In order to evaluate the left ventricular remodeling in patients with myocardial infarction after revascularization with intravenous real-time myocardial contrast echocardiography （RT-MCE）, intravenous RT-MCE was pe...In order to evaluate the left ventricular remodeling in patients with myocardial infarction after revascularization with intravenous real-time myocardial contrast echocardiography （RT-MCE）, intravenous RT-MCE was performed on 20 patients with myocardial infarction before coronary revascularization. Follow-up echocardiography was performed 3 months after coronary revascularization. Segmental wall motion was assessed using 18-segment LV model and classified as normal, hypokinesis, akinesis and dyskinesis. Myocardial perfusion was assessed by visual interpretation and divided into 3 conditions： homogeneous opacification=l; partial or reduced opaciflcation or subendocardial contrast defect=2; constrast defect=3. Myocardial perfusion score index （MPSI） was calculated by dividing the total sum of contrast score by the total number of segments with abnormal wall motion. Twenty patients were classified into 2 groups according to the MPSI： MPSI≤I.5 as good myocardial perfusion, MPSI〉1.5 as poor myocardial perfusion. To assess the left ventricular remodeling, the following comparisons were carried out： （1） Comparisons of left ventricular ejection fraction （LVEF）, left ventricular end-systolic volume （LVESV） and left ventricular end-diastolic volume （LVEDV） before and 3 months after revascularization in two groups;（2） Comparisons of LVEF, LVESV and LVEDV pre-revascularization between two groups and comparisons of these 3 months post-revascularization between two groups; （3） Comparisons of the differences in LVEF, LVESV and LVEDV between 3 months post-and pre-revascularization （ALVEF, ALVESV and ALVEDV） between two groups; （4） The linear regression analysis between ALVEF, ALVESV, ALVEDV and MPSI. The results showed that the LVEF obtained 3 months after revascularization in patients with MPSI〉1.5 was obviously lower than that in those with MPSI〈1.5. The LVEDV obtained 3 months post-revascularization in patients with MPSI〉1.5 was obviously larger than that in those with MPSI≤1.5 （P=0.002 and 0.04）. The differences in ALVEF and ALVEDV between patients with MPSI〉I.5 and those with MPSI≤1.5 were significant （P=0.002 and 0.001, respectively）. Linear regression analysis revealed that MPSI had a negative correlation with ALVEF and a positive correlation with ALVESV, ALVEDV （P=0.004, 0.008, and 0.016, respectively）. It was concluded that RT-MCE could accurately evaluate the left ventricular remodeling in patients with myocardial infarction after revascularization.展开更多
To evaluate the feasibility of real-time myocardial contrast echocardiography （RTMCE） by quantitative analysis of myocardial perfusion in rabbits, transthoracic RTMCE was performed in 10 healthy rabbits by using con...To evaluate the feasibility of real-time myocardial contrast echocardiography （RTMCE） by quantitative analysis of myocardial perfusion in rabbits, transthoracic RTMCE was performed in 10 healthy rabbits by using continuous infusion of SonoVue into the auricular vein. The short axis view at the papillary muscle level was obtained. The duration of the time that the contrast took to appear in right heart, left heart and myocardium was recorded. The regional myocardial signal intensity （SI） versus re-filling time plots were fitted to an exponential function： y（t） =A（1–e–β（t–t0）） ＋ C, where y is SI at any given time, A is the SI plateau that reflects myocardial blood volume, and β is the slope of the refilling curve that reflects myocardial microbubble velocity. The A, β and A×β values at different infusion rate of SonoVue were analyzed and the A, β and A×β values in each segment in the short axis view at the papillary muscle level were compared. All the animal experiments were successful and high-quality im-ages were obtained. The best intravenous infusion rate for SonoVue was 30 mL/h. The contrast appeared in right heart, left heart and myocardium at 7.5±2.2 s, 9.1±2.4 s and 12.2±1.6 s respectively. After 16.6±2.3s, myocardial opacification reached a steady state. The mean A, β and A×β value in the short axis view at the papillary muscle level were 9.8±3.0 dB, 1.4±0.5 s-1 and 13.5±3.6 dB×s-1 respectively. A, β and A×β values showed no significant differences among 6 segments. It was suggested that RTMCE was feasible for quantitative analysis of myocardial perfusion in rabbits. It provides a non-invasive method to evaluate the myocardial perfusion in rabbit disease models.展开更多
The myocardial viability after myocardial infarction was evaluated by intravenous myocardial contrast echocardiography. Intravenous real-time myocardial contrast echocardiography was performed on 18 patients with myoc...The myocardial viability after myocardial infarction was evaluated by intravenous myocardial contrast echocardiography. Intravenous real-time myocardial contrast echocardiography was performed on 18 patients with myocardial infarction before coronary revascularization. Follow-up echocardiography was performed 3 months after coronary revascularization. Segmental wall motion was assessed using 18-segment LV model and classified as normal, hypokinesis, akinesis and dyskinesis. Viable myocardium was defined by evident improvement of segmental wall motion 3 months after coronary revascularization. Myocardial perfusion was assessed by visual interpretation and divided into 3 conditions： homogeneous opacification; partial or reduced opaciflcation or subendocardial contrast defect; contrast defect. The former two conditions were used as the standard to define the viable myocardium. The results showed that 109 abnormal wall motion segments were detected among 18 patients with myocardial infarction, including 47 segments of hypokinesis, 56 segments of akinesis and 6 segments of dyskinesis. The wall motion of 2 segments with hypokinesis before coronary revascularization which showed homogeneous opacification, 14 of 24 segments with hypokinese and 20 of 24 segments with akinese before coronary revascularization which showed partial or reduced opaciflcation or subendocardial contrast defect was improved 3 months after coronary revascularization. In our study, the sensitivity and specificity of evaluation of myocardial viability after myocardial infarction by intravenous real-time myocardial contrast echocardiography were 94.7% and 78.9%, respectively. It was concluded that intravenous real-time myocardial contrast echocardiography could accurately evaluate myocardial viability after myocardial infarction.展开更多
Objective To evaluate the feasibility and accuracy of measurement of myocardial perfusion defects with intravenous contrast-enhanced real-time three-dimensional echocardiography (CE-RT3DE). Methods RT3DE was performed...Objective To evaluate the feasibility and accuracy of measurement of myocardial perfusion defects with intravenous contrast-enhanced real-time three-dimensional echocardiography (CE-RT3DE). Methods RT3DE was performed in 21 open-chest mongrel dogs undergoing acute ligation of the left anterior descending artery (LAD, n=14) or distal branch of the left circumflex artery (LCX, n=7). A perfluorocarbon microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defects with Philips Sonos-7500 ultrasound system. Evans blue dye was injected into the occluded coronary artery for subsequent anatomic identification of underperfused myocardium. In vitro anatomic measurement of myocardial mass after removal of the animal’s heart was regarded as the control. Blinded off-line calculation of left ventricular mass and perfusion defect mass from RT3DE images were performed using an interactive aided-manual tracing technique.Results Total left ventricular (LV) myocardial mass ranged from 38.9 to 78.5 (mean±SD: 60.0±10.1) g. The mass of perfusion defect ranged from 0 to 21.4 (mean±SD: 12.0±5.0) g or 0 to 27% of total LV mass (mean±SD: 19%±6%). The RT3DE estimation of total LV mass (mean±SD: 59.8±9.9 g) strongly correlated with the anatomic measurement (r=0.98; y=2.01+0.96x). The CE-RT3DE calculation of the mass of underperfused myocardium (mean±SD: 12.3±5.3 g) also strongly correlated with the anatomic measurement (r=0.96; y=-0.10+1.04x) and when expressed as percentage of total LV mass (r=0.95; y=-0.20+1.04x). Conclusions RT3DE with myocardial contrast opacification could accurately estimate underperfused myocardial mass in dogs of acute coronary occlusion and would play an important role in quantitative assessment of myocardial perfusion defects in patients with coronary artery disease.展开更多
Conventional echocardiography can sometimes pose a challenge to diagnosis due to sub-optimal images.Ultrasound contrast agents(UCAs)have been shown to drastically enhance imaging quality,particularly depicting the lef...Conventional echocardiography can sometimes pose a challenge to diagnosis due to sub-optimal images.Ultrasound contrast agents(UCAs)have been shown to drastically enhance imaging quality,particularly depicting the left ventricular endocardial borders.Their use during echocardiography has become a valuable tool in non-invasive diagnostics.UCAs provide higher-quality images that may ultimately reduce the length of hospital stays and improve patient care.The higher cost associated with UCAs in many situations has been an impediment to frequent use.However,when used as an initial diagnostic test,UCA during rest echocardiogram is more cost-effective than the traditional diagnostic approach,which frequently includes multiple tests and imaging studies to make an accurate diagnosis.They can be easily performed across multiple patient settings and provide optimal images that allow clinicians to make sound medical decisions.This consequently allows for better diagnostic accuracies and improvement in patient care.展开更多
The clinically applied value of myocardial perfusion and systolic function in patients with coronary artery disease after coronary artery bypass surgery using real-time myocardial contrast echocardiography （RT-MCE） ...The clinically applied value of myocardial perfusion and systolic function in patients with coronary artery disease after coronary artery bypass surgery using real-time myocardial contrast echocardiography （RT-MCE） combined with two-dimensional strain echocardiography was assessed. Twenty patients underwent intravenous RT-MCE by intravenous injections of SonoVue before and after coronary artery bypass surgery. Two-dimensional images were recorded from the left ventricular four-chamber view, two-chamber view and the apical view before, and two weeks and three months after coronary artery bypass surgery, and the peak systolic longitudinal strain was measured. The results showed that myocardial perfusion was significantly increased after coronary artery bypass surgery in about 71.6% segments. In the group that myocardial perfusion was improved, the peak systolic longitu- dinal strain three months after bypass surgery was significantly higher than that before operation [（-15.78±5.91）% vs （-10.45±8.31）%, P〈0.05]. However, the parameters did not change in the group without myocardial perfusion improvement [（-10.33±6.53）% vs （-9.41±6.09）%, P〉0.05]. It was concluded that whether or not the improvement of myocardial perfusion can mirror the recovery trend of regional systolic function, two-dimensional strain echocardiography can observe dynamic change of regional systolic function. The combination of myocardial perfusion with two-dimensional strain echocardiography can more accurately assess the curative effectiveness of coronary artery bypass surgery.展开更多
Background Myocardial blood flow(MBF) can be quantified with myocardial contrast echocardiography (MCE) during a venous infusion of microbubble. A minimal MBF is required to maintain cell membrane integrity and myocar...Background Myocardial blood flow(MBF) can be quantified with myocardial contrast echocardiography (MCE) during a venous infusion of microbubble. A minimal MBF is required to maintain cell membrane integrity and myocardial viability in ischemic condition. Thus, we hypothesized that MCE could be used to assess myocardial viability by the determination of MBF. Methods and ResultsMCE was performed at 4 hours after ligation of proximal left anterior descending coronary artery in 7 dogs with constant venous infusions of microbubbles. The video intensity versus pulsing interval plots derived from each myocardial pixel were fitted to an exponential function: y=A(1-e-βt), where y is Ⅵ at pulsing interval t, A reflects microvascular cross - sectional area (or myocardial blood volume), and βreflects mean myocardial microbubble velocity. The product of A·β represents MBF. MBF was also obtained by ra-diolabeled microsphere method servered as reference. MBF derived by radiolabeled microsphere - method in the regions of normal, ischemia and infarction was 1.5+0.3, 0.7+0.3, 0. 3+0. 2 mL @ min-1@ g-1 respectively. The product of A·β obtained by MCE in those regions was 52. 46±15. 09, 24. 36±3. 89, 3. 74 ±3. 80 respectively. There was good correlation between normalized MBF and the normalized A·β ( r = 0. 81, P=0. 001). Conclusions MCE has an ability to determine myocardial viability in myocardial infarction canine model.展开更多
Our understanding of coronary syndromes has evolved in the last two decades out of the obstructive atherosclerosis of epicardial coronary arteries paradigm to include anatomo-functional abnormalities of coronary micro...Our understanding of coronary syndromes has evolved in the last two decades out of the obstructive atherosclerosis of epicardial coronary arteries paradigm to include anatomo-functional abnormalities of coronary microcirculation. No current diagnostic technique allows direct visualization of coronary microcirculation,but functional assessments of this circulation are possible. This represents a challenge in cardiology. Myocardial contrast echocardiography(MCE) was a breakthrough in echocardiography several years ago that claimed the capability to detect myocardial perfusion abnormalities and quantify coronary blood flow. Research demonstrated that the integration of quantitative MCE and fractional flow reserve improved the definition of ischemic burden and the relative contribution of collaterals in non-critical coronary stenosis. MCE identified no-reflow and low-flow within and around myocardial infarction,respectively,and predicted the potential functional recovery of stunned myocardium using appropriate interventions. MCE exhibited diagnostic performances that were comparable to positron emission tomography in microvascular reserve and microvascular dysfunction in angina patients. Overall,MCE improved echocardiographic evaluations of ischemic heart disease in daily clinical practice,but the approval of regulatory authorities is lacking.展开更多
Purpose: The aim of the present study was to evaluate the diagnostic accuracy for quantification of left ventricular (LV) volumes and LV ejection fraction (LVEF) with current echocardiographic methods of planimetry fo...Purpose: The aim of the present study was to evaluate the diagnostic accuracy for quantification of left ventricular (LV) volumes and LV ejection fraction (LVEF) with current echocardiographic methods of planimetry for analysis of LV remodeling after myocardial infarction in daily clinical routine. Methods: 26 patients were investigated directly after interventional therapy at hospital pre-discharge and at 6 month follow-up. Standardized 2D transthoracic native and contrast echocardiography were performed in all patients. Due to methodological aspects the results of LV volumes and LVEF using native echocardiography were compared to the results of LV opacification (LVO) imaging for analysis in mono-, bi- and triplane data sets using the Simpson’s rule. In addition corresponding multidimensional data sets were analyzed. Results: The assessment of LV volumes and LVEF is more accurate with contrast echocardiography. The comparison of LV volumes and LVEF shows significant increases using contrast echocardiography (p < 0.001). Larger left ventricular end-diastolic volumes (LVEDV) are measured at follow up (p < 0.05). Significant differences (p < 0.001) are found for the determination of LVEDV and LVEF relating to apical mono-, bi-, tri- and multiplane data sets. Standard deviations of the triplane approach, however, are significantly lower than using other modalities. Conclusion: Depending on the localization of the myocardial infarction LV volumes and LVEF are less reliably evaluated using the mono- or biplane approach. According to standardization and simultaneous acquisition of all LV wall segments the triplane approach is currently the best approach to determine LV systolic function. In addition, contrast echocardiography is indicated to improve endocardial border delineation in patients using the triplane or multiplane approach. To our knowledge the present study is the first systematic evaluation of all current possibilities for determination of LV volumes and LVEF by native and contrast echocardiography.展开更多
Background Both real-time three-dimensional echocardi ography (RT3DE) and myocardial contrast echocardiography (MCE) are novel imaging techniques. The purpose of this study was to confirm the feasibility and accuracy ...Background Both real-time three-dimensional echocardi ography (RT3DE) and myocardial contrast echocardiography (MCE) are novel imaging techniques. The purpose of this study was to confirm the feasibility and accuracy of RT3DE combined with MCE for quantitative evaluation of myocardial perfusion defects. Methods Thirteen dogs underwent ligation of the left anterior descending artery (LAD, n=6) or distal branch of the left circumflex artery (LCX, n=7) under general anaesthesia. Three to four ml of a perfluoropropane (C 3F 8) microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defects with a commercially available Philips SONOS-7500 ultrasound system. After removal of the dog hearts, Evans blue dye was injected via the left and righ t coronary arteries to stain the myocardium at risk. In vitro anatomic measurements of myocardial mass after removal of the animals’ hearts were used as control s. Results Left ventricular (LV) mass determined by RT3DE ranged 36.7-68.9 g [mean, (54.6±9.6) g] before coronary artery ligation, and correlated highly (r=0.99) with in vitro measurement of LV mass [range, 38.9-71.1 g; mean, (55.6±9.3) g]. There was no significant difference between RT3DE and in vitro measurements of LV mass [range, 36.7-68.9 g; mean, (51.3±12.5) g. Or range, 38.9-71. 1 g; mean, (53.7±12.3) g, respectively] and under-perfused mass [range, 0-21.4 g; mean, (12.0±6.9) g. Or range, 0-19.8 g; mean, (10.8±6.3) g, respectively] after th e LAD ligation (P>0.05). Likewise, no significant difference was present between RT3DE and in vitro measurements of LV mass [range, 50.1-65.4 g; mean, (57.5±5.9 ) g. Or range, 51.5-65.8 g; mean, (57.3±6.4) g, respectively] and under-perfused m ass [range, 0-25.6 g; mean, (13.3±9.6) g. Or range, 0-22.7 g; mean, (12.8±8.1 ) g, respectively] after the LCX ligation (P>0.05). For all the animals with coronary ligation, LV mass measured by RT3DE ranged 35.9-68.6 g [mean, (54.8±10.0) g] a nd there was no significant difference between RT3DE and in vitro measurements of LV mass and under-perfused mass (P>0.05, r=0.99). Further, the under-perfused mass derived from RT3DE [range, 0-25.6 g; mean, (12.7±8.2) g] correlate d strongly with the in vitro measurements [range, 0-22.7 g; mean, (11.9±7.2) g] ( r=0.96). Conclusion RT3DE with MCE is a rapid and accurate method for estimating LV myocardial mass and quantifying perfusion defects.展开更多
Background No-reflow is associated with an adverse outcome and higher mortality in patients with ST-segment elevation acute myocardial infarction （STEMI） who undergo percutaneous coronary intervention （PCI） and is...Background No-reflow is associated with an adverse outcome and higher mortality in patients with ST-segment elevation acute myocardial infarction （STEMI） who undergo percutaneous coronary intervention （PCI） and is considered a dynamic process characterized by multiple pathogenetic components. The aim of this study was to investigate the effectiveness of a combination therapy for the prevention of no-reflow in patient with acute myocardial infarction （AMI） undergoing primary PCI. Methods A total of 621 patients with STEMI who underwent emergency primary PCI were enrolled in this study. Patients with high risk of no-reflow （no-flow score 〉 10, by using a no-flow risk prediction model, n = 216） were randomly divided into a controlled group （n = 108） and a combination therapy group （n = 108）. Patients in the controlled group received conventional treatment, while patients in combination therapy group received high-dose （80 mg） atorvastatin pre-treatment, intracoronary administration of adenosine （140 ~tg/min per kilogram） during PCI procedure, platelet membrane glycoprotein lib/Ilia receptor antagonist （tirofiban, 101.tg/kg bolus followed by 0.15 ~tg/kg per minute） and thrombus aspiration. Myocardial contrast echocardiography was performed to assess the myocardial perfusion 72 h after PCI. Major adverse cardiac events （MACE） were followed up for six months. Results Incidence of no-reflow in combination therapy group was 2.8%, which was similar to that in low risk group 2.7% and was significantly lower than that in control group （35.2%, P 〈 0.01）. The myocardial perfusion （A= 13） values were higher in combination therapy group than that in control group 72 h after PCI. After 6 months, there were six （6.3%） MACE events （one death, two non-fatal MIs and three revasculafizations） in combination therapy group and 12 （13.2%） （four deaths, three non-fatal MIs and five revascularizations, P 〈 0.05） in control group. Conclusions Combination of thrombus aspiration, high-dose statin pre-treatment, intmcoronary administration of adenosine during PCI procedure and platelet membrane glycoprotein Ⅱ b/Ⅲa receptor antagonist reduces the incidence of no-reflow after primary PCI in patients with acute myocardial infarction who are at high risk of no-reflow.展开更多
Sympathetic nerve and vagus nerve remodeling play an important part in cardiac function post-myocardial infarction （MI）. Increasing evidence indicates that neuregulin-1 （NRG-1） improves cardiac function following ...Sympathetic nerve and vagus nerve remodeling play an important part in cardiac function post-myocardial infarction （MI）. Increasing evidence indicates that neuregulin-1 （NRG-1） improves cardiac function following heart failure. Since its impact on cardiac function and neural remodeling post-MI is poorly understood, we aimed to investigate the role of NRG-1 in autonomic nervous system remodeling post-MI. Forty-five Sprague-Dawley rats were equally randomized into three groups： sham （with the left anterior descending coronary artery exposed but without ligation）, MI （left anterior descending coronary artery ligation）, and MI plus NRG-1 （left anterior descending coronary artery ligation followed by intraperitoneal injection of NRG-1 （10 lag/kg, once daily for 7 days））. At 4 weeks after MI, echocardi- ography was used to detect the rat cardiac function by measuring the left ventricular end-systolic inner diameter, left ventricular diastolic diameter, left ventricular end-systolic volume, left ventricular end-diastolic volume, left ventricular ejection fraction, and left ventricular fractional shortening, mRNA and protein expression levels of tyrosine hydroxylase, growth associated protein-43 （neuronal specific pro- tein）, nerve growth factor, choline acetyltransferase （vagus nerve marker）, and vesicular acetylcholine transporter （cardiac vagal nerve fiber marker） in ischemic myocardia were detected by real-time PCR and western blot assay to assess autonomous nervous remodeling. After MI, the rat cardiac function deteriorated significantly, and it was significantly improved after NRG-1 injection. Compared with the MI group, mRNA and protein levels of tyrosine hydroxylase and growth associated protein-43, as well as choline acetyltransferase mRNA level significantly decreased in the MI plus NRG-1 group, while mRNA and protein levels of nerve growth factor and vesicular acetylcholine transporters, as well as choline acetyltransferase protein level slightly decreased. Our results indicate that NRG- 1 can improve cardiac function and regulate sympathetic and vagus nerve remodeling post-MI, thus reaching a new balance of the autonomic nervous system to protect the heart from injury.展开更多
Background Innovative advancements in ultrasound instrumentation present a number of imaging modalities for myocardial contrast echocardiography （MCE） in ischemic syndromes. How well they compare to each other in di...Background Innovative advancements in ultrasound instrumentation present a number of imaging modalities for myocardial contrast echocardiography （MCE） in ischemic syndromes. How well they compare to each other in diagnostic accuracy in the detection of acute myocardial infarction is unclear. The purpose of this study was to assess the relative accuracy of 3 different imaging modes of MCE, low mechanical index （MI） real-time perfusion imaging （RTPI）, triggered harmonic angio mode （HA）, and ultraharmonic imaging mode （UH） in the detection of acute experimental myocardial infarction within the time frame suitable for potential reperfusion. Methods MCE was performed in 10 open-chest dogs using RTPI, triggered HA and triggered UH modes at baseline and one hour after occlusion of left anterior descending coronary artery. Presence or absence of peffusion defects, and the perfusion defect size when present, were analyzed and compared with the infarct size delineated by triphenyltetrazolium chloride （TTC） staining. Results The infarct area was （15.8-2.4）% by TTC staining; Peffusion defect area by MCE was similar to anatomic infarct area in all the three MCE approaches： （16.1-2.7）% by RTPI mode, （15.5-2.9）% by HA mode, and （15.5-3.0）% by UH mode. The sensitivity, specificity and overall diagnostic accuracy in the detection of myocardial infarction were 100%, 88%, and 94% for RTPI mode, 88%, 100%, and 94 % for HA mode, and 100%, 75%, and 88% for UH mode. Conclusion All modes of MCE, RTPI, triggered HA mode and triggered UH mode have excellent diagnostic accuracy in the immediate hour of acute coronary occlusion within the optimal time frame suitable for reperfusion therapy.展开更多
Background Quantitatively assessing myocardial perfusion and its reserve is of great importance for the diagnosis and stratification of patients with coronary artery disease （ CAD）, and represents an important goal ...Background Quantitatively assessing myocardial perfusion and its reserve is of great importance for the diagnosis and stratification of patients with coronary artery disease （ CAD）, and represents an important goal of myocardial contrast echocardiography. In this study we sought to test the usefulness of low dose dobutamine stress real-time myocardial contrast echocardiography （RT-MCE） in the assessment of CAD, and to explore the relationship between perfusion reserve and contractile reserve. Methods Twenty-six patients with suspected or clinical diagnosed CAD were enrolled and underwent RT-MCE at baseline and under low dose dobutamine stress, and subsequent coronary angiography. RT-MCE images were analyzed quantitatively from microbubble replenishment curves for myocardial perfusion and its reserve. Results At baseline, significant differences in beta （0.28± 0. 12, 0. 25± 0. 09, 0.22 ± 0. 06, 0. 20± 0.07 respectively, P 〈0. 01） and A x beta （1.37 ±0. 46, 1.28±0. 47, 1. 13 ±0. 37, 0.91±0. 32, respectively, P 〈0. 01 ） were observed among four segment groups with graded coronary artery stenosis severity （normal; 30% -69% stenosis; 70% -90% stenosis; and beyond 90% stenosis） , but not observed in parameter A. When under stress, significant differences in A （5.73 ± 1.28, 5.63 ± 1.01,4.96 ±0.81,4.57 _＋0.62, respectively, P〈0.01）, beta （0.67 ±0. 17, 0.55 ±0. 19, 0.32 ±0. 13, 0.25 ±0.08, respectively, P 〈0.01） and A x beta （3.81 ± 1.20, 3. 11±1.17, 1.59 ±0. 82, 1. 12 _＋0. 37, respectively, P 〈0. 01 ） were observed among the formerly mentioned groups. Graded decreases in A reserve （ 1.20 ±0. 53, 1.11 ±0. 16, 0.98 ±0. 12, 0. 99 ±0.13, respectively, P〈0.01）, beta reserve （2.65 ±1.07, 2. 32±0.82, 1.44±0.40, 1.29±0.34, respectively, P〈0.01） and A xbeta reserve （3.05 ± 1.63, 2.59 ±1.01, 1.42 ±0.44, 1.27±0.34, respectively, P 〈 0. 01 ） could also be observed with increasing coronary stenosis severity. In five segments groups scored by WMS （ 1 - 5 ） , concordance between contractile function and myocardial perfusion could be found both at rest （beta： 0.28±0. 11, 0. 22 ±0. 08, 0. 21 ±0.05, 0. 17 ±0.05,0. 19 ±0.06, respectively, P 〈0.01; A xbeta： 1.29 ±0.48, 0.98 ±0.45, 0.94±0.29, 0.76 ±0.30, 0.92 ±0.32, respectively, P〈 0.01） and under stress （beta： 0.59 ±0.20, 0.35 ±0.15, 0.27 ±0.08, 0. 17±0.05, 0.20±0.05, respectively, P〈0.01; A xbeta： 3.07 ±1.38, 1.62±0.82, 1.28 ±0.40, 0.78 ±0.24, 0.93 v0.22, respectively, P 〈0. 01 ）. This concordance is also valid in terms of the reserves, and the MCE parameters in segments with ameliorated contractile function are significantly higher than in those without. Conclusions Quantitative RT-MCE in conjunction with dobutamine stress shows promise in identifying and stratifying CAD and in exploring the perfusion-contractile correlation.展开更多
Background Time-intensity curves derived from microbubble destruction/refilling sequences and recorded using myocardial contrast echocardiography (MCE) can provide parameters that correlate with coronary blood flow. ...Background Time-intensity curves derived from microbubble destruction/refilling sequences and recorded using myocardial contrast echocardiography (MCE) can provide parameters that correlate with coronary blood flow. The response of these parameters to adenosine vasodilatation correlates with coronary flow reserve (CFR) measured by fluorescent microsphere techniques (FMT). Currently, no data exist regarding the effect of physiological variables, such as hypoxia, on the determination of CFR by MCE. The purpose of this study was to define the effects of decreases in blood partial pressure of oxygen (PO_2) on CFR as measured by MCE. Methods Studies were performed in 9 closed chest swine. Low-energy, real-time MCE was performed with commercial instruments in short axis view at papillary muscle level while infusing BR_1 at 30 ml/h. High-energy ultrasound bursts (referred to as FLASH frames) destroyed the bubbles every 15 cardiac cycles, and resultant time-intensity curves derived from these sequences were fitted to the exponential function y = A (1-e -bt) +c, from which the rate of signal rise (b) was obtained. CFR was calculated as the ratio of b values after adenosine infusion to baseline and was obtained during the control period and after decreasing blood PO_2 by giving nitrogen via a respirator to create artificial hypoxic conditions. CFR was independently determined by FMT. Results Nitrogen led to significant decreases in mean PO_2, from (120.6±18.9) mmHg to (51.8±15.9) mmHg (P<0.01). Adenosine produced a similar increase in CFR (2.5 fold vs 3.1 fold) as assessed by MCE and FMT during the control period. The decrease in PO_2 post nitrogen resulted in a slight increase in values at rest: 0.46±0.15 to 0.53±0.18 for b and (1.39±0.66) ml·min -1·g -1 to (1.72±0.30) ml·min -1·g -1 for myocardial blood flow (MBF) (both P<0.05). In addition, values decreased in response to adenosine using both techniques: 1.05±0.35 to 0.82±0.27 for b and (4.30±3.16) ml·min -1·g -1 to (3.93±1.27) ml·min -1·g -1 for MBF (both P<0.05). Thus, CFR was markedly reduced under hypoxic conditions, to 1.4 by MCE (P<0.05 compared with the baseline), and to 2.5 by FMT (P>05 compared with the baseline). Conclusions CFR values diminish under hypoxic conditions according to both MCE and FMT. The reductions in CFR involve both an increase in resting values and a decrease in post adenosine measurements, as determined by both techniques. The reduction in CFR under hypoxia is slightly greater using MCE than using FMT. Physiological variables, such as hypoxia, must be taken into consideration when assessing CFR by MCE.展开更多
文摘In order to evaluate the left ventricular remodeling in patients with myocardial infarction after revascularization with intravenous real-time myocardial contrast echocardiography （RT-MCE）, intravenous RT-MCE was performed on 20 patients with myocardial infarction before coronary revascularization. Follow-up echocardiography was performed 3 months after coronary revascularization. Segmental wall motion was assessed using 18-segment LV model and classified as normal, hypokinesis, akinesis and dyskinesis. Myocardial perfusion was assessed by visual interpretation and divided into 3 conditions： homogeneous opacification=l; partial or reduced opaciflcation or subendocardial contrast defect=2; constrast defect=3. Myocardial perfusion score index （MPSI） was calculated by dividing the total sum of contrast score by the total number of segments with abnormal wall motion. Twenty patients were classified into 2 groups according to the MPSI： MPSI≤I.5 as good myocardial perfusion, MPSI〉1.5 as poor myocardial perfusion. To assess the left ventricular remodeling, the following comparisons were carried out： （1） Comparisons of left ventricular ejection fraction （LVEF）, left ventricular end-systolic volume （LVESV） and left ventricular end-diastolic volume （LVEDV） before and 3 months after revascularization in two groups;（2） Comparisons of LVEF, LVESV and LVEDV pre-revascularization between two groups and comparisons of these 3 months post-revascularization between two groups; （3） Comparisons of the differences in LVEF, LVESV and LVEDV between 3 months post-and pre-revascularization （ALVEF, ALVESV and ALVEDV） between two groups; （4） The linear regression analysis between ALVEF, ALVESV, ALVEDV and MPSI. The results showed that the LVEF obtained 3 months after revascularization in patients with MPSI〉1.5 was obviously lower than that in those with MPSI〈1.5. The LVEDV obtained 3 months post-revascularization in patients with MPSI〉1.5 was obviously larger than that in those with MPSI≤1.5 （P=0.002 and 0.04）. The differences in ALVEF and ALVEDV between patients with MPSI〉I.5 and those with MPSI≤1.5 were significant （P=0.002 and 0.001, respectively）. Linear regression analysis revealed that MPSI had a negative correlation with ALVEF and a positive correlation with ALVESV, ALVEDV （P=0.004, 0.008, and 0.016, respectively）. It was concluded that RT-MCE could accurately evaluate the left ventricular remodeling in patients with myocardial infarction after revascularization.
文摘To evaluate the feasibility of real-time myocardial contrast echocardiography （RTMCE） by quantitative analysis of myocardial perfusion in rabbits, transthoracic RTMCE was performed in 10 healthy rabbits by using continuous infusion of SonoVue into the auricular vein. The short axis view at the papillary muscle level was obtained. The duration of the time that the contrast took to appear in right heart, left heart and myocardium was recorded. The regional myocardial signal intensity （SI） versus re-filling time plots were fitted to an exponential function： y（t） =A（1–e–β（t–t0）） ＋ C, where y is SI at any given time, A is the SI plateau that reflects myocardial blood volume, and β is the slope of the refilling curve that reflects myocardial microbubble velocity. The A, β and A×β values at different infusion rate of SonoVue were analyzed and the A, β and A×β values in each segment in the short axis view at the papillary muscle level were compared. All the animal experiments were successful and high-quality im-ages were obtained. The best intravenous infusion rate for SonoVue was 30 mL/h. The contrast appeared in right heart, left heart and myocardium at 7.5±2.2 s, 9.1±2.4 s and 12.2±1.6 s respectively. After 16.6±2.3s, myocardial opacification reached a steady state. The mean A, β and A×β value in the short axis view at the papillary muscle level were 9.8±3.0 dB, 1.4±0.5 s-1 and 13.5±3.6 dB×s-1 respectively. A, β and A×β values showed no significant differences among 6 segments. It was suggested that RTMCE was feasible for quantitative analysis of myocardial perfusion in rabbits. It provides a non-invasive method to evaluate the myocardial perfusion in rabbit disease models.
文摘The myocardial viability after myocardial infarction was evaluated by intravenous myocardial contrast echocardiography. Intravenous real-time myocardial contrast echocardiography was performed on 18 patients with myocardial infarction before coronary revascularization. Follow-up echocardiography was performed 3 months after coronary revascularization. Segmental wall motion was assessed using 18-segment LV model and classified as normal, hypokinesis, akinesis and dyskinesis. Viable myocardium was defined by evident improvement of segmental wall motion 3 months after coronary revascularization. Myocardial perfusion was assessed by visual interpretation and divided into 3 conditions： homogeneous opacification; partial or reduced opaciflcation or subendocardial contrast defect; contrast defect. The former two conditions were used as the standard to define the viable myocardium. The results showed that 109 abnormal wall motion segments were detected among 18 patients with myocardial infarction, including 47 segments of hypokinesis, 56 segments of akinesis and 6 segments of dyskinesis. The wall motion of 2 segments with hypokinesis before coronary revascularization which showed homogeneous opacification, 14 of 24 segments with hypokinese and 20 of 24 segments with akinese before coronary revascularization which showed partial or reduced opaciflcation or subendocardial contrast defect was improved 3 months after coronary revascularization. In our study, the sensitivity and specificity of evaluation of myocardial viability after myocardial infarction by intravenous real-time myocardial contrast echocardiography were 94.7% and 78.9%, respectively. It was concluded that intravenous real-time myocardial contrast echocardiography could accurately evaluate myocardial viability after myocardial infarction.
文摘Objective To evaluate the feasibility and accuracy of measurement of myocardial perfusion defects with intravenous contrast-enhanced real-time three-dimensional echocardiography (CE-RT3DE). Methods RT3DE was performed in 21 open-chest mongrel dogs undergoing acute ligation of the left anterior descending artery (LAD, n=14) or distal branch of the left circumflex artery (LCX, n=7). A perfluorocarbon microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defects with Philips Sonos-7500 ultrasound system. Evans blue dye was injected into the occluded coronary artery for subsequent anatomic identification of underperfused myocardium. In vitro anatomic measurement of myocardial mass after removal of the animal’s heart was regarded as the control. Blinded off-line calculation of left ventricular mass and perfusion defect mass from RT3DE images were performed using an interactive aided-manual tracing technique.Results Total left ventricular (LV) myocardial mass ranged from 38.9 to 78.5 (mean±SD: 60.0±10.1) g. The mass of perfusion defect ranged from 0 to 21.4 (mean±SD: 12.0±5.0) g or 0 to 27% of total LV mass (mean±SD: 19%±6%). The RT3DE estimation of total LV mass (mean±SD: 59.8±9.9 g) strongly correlated with the anatomic measurement (r=0.98; y=2.01+0.96x). The CE-RT3DE calculation of the mass of underperfused myocardium (mean±SD: 12.3±5.3 g) also strongly correlated with the anatomic measurement (r=0.96; y=-0.10+1.04x) and when expressed as percentage of total LV mass (r=0.95; y=-0.20+1.04x). Conclusions RT3DE with myocardial contrast opacification could accurately estimate underperfused myocardial mass in dogs of acute coronary occlusion and would play an important role in quantitative assessment of myocardial perfusion defects in patients with coronary artery disease.
文摘Conventional echocardiography can sometimes pose a challenge to diagnosis due to sub-optimal images.Ultrasound contrast agents(UCAs)have been shown to drastically enhance imaging quality,particularly depicting the left ventricular endocardial borders.Their use during echocardiography has become a valuable tool in non-invasive diagnostics.UCAs provide higher-quality images that may ultimately reduce the length of hospital stays and improve patient care.The higher cost associated with UCAs in many situations has been an impediment to frequent use.However,when used as an initial diagnostic test,UCA during rest echocardiogram is more cost-effective than the traditional diagnostic approach,which frequently includes multiple tests and imaging studies to make an accurate diagnosis.They can be easily performed across multiple patient settings and provide optimal images that allow clinicians to make sound medical decisions.This consequently allows for better diagnostic accuracies and improvement in patient care.
文摘The clinically applied value of myocardial perfusion and systolic function in patients with coronary artery disease after coronary artery bypass surgery using real-time myocardial contrast echocardiography （RT-MCE） combined with two-dimensional strain echocardiography was assessed. Twenty patients underwent intravenous RT-MCE by intravenous injections of SonoVue before and after coronary artery bypass surgery. Two-dimensional images were recorded from the left ventricular four-chamber view, two-chamber view and the apical view before, and two weeks and three months after coronary artery bypass surgery, and the peak systolic longitudinal strain was measured. The results showed that myocardial perfusion was significantly increased after coronary artery bypass surgery in about 71.6% segments. In the group that myocardial perfusion was improved, the peak systolic longitu- dinal strain three months after bypass surgery was significantly higher than that before operation [（-15.78±5.91）% vs （-10.45±8.31）%, P〈0.05]. However, the parameters did not change in the group without myocardial perfusion improvement [（-10.33±6.53）% vs （-9.41±6.09）%, P〉0.05]. It was concluded that whether or not the improvement of myocardial perfusion can mirror the recovery trend of regional systolic function, two-dimensional strain echocardiography can observe dynamic change of regional systolic function. The combination of myocardial perfusion with two-dimensional strain echocardiography can more accurately assess the curative effectiveness of coronary artery bypass surgery.
基金This work was supported in part by grants from thescience and technology foundation of China(39870329).
文摘Background Myocardial blood flow(MBF) can be quantified with myocardial contrast echocardiography (MCE) during a venous infusion of microbubble. A minimal MBF is required to maintain cell membrane integrity and myocardial viability in ischemic condition. Thus, we hypothesized that MCE could be used to assess myocardial viability by the determination of MBF. Methods and ResultsMCE was performed at 4 hours after ligation of proximal left anterior descending coronary artery in 7 dogs with constant venous infusions of microbubbles. The video intensity versus pulsing interval plots derived from each myocardial pixel were fitted to an exponential function: y=A(1-e-βt), where y is Ⅵ at pulsing interval t, A reflects microvascular cross - sectional area (or myocardial blood volume), and βreflects mean myocardial microbubble velocity. The product of A·β represents MBF. MBF was also obtained by ra-diolabeled microsphere method servered as reference. MBF derived by radiolabeled microsphere - method in the regions of normal, ischemia and infarction was 1.5+0.3, 0.7+0.3, 0. 3+0. 2 mL @ min-1@ g-1 respectively. The product of A·β obtained by MCE in those regions was 52. 46±15. 09, 24. 36±3. 89, 3. 74 ±3. 80 respectively. There was good correlation between normalized MBF and the normalized A·β ( r = 0. 81, P=0. 001). Conclusions MCE has an ability to determine myocardial viability in myocardial infarction canine model.
文摘Our understanding of coronary syndromes has evolved in the last two decades out of the obstructive atherosclerosis of epicardial coronary arteries paradigm to include anatomo-functional abnormalities of coronary microcirculation. No current diagnostic technique allows direct visualization of coronary microcirculation,but functional assessments of this circulation are possible. This represents a challenge in cardiology. Myocardial contrast echocardiography(MCE) was a breakthrough in echocardiography several years ago that claimed the capability to detect myocardial perfusion abnormalities and quantify coronary blood flow. Research demonstrated that the integration of quantitative MCE and fractional flow reserve improved the definition of ischemic burden and the relative contribution of collaterals in non-critical coronary stenosis. MCE identified no-reflow and low-flow within and around myocardial infarction,respectively,and predicted the potential functional recovery of stunned myocardium using appropriate interventions. MCE exhibited diagnostic performances that were comparable to positron emission tomography in microvascular reserve and microvascular dysfunction in angina patients. Overall,MCE improved echocardiographic evaluations of ischemic heart disease in daily clinical practice,but the approval of regulatory authorities is lacking.
文摘Purpose: The aim of the present study was to evaluate the diagnostic accuracy for quantification of left ventricular (LV) volumes and LV ejection fraction (LVEF) with current echocardiographic methods of planimetry for analysis of LV remodeling after myocardial infarction in daily clinical routine. Methods: 26 patients were investigated directly after interventional therapy at hospital pre-discharge and at 6 month follow-up. Standardized 2D transthoracic native and contrast echocardiography were performed in all patients. Due to methodological aspects the results of LV volumes and LVEF using native echocardiography were compared to the results of LV opacification (LVO) imaging for analysis in mono-, bi- and triplane data sets using the Simpson’s rule. In addition corresponding multidimensional data sets were analyzed. Results: The assessment of LV volumes and LVEF is more accurate with contrast echocardiography. The comparison of LV volumes and LVEF shows significant increases using contrast echocardiography (p < 0.001). Larger left ventricular end-diastolic volumes (LVEDV) are measured at follow up (p < 0.05). Significant differences (p < 0.001) are found for the determination of LVEDV and LVEF relating to apical mono-, bi-, tri- and multiplane data sets. Standard deviations of the triplane approach, however, are significantly lower than using other modalities. Conclusion: Depending on the localization of the myocardial infarction LV volumes and LVEF are less reliably evaluated using the mono- or biplane approach. According to standardization and simultaneous acquisition of all LV wall segments the triplane approach is currently the best approach to determine LV systolic function. In addition, contrast echocardiography is indicated to improve endocardial border delineation in patients using the triplane or multiplane approach. To our knowledge the present study is the first systematic evaluation of all current possibilities for determination of LV volumes and LVEF by native and contrast echocardiography.
文摘Background Both real-time three-dimensional echocardi ography (RT3DE) and myocardial contrast echocardiography (MCE) are novel imaging techniques. The purpose of this study was to confirm the feasibility and accuracy of RT3DE combined with MCE for quantitative evaluation of myocardial perfusion defects. Methods Thirteen dogs underwent ligation of the left anterior descending artery (LAD, n=6) or distal branch of the left circumflex artery (LCX, n=7) under general anaesthesia. Three to four ml of a perfluoropropane (C 3F 8) microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defects with a commercially available Philips SONOS-7500 ultrasound system. After removal of the dog hearts, Evans blue dye was injected via the left and righ t coronary arteries to stain the myocardium at risk. In vitro anatomic measurements of myocardial mass after removal of the animals’ hearts were used as control s. Results Left ventricular (LV) mass determined by RT3DE ranged 36.7-68.9 g [mean, (54.6±9.6) g] before coronary artery ligation, and correlated highly (r=0.99) with in vitro measurement of LV mass [range, 38.9-71.1 g; mean, (55.6±9.3) g]. There was no significant difference between RT3DE and in vitro measurements of LV mass [range, 36.7-68.9 g; mean, (51.3±12.5) g. Or range, 38.9-71. 1 g; mean, (53.7±12.3) g, respectively] and under-perfused mass [range, 0-21.4 g; mean, (12.0±6.9) g. Or range, 0-19.8 g; mean, (10.8±6.3) g, respectively] after th e LAD ligation (P>0.05). Likewise, no significant difference was present between RT3DE and in vitro measurements of LV mass [range, 50.1-65.4 g; mean, (57.5±5.9 ) g. Or range, 51.5-65.8 g; mean, (57.3±6.4) g, respectively] and under-perfused m ass [range, 0-25.6 g; mean, (13.3±9.6) g. Or range, 0-22.7 g; mean, (12.8±8.1 ) g, respectively] after the LCX ligation (P>0.05). For all the animals with coronary ligation, LV mass measured by RT3DE ranged 35.9-68.6 g [mean, (54.8±10.0) g] a nd there was no significant difference between RT3DE and in vitro measurements of LV mass and under-perfused mass (P>0.05, r=0.99). Further, the under-perfused mass derived from RT3DE [range, 0-25.6 g; mean, (12.7±8.2) g] correlate d strongly with the in vitro measurements [range, 0-22.7 g; mean, (11.9±7.2) g] ( r=0.96). Conclusion RT3DE with MCE is a rapid and accurate method for estimating LV myocardial mass and quantifying perfusion defects.
文摘Background No-reflow is associated with an adverse outcome and higher mortality in patients with ST-segment elevation acute myocardial infarction （STEMI） who undergo percutaneous coronary intervention （PCI） and is considered a dynamic process characterized by multiple pathogenetic components. The aim of this study was to investigate the effectiveness of a combination therapy for the prevention of no-reflow in patient with acute myocardial infarction （AMI） undergoing primary PCI. Methods A total of 621 patients with STEMI who underwent emergency primary PCI were enrolled in this study. Patients with high risk of no-reflow （no-flow score 〉 10, by using a no-flow risk prediction model, n = 216） were randomly divided into a controlled group （n = 108） and a combination therapy group （n = 108）. Patients in the controlled group received conventional treatment, while patients in combination therapy group received high-dose （80 mg） atorvastatin pre-treatment, intracoronary administration of adenosine （140 ~tg/min per kilogram） during PCI procedure, platelet membrane glycoprotein lib/Ilia receptor antagonist （tirofiban, 101.tg/kg bolus followed by 0.15 ~tg/kg per minute） and thrombus aspiration. Myocardial contrast echocardiography was performed to assess the myocardial perfusion 72 h after PCI. Major adverse cardiac events （MACE） were followed up for six months. Results Incidence of no-reflow in combination therapy group was 2.8%, which was similar to that in low risk group 2.7% and was significantly lower than that in control group （35.2%, P 〈 0.01）. The myocardial perfusion （A= 13） values were higher in combination therapy group than that in control group 72 h after PCI. After 6 months, there were six （6.3%） MACE events （one death, two non-fatal MIs and three revasculafizations） in combination therapy group and 12 （13.2%） （four deaths, three non-fatal MIs and five revascularizations, P 〈 0.05） in control group. Conclusions Combination of thrombus aspiration, high-dose statin pre-treatment, intmcoronary administration of adenosine during PCI procedure and platelet membrane glycoprotein Ⅱ b/Ⅲa receptor antagonist reduces the incidence of no-reflow after primary PCI in patients with acute myocardial infarction who are at high risk of no-reflow.
基金supported by a grant from the National Key Basic Research Development Program,the“973”Program,No.2012CB518604the National Natural Science Foundation of China,No.81260052+1 种基金the Natural Science Foundation of Hubei Province,No.2014CKB497,2014BKB075,and 2015BKA339the Natural Science Foundation of Henan Province of China,No.201602262
文摘Sympathetic nerve and vagus nerve remodeling play an important part in cardiac function post-myocardial infarction （MI）. Increasing evidence indicates that neuregulin-1 （NRG-1） improves cardiac function following heart failure. Since its impact on cardiac function and neural remodeling post-MI is poorly understood, we aimed to investigate the role of NRG-1 in autonomic nervous system remodeling post-MI. Forty-five Sprague-Dawley rats were equally randomized into three groups： sham （with the left anterior descending coronary artery exposed but without ligation）, MI （left anterior descending coronary artery ligation）, and MI plus NRG-1 （left anterior descending coronary artery ligation followed by intraperitoneal injection of NRG-1 （10 lag/kg, once daily for 7 days））. At 4 weeks after MI, echocardi- ography was used to detect the rat cardiac function by measuring the left ventricular end-systolic inner diameter, left ventricular diastolic diameter, left ventricular end-systolic volume, left ventricular end-diastolic volume, left ventricular ejection fraction, and left ventricular fractional shortening, mRNA and protein expression levels of tyrosine hydroxylase, growth associated protein-43 （neuronal specific pro- tein）, nerve growth factor, choline acetyltransferase （vagus nerve marker）, and vesicular acetylcholine transporter （cardiac vagal nerve fiber marker） in ischemic myocardia were detected by real-time PCR and western blot assay to assess autonomous nervous remodeling. After MI, the rat cardiac function deteriorated significantly, and it was significantly improved after NRG-1 injection. Compared with the MI group, mRNA and protein levels of tyrosine hydroxylase and growth associated protein-43, as well as choline acetyltransferase mRNA level significantly decreased in the MI plus NRG-1 group, while mRNA and protein levels of nerve growth factor and vesicular acetylcholine transporters, as well as choline acetyltransferase protein level slightly decreased. Our results indicate that NRG- 1 can improve cardiac function and regulate sympathetic and vagus nerve remodeling post-MI, thus reaching a new balance of the autonomic nervous system to protect the heart from injury.
文摘Background Innovative advancements in ultrasound instrumentation present a number of imaging modalities for myocardial contrast echocardiography （MCE） in ischemic syndromes. How well they compare to each other in diagnostic accuracy in the detection of acute myocardial infarction is unclear. The purpose of this study was to assess the relative accuracy of 3 different imaging modes of MCE, low mechanical index （MI） real-time perfusion imaging （RTPI）, triggered harmonic angio mode （HA）, and ultraharmonic imaging mode （UH） in the detection of acute experimental myocardial infarction within the time frame suitable for potential reperfusion. Methods MCE was performed in 10 open-chest dogs using RTPI, triggered HA and triggered UH modes at baseline and one hour after occlusion of left anterior descending coronary artery. Presence or absence of peffusion defects, and the perfusion defect size when present, were analyzed and compared with the infarct size delineated by triphenyltetrazolium chloride （TTC） staining. Results The infarct area was （15.8-2.4）% by TTC staining; Peffusion defect area by MCE was similar to anatomic infarct area in all the three MCE approaches： （16.1-2.7）% by RTPI mode, （15.5-2.9）% by HA mode, and （15.5-3.0）% by UH mode. The sensitivity, specificity and overall diagnostic accuracy in the detection of myocardial infarction were 100%, 88%, and 94% for RTPI mode, 88%, 100%, and 94 % for HA mode, and 100%, 75%, and 88% for UH mode. Conclusion All modes of MCE, RTPI, triggered HA mode and triggered UH mode have excellent diagnostic accuracy in the immediate hour of acute coronary occlusion within the optimal time frame suitable for reperfusion therapy.
文摘Background Quantitatively assessing myocardial perfusion and its reserve is of great importance for the diagnosis and stratification of patients with coronary artery disease （ CAD）, and represents an important goal of myocardial contrast echocardiography. In this study we sought to test the usefulness of low dose dobutamine stress real-time myocardial contrast echocardiography （RT-MCE） in the assessment of CAD, and to explore the relationship between perfusion reserve and contractile reserve. Methods Twenty-six patients with suspected or clinical diagnosed CAD were enrolled and underwent RT-MCE at baseline and under low dose dobutamine stress, and subsequent coronary angiography. RT-MCE images were analyzed quantitatively from microbubble replenishment curves for myocardial perfusion and its reserve. Results At baseline, significant differences in beta （0.28± 0. 12, 0. 25± 0. 09, 0.22 ± 0. 06, 0. 20± 0.07 respectively, P 〈0. 01） and A x beta （1.37 ±0. 46, 1.28±0. 47, 1. 13 ±0. 37, 0.91±0. 32, respectively, P 〈0. 01 ） were observed among four segment groups with graded coronary artery stenosis severity （normal; 30% -69% stenosis; 70% -90% stenosis; and beyond 90% stenosis） , but not observed in parameter A. When under stress, significant differences in A （5.73 ± 1.28, 5.63 ± 1.01,4.96 ±0.81,4.57 _＋0.62, respectively, P〈0.01）, beta （0.67 ±0. 17, 0.55 ±0. 19, 0.32 ±0. 13, 0.25 ±0.08, respectively, P 〈0.01） and A x beta （3.81 ± 1.20, 3. 11±1.17, 1.59 ±0. 82, 1. 12 _＋0. 37, respectively, P 〈0. 01 ） were observed among the formerly mentioned groups. Graded decreases in A reserve （ 1.20 ±0. 53, 1.11 ±0. 16, 0.98 ±0. 12, 0. 99 ±0.13, respectively, P〈0.01）, beta reserve （2.65 ±1.07, 2. 32±0.82, 1.44±0.40, 1.29±0.34, respectively, P〈0.01） and A xbeta reserve （3.05 ± 1.63, 2.59 ±1.01, 1.42 ±0.44, 1.27±0.34, respectively, P 〈 0. 01 ） could also be observed with increasing coronary stenosis severity. In five segments groups scored by WMS （ 1 - 5 ） , concordance between contractile function and myocardial perfusion could be found both at rest （beta： 0.28±0. 11, 0. 22 ±0. 08, 0. 21 ±0.05, 0. 17 ±0.05,0. 19 ±0.06, respectively, P 〈0.01; A xbeta： 1.29 ±0.48, 0.98 ±0.45, 0.94±0.29, 0.76 ±0.30, 0.92 ±0.32, respectively, P〈 0.01） and under stress （beta： 0.59 ±0.20, 0.35 ±0.15, 0.27 ±0.08, 0. 17±0.05, 0.20±0.05, respectively, P〈0.01; A xbeta： 3.07 ±1.38, 1.62±0.82, 1.28 ±0.40, 0.78 ±0.24, 0.93 v0.22, respectively, P 〈0. 01 ）. This concordance is also valid in terms of the reserves, and the MCE parameters in segments with ameliorated contractile function are significantly higher than in those without. Conclusions Quantitative RT-MCE in conjunction with dobutamine stress shows promise in identifying and stratifying CAD and in exploring the perfusion-contractile correlation.
文摘Background Time-intensity curves derived from microbubble destruction/refilling sequences and recorded using myocardial contrast echocardiography (MCE) can provide parameters that correlate with coronary blood flow. The response of these parameters to adenosine vasodilatation correlates with coronary flow reserve (CFR) measured by fluorescent microsphere techniques (FMT). Currently, no data exist regarding the effect of physiological variables, such as hypoxia, on the determination of CFR by MCE. The purpose of this study was to define the effects of decreases in blood partial pressure of oxygen (PO_2) on CFR as measured by MCE. Methods Studies were performed in 9 closed chest swine. Low-energy, real-time MCE was performed with commercial instruments in short axis view at papillary muscle level while infusing BR_1 at 30 ml/h. High-energy ultrasound bursts (referred to as FLASH frames) destroyed the bubbles every 15 cardiac cycles, and resultant time-intensity curves derived from these sequences were fitted to the exponential function y = A (1-e -bt) +c, from which the rate of signal rise (b) was obtained. CFR was calculated as the ratio of b values after adenosine infusion to baseline and was obtained during the control period and after decreasing blood PO_2 by giving nitrogen via a respirator to create artificial hypoxic conditions. CFR was independently determined by FMT. Results Nitrogen led to significant decreases in mean PO_2, from (120.6±18.9) mmHg to (51.8±15.9) mmHg (P<0.01). Adenosine produced a similar increase in CFR (2.5 fold vs 3.1 fold) as assessed by MCE and FMT during the control period. The decrease in PO_2 post nitrogen resulted in a slight increase in values at rest: 0.46±0.15 to 0.53±0.18 for b and (1.39±0.66) ml·min -1·g -1 to (1.72±0.30) ml·min -1·g -1 for myocardial blood flow (MBF) (both P<0.05). In addition, values decreased in response to adenosine using both techniques: 1.05±0.35 to 0.82±0.27 for b and (4.30±3.16) ml·min -1·g -1 to (3.93±1.27) ml·min -1·g -1 for MBF (both P<0.05). Thus, CFR was markedly reduced under hypoxic conditions, to 1.4 by MCE (P<0.05 compared with the baseline), and to 2.5 by FMT (P>05 compared with the baseline). Conclusions CFR values diminish under hypoxic conditions according to both MCE and FMT. The reductions in CFR involve both an increase in resting values and a decrease in post adenosine measurements, as determined by both techniques. The reduction in CFR under hypoxia is slightly greater using MCE than using FMT. Physiological variables, such as hypoxia, must be taken into consideration when assessing CFR by MCE.
