Real-time Myocardial Contrast Echocardiography Research Articles

Automatic Myocardial Contrast Echocardiography Image Quality Assessment Using Deep Learning: Impact on Myocardial Perfusion Evaluation.

The image quality of myocardial contrast echocardiography (MCE) is critical for precise myocardial perfusion evaluation but challenging for echocardiographers. Differences in quality may lead to diagnostic heterogeneity. This study was aimed at achieving automatic MCE image quality assessment using a deep neural network (DNN) and investigating its impact on myocardial perfusion evaluation. The Resnet-18 model was used for training and testing on internal and external data sets. Quality assessment involved three aspects: left ventricular opacification (LVO), shadowing, and flash adequacy; the quality score was calculated based on image quality. This study explored the impact of the DNN-based quality score on perfusion evaluation (normal, delay or obstruction) by echocardiographers (two seniors, one junior and one novice). Additionally, the effect of the score difference between re-scans on perfusion evaluation was investigated. The time cost for DNN prediction was 0.045 s/frame. In internal validation and external testing, the DNN achieved F1 and macro F1 scores >90% for quality assessment and had high intraclass correlation coefficients (0.954 and 0.892, respectively) in sequence quality scores. The proportion of segments deemed uninterpretable increased as the DNN-based quality score decreased. The agreement of perfusion assessment between one senior and others decreased as the quality score decreased. And the greater the score difference between the re-scans, the lower was the agreement on perfusion assessment by the same echocardiographer. This study determined the effectiveness of DNN for real-time automatic MCE quality assessment. It has the potential to reduce the variability in perfusion evaluation among echocardiographers.

Comparative analysis of instantaneous wave-free ratio and quantitative real-time myocardial contrast echocardiography for the assessment of myocardial perfusion.

The field of coronary artery physiology is developing rapidly and changing the practice of interventional cardiology. A new functional evaluation technique using the instantaneous wave-free ratio (iFR) has become an alternative to fractional flow reserve. Future research studies need to determine whether physiological indicators play a role in evaluating myocardial perfusion in the catheter room. Thirty-eight patients scheduled for coronary angiography and iFR evaluation underwent a real-time myocardial contrast echocardiography (RT-MCE) examination at rest. The myocardial perfusion parameters (A, β, and A × β) on the myocardial perfusion curve were quantitatively analyzed using Q-Lab software. Coronary angiography and iFR assessment were completed within 1 week after the RT-MCE examination in all patients. Correlation analysis was used to identify iFR- and MCE-related indicators. The sensitivity and specificity of iFR in the quantitative detection of coronary microcirculation were obtained. The correlation coefficients between iFR and A, β, and A × β were 0.81, 0.66, and 0.82, respectively. The cut-off value for iFR was 0.85 for microvascular ischemia detection, while the sensitivity and specificity for the diagnosis of myocardial perfusion were 90.7 and 89.9%, respectively. The receiver operating characteristic (ROC) curve area for iFR was 0.946 in the segments related to myocardial blood flow. The iFR is an effective tool for detecting myocardial microcirculation perfusion, with satisfactory diagnostic performance and a demonstrated role in physiological indices used for the perfusion assessment.

Diagnostic accuracy of cardiac testing for coronary artery disease in potential liver transplant recipients: A systematic review and meta-analysis.

BackgroundThe incidence of coronary artery disease (CAD) in Liver transplant (LT) patients is much higher than prior estimates and the morbidity and mortality are significant in this group of patients. Coronary angiography is the gold standard for detection of CAD, a non-invasive test that allows appropriate risk stratification would be preferred. In this systematic review and meta-analysis, we sought to assess the pooled diagnostic accuracy of various noninvasive cardiac imaging tests in detecting CAD in patients listed for LT.MethodsWe performed a systematic review and meta-analysis of studies comparing sensitivity and specificity of non-invasive tests to that of coronary angiography in diagnosing coronary artery disease in patients undergoing liver transplantation.ResultsFive studies (616 participants) evaluated myocardial perfusion imaging (MPI); five studies (1243 participants) dobutamine stress echocardiography (DSE); and three (87 participants), other tests. MPI had a pooled sensitivity of 0.62 (95% CI 0.37, 0.83), specificity of 0.60 (95% CI 0.39, 0.79), diagnostic odds ratio (DOR) of 2.5 (95% CI 1.7, 5.64) and Area under the curve (AUC) 0.649. DSE had a pooled sensitivity of 0.25 (95%CI 0.09, 0.51), specificity of 0.68 (95% CI 0.44, 0.84) and DOR of 0.7 (95% CI 0.12, 3.84).ConclusionsOur results show that both MPI and DSE are not effective screening tools for detecting CAD in patients with end-stage liver disease (ESLD). Future studies are needed to evaluate the role of real-time myocardial contrast echocardiography (RTMCE) and coronary artery calcium score (CAC) with coronary CT angiography in patients with ESLD.

Feasibility of Real-Time Myocardial Contrast Echocardiography to Detect Cardiac Allograft Vasculopathy in Pediatric Heart Transplant Recipients

Cardiac allograft vasculopathy (CAV) is an important adverse prognostic factor for pediatric heart transplant (HT) recipients. Invasive coronary angiography (ICA) is the gold standard for CAV detection but lacks sensitivity for early microvascular changes and cumulative radiation exposure is of concern. Real-time myocardial contrast echocardiography (RTMCE) using ultrasound enhancing (contrast) agents performed during dobutamine stress echocardiography (DSE) can assess myocardial function, perfusion, and microvascular integrity. The objective of this study was to determine the safety and feasibility of RTMCE during DSE to detect CAV in a pediatric HT population. HT patients 10-21years of age were recruited to undergo DSE with RTMCE to determine technical feasibility, test tolerability and adverse event rate, and detection of perfusion defects compared with ICA-detected CAV. Thirty-six patients from two centers were enrolled, with a mean age 13.5±4.3years; 21 (58%) were male. Wall motion and myocardial perfusion were qualitatively assessed and compared with ICA findings of CAV. Myocardial blood flow (MBF) at rest and peak stress was quantified, and myocardial blood flow reserve (MBFR) was defined as the ratio of peak to rest MBF. Five (14%) patients had CAV by ICA, two with obstructive disease and three with mild CAV. Real-time myocardial contrast echocardiography was feasible in 32 (89%) patients. Three patients had wall motion defects, including one with a mixed defect and two with fixed defects. A perfusion abnormality was present in five patients, two of whom had obstructive CAV and one with mild CAV. Sensitivity and specificity of RTMCE for CAV detection were 60% and 94%, respectively, and diagnostic accuracy was 89%. MBFR assessment was feasible in 20 (63%) patients. The mean MBFR was 3.4±0.7. Patients with CAV had lower MBFR than those without (2.0±0.2 vs 3.7±0.8; P<.01). There were no serious adverse events related to RTMCE. Dobutamine stress RTMCE appears to be safe and feasible for the assessment of CAV in pediatric HT recipients. Further assessment is warranted to determine whether this noninvasive technique could provide a reliable alternative to ICA.

Assessment of the Preventive Effect Against Diabetic Cardiomyopathy of FGF1-Loaded Nanoliposomes Combined With Microbubble Cavitation by Ultrasound

Acidic fibroblast growth factor (FGF1) has great potential in preventing diabetic cardiomyopathy. This study aimed to evaluate the preventive effect of FGF1-loaded nanoliposomes (FGF1-nlip) combined with ultrasound-targeted microbubble destruction (UTMD) on diabetic cardiomyopathy (DCM) using ultrasound examination. Nanoliposomes encapsulating FGF1 were prepared by reverse phase evaporation. DM model rats were established by intraperitoneal injection of streptozotocin (STZ), and different forms of FGF1 (FGF1 solution, FGF1-nlip, and FGF1-nlip+UTMD) were used for a 12-week intervention. According to the transthoracic echocardiography and velocity vector imaging (VVI) indexes, the LVEF, LVFS, and VVI indexes (Vs, Sr, SRr) in the FGF1-nlip+UTMD group were significantly higher than those in the DM model group and other FGF1 intervention groups. From the real-time myocardial contrast echocardiography (RT-MCE) indexes, the FGF1-nlip+UTMD group A and A×β showed significant differences from the DM model group and other FGF1 intervention groups. Cardiac catheter hemodynamic testing, CD31 immunohistochemical staining, and electron microscopy also confirmed the same conclusion. These results confirmed that the abnormalities, including myocardial dysfunction and perfusion impairment, could be suppressed to different extents by the twice weekly FGF1 treatments for 12 consecutive weeks (free FGF1, FGF1-nlip, and FGF1-nlip+UTMD), with the strongest improvements observed in the FGF1-nlip+UTMD group. In conclusion, the VVI and RT-MCE techniques can detect left ventricular systolic function and perfusion changes in DM rats, providing a more effective experimental basis for the early detection and treatment evaluation of DCM, which is of great significance for the prevention of DCM.

Evaluation of regional myocardial perfusion in methamphetamine abusers using real-time myocardial contrast echocardiography.

To evaluate the feasibility of assessing regional myocardial perfusion using real-time myocardial contrast echocardiography(MCE) at rest for detecting coronary microcirculation abnormalities in methamphetamine abusers.Materialand methods: Twenty-two male methamphetamine abusers (11 without chest pain, 11 with chest pain), free of ascertainedcoronary artery disease, were enrolled in this study. A control group of 22 age-matched male healthy participants was studiedfor comparison. Standard 2D, flow and tissue Doppler echo with measurements of cardiac morphologic and functional indicators,MCE with measurements of regional myocardial perfusion were performed, respectively. Compared to healthyparticipants, methamphetamine abusers had higher blood pressure, greater left ventricular mass index and more impaireddiastolic function, with preserved cardiac sizes and systolic function. Methamphetamine abusers with chest pain had a fasterheart rate than those without chest pain and healthy participants. MCE in methamphetamine abusers, especially with chestpain, had significant longer contrast agent arrival times, less functional capillary blood volumes, slower microvascular flowvelocities and less myocardial perfusion than healthy participants (p<0.05). Moreover, along with the increases of dosage andduration of use (from group A to group C, group A: 1-2 g/day, <2 years; group B: 2-3 g/day, 2-5 years; group C: >3 g/day, >5years) the reductions in the myocardial perfusion indices were more significant (p<0.01). The cutoff value with 5.1 dB2/s ofthe myocardial perfusion at the left ventricular apex had a sensitivity of 87.5%, specificity of 75.2% and accuracy of 81.9% fordifferentiating methamphetamine abusers from normal subjects. Real-time MCE can effectively detect coronarymicrocirculation abnormalities in methamphetamine abusers at rest and myocardial perfusion is significantly reduced in methamphetamineabusers. This finding may be involved in the occurrence and development of cardiac damage.

Chinese Medicine Shensong Yangxin Capsule () Ameliorates Myocardial Microcirculation Dysfunction in Rabbits with Chronic Myocardial Infarction.

To investigate the effect of Chinese compound Shensong Yangxin Capsule ( , SSYX) on myocardial microcirculation in myocardial-infarcted rabbits. Myocardial infarction (MI) was established in rabbits by ligation of the left circumflex coronary. Thirty rabbits were randomly divided into the control group, the MI group (model), and the MI treated with SSYX group (MI+SSYX) by a random number table method. After 4 weeks of administration, low-energy real-time myocardial contrast echocardiography (RT-MCE) was conducted to assess the microcirculatory perfusion. Immunofluorescence double staining was used to detect the capillary density. The endothelial ultrastructure was observed with a transmission electron microscope. The mRNA expression levels of vascular endothelial growth factor (VEGF), endothelin 1 (ET-1), prostaglandin I2 (PGI2) and endothelial nitric oxide synthase (eNOS) were measured by real-time quantitative polymerase chain reaction (Real-time PCR). The plasmic levels of ET-1, thromboxane A2 (TXA2), nitric oxide (NO) and von willebrand factor (vWF) were examined with enzyme-linked immunosorbent assays (ELISA). SSYX significantly improved the myocardial blood volume, myocardial micro bubble velocity, and myocardial inflow according to the examination of RT-MCE, and it visibly ameliorated the capillary endothelial structure. Furthermore, compared with the MI group, the plasma levels of TXA2, ET-1 and vWF contents significantly decreased in the MI+SSYX group, and the ET-1 mRNA expression levels of myocardium in the border zone significantly decreased, and the VEGF, PGI2 and eNOS mRNA expression levels significantly increased (all P<0.05). SSYX has favorable advantages in ameliorating the impaired myocardial microcirculation following MI. The mechanisms of the effect are related to the ability of SSYX in balancing the endothelial-derived vasodilators and vasoconstrictors, and up-regulating the expression of VEGF and eNOS.

Discrepant myocardial microvascular perfusion and mechanics after acute myocardial infarction: Characterization of the “Tako-tsubo effect” with real-time myocardial perfusion contrast echocardiograph

BackgroundIn patients with acute anterior myocardial infarction (MI), sometimes an “apical ballooning” contractile dysfunction pattern that exceeds factual myocardial injury is identified in the ventriculography and bedside echocardiography. The hemodynamic consequences/sequela of this “Tako-tsobu effect” has not been well delineated. Of note, this anatomic imaging finding often misleads frontline physicians who assume reciprocal causation of persistent cardiac pump failure and ventricular pressure overload. Methods and resultsUsing real-time myocardial perfusion contrast echocardiography (MCE), we investigated myocardial (microvascular) perfusion in 60 patients after acute MI and coronary revascularization. Twenty-eight percent of the studied patients showed significantly mismatched myocardial perfusion and contractile defects. In these patients, an integrated imaging assessment with coronary angiography/ventriculography, deformation echocardiography, and MCE proved that the myocardial mechanic abnormalities significantly exceeded the defected perfusion areas. Compared with 72% of the patients without perfusion-contractility mismatch, apparently worse systolic functions (left ventricular ejection, wall motion score, and systolic longitudinal strain) in these patients did not change diastolic ventricular filling pressures (E/E′ and E/A) or hemodynamic consequences/adverse events. Both systolic and diastolic functions in patients with perfusion-contractility mismatch appeared to be comparable with those in patients with Tako-tsubo syndrome. ConclusionsReal-time MCE identifies discrepant myocardial microvascular perfusion and mechanics in patients with acute MI. The “Tako-tsubo effect” in patients with perfusion-contractility mismatch does not cause diastolic filling pressure change or worse hemodynamic consequence/cardiac event.

Prevalence and Predictive Value of Microvascular Flow Abnormalities after Successful Contemporary Percutaneous Coronary Intervention in Acute ST-Segment Elevation Myocardial Infarction

Although microvascular flow abnormalities have been observed following epicardial recanalization in acute ST-segment elevation myocardial infarction (STEMI), the prevalence and severity of these abnormalities in the current era of rapid percutaneous coronary intervention (PCI) has not been evaluated. The objective of this study was to assess microvascular perfusion (MVP) following successful primary PCI in patients with STEMI and how it affects clinical outcome. In this single-center, retrospective study, 170 patients who successfully underwent emergent PCI for STEMI were assessed using real-time myocardial contrast echocardiography using a continuous infusion of intravenous commercial microbubbles (3% Definity). Three patterns of myocardial contrast replenishment were observed following intermittent high-mechanical index impulses: infarct zone replenishment within 4sec (normal MVP), delays in contrast replenishment but normal plateau intensity (delayed MVP [dMVP]), and both delays in replenishment and reduced plateau intensity (microvascular obstruction [MVO]). Changes in left ventricular ejection fraction at 6months and clinical event rate at 12months (death, recurrent infarction, need for defibrillator placement, or heart failure admission) were compared. Normal MVP was seen in 62 patients (36%), dMVP in 49 (29%), and MVO in 59 (35%). Left anterior descending coronary artery infarct location was the only parameter independently associated with dMVP or MVO, independent of age, cardiac risk factors, door-to-dilation time, pre-PCI Thrombolysis In Myocardial Infarction flow grade, and thrombus burden. A dMVP pattern had a similar reduction in left ventricular ejection fraction as MVO at hospital discharge but had recovery of left ventricular ejection fraction at 6months and a greater than fourfold lower event rate than the MVO group (P<.001). MVO and dMVP are frequently seen following contemporary successful PCI for STEMI, especially following left anterior descending coronary artery infarction. Despite a similar area at risk, a dMVP pattern has better functional recovery and clinical outcome than MVO.

Outcomes of non-invasive diagnostic modalities for the detection of coronary artery disease: network meta-analysis of diagnostic randomised controlled trials

ObjectiveTo evaluate differences in downstream testing, coronary revascularisation, and clinical outcomes following non-invasive diagnostic modalities used to detect coronary artery disease.DesignSystematic review and network meta-analysis.Data sourcesMedline, Medline in process, Embase,...

Emergency Cardiology: From ED to CCU

In patients with acute anterior myocardial infarction (MI), sometimes an “apical ballooning” contractile dysfunction pattern that exceeds factual myocardial injury is identified in the ventriculography and bedside echocardiography. The hemodynamic consequences/sequela of this “Tako-tsobu effect” has not been well delineated. Of note, this anatomic imaging finding often misleads frontline physicians who assume reciprocal causation of persistent cardiac pump failure and ventricular pressure overload.Using real-time myocardial perfusion contrast echocardiography (MCE), we investigated myocardial (microvascular) perfusion in 60 patients after acute MI and coronary revascularization. Twenty-eight percent of the studied patients showed significantly mismatched myocardial perfusion and contractile defects. In these patients, an integrated imaging assessment with coronary angiography/ventriculography, deformation echocardiography, and MCE proved that the myocardial mechanic abnormalities significantly exceeded the defected perfusion areas. Compared with 72% of the patients without perfusion-contractility mismatch, apparently worse systolic functions (left ventricular ejection, wall motion score, and systolic longitudinal strain) in these patients did not change diastolic ventricular filling pressures (E/E′ and E/A) or hemodynamic consequences/adverse events. Both systolic and diastolic functions in patients with perfusion-contractility mismatch appeared to be comparable with those in patients with Tako-tsubo syndrome.Real-time MCE identifies discrepant myocardial microvascular perfusion and mechanics in patients with acute MI. The “Tako-tsubo effect” in patients with perfusion-contractility mismatch does not cause diastolic filling pressure change or worse hemodynamic consequence/cardiac event.

TCT-133 Clinical Impact of Persistent Microvascular Obstruction Following Successful Percutaneous Coronary Intervention in Acute ST segment Elevation Myocardial Infarction

In the contemporary era of primary percutaneous coronary intervention (PPCI) to treat acute ST segment elevation myocardial infarction (STEMI), the frequency and predictors of persistent microvascular obstruction (MVO) have not been elucidated. Real time myocardial contrast echocardiography (RTMCE)

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.

The Dose-Response Effect of Hyperinsulinaemic Euglycaemia Using Insulin-Dextrose Clamps on Myocardial Microvascular Function

Background and Aims: Insulin is a potent vasodilator which acts via the endothelial nitrous oxide pathway. Supraphysiological hyperinsulinaemic euglycaemia has been shown to increase myocardial blood flow. However the optimal dose of parenteral insulin infusion to exert maximum vasodilatory effect on the coronary microcirculation is unknown. Therefore, we investigated the relationship between myocardial blood flow reserve (MBFR), a measure of coronary microvascular function, and insulin infusion dose. Method and Results: 21 healthy volunteers (mean age 66 yrs (range 47-79)) underwent hyperinsulinaemic euglycaemic (HE) clamps for 60 minutes (8, 5, and 8 participants received 0.5, 1.5, and 3.0 mU/kg/min insulin, respectively). Baseline demographic and biochemical indices were similar across all three groups. Low-power real-time myocardial contrast echocardiography with flash impulse imaging was performed using vasodilator dipyridamole stress to quantify MBFR at baseline, and at 60 minutes after commencing the HE clamp. Mean(SD) baseline MBFR values were 2.2(0.4), 2.5(0.2), and 2.6(0.3), and post-insulin MBFR's were 2.3(0.7), 3.4(0.8), and 2.2(0.3) in the 0.5, 1.5, and 3.0 mU/kg/min dose groups, respectively. This represents an increase in MBFR of 5% and 36% in the 0.5 and 1.5 insulin dose groups, and a decrease in MBFR of 15% in the 3.0 insulin dose group (p = 0.89, 0.04, 0.04, respectively). Conclusion: We observed a non-linear dose effect of insulin infusion dose on coronary microvascular dilatation in healthy volunteers. Of the 3 insulin doses tested, 0.5mU/kg/min had no effect, 1.5mU/kg/min resulted in a 36% increase, and 3.0mU/kg/min resulted in a 15% decrease, in MBFR.

Comparison of Fractional Flow Reserve Assessment With Demand Stress Myocardial Contrast Echocardiography in Angiographically Intermediate Coronary Stenoses

Real-time myocardial contrast echocardiography (RTMCE) directly measures capillary flow (CBF), which in turn is a major regulator of coronary flow and resistance during demand or hyperemic stress. Although fractional flow reserve (FFR) was developed to assess the physiological relevance of an epicardial stenosis, it assumes maximal microvascular vasodilation and minimal resistance during vasodilator stress. Therefore, we sought to determine the relationship between CBF assessed with RTMCE during stress echocardiography and FFR in intermediate coronary lesions. Sixty-seven vessels with 50% to 80% diameter stenoses by quantitative coronary angiography in 58 consecutive patients were examined with FFR and RTMCE (mean age, 60±13 years). RTMCE was performed using an incremental dobutamine (n=32) or exercise (n=26) stress protocol, and myocardial perfusion was assessed using a continuous infusion of ultrasound contrast. The presence or absence of inducible perfusion defects and wall motion abnormalities were correlated with FFR. Mean percent diameter stenosis was 60±9%. Eighteen stenoses (27%) had an FFR ≤ 0.8. Although 17 of the 18 stenoses that were FFR+ had abnormal CBF during RTMCE, 28 of the 49 stenoses (57%) that were FFR had abnormal CBF, and 24 (49%) had abnormal wall motion in the corresponding coronary artery territory during stress echocardiography. In a significant percentage of intermediate stenoses with normal FFR values, CBF during demand stress is reduced, resulting in myocardial ischemia.

The Effect of Hyperinsulinaemic Euglycaemia on Myocardial Blood Flow Reserve in Healthy Volunteers Over Time

Background and Aims: The vasodilator effect of insulin is incompletely understood. Previous insulin use in acute coronary syndrome trials have shown disappointing results. Our group has shown that hyperinsulinaemic euglycaemia increases myocardial blood flow reserve (MBFR) by 20% in healthy individuals. The time taken for hyperinsulinaemia to exert an effect on the coronary microcirculation is unknown. It is also not known whether this effect can diminish with time. This study investigated the relationship between hyperinsulinaemic clamp time on MBFR. Method & Results: Five healthy male volunteers (mean age 37 yrs (range 21-54)) underwent hyperinsulinaemic euglycaemic clamps. Low-power real-time myocardial contrast echocardiography was performed with flash impulse imaging using low-dose adenosine stress to measure MBFR at baseline. This was repeated at 30, 60, and 120 minutes after commencing insulin infusion at a fixed concentration of 1.5mU/kg/min. Mean(SD) baseline MBFR was 2.5(0.3). MBFR values at 30, 60 and 120 minutes were 3.1(0.8), 3.5(0.6), and 4.1(0.8), respectively. This represents an increase in MBFR of 24%, 40% and 64% with respect to baseline values. Mean fasting serum insulin was 2.3(1.8), 43.2(30.8), 50.6(20.9), and 45.8(21.5) mU/L, respectively. There was no significant difference between baseline and 30-minute MBFR (p=0.06). However there were significant increases in MBFR between baseline versus 60mins (p=0.009), and 60 versus 120mins (p=0.006). Conclusion: Hyperinsulinaemic euglycaemia increases MBFR significantly at 60 minutes of commencing hyperinsulinaemic clamps. This effect is maintained at 120 minutes.

Paeonol Protects Rat Heart by Improving Regional Blood Perfusion during No-Reflow

No-reflow phenomenon, defined as inadequate perfusion of myocardium without evident artery obstruction, occurs at a high incidence after coronary revascularization. The mechanisms underlying no-reflow is only partially understood. It is commonly caused by the swelling of endothelial cells, neutrophil accumulation, and vasoconstriction, which are all related to acute inflammation. Persistent no-reflow can lead to hospitalization and mortality. However, an effective preventive intervention has not yet been established. We have previously found that paeonol, an active extraction from the root of Paeonia suffruticosa, can benefit the heart function by inhibiting tissue damage after ischemia, reducing inflammation, and inducing vasodilatation. To further investigate the potential cardioprotective action of paeonol on no-reflow, healthy male Wistar rats were randomly divided into four groups: sham, ischemia-reperfusion (I/R) injury (left anterior descending coronary artery was ligated for 4 h followed by reperfusion for 8 h), and I/R injury pretreated with paeonol at two different doses. Real-time myocardial contrast echocardiography was used to monitor regional blood perfusion and cardiac functions. Our data indicated that paeonol treatment significantly reduces myocardial infarct area and no-reflow area (n = 8; p < 0.05). Regional myocardial perfusion (A·β) and cardiac functions such as ejection fraction, stroke volume, and fractional shortening were elevated by paeonol (n = 8; p < 0.05). Paeonol also lowered the serum levels of lactate dehydrogenase, creatine kinase, cardiac troponin T, and C-reactive protein, as indices of myocardial injury. Paeonol exerts beneficial effects on attenuating I/R-associated no-reflow injuries, and may be considered as a potential preventive treatment for cardiac diseases or post-coronary revascularization in which no-reflow often occurs.

Safety and Efficacy of Cardiac Ultrasound Contrast in Children and Adolescents for Resting and Stress Echocardiography

Small pilot studies of ultrasound contrast (UC) echocardiography in children have suggested that it is safe; therefore, larger scale evaluation of safety and efficacy in this population is of particular interest. This was a retrospective study (January 2005 to June 2014). Known intracardiac shunt was the only exclusion criterion. UC echocardiography was performed on commercially available ultrasound systems using Definity (3% infusion). When indicated, real-time myocardial contrast echocardiography was performed at rest and stress, with examination of myocardial contrast replenishment, plateau intensity, and wall motion. The primary outcome was short-term safety and efficacy (<24hours). In all, 113 patients (55% male; mean age, 17.8±3years; age range, 5-21 years) underwent UC echocardiography for left ventricular opacification or stress wall motion and perfusion analysis. Diagnosis categories were congenital heart disease (30%), acquired heart disease (21%), and other (suspected cardiac complications of disease of other organ systems; 49%). Twelve patients (11%) with right ventricular systolic pressures>40mmHg received UC without complications; four of these (33%) had the highest right ventricular-right atrial gradient recorded with ultrasound contrast-enhanced Doppler. Myocardial perfusion and/or UC echocardiography-detected wall motion abnormalities were seen in 13 patients (12%); four had confirmed correlations by angiography or magnetic resonance imaging. There were 13 instances of adverse events or reported symptoms during UC echocardiography. All symptoms and events were transient, all patients completed protocols, and there were no immediate sequelae. These data demonstrate the usefulness and safety of UC echocardiography in children and adolescents for a wide variety of indications. UC echocardiography provided myocardial perfusion and wall motion information important in clinical decision making.

Improvement of left ventricular myocardial perfusion after acidic fibroblast growth factor delivered by using ultrasound-targeted microbubble destruction in rats with diabetic cardiomyopathy: an preliminary study

Objective To investigate the protective effects of left ventricular myocardial perfusion after delivery of acidic fibroblast growth factor (aFGF) in rats with diabetic cardiomyopathy (DCM) by using ultrasound-targeted microbubble destruction (UTMD) with real-time myocardial contrast echocardiography(RT-MCE). Methods Among 64 male SD rats, 52 rats were randomly selected and were induced DCM by streptozotocin through intraperitoneal injecting, the other rats as normal control group. DCM rats were randomly divided into the DCM model group, aFGF only group, SonoVue-aFGF group and the SonoVue-aFGF+ UTMD group in this study. The aFGF only group rats were injected with aFGF solution through tail vein, the SonoVue-aFGF group were injected with SonoVue-aFGF solution through tail vein and SonoVue-aFGF+ UTMD group rats were injected with SonoVue-aFGF solution through tail vein and using UTMD simultaneously. All rats underwent conventional echocardiography and RT-MCE exams before and 4 weeks after intervention. Left ventricular ejection fraction (LVEF) and left ventricular fraction shortening(LVFS) were measured by conventional echocardiography. The plateau intensity (A), initial slope of the curve (β) and myocardial blood flow (A×β) of left ventricular anterior wall at the papillary muscle level were measured in left ventricular short-axis view by RT-MCE. Results Before intervention, LVEF and LVFS in the DCM model group, aFGF only group, SonoVue-aFGF group and the SonoVue-aFGF+ UTMD group were significantly lower than in the normal control group (P 0.05), however A and A×β in the SonoVue-aFGF+ UTMD group were significantly increased than those in the DCM model group(P<0.01). Compared with the same group before intervention, A and A×β in the SonoVue-aFGF+ UTMD group were higher (P<0.05) and these in the DCM model group were lower during four weeks after intervention (P<0.05). Conclusions Acidic fibroblast growth factor delivered by using UTMD can improve the left ventricular myocardial perfusion in diabetic cardiomyopathy rats. Key words: Echocardiography; Diabetic cardiomyopathies; Fibroblast growth factor; Microbubbles; Ventricular function, left

Regadenoson Stress Real-Time Myocardial Perfusion Echocardiography for Detection of Coronary Artery Disease: Feasibility and Accuracy of Two Different Ultrasound Contrast Agents.

The aim of this study was to compare the efficacy of myocardial perfusion (MP) and wall motion (WM) analysis obtained with real-time myocardial contrast echocardiography (RTMCE) and two widely used contrast agents in detecting coronary artery disease after injection of the vasodilator regadenoson. One hundred fifty patients were studied at two academic centers using regadenoson (400-μg intravenous bolus) vasodilator stress RTMCE (7.5% Optison infusion [n = 50] or 1.5% Definity infusion [n = 100]). Both MP and WM with RTMCE were analyzed at rest and after regadenoson bolus. Comparisons of WM and MP sensitivity, specificity, and accuracy were made. Quantitative angiography was performed in all patients within 1 month of the regadenoson stress study (>50% and >70% diameter stenosis was considered significant). Reviewers were blinded to all clinical and quantitative angiographic data. Rate-pressure product after regadenoson was higher in Optison than Definity patients (P = .004). Using a 50% diameter stenosis on quantitative angiography as a reference standard, overall sensitivity, specificity, and accuracy for combined WM and MP analysis were not different for both agents (Optison, 77%, 64%, and 73%; Definity, 80%, 74%, and 78%; P = NS). The sensitivity, specificity, and accuracy of WM analysis alone for Optison were 68%, 71%, and 69% compared with 60%, 72%, and 66% for Definity (P = NS). Adding MP analysis improved the sensitivity and accuracy of Definity for detecting both >50% and >70% stenoses (P < .001 vs WM), while MP analysis did not improve the sensitivity of Optison for detecting either >50 or >70% stenoses. RTMCE during regadenoson stress using either Optison or Definity is a rapid and effective method for the detection of coronary artery disease. The ability of MP imaging to improve WM accuracy may depend on the rate-pressure product achieved.