实时心肌声学造影对冠心病患者心肌灌注的定量评价

目的探讨实时心肌声学造影(RTMCE)定量分析冠心病患者心肌血流量的临床应用价值。方法对20例冠脉造影左前降支冠脉狭窄>75%以上的冠心病患者(观察组)和20例健康体检者(对照组)行静息状态下RTMCE检查,同时应用超声心动图检测造影剂峰值密度(A)、心肌血流速率(β)、心肌血流量(MBF,MBF=A×β)、左室舒张末期内径(LVEDD)、左室收缩末期内径(LVESD)、射血分数(EF)、舒张早期峰值血流速度(Emax)、舒张晚期峰值血流速度(Amax)。比较两组相应节段的心肌灌注情况和心脏功能。结果观察组β及MFB均显著低于对照组(P均<0.01),LVEDD、LVSED、EF、Emax、Amax、Emax/Amax、Dt等两组比较无明显差异。结论冠心病患者心肌血流速度减慢,存在心肌微循环损伤;RIMCE可定量评价缺血心肌的血流灌注状况。     

Quantifying myocardial perfusion using contrast echocardiography

There is a complex relation between what can be seen using perfusion imaging techniques, and what can be measured.     

Evaluation of regional myocardial function in ischemic heart disease by echocardiography

Echocardiography can display motion abnormalities of acutely or chronically ischemic myocardium. In experimental studies, this permits the evaluation of the effect on regional dyskinesis of potentially therapeutic interventions. In clinical studies, the demonstration of segmental dyskinesis has been primarily useful for diagnostic purposes. As more experience is gained with the newer two-dimensional cross-sectional ultrasound techniques, it appears likely that these will afford a major advance in the diagnosis of ischemic heart disease by permitting the routine noninvasive demonstration of segmental ventricular dyskinesis and assessment of regional myocardial function.     

Changes in myocardial perfusion in ischemic heart disease as affected by nitrong

The effect of nitrong on myocardial perfusion in patients with ischemic heart disease was studied by a new method of myocardial perfusion scintigraphy usingd 201Tl. Myocardial scintigraphy with 201Tl, as an informative and atraumatic method, may be used for objective appraisal of the effect of antianginal agents. It is shown that in comparison to a placebo, nitrong causes a favourable effect on perfusion of the myocardium in patients with ischemic heart disease both at rest and under conditions of increased myocardial blood flow induced by physical exercise.     

Detection of resting myocardial perfusion defects by SonoVue myocardial contrast echocardiography

BACKGROUND: SonoVue is a new microbubble contrast agent containing sulfur hexafluoride. We assessed the efficacy of SonoVue myocardial contrast echocardiography (MCE) to detect resting perfusion abnormalities. Methods: Nineteen adult patients with a wall motion abnormality in a screening echocardiogram were studied. Each patient received up to four bolus injections of 2.0 mL SonoVue (Bracco Diagnostics, Inc.) during echocardiographic examination using either B-mode(n = 12)or power Doppler(n = 7)imaging. Each patient also had SPECT nuclear perfusion imaging performed. Segmental assessment of myocardial perfusion from SonoVue MCE images were compared with corresponding SPECT nuclear images. RESULTS: Using B-mode imaging, the mean number of views obtained with a single SonoVue injection ranged from 1.4 to 1.9, with 2 or 3 injections required for a complete examination. Ninety-four percent of segments were scored as diagnostic. Agreement between B-mode and SPECT images was 72% for segments with a perfusion defect, 86% for normal perfusion, and 80% for segments with either perfusion defect or normal perfusion (all views combined). Using power Doppler imaging, the mean number of views obtained with a single SonoVue injection ranged from 1.0 to 1.3, with 2 to 4 injections required for a complete examination. Sixty-eight percent of segments were scored as diagnostic. Agreement between power Doppler and SPECT images was 67% for perfusion defects, 53% for segments with normal perfusion, and 59% for segments with either perfusion defect or normal perfusion (all views combined). CONCLUSIONS: SonoVue MCE has the potential to assess myocardial perfusion at rest. B-mode imaging was more accurate than power Doppler imaging when compared with SPECT nuclear imaging.     

Intraoperative cardioplegic contrast echocardiography for assessing myocardial perfusion during open heart surgery

Aortic root hypothermic, hyperkalemic cardioplegic perfusion has been shown to preserve ventricular function during open heart surgery. However, significant coronary artery stenoses may prevent adequate perfusion of myocardial regions distal to the lesions, leading to intraoperative ischemia and damage. The purpose of this study was to evaluate for the first time in human patients the use of intraoperative contrast cardioplegic echocardiography for identifying potentially jeopardized myocardial regions as defined by cardiac catheterization. Forty-two patients, 23 men and 19 women, aged 28 to 83 years (mean 56.7 +/- 2), who had undergone cardiac catheterization and coronary arteriography, underwent open heart surgery; 30 had coronary artery disease. Echocardiograms of the left ventricle, performed on the open heart in the papillary muscle short-axis plane during routine aortic root cardioplegia were divided into three regions according to the coronary anatomy: septal (left anterior descending artery), anterolateral (left circumflex) and inferoposterior (right coronary artery). Intraoperatively, myocardial segments at greatest potential ischemic risk were identified by several findings alone or in combination: lack of spontaneous contrast and delayed whiting out or persistent fine fibrillation. The ability of intraoperative echographic interpretation to identify high risk segments based on preoperative catheterization findings was excellent. Thus, the sensitivity of cardioplegic contrast echocardiography for predicting significant (greater than 70% stenosis) coronary lesions was 96, 100 and 58% for left anterior descending, left circumflex and right coronary artery regions, respectively. Specificity was 94, 78 and 100% for anterior descending, circumflex and right coronary artery regions, respectively. Overall sensitivity and specificity for all regions was 82 and 92%, respectively. Importantly, the echocardiogram was most helpful in observing septal region perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coronary collaterals assessed with myocardial contrast echocardiography in healed myocardial infarction

The epicardial coronary collateral vessels are visualized with coronary angiography, but this method does not provide significant information about the myocardial perfusion supplied with the collaterals. In this study, myocardial contrast echocardiography (MCE) was performed to assess the coronary collaterals in 29 patients with old myocardial infarction. MCE was performed by intracoronary injection of 2 ml agitated amidotrizoate sodium meglumine. The peak background-subtracted gray level (PGL) in the infarct area was determined from the digitized echocardiographic images obtained before and after injection into the noninfarct and donor artery. PGL was compared with the 3-point coronary angiographic grades of collaterals. PGL in the infarct area was significantly lower in patients with poor collaterals than in patients with moderate to good collaterals (5 +/- 4 vs 18 +/- 8 U mean +/- standard deviation, p less than 0.01). PGL in the infarct area was less than 10 U in the 3 patients with severe asynergy despite the moderate to good collateral supply, suggesting that activity of the collaterals was not good enough to preserve the wall motion effectively. It is concluded that (1) the degree of MCE enhancement in the infarct area generally corresponded to the collateral grades assessed with coronary angiography, and (2) MCE may provide a measure of the collateral perfusion.     

Potential clinical applications of myocardial contrast echocardiography in evaluating myocardial perfusion in coronary artery disease

Myocardial contrast echocardiography (MCE) is a relatively new technique that uses microbubbles to produce myocardial opacification. Recent advances in echocardiography have resulted in improved detection of microbubbles within the myocardium allowing combined acquisition of function and perfusion data, thus making MCE suitable for bedside use. Regardless of the imaging modality chosen or the type of stress used, MCE detects changes developing in the coronary microcirculation, providing important information for the evaluation of severity of coronary artery disease and for the detection of viable myocardial tissue in acute or chronic coronary artery disease.     

Residual myocardial perfusion in reversibly damaged myocardium by dipyridamole contrast echocardiography

In patients with previous myocardial infarction and left ventricularasynergy, dipyridamole infusion may have the capacity to unmaskmyocardial viability through transient recovery of contractilefunction in asynergic segments. The purpose of this study wasto assess simultaneous changes in myocardial perfusion and LVfunction—elicited by dipyridamole infusion—in infarcted,asynergic segments. The echo contrast agent Albunex was injectedinto the left coronary artery of 19 patients (17 males, age49–70 years) with previous myocardial infarction and baselineleft ventricular asynergy, both before and after dipyridamoleinfusion (up to 0·56 mg. kg^–1, i.v.). Analysiswas not possible in three patients due to inadequate image qualityand in two due to weak contrast. There were no major adverseevents, or changes in vital signs or demonstrated on the electrocardiogram.After dipyridamole, 7/14 patients, showed an improvement inregional function of asynergic segments (‘responders’),whereas seven patients did not (‘non-responders’).Among non-responders, five had a myocardial perfusion deficitcorresponding to 41% of the total left ventricular area beforedipyridamole and to 38% after dipyridamole. No baseline perfusiondeficits were observed in the remaining two non-responders;one of these, however, developed transient asynergy and perfusiondeficit after dipyridamole. Among responders, five showed anormal perfusion pattern, both before and after dipyridamole,while the remaining two showed a perfusion deficit which markedlydecreased after dipyndamole (from 32% to 13% of total left ventriculararea). Thus, residual contractile reserve of asynergic, infarctedventricular segments appears to be associated with myocardialperfusion either preserved at baseline or recruitable by a coronarydilator stimulus.     

Collateral vessels assessed by myocardial contrast echocardiography in patients with coronary artery lesions after Kawasaki disease

Summary Using myocardial contrast echocardiography (MCE), coronary arteriography, and thallium-201 myocardial imaging (TMI), we examined the characteristics and the role of collateral vessels in 35 patients with coronary artery lesions after Kawasaki disease. The male/female ratio was 25∶10. The patients' ages at examination ranged from 1.0 to 20.3 years (mean, 10.8 years). The age at onset of Kawasaki disease ranged from 0.3 to 11.6 years (mean, 2.6 years). The coronary artery lesions were: dilated lesions without coexistent stenotic lesions in 5 patients (14%), localized stenosis with less than 50% narrowing in 5 patients (14%), localized stenosis with 50% or more narrowing in 4 patients (11%), and obstructive lesions, such as occlusion and/or segmental stenosis, in 21 patients (60%). In the group with no stenotic lesions and the group with less than 50% localized stenosis, the perfusion area of the right coronary artery was 32.6±8.4% and that of the left coronary artery was 76.3±7.9%. The total perfusion area of the right and the left coronary arteries was 108.9±2.6%, which value was inversely correlated with age at examination (r=0.716,P=0.020). In the group with more than 50% localized stenosis, an increase in overlap areas detected by MCE, where a perfusion defect was seen on TMI, was not found, except in 1 patient with 99% stenosis. In the patients with obstructive lesions, development of collateral channels was better in the perfusion area of the occluded right coronary artery than in that of the occluded left coronary artery, and well developed collateral channels were significantly correlated with good wall motion. We conclude that overlapping perfusion occurs in younger rather than in older children without stenotic coronary systems and this may contribute to the good development of collateral circulation in infants and young children with coronary artery lesions after Kawasaki disease.     

Intraoperative assessment of myocardial perfusion using contrast echocardiography

Myocardial contrast echocardiography is a new technique capable of assessing regional myocardial perfusion in vivo in real time. This article reviews the background, principles, experimental validation, and clinical uses of intraoperative myocardial contrast echocardiography. Data can be derived both for online visual and computer analyses. The technique can be useful in determining the sequence of bypass graft placement and the success of graft anastamoses. Anastamoses can be revised immediately if needed. It is hoped that this technique will improve intraoperative myocardial preservation and will diminish the rate of perioperative myocardial infarction.     

超声心肌声学造影评价冠状动脉狭窄程度对心肌灌注的影响

目的经冠状动脉超声心肌声学造影(MCE)检测基础状态下不同狭窄程度冠状动脉所供应心肌组织灌注状况。方法30例患者行选择性冠状动脉造影,按有无冠状动脉病变及病变血管狭窄程度,将所涉及的共93个心肌节段分为对照组(18个)和病变组(75个),其中病变组又分为轻度狭窄组(12个)、中度狭窄组(28个)、重度狭窄组(35个);超声声学造影剂由冠状动脉直接注入,完成MCE。对心肌灌注进行定性分析,并由心肌灌注时间强度曲线进行定量分析。结果112个心肌节段中有93个(83.0%)获得较满意图像,经视觉判断,病变组共75个心肌节段中,正常灌注的为58个(77.3%),低灌注为17个(22.7%),其中,轻度狭窄组均为正常心肌灌注。定量分析显示,重度狭窄组反映心肌灌注的3个参数值与对照组均存在明显差异(P<0.05);而轻、中度狭窄组各参数值与对照组无明显差异。结论基础状态下,狭窄程度>90%的冠状动脉病变,其心肌组织灌注水平较正常偏低;而当血管狭窄程度≤90%时,心肌灌注水平与正常相似。     

Diagnosis of ischaemic heart disease by myocardial contrast echocardiography during supine bicycle stress

INTRODUCTION: Myocardial contrast echocardiography (MCE) is a new imaging modality for diagnosing ischaemic heart disease (IHD). AIM: The aim of this study was to assess 1) the feasibility of MCE during supine bicycle stress and 2) the value of this method in the diagnosis of IHD. METHODS: Supine bicycle stress was performed in 44 consecutive patients (pts) referred for coronary angiography with an intermediate pre-test probability of IHD. MCE was carried out at peak stress and during recovery (once the heart rate returned to the pre-exercise value). During MCE an ultrasound contrast agent (Sonovue) was administered intravenously in a continuous mode using an infusion pump (BR-INF 100, Bracco Research). The acquired images were qualitatively assessed for perfusion and wall motion abnormalities. The 18-segment division of the left ventricle was used in the analysis. Coronary angiography was performed in all pts within 15 days of the exercise test. A quantitative analysis of coronary artery stenoses was carried out using the CAAS system. RESULTS: MCE could not be performed in 2 pts due to technical difficulties. Coronary angiography revealed significant coronary artery stenosis in 25 pts. The sensitivity and specificity of MCE in the diagnosis of IHD were 92.0% and 82.4%, respectively. The positive and negative predictive values were found to be 88.5% and 87.5%, respectively, while the agreement between coronary angiography and MCE was 88.1% (kappa=0.75). CONCLUSIONS: MCE during supine bicycle stress and continuous intravenous administration of an ultrasound contrast agent is a feasible technique and allows accurate diagnosis of IHD in pts in whom the pre-test probability of the disease is intermediate.     

Myocardial perfusion assessed by contrast echocardiography correlates with angiographic perfusion parameters in patients with a first acute myocardial infarction successfully treated with angioplasty

BACKGROUND:

Angiographic flow in an epicardial artery does not define perfusion at the microvascular level.

AIM:

To compare myocardial contrast echocardiography (MCE) with angiographic methods of assessing microvascular reperfusion in patients with acute myocardial infarction (AMI).

METHODS:

One hundred consecutive patients with a first ST segment elevation myocardial infarction and single-vessel disease were successfully treated with primary percutaneous coronary intervention. Regional contrast score index (RCSI), corrected Thrombolysis In Myocardial Infarction (TIMI) frame count (cTFC), TIMI myocardial perfusion grade (TMPG) and myocardial blush grade were evaluated.

RESULTS:

Among 717 asynergic segments on MCE, 168 revealed a lack of perfusion. TMPG and cTFC correlated significantly with RCSI (P=0.031 and P=0.027, respectively). Myocardial blush grade did not correlate with RCSI (P=0.067). Patients with anterior AMI had significantly more segments with a perfusion defect on MCE than patients with inferior AMI (P=0.0001).

CONCLUSIONS:

MCE results correlate with angiographic methods of perfusion assessment such as TMPG and cTFC. Anterior AMI is associated with a greater extent of perfusion defect. MCE results correlate also with recovery of systolic left ventricular function and clinical outcome at six month follow-up.     

Assessment of myocardial viability by dobutamine stress echocardiography in patients with ischemic heart disease

Detection of viable (hibernating) myocardium is necessary for determination of prognosis and tactics of treatment of patients with ischemic heart disease. For detection of viable myocardium and investigation of possibilities of its restoration 60 patients with ischemic heart disease (54 men, mean age 52+/-8 years) were examined before coronary artery bypass grafting or coronary angioplasty. Presence of viable myocardium was characteristic for patients with multivessel coronary artery disease (83%) with stenoses >90%, with well developed collateral circulation (81%). Sustained restoration of contractility of hibernating segments for 1 year after revascularization was noted in 70% of cases. Dobutamine stress echocardiography was found to have high diagnostic potential for detection of viable myocardium.     

New imaging technology: measurement of myocardial perfusion by contrast echocardiography

Myocardial perfusion imaging has long been a goal for the non-invasive echocardiographic assessment of the heart. However, many factors at play in perfusion imaging have made this goal elusive. Harmonic imaging and triggered imaging with newer contrast agents have made myocardial perfusion imaging potentially practical in the very near future. The application of indicator dilution theory to the coronary circulation and bubble contrast agents is fraught with complexities and sources of error. Therefore, quantification of myocardial perfusion by non-invasive echocardiographic imaging requires further investigation in order to make this technique clinically viable.     

Evaluation of transmural myocardial perfusion by ultra-harmonic myocardial contrast echocardiography in reperfused acute myocardial infarction.

BACKGROUND: The transmural distribution of myocardial perfusion is important for predicting the contractile reverse of an infarcted wall in reperfused acute myocardial infarction (AMI). Evaluating transmural myocardial perfusion by myocardial contrast echocardiography (MCE) could predict the long-term recovery of left ventricular (LV) function. METHODS AND RESULTS: The study group comprised 20 consecutive patients with a first-episode anterior AMI with total occlusion of the proximal left anterior descending artery, who underwent successful percutaneous coronary intervention within 24 h of onset. MCE was performed on the 15th day after the onset, using ultraharmonic gray-scale imaging with intermittent end-systolic triggering every 4 beats or every 6 beats. Regions of interest were placed over both the endocardial and epicardial region at the mid-septal level. Regional wall motion (RWM) of the infarcted anterior wall and global LV function were assessed by 2-dimensional echocardiography and left ventriculography in both the acute and chronic phase. The transmural distribution of myocardial perfusion by MCE demonstrated a significant relation with RWM score index (r = 0.75, p = 0.0004). Recovery of RWM and LV ejection fraction (LVEF) at 6 months after reperfusion was significantly greater in the group with good perfusion of the epicardium according to MCE than in the poor perfusion group [RWM (SD/cord); -1.23+/-0.91 vs -3.51+/-0.84, p = 0.001, LVEF (%); 63.8+/-10.4 vs 47.0+/-3.4, p = 0.04]. CONCLUSIONS: Assessing the transmural distribution of myocardial perfusion by MCE can predict the long-term recovery of LV function after a reperfused AMI.