小剂量多巴酚丁胺超声心动图联合心肌声学造影对心肌梗死后存活心肌的诊断价值

目的前瞻性评价小剂量多巴酚丁胺超声心动图(LDDE)联合心肌声学造影(MCE)对心肌梗死后存活心肌的诊断价值。方法对24例心肌梗死者进行静态MCE、LDDE及3个月后静态超声心动图随访分析。MCE和室壁运动均用16段划分法进行目测半定量计分。心肌造影计分(MCS)回声均匀性增强为1分,回声低淡不均匀为0.5分,缺损为0分。室壁运动计分(WMS)用常规计分法。结果随访时,运动改善的心肌节段中MCS1分占49.4%、0.5分占50.6%,对LDDE均有反应;运动无改善的节段MCS0.5分占9.5%,0分占90.5%,对LDDE有反应者占13.3%,无反应占86.7%。预测存活心肌的敏感性、特异性及准确率分别为LDDE86%、86.7%、86.4%;MCE100%、89.7%、94.6%;LDDE联合MCE86.1%、100%、94.0%。结论心肌微血管结构与功能的完善是心肌存活的基本条件。MCE灌注正常和低灌注,且对多巴酚丁胺有反应的心肌有收缩力储备;而对多巴酚丁胺无反应的低灌注或无灌注心肌则多不能恢复收缩功能。LDDE联合MCE能提高检测存活心肌的特异性及准确率。     

超声心肌声学造影对存活心肌的评价及临床意义

超声心肌声学造影为一种诊断心肌组织水平灌注的新型超声技术,可从微循环完整性的角度评价存活心肌。存活心肌的识别对冠状动脉粥样硬化性心脏病患者选择积极、合理的治疗方案、评估疗效及预后有重要临床价值。本文就该技术对存活心肌的评价及临床意义作一综述。     

经静脉心肌声学造影剂的研制

目的 :制备可经静脉注射产生心肌对比增强效果的声学对比造影剂 ,观察其心肌显影效果。方法 :1按不同比例将 5 0 g· L- 1 葡萄糖或 9g· L- 1 Na Cl,C3 F8气体与人血白蛋白混合后进行超声振荡。 Coulter’ s计数器对造影剂进行质量分析。 2经犬股静脉注射自制对比造影剂 0 .2 ml,经胸壁扫查犬左室乳头肌水平短轴切面。结果 :1造影剂微泡液的相对浓度为 4 .2 3 9× 10 9/m l,微泡平均直径 3 .789μm,小于 9.89μm微泡占 99.5 %。 2经静脉注射后 ,均产生不同程度的心肌对比增强效果 ,心肌显影持续时间 1～ 3 min。注射前后犬血流动力学无显著性改变。结论 :自制经静脉注射对比造影剂符合心肌声学造影的要求 ;初步动物实验表明经静脉注射可产生肉眼可辨的心肌显影 ;反复注射无明显血流动力学改变     

实时三维斑点追踪成像结合实时心肌声学造影预测心肌梗死后患者心肌存活性的临床研究

摘要 目的 探讨实时三维斑点追踪成像技术（RT-3D-STI）结合实时心肌声学造影（RT-MCE）技术评价心肌梗死后患者心肌存活性的临床应用价值。方法 选取 25 例根据心电图、心肌酶学及冠脉造影确诊,且成功进行冠状动脉血运重建术的心肌梗死患者。所有患者于术前 1 周内行 RT-MCE 检查,对心肌灌注结果进行半定量评价;分别于术前及术后 6 个月行二维超声分析左室各节段心肌进行室壁运动,根据术后室壁运动是否改善将室壁运动异常的心肌节段分为两组：存活心肌组和非存活心肌组;同时行 RT-3D-STI 技术测得左室心肌整体及各节段三维峰值长轴应变 (3D-LPS) 、环向应变 (3D-CPS) 、面积应变 (3D-APS) 及径向应变 (3D-RPS) 参数指标。结果 血运重建术前,存活心肌组 3D-PLS、3D-PAS、3D-PCS、3D-PRS 明显高于无存活心肌组（P <0.05）;单参数 ROC 曲线分析结果显示,静息状态下,以术前 3D-PAS ≤ -16.5% 作为截断值判断心肌梗死后存活心肌的 AUC 为 0.944,敏感性为 91.3%,特异性为 93.8%,明显高于其它应变值;多参数联合分析结果显示,三维应变参数联合判断心肌梗死后存活心肌的 AUC 为 0.969,灵敏度及特异度分别为 95.7%、 90.6%。血运重建术前,RT-MCE 评价存活心肌的敏感度及特异度分别为 93.1％、 68.8％,一致性分析得出 Kappa 值为0.645。结论 在静息状态下, RT-3D-STI 技术预测心肌梗死后心肌的存活性地价值高于 RT-MCE 技术,其中三维应变参数以 3D-PAS ≤ -16.5% 作为截断值判断心肌梗死后心肌存活性的价值最高,且两种技术联合应用能更好地评价心肌存活性。     

小剂量腺苷超声心动图试验检测急性心肌梗死后患者存活心肌

目的 评价小剂量腺苷超声心动图试验(LDAE)对急性心肌梗死早期存活心肌检出的准确性.方法 对36例急性心肌梗死患者于发病后3～10 d行剂量递增的LDAE(腺苷80、100和110μg·kg-1·min),所有患者在LDAE前后接受经皮冠状动脉介入术.采用17节段半定量分析法分析二维超声图像.心肌梗死后2～3个月随访二维超声,以局部室壁运动改善作为心肌存活标准,评价LDAE检测存活心肌的敏感性、特异性和小剂量腺苷对血液动力学的影响.结果 腺苷110μg·kg·min时与用药前比较,心率轻度增快[(78.1±10.9)次/min比(70.7±10.8)次/min,P<0.01],左室收缩末期容积减小[(20.1±9.3)ml比(30.4±1.9)ml,P<0.01]和射血分数升高(74.7%±9.8%比62.6%±10.4%,P<0.01).腺苷不良反应总发生率38.9%(14/36),但症状轻微.LDAE检出存活心肌的敏感性、特异性、诊断准确性、阳性预测值和阴性预测值分别为90.3%、80.8%、86.0%、84.8%和87.5%.腺苷剂量100μg·kg·min时敏感性(88.5%)和特异性(86.0%)好而不良反应无明显增加.结论 LDAE是检测急性心肌梗死后患者存活心肌的较好而安全的新方法 ,有较高的敏感性和特异性,腺苷剂量100μg·kg·min可作为LDAE进一步研究的推荐剂量.     

用心脏超声技术检测心肌存活性的研究进展

近年来对冠心病存活心肌的研究已成为国内外研究的热点 ,随着新一代超声造影剂及许多超声新技术的涌现 ,使得超声心动图在检测心肌存活性方面具有独到的优势     

心肌声学造影在肥厚型梗阻性心肌病化学消融中的作用

目的探讨心肌灌注声学造影（Myocardial Contrast Echocardiography,MCE）技术在肥厚型梗阻性心肌病（Hypertrophic Obstructive Cardiomyopathy,HOCM）经皮导管肥厚室间隔化学消融术（Pereutaneous Transluminal Septal Myocardial Ablation,PTSMA）中的应用价值。方法对109例HOCM患者在PTSMA术中向拟订靶血管远端注入声学造影剂后即刻观察造影剂显影范围,选择靶血管,判断预后效果,以及制定治疗方案。结果109例HOCM患者于PTSMA术中全部施行MCE检查,101例MCE技术判断适于PTSMA术,术后无并发症,左室流血道压力阶差（Left ventrieular outcome tract pressure gradients,LVOTPG）由术前78．0±30．7mmHg降至术后即刻37．4±30．0mmHg（p〈0．001）、术后6月随访进一步下降至33．3±23．4mmHg（p〈0．001）,差异有明显统计学意义。8例患者压力阶差下降不明显,症状无改善,于术后或直接行外科Morrow手术。结论MCE技术可在PTSMA术中判断远期疗效,判定正确的靶血管,避免严重的并发症、个性化制定治疗方案等方面起到关键的作用。     

小剂量腺苷负荷超声心动图试验与双核素心肌显像检测急性心肌梗死后患者存活心肌比较

目的:比较小剂量腺苷负荷超声心动图试验(LDASE)与99mTc-甲氧基异丁腈(MIBI)/18F-脱氧葡萄糖(FDG)双核素同时采集法(DISA)单光子发射断层显像(SPECT)对急性心肌梗死(AMI)患者早期存活心肌检出的准确性.方法:对36例AMI患者于发病后3～10 d内行LDASE与DISA-SPECT.所有患者在LDASE前后接受经皮冠状动脉介入治疗术.AMI后3个月随访二维超声心动图,以局部室壁运动改善作为心肌存活的金标准,比较2种方法检测存活心肌的敏感性和特异性.结果:LDASE检出存活心肌敏感性为90.3%,特异性为80.8%,阳性预测值与阴性预测值分别为84.8%和87.5%,准确性为86.0%;DISA-SPECT检出存活心肌敏感性81.2%,特异性78.3%,阳性预测值81.1%,阴性预测值83.1%,准确性80.2%.2种方法对运动异常节段存活心肌检出一致性为72.6%,差异无统计学意义.结论:对AMI后患者,LDASE与DISA-SPECT均为检出存活心肌较敏感和特异的技术.     

心肌造影负荷超声心动图研究进展

心肌造影负荷超声心动图将心肌造影与负荷超声相结合,通过检测心肌微循环完整性和心肌血流灌注情况,为临床上冠心病的评价提供了一种简便、可靠、准确的新方法。现就心肌造影负荷超声心动图研究与应用现状作一综述。     

心肌声学造影定量心肌血流判断存活心肌的实验研究

目的　评价经静脉心肌声学造影 (MCE)判断存活心肌的可行性。方法　建立急性心肌梗死犬模型 ,经外周静脉持续滴注微泡造影剂 ,通过计算A·β值测定心肌相对血流量。以放射性微球法测定的心肌血流量 (MBF)为标准 ,了解A·β值测定MBF的准确性。通过A·β值估测心肌存活与否 ,病理检查验证其可靠性。结果　放射性微球法所测的正常区、缺血区、坏死区的MBF分别为 ( 1 5± 0 3)、( 0 7± 0 3)、( 0 3± 0 2 )ml·min-1·g-1;MCE测得的A·β值分别为 5 2 46± 15 0 9、2 4 36±3 89、3 74± 3 80 ;正常区、缺血区、坏死区的MBF和A·β值“标化”后分别为 1 0± 0 0、0 44± 0 17、0 17± 0 11和 1 0± 0 0、0 48± 0 0 9、0 0 7± 0 0 8,二者的相关性良好 (r=0 81,P =0 0 0 1)。MCE对坏死心肌的判定结果与病理结果吻合。结论　心肌声学造影可用于活体状态下评价存活心肌 ,“标化”后的A·β值 <0 2 3提示心肌坏死。     

Assessment of myocardial viability using myocardial contrast echocardiography

Myocardial contrast echocardiography (MCE) is a technique that uses microbubbles as a tracer during simultaneous ultrasound of the heart. The microbubbles can be used to provide quantitative information regarding the adequacy of myocardial blood flow (MBF), as well as the spatial extent of microvascular integrity. In acute myocardial infarction, MCE can identify the presence of collateral flow within the risk area, and can therefore predict preservation of myocardial viability and ultimate infarct size even prior to reperfusion. After reperfusion, the extent of microvascular no-reflow can be determined, and has significant implications for recovery of left ventricular function. In chronic ischemic heart disease, MCE has also been shown to successfully differentiate viable from necrotic myocardium. This technique can accurately predict recovery of function after revascularization. More importantly, MCE can be used to identify viable segments that may help to prevent infarct expansion and remodeling, and thus improve patient outcomes.     

Serial evaluation of perfusion defects in patients with a first acute myocardial infarction referred for primary PTCA using intravenous myocardial contrast echocardiography.

AIMS: To investigate whether myocardial contrast echocardiography using Sonazoid could be used for the serial evaluation of the presence and extent of myocardial perfusion defects in patients with a first acute myocardial infarction treated with primary PTCA, and specifically, (1) to evaluate safety and efficacy of myocardial contrast echocardiography to detect TIMI flow grade 0--2, (2) to evaluate the success of reperfusion and (3) to predict left ventricular recovery after 4 weeks follow-up. METHODS AND RESULTS: Fifty-nine patients underwent serial myocardial contrast echocardiography, immediately before primary PTCA (MCE1), 1 h (MCE2) and 12--24 h after PTCA (MCE3). A perfusion defect was observed in 21 of 24 patients (88%) with anterior acute myocardial infarction. All but one had TIMI flow grade 0--2 prior to PTCA. Nine of 31 patients (29%) with inferior acute myocardial infarction showed a perfusion defect and all had TIMI flow grade 0-2 prior to PTCA. Restoration of TIMI flow grade 3 was achieved in 73% of the patients by primary PTCA. A reduction in size of the initial perfusion defect of at least one segment (16 segment model) or no defect vs persistent defect in patients with anterior acute myocardial infarction was associated with improved global left ventricular function at 4 weeks; mean global wall motion score index 1.29+/-0.21 vs 1.66+/-0.31 (P=0.009). Multiple regression analysis in patients with an anterior acute myocardial infarction revealed that the extent of the perfusion defect at MCE3 was a significant (P=0.0005) independent predictor for left ventricular recovery at 4 weeks follow-up. The only other independent predictor was TIMI flow grade 3 post PTCA (P=0.007). CONCLUSION: Intravenous myocardial contrast echocardiography immediately prior to primary PTCA seems safe and is capable of detecting the presence of a perfusion defect and its subsequent dynamic changes, particularly in patients with a first anterior acute myocardial infarction. A significant reduction in size of the initial perfusion defect using serial myocardial contrast echocardiography predicts functional recovery after 4 weeks and these findings underscore the potential diagnostic value of intravenous myocardial contrast echocardiography.     

Assessment of myocardial viability with myocardial contrast echocardiography

The application of noninvasive imaging techniques to assess myocardial viability has become an important part of routine management of patients with acute myocardial infarction and chronic coronary artery disease. Information regarding the presence and extent of viability may help identify patients likely to benefit from revascularization or therapy directed at attenuating left ventricular remodeling. Myocardial contrast echocardiography (MCE) is capable of defining the presence and extent of viability by providing an accurate assessment of microvascular integrity needed to maintain myocellular viability. It is especially suited for the spatial assessment of perfusion, even when myocardial blood flow is reduced substantially in the presence of severe epicardial stenoses or in a bed dependent on collateral perfusion. The routine use of MCE to evaluate viability in patients with acute and chronic coronary artery disease is now feasible with the advent of new imaging technologies and microbubble agents capable of myocardial opacification from venous injections. The utility of this technique for determining treatment strategies has not been established but is forthcoming.     

Identification of viable myocardium by perfusion imaging with intravenous contrast echocardiography after acute myocardial infarction

Myocardial perfusion contrast echocardiography is evolving into an effective method for the evaluation of myocardial blood flow after acute coronary events. The direct injection of ultrasound contrast agents into the aortic and coronary circulation has been shown to accurately identify areas of viable myocardial tissue. Recently, intravenous ultrasound contrast has been found to be useful in detecting microvascular blood flow after the restoration of blood flow in patients with myocardial infarction. We present the case of a patient in whom intravenous ultrasound contrast assisted in the detection of viable myocardial tissue after an acute ischemic syndrome.     

Combined use of dobutamine echocardiography and myocardial contrast echocardiography in predicting regional dysfunction recovery after coronary revascularization in patients with recent myocardial infarction

BACKGROUND: Myocardial contrast echocardiography and dobutamine echocardiographyhave recently emerged as potentially useful clinical tools todetect reversible myocardial dysfunction. However, the relativeaccuracy of these two techniques in predicting regional wallmotion improvement after coronary interventions is still unclear.The aim of the present study was to compare their diagnosticvalue in predicting functional recovery after coronary revascularizationin patients with recent acute myocardial infarction. METHODS AND RESULTS: Twenty-four patients with acute myocardial infarction underwentmyocardial contrast echocardiography and dobutamine echocardiographywithin 2 weeks of hospital admission. Infarct zone contrastscore and wall motion score indexes were derived in each patient.Infarct-related artery revascularization was performed beforehospital discharge in all selected patients. Resting echocardiographywas repeated 3 months after revascularization, and regionalfunction recovery was analysed. The degree of wall motion scoreimprovement at 3-month follow-up and the percentage of positiveresponses to dobutamine echo were greater (P<0·001and P<0·002, respectively) in patients with a higherbaseline contrast score (0·50). Conversely, no significantchanges were observed either during dobutamine echo or afterrevascularization in the group of patients without residualperfusion within the infarct area. Diagnostic agreement betweenboth techniques in predicting reversible dysfunction was high(81% of segments). The sensitivity and negative predictive valuein predicting functional outcome were 100% (95% confidence interval[CI], 87% to 100%) and 100% (95% CI, 93% to 100%) by contrastecho, and 85% (95% CI, 66% to 96%) and 93% (95% CI, 84% to 98%)by dobutamine echo. The specificity and positive predictivevalue were 90% (95% CI, 80% to 96%) and 81% (95% CI, 64% to93%) by contrast echo, and 88% (95% CI, 78% to 95%) and 76%(95% CI, 58% to 90%) by dobutamine echo. The combination ofmyocardial contrast and dobutamine echocardiography positiveresponses improved specificity and positive predictive valuein detecting functional recovery after revascularization to100% (95% CI, 94% to 100%) and 100% (95% CI, 85% to 100%), respectively.However, the sensitivity and negative predictive value slightlydecreased with the use of both methods (85% [95% CI, 66% to96%)] and (93% [95% CI, 85% to 98%)], respectively. CONCLUSIONS: In patients with recent myocardial infarction, reversible dysfunctionafter coronary revascularization and the response to dobutamineinfusion are strictly dependent on microvascular integrity.However, microvascular perfusion does not always imply functionalrecovery after coronary revascularization. The integration withdob utamine echo results seems particularly helpful to furtherimprove myocardial contrast echo specificity and positive predictivevalues.     

Usefulness of quantitative intravenous myocardial contrast echocardiography to analyze microvasculature perfusion in patients with a recent myocardial infarction and an open infarct-related artery: comparison with intracoronary myocardial contrast echocardiography.

AIMS: We analyzed the usefulness of quantitative intravenous myocardial contrast echocardiography to study microvasculature perfusion after infarction in comparison with intracoronary myocardial contrast echocardiography. METHODS AND RESULTS: Thirty-two patients with a first ST elevation myocardial infarction, single-vessel disease and an open artery (TIMI 3) were studied before discharge. Myocardial perfusion in the risk area was quantified with intracoronary and intravenous myocardial contrast echocardiography. Perfusion was normal (intracoronary contrast echocardiography normalized videointensity >0.75) in 78 out of 97 dysfunctional segments (80%). Sensitivity and specificity of intravenous contrast echocardiography to predict normal perfusion were 87% and 63% for 'first-pass myocardial blood flow' (upslope of contrast arrival x peak intensity after intravenous bolus injection of contrast) and 91% and 89% for end-systolic single-triggered images captured every 6 cycles, respectively. In an analysis per patients, normal perfusion (0 or 1 hypoperfused segments with intracoronary contrast echocardiography) was observed in 22 cases (69%). End-systolic single-triggered images showed a strong correlation with intracoronary contrast echocardiography (R2 = 0.82, p = 0.0001). CONCLUSIONS: Intravenous contrast echocardiography is a useful technique to analyze microvasculature perfusion soon after infarction. A quantitative analysis of single-triggered images is an easy-to-obtain and reliable method to define perfusion when compared with intracoronary contrast echocardiography.     

Prognostic implications of evaluation of contractile reserve in akinetic and hypokinetic segments during low dose dobutamine echocardiography in patients with acute myocardial infarction

Background: Previous studies have reported the prognostic value of myocardial viability (MV) detected using low-dose dobutamine echocardiography (DbE). However, viability was frequently evaluated as improvement in regional wall motion score index, which includes increased function in hypokinetic segments, in which viable myocardium is necessarily present. It is not known whether an evaluation focusing on akinetic segments, in which the possible presence of viable myocardium is unknown, might have more prognostic value. The aim of this study was to compare the prognostic value of the improvement of myocardial function during dobutamine infusion in akinetic and hypokinetic regions in patients with acute myocardial infarction (AMI). Methods: 191 patients with uncomplicated AMI and at least one akinetic segment were retrospectively selected from those consecutively examined at our echo-laboratory to evaluate MV using DbE. Myocardial viability was evaluated both as an increment in RWMSI (ΔRWMSI), which takes into consideration improvement in both akinetic and hypokinetic regions, and as an improvement of function in akinetic (Δ akinetic) and hypokinetic (Δ hypokinetic), segments considered separately. Follow-up evaluation was performed at 30±13 months. Results: On the basis of the ΔRWMSI, 94/191 patients were judged to have myocardial viability, whereas considering myocardial viability in akinetic segments only, 72/191 patients showed viability. At follow-up 18 patients had died (six viable considering ΔRWMSI; three viable considering Δ akinetic). The presence of a previous AMI, the site of AMI, RWMSI and the number of akinetic segments, and ΔRWMSI and Δ akinetic were related to mortality at univariate Cox analysis. At multivariate stepwise Cox regression analysis Δ akinetic, but not Δ hypokinetic proved to be significantly related to mortality. The Kaplan–Meier survival curves were no different in patients with or without viable myocardium evaluated as ΔRWMSI, while they were significantly different considering patients with or without viability in akinetic segments (P=0.04). Conclusion: In conclusion our study confirms the prognostic importance of the evaluation of myocardial viability in infarcted patients. However, it points out that it is the presence of viability in akinetic segments that affects long-term survival in these patients. This supports the hypothesis that other mechanisms, above and beyond the effect on regional wall motion, are involved in the beneficial effects of myocardial viability.