiology of myocardial dysfunction after subarachnoid hemorrhage (SAH) remains unclear. Using myocardial real-time perfusion contrast echocardiography (RTP-CE), the authors evaluated microvascular function in patients with acute SAH. Over a 15-month period, 10 patients with acute SAH and evidence of cardiac dysfunction were prospectively enrolled. The authors performed RTP-CE within 48 hours of SAH diagnosis. Wall motion and myocardial perfusion were evaluated in 16 left ventricle segments. Qualitative and quantitative RTP-CE analyses were conducted to compare patients with and without regional wall motion abnormalities (RWMAs). Follow-up RTP-CE at a mean of 53.7 +/- 43 days was undertaken in patients with baseline RWMAs. Ten patients with SAH and evidence of cardiac dysfunction were prospectively enrolled. There were 3 men and 7 women whose mean age was 63.5 +/- 10.1 years. The authors documented evidence of RWMAs in 6 patients. Normal perfusion was demonstrated by RTP-CE in all patients at baseline and follow-up, despite the presence of RWMAs. Compared with patients presenting with normal wall motion, in patients with RWMAs there was a trend for higher quantitative RTP-CE parameters, suggesting hyperemia with mean myocardial blood flow velocity (beta, s(-1)) of 1.08 +/- 0.61 (95% CI 0-2.61) compared with 1.62 +/- 0.64 (95% CI 0.94-2.29) and myocardial blood flow (A x beta, dB/s) of 0.99 +/- 0.41 (95% CI 0-2.0) versus 1.63 +/- 0.86 (95% CI 0.72-2.53). Follow-up RTP-CE was feasible in 3 patients with RWMAs. Regional systolic function was restored in those who completed follow-up. The authors found that RTP-CE readily evaluates microvascular function in patients with SAH. Wall motion and perfusion dissociation were observed. Quantitative RTP-CE showed a trend for microvascular hyperemia in patients with RWMAs, suggesting that post-SAH myocardial dysfunction could occur in the absence of microvascular dysfunction.

Study on correlation between myocardial perfusion and cardiac resynchronization therapy using real-time contrast echocardiography

充血性心力衰竭是各种器质性心脏病的终末阶段,心功能NYHA分级为Ⅲ～Ⅳ级的患者预后较差,1年死亡率高达50%以上.近年来,心脏再同步化治疗(CRT)的兴起为难治性心力衰竭的治疗带来了希望.但是,按照目前的指南,仍然有一部分患者不能取得良好疗效.双室起搏后,有效的心肌灌注是保证心室同步化的前提,本综述回顾了实时心肌超声造影(RT-MCE)评价心肌灌注与CRT疗效之间的相关性。

Abstract 1068: Evaluation of Malignant and Benign Cardiac Masses by Quantitative Real-Time Contrast Echocardiography

Primary tumors of the heart are rare, most of them benign. However the differential diagnosis between benign and malignant tumors is very difficult. Quantitative Real-time Contrast Echocardiography(QRTCE) can evaluate the vascularity of cardiac masses and therefore help in characterizing the nature of cardiac masses. To evaluate the perfusion of cardiac masses and to compare the quantitative perfusion parameters of malignant and benign cardiac tumors by QRTCE. We studied 42 patients with cardiac masses, 23(54.8%) women, mean age 47.2±17.9 years old, 23(54.8%) with malignant tumor and 19 (45.2%) with benign tumors. Contrast-enhanced images were obtained after intravenous administration of PESDA(perfluorocarbon-exposed sonicated dextrose and albumin) or Definity®(lipid-encapsulated microbubbles) contrast. Q-lab software was applied to quantitative the perfusion of mass and adjacent cavity. The CE-derived rate of microbubble velocity(β), blood volume(A), blood flow(A × β) and relative blood flow(A/Acavity × β) were obtained by curve fitting of videointensity versus time plots, after the transient destruction of microbubbles by high-energy ultrasound. All malignant cardiac and 16 benign masses were confirmed by pathology. Blood velocity (β) was greater in the malignant than benign mass (1.4±2.04 × 0.71±0.48 dB, p=0.001). Malignant and benign mass A, A×B and A/Acavity × β values were 4.11±3.99 × 3.4±2.53, p=0.095; 3.69±3.95 × 2.85±3.36, p=0.113; 0.18±0.24 × 0.13±0.17, p=0.442; respectively. The malignant tumors were primary cardiac lymphoma (n=2), mediastinal lymphoma (n=5), pericardial mesothelioma(n=1) and metastatic tumors(n=15). Myxoma (n=15), lypoma(n=1), paraganglioma(1) and rabdomyoma(n=2) constituted the benign masses. QRTCE provides important information to differentiate the nature of cardiac masses by the demonstration of higher values of resting myocardial blood flow.

Real-time dobutamine stress myocardial perfusion echocardiography predicts outcome in the elderly

Although there is an increasing number of studies showing the value of perfusion imaging with real-time contrast echocardiography (RTCE) for detecting coronary artery disease (CAD), no data exist regarding the value of this technique for detecting CAD and predicting outcome in the elderly. We examined the outcome of 399 patients > or =70 years old who underwent dobutamine stress RTCE for known or suspected CAD. Myocardial perfusion imaging (MPI) was performed using low mechanical index pulse sequence schemes following intravenous small bolus injections of ultrasound contrast. Quantitative coronary angiography (QCA) was performed within 1 month of the stress test in 60 patients. Events were defined as cardiac death or non-fatal myocardial infarction (MI). Sensitivity of MPI for detecting CAD by QCA was 94% [confidence interval (CI) 91-99], specificity was 67% (CI 36-74), and accuracy was 90% (CI 82-95). During a median follow-up of 21 months, 46 events occurred (31 cardiac deaths, 15 non-fatal MI). Univariate predictors of outcome were diuretic use (P = 0.03), abnormal stress wall motion (P < 0.0001), and abnormal stress MPI (P < 0.0001). Abnormal stress MPI, however, was the most significant predictor of outcome (chi(2) 7.5; P = 0.006). Myocardial perfusion analysis during dobutamine stress RTCE provides incremental predictive value in determining the outcome of elderly patients being evaluated for the presence of CAD.

Effect of Systemic Blood Pressure on Microcollateral Circulation Evaluated by Real-Time Contrast Echocardiography

In acute myocardial infarction, residual collateral-derived myocardial blood flow (CBF) within the ischemic area is one of the major determinants of infarct size. Management of systemic blood pressure (sBP) related to maintain collateral circulation is still difficult. The aim of this study was to reveal the influence of sBP on the rescue of area at risk by collateral circulation. Real-time myocardial contrast echocardiography just after the onset of complete occlusion of the left circumflex coronary artery was performed in collateral-rich open-chest dogs. The video intensity of the ischemic area was evaluated during the occlusion and the CBF (A x beta) was calculated from a replenishment curve: y = A (1 - e(-beta t)). To analyze the effect of sBP on the collateral circulation, sBP was altered by infusion of nitroglycerin or etilefrine hydrochloride. To evaluate the defect size (%DS), every end-systolic myocardial contrast echocardiography image after left circumflex coronary artery occlusion was converted into binary images using custom offline software. The %DS increased and CBF slightly decreased at low sBP. The %DS decreased and CBF increased at high sBP. At excessively high sBP, %DS increased and CBF decreased again. Real-time myocardial contrast echocardiography, which is a useful noninvasive method to evaluate the collateral perfusion quantitatively, has a crucial role in the decision of patient treatment and management strategy of acute myocardial infarction.

Three-Dimensional Reconstruction of Coronary Arteriole Plexus Image by Contrast Echocardiography Using a High-Frequency Transducer

This study was established to examine the efficacy of a high-frequency liner probe for visualizing fine anatomy of coronary microcirculation. The vessel size and its velocity-time integral at the anterior wall in dogs by real-time contrast echocardiography with high-frequency liner probe and pulse Doppler methods, and the coronary flow volume, were measured before and after adenosine triphosphate injection. A 3-dimensional (3D) image was reconstructed by the built-in 3D system using intermittent flash echocardiographic images. The increments of flow volume calculated from vessel sizes and velocity-time integral were well correlated with those of coronary flow volume. Using intermittent flash echocardiographic images, fine dots and lines of contrast echocardiographic-expected arterioles were evident, and easily and quickly reconstructed as coronary plexus by 3D system. A high-frequency liner probe provides the fine-vessel images to evaluate those morphologic changes; a 3D reconstruction image could provide new information about coronary arterioles.

Brief Communications: Visualization of Coronary Arteries in Rats by 3-Dimensional Real-Time Contrast Echocardiography

Angiogenesis is under intense investigation to advance the treatment of various ischemic diseases. Small animals, such as mice and rats, are often used for this purpose. However, evaluating the structure of coronary arteries in small animals in situ is not easy. We succeeded in visualizing the coronary artery in rats on 3-dimensional real-time contrast echocardiography using a high-frequency transducer. These methods will be applied for more convenient assessment in a new study, examining issues such as angiogenesis using rats in situ.

808 Rapid real-time 3-dimensional contrast echocardiography for assessment of left ventricular volumes and ejection fraction: A comparison with magnetic resonance imaging

808 Rapid real-time 3-dimensional contrast echocardiography for assessment of left ventricular volumes and ejection fraction: A comparison with magnetic resonance imaging

Prognostic Value of Dobutamine Stress Myocardial Contrast Perfusion Echocardiography

Myocardial perfusion (MP) imaging with real-time contrast echocardiography (RTCE) improves the sensitivity of dobutamine stress echocardiography for detecting coronary artery disease. Its prognostic value is unknown. We sought to determine the value of MP and wall motion (WM) analysis during dobutamine stress echocardiography in predicting the outcome of patients with known or suspected coronary artery disease. We retrospectively studied 788 patients with RTCE during dobutamine stress echocardiography using intravenous commercially available contrast agents. The incremental prognostic value of MP imaging over clinical risk factors and other echocardiographic data was examined through the use of a log-likelihood test (Cox model). During a median follow-up of 20 months, 75 events (9.6%) occurred (58 deaths, 17 nonfatal myocardial infarctions). Abnormal MP had significant incremental value over clinical factors, resting ejection fraction, and WM responses in predicting events (P<0.001). By multivariate analysis, the independent predictors of death and nonfatal myocardial infarction were resting left ventricular ejection fraction <50% (relative risk [RR], 1.9; 95% CI, 1.2 to 3.2; P=0.01), hypercholesterolemia (RR, 0.5; 95% CI, 0.3 to 0.9; P=0.01), and abnormal MP (RR, 5.2; 95% CI, 3.0 to 9.0; P<0.0001). The 3-year event free survival was 95% for patients with normal WM and MP, 82% for normal WM and abnormal MP, and 68% for abnormal WM and MP. MP imaging during dobutamine stress RTCE provides incremental prognostic information in patients with known or suspected coronary artery disease. Patients with normal MP have a better outcome than patients with normal WM.

Quantification of resting myocardial blood flow velocity in normal humans using real-time contrast echocardiography. A feasibility study

BackgroundReal-time myocardial contrast echocardiography (MCE) is a novel method for assessing myocardial perfusion. The aim of this study was to evaluate the feasibility of a very low-power real-time MCE for quantification of regional resting myocardial blood flow (MBF) velocity in normal human myocardium.MethodsTwenty study subjects with normal left ventricular (LV) wall motion and normal coronary arteries, underwent low-power real-time MCE based on color-coded pulse inversion Doppler. Standard apical LV views were acquired during constant IV. infusion of SonoVue®. Following transient microbubble destruction, the contrast replenishment rate (β), reflecting MBF velocity, was derived by plotting signal intensity vs. time and fitting data to the exponential function; y (t) =A (1-e-β(t-t0)) + C.ResultsQuantification was feasible in 82%, 49% and 63% of four-chamber, two-chamber and apical long-axis view segments, respectively. The LAD (left anterior descending artery) and RCA (right coronary artery) territories could potentially be evaluated in most, but contrast detection in the LCx (left circumflex artery) bed was poor. Depending on localisation and which frames to be analysed, mean values of were 0.21–0.69 s-1, with higher values in medial than lateral, and in basal compared to apical regions of scan plane (p = 0.03 and p < 0.01). Higher β-values were obtained from end-diastole than end-systole (p < 0.001), values from all-frames analysis lying between.ConclusionLow-power real-time MCE did have the potential to give contrast enhancement for quantification of resting regional MBF velocity. However, the technique is difficult and subjected to several limitations. Significant variability in β suggests that this parameter is best suited for with-in patient changes, comparing values of stress studies to baseline.

Safety of dobutamine stress real-time myocardial contrast echocardiography

The aim of this study was to determine the safety of dobutamine stress myocardial perfusion imaging (MPI) obtained by real-time contrast echocardiography (RTCE) and intravenous ultrasound contrast in a large cohort of patients with suspected coronary artery disease (CAD). Despite the increasing number of studies showing the potential clinical utility of myocardial contrast perfusion imaging with commercially available contrast agents, the safety of this technique in a clinical setting has not been demonstrated. Over a four-year period, 1,486 patients underwent dobutamine stress RTCE with low mechanical index pulse sequence schemes after intravenous injections of commercially available contrast agents (35% Definity, Bristol Myers Squibb Medical Imaging Inc., North Billerica, Massachusetts; 65% Optison, GE-Amersham, Princeton, New Jersey). The hemodynamic and adverse effects of RTCE were compared with 1,012 patients who underwent conventional dobutamine stress echocardiography (DSE) without contrast. The feasibility of image analysis was defined as the ability to analyze MPI in at least two of the three standard segments in each left ventricular wall. No myocardial infarction or death occurred during dobutamine stress. There was no difference in the incidence of nonsustained ventricular tachycardia, sustained ventricular tachycardia, or supraventricular tachycardia during dobutamine infusion between RTCE and DSE. Myocardial perfusion imaging was considered feasible for analysis in 94% of the walls at baseline and 95% at peak stress. The anterior, lateral, and posterior walls were the most common regions in which MPI was not feasible. Myocardial perfusion imaging with RTCE had a higher accuracy for detecting patients with angiographically significant CAD than the analysis of wall motion (84% vs. 66%, respectively; p < 0.001). Dobutamine stress RTCE appears to be a safe and feasible technique for evaluating patients with known or suspected CAD.

Comparison of real-time contrast echocardiography and low-dose dobutamine stress echocardiography in predicting the left ventricular functional recovery in patients after acute myocardial infarction under different therapeutic intervention

Background Early prediction of left ventricular (LV) functional recovery after acute myocardial infarction (AMI) remains challenging. This prospective study aims to compare real-time myocardial contrast echocardiography (MCE) with low-dose dobutamine stress echocardiography (LDDSE) in predicting the LV functional recovery in patients after AMI who underwent different therapeutic interventions. Methods Ninety-two patients with AMI were divided into 3 groups: primary coronary intervention group ( n=34), thrombolysis group ( n=30) and conservative therapy group ( n=28). MCE was performed 2.3±0.7 days after chest pain onset. LDDSE was done within 2 days of MCE study. Follow-up echocardiography was performed 4 months later. Results Patients treated by primary coronary intervention or thrombolysis had significantly lower regional perfusion score (0.65±0.53 vs. 1.01±0.49, p=0.008; 0.78±0.55 vs. 1.01±0.49, p=0.03), better contractile reserve (regional dobutamine Δwall motion score -1.12±0.39 vs. −0.80±0.43, p=0.01; −0.99±0.50 vs. −0.80±0.43, p=0.08) and LV function recovery (regional Δwall motion score −1.67±0.53 vs. −1.02±0.46, p=0.003; −1.42±0.58 vs. −1.02±0.46, p=0.03) than those of conservative therapy group. MCE and LDDSE showed good concordance for predicting LV functional recovery (kappa=0.63, p<0.001). Perfusion score index had a good correlation with LV functional recovery ( r=−0.75, p<0.001). Conclusions This study demonstrates that perfusion score index obtained from real-time MCE is comparable to LDDSE in predicting the LV functional recovery even under different therapeutic interventions. Revascularization results in better preservation of myocardial microvascular integrity, regional contractile reserve and LV functional recovery.