Detection of functional recovery using low-dose dobutamine and myocardial contrast echocardiography after acute myocardial infarction treated with successful thrombolytic therapy

OBJECTIVE: We studied the value of low-dose dobutamine stress echocardiography (LDDE) and myocardial contrast echocardiography (MCE) in early prediction of left ventricular functional recovery (LVFR) after acute myocardial infarction (AMI) treated with successful thrombolysis. DESIGN: LDDE and MCE using second-harmonic intermittent imaging were performed in first week after AMI. LVFR was defined as an absolute > or =5% increase in ejection fraction, from early to 6 months of follow-up by Technetium-99m-Sestamibi single-photon emission computed tomography. PATIENTS: Out of 50 patients studied, 19 evolved with LVFR (group 1) and 31 without LVFR (group 2). Regional dysfunction was detected in 103 (37%) infarcted-related segments in group 1 and in 173 (63%) segments in group 2. RESULTS: Sensitivity, specificity, positive, and negative predictive values and accuracy for detecting LVFR by LDDE were 94.7% (18/19), 87.1% (27/31), 81.8% (18/22), 96.4% (27/28), and 90% (45/50), respectively, and by MCE were 94.7% (18/19), 51.6% (16/31), 54.5% (18/33), 94.1% (16/17), and 68% (34/50). In group 1, functional improvement was observed in 86.9% (53/61) of segments with contractile reserve by LDDE and in 65.8% (52/79) of segments with microvascular perfusion by MCE. In group 2, functional improvement was observed in 78.3% (18/23) of segments with contractile reserve by LDDE and in 25.5% (25/98) of segments with microvascular perfusion by MCE. All segments without perfusion by MCE evolved without functional recovery. CONCLUSION: LDDE was an accurate predictor of late left ventricular function recovery after AMI, while MCE was sensitive and has a high negative predictive value demonstrating that microvascular perfusion is essential for LVFR.     

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。     

NC100100, a new echo contrast agent for the assessment of myocardial perfusion--safety and comparison with technetium-99m sestamibi single-photon emission computed tomography in a randomized multicenter study

BACKGROUND AND HYPOTHESIS: Myocardial contrast echocardiography using second-generation agents has been proposed to study myocardial perfusion. A placebo-controlled, multicenter trial was conducted to evaluate the safety, optimal dose, and imaging mode for NC100100, a novel intravenous second-generation echo contrast agent, and to compare this technique with technetium-99m sestamibi (MIBI) single-photon emission computed tomography (SPECT). METHODS: In a placebo-controlled, multicenter trial, 203 patients with myocardial infarction > 5 days and < 1 year previously underwent rest SPECT and MCE. Fundamental and harmonic imaging modes combined with continuous and electrocardiogram-- (ECG) triggered intermittent imaging were used. Six dose groups (0.030, 0.100, and 0.300 microliter particles/kg body weight for fundamental imaging; and 0.006, 0.030, and 0.150 microliter particles/kg body weight for harmonic imaging) were tested. A saline group was also included. Safety was followed for 72 h after contrast injection. Myocardial perfusion by MCE was compared with myocardial rest perfusion imaging using MIBI as a tracer. RESULTS: NC100100 was well tolerated. No serious adverse events or deaths occurred. No clinically relevant changes in vital signs, laboratory parameters, and ECG recordings were noted. There was no significant difference between adverse events in the NC100100 (25.7%) and in the placebo group (17.9%, p = 0.3). Intermittent harmonic imaging using the intermediate dose was superior to all other modalities, allowing the assessment of perfusion in 76% of all segments. Eighty segments (96%) with normal perfusion by SPECT imaging also showed myocardial perfusion with MCE. However, a substantial percentage of segments (61-80%) with perfusion defects by SPECT imaging also showed opacification by MCE. This resulted in an overall agreement of 66-81% and a high specificity (80-96%), but in low sensitivity (20-39%) of MCE for the detection of perfusion defects. CONCLUSION: NC100100 is safe in patients with myocardial infarction. Intermittent harmonic imaging with a dose of 0.03 microliter particles/kg body weight can be proposed as the best imaging protocol. Myocardial contrast echocardiography with NC 100100 provides perfusion information in approximately 76% of segments and results in myocardial opacification in the vast majority of segments with normal perfusion as assessed by SPECT. Although the discrepancies between MCE and SPECT with regard to the definition of perfusion defects requires further investigation, MCE with NC 100100 is a promising technique for the noninvasive assessment of myocardial perfusion.     

Comparison of myocardial contrast echocardiography with NC100100 and (99m)Tc sestamibi SPECT for detection of resting myocardial perfusion abnormalities in patients with previous myocardial infarction

OBJECTIVE—To determine whether myocardial contrast echocardiography (MCE) following intravenous injection of perfluorocarbon microbubbles permits identification of resting myocardial perfusion abnormalities in patients who have had a previous myocardial infarction.
PATIENTS AND INTERVENTIONS—22 patients (mean (SD) age 66 (11) years) underwent MCE after intravenous injection of NC100100, a novel perfluorocarbon containing contrast agent, and resting ^99mTc sestamibi single photon emission computed tomography (SPECT). With both methods, myocardial perfusion was graded semiquantitatively as 1 = normal, 0.5 = mild defect, and 0 = severe defect.
RESULTS—Among the 203 normally contracting segments, 151 (74%) were normally perfused by SPECT and 145 (71%) by MCE. With SPECT, abnormal tracer uptake was mainly found among normally contracting segments from the inferior wall. By contrast, with MCE poor myocardial opacification was noted essentially among the normally contracting segments from the anterior and lateral walls. Of the 142 dysfunctional segments, 87 (61%) showed perfusion defects by SPECT, and 94 (66%) by MCE. With both methods, perfusion abnormalities were seen more frequently among akinetic than hypokinetic segments. MCE correctly identified 81/139 segments that exhibited a perfusion defect by SPECT (58%), and 135/206 segments that were normally perfused by SPECT (66%). Exclusion of segments with attenuation artefacts (defined as abnormal myocardial opacification or sestamibi uptake but normal contraction) by either MCE or SPECT improved both the sensitivity (76%) and the specificity (83%) of the detection of SPECT perfusion defects by MCE.
CONCLUSIONS—The data suggest that MCE allows identification of myocardial perfusion abnormalities in patients who have had a previous myocardial infarction, provided that regional wall motion is simultaneously taken into account.


Keywords: myocardial contrast echocardiography; NC100100; single photon emission computed tomography; perfusion     

The diagnostic value of adenosine stress-contrast echocardiography for diagnosis of coronary artery disease in hypertensive patients: comparison to Tl-201 single-photon emission computed tomography

BACKGROUND: The use of the vasodilating agent adenosine as stressor in conjunction with myocardial contrast echocardiography has not been extensively evaluated in hypertensive patients. Our aim was to evaluate the diagnostic value of adenosine myocardial contrast echocardiography (MCE) in comparison to single-photon emission computed tomography (SPECT), with reference to angiographic findings, in a hypertensive population. METHODS: Fifty hypertensive subjects, treated with standard antihypertensive treatment, were submitted to adenosine stress MCE, adenosine SPECT, and coronary angiography within a 1-month period, without any intervening events. RESULTS: Sensitivity, specificity, and accuracy were 88%, 89%, 88% for MCE and 80%, 94%, 85% for SPECT, respectively (P = not significant). In the analysis by coronary territory, it appears that MCE and SPECT are both more accurate in detecting lesions of the anterior than of the posterior coronary system, as suggested by the good concordance to angiography results in the left anterior descending artery territory (k = 0.640 and 0.671, respectively). Agreement with angiographic findings was moderate for the right coronary artery (k = 0.561 and 0.539, respectively), whereas left circumflex artery lesions were more accurately detected by MCE than by SPECT (k = 0.533 and 0.400, respectively), that is, MCE appears to be superior in the left circumflex artery territory. CONCLUSIONS: In hypertensive patients, adenosine MCE has similar overall diagnostic accuracy with SPECT for assessment of coronary artery disease but is superior in the left circumflex artery territory.     

Assessment of Myocardial Viability in Patients With Postischemic Left Ventricular Dysfunction: Role of Myocardial Contrast Echocardiography

The distinction between viable and nonviable dysfunctional left ventricular (LV) segments after acute myocardial infarction is very important, because revascularization increases survival only in patients with viable myocardial tissue. Recent studies have highlighted a mismatch between two highly specific investigations for viability assessment: dobutamine echocardiography, which measures inotropic reserve, and myocardial contrast echocardiography (MCE), which measures microvascular perfusion. Viability and functional reserve are not synonymous. Maintenance of microvascular perfusion, independently of functional reserve, attenuates left ventricular remodelling, reduces the risk of major cardiac events, and increases survival. MCE provides similar perfusion information as myocardial blush, but image quality is much higher. Quantitative analysis of digital data provides more accurate diagnostic MCE information than qualitative analysis of video signal intensity. In a recent study relating MCE findings to histologic data, MCE-derived quantitative data were closely correlated with microvascular density and capillary area, and inversely correlated with collagen content. One of the contrast agents routinely used for MCE is SonoVue, a second generation microbubble contrast agent, which is characterized by high response to ultrasound energy, ease of destruction at high energy, and strong harmonic signal at low energy. Recommendations for the assessment of postischemic LV dysfunction: routine use of MCE, followed by dobutamine echocardiography if perfusion is documented. If MCE is negative, revascularization is not indicated; if both tests are positive, revascularization is strongly recommended; if they are discordant, useful information can be obtained by assessing the extent of ²⁰¹T1 viability. (ECHOCARDIOGRAPHY, Volume 20, Supplement 1, 2003)     

Physiologic assessment of left anterior descending coronary artery stenosis by quantitative intravenous myocardial contrast echocardiography in humans: comparison with exercise single-photon emission computed tomography

OBJECTIVE: To clarify the potential of quantitative intravenous myocardial contrast echocardiography (MCE) for physiologic assessment of the left anterior descending artery (LAD) stenosis. METHODS: We studied 38 patients with suspected coronary artery disease. MCE was performed by continuous infusion of Levovist and intermittent ultrasonic exposure. Images were obtained from the apical four-chamber view at rest and after dipyridamole infusion. The background-subtracted intensity versus pulsing interval plots were fitted to an exponential function,Y=A(1 e-ss), to obtain the plateau level (A) and rate of rise (ss) of background-subtracted intensity both at rest and after dipyridamole infusion. We compared the results with those of exercise thallium-201 single-photon emission computed tomography (SPECT). RESULTS: Of the 38 patients, 18 patients exhibited redistribution in the LAD territories with SPECT (group A), although 20 did not (group B). The ss reserve (DIP/rest) in group A was significantly lower than those in group B (0.8 +/- 0.5 versus 2.0 +/- 1.1, P < 0.001), while the A reserve did not differ between the two groups (1.2 +/- 0.6 versus 1.0 +/- 0.5, P = NS). The ss reserve <1.1, which was the optimal cutoff value, provided sensitivity of 79% and specificity of 84% for the presence of redistribution in SPECT. CONCLUSIONS: Quantitative intravenous MCE allows us to estimate physiologic severity of the LAD stenosis in the clinical setting.     

静息与负荷心肌造影超声心动图识别存活心肌的对比研究

目的探讨负荷心肌造影超声心动图(MCSE)对心肌梗死后存活心肌评价的疗效和安全性。方法选择冠状动脉造影证实的心肌梗死患者30例。首先在静息状态下行心肌造影超声心动图(MCE),MCE心肌灌注结果采用半定量评价。多巴酚丁胺负荷静脉滴注剂量分别为5、10、20μg·kg~(-1)·min~(-1),每期3 min观察心率、血压变化于达到负荷剂量后再次行MCE,并以~(18)F-脱氧葡萄糖正电子发射计算机体层扫描(PET)作为金标准评价其敏感性和特异性。结果 MCE总共评价360个梗死节段,静息MCE评价1、0.5、0分为264、22、74个节段。多巴酚丁胺负荷MCSE评价1、0.5、0分为286、30、44个节段,评价MCE敏感性和特异性分别为38.10%、88.89%,kappa=0.285(P0.01)。评价MCSE敏感性和特异性分别为86.21%、88.89%,kappa=0.746(P0.05)。结论MCE及MCSE安全性良好。MCE及MCSE均与冠状动脉造影心肌梗死部位有较好的相关性,以PET作为金标准,MCSE具有较高的敏感性和特异性,是评价梗死节段内存活心肌的较好方法。     

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.     

Combined assessment of microvascular integrity and contractile reserve improves differentiation of stunning and necrosis after acute anterior wall myocardial infarction

OBJECTIVES: We sought to determine the relative accuracy of myocardial contrast echocardiography (MCE) and low-dose dobutamine echocardiography (LDDE) in predicting recovery of left ventricular (LV) function in patients with a recent anterior wall myocardial infarction (MI). BACKGROUND: Left ventricular dysfunction after acute MI may be secondary to myocardial stunning or necrosis. Myocardial contrast echocardiography allows real-time echocardiographic perfusion assessment from a venous injection of a fluorocarbon-based contrast agent. Although this technique is promising, it has not been compared with LDDE. METHODS: Forty-six patients underwent baseline wall motion assessment, MCE, and LDDE two days after admission, as well as follow-up echocardiography after a mean period of 53 days. RESULTS: Perfusion by MCE predicted recovery of segmental function with a sensitivity of 69%, specificity of 85%, positive predictive value of 74%, negative predictive value of 81%, and overall accuracy of 78%. Contractile reserve by LDDE predicted recovery of segmental function with a sensitivity of 50%, specificity of 88%, positive predictive value of 72%, negative predictive value of 73%, and overall accuracy of 73%. Concordant test results occurred in 74% of segments and further increased the overall accuracy to 85%. The mean wall motion score at follow-up was significantly better in perfused versus nonperfused segments (1.9 vs. 2.6, p < 0.0001) and in segments with contractile reserve, compared with segments lacking contractile reserve (1.9 vs. 2.5, p < 0.0001). CONCLUSION: Myocardial contrast echocardiography compares favorably with LDDE in predicting recovery of regional LV dysfunction after acute anterior wall MI. Concordant contractile reserve and myocardial perfusion results further enhance the diagnostic accuracy.     

Contrast echocardiography and acute coronary syndromes

Since microvascular perfusion parallels myocardial viability, myocardial contrast echocardiography (MCE) can provide informations regarding myocardial recovery after an acute myocardial infarction (AMI). Recent studies have demonstrated the role of MCE to evaluate the value of perfusion and function during rest and dobutamine stress echo in patients early after AMI in terms of risk stratification and management of these patients.     

The value of myocardial contrast echocardiography compared with SPECT in detecting myocardial perfusion abnormalities in patients with anterior acute myocardial infarction

BACKGROUND: Microvasculature damage after myocardial infarction (MI), known as "no-reflow" phenomenon, may occur in some patients with acute MI in spite of invasive treatment and opened infarct-related coronary artery. There are several non-invasive and invasive methods used for the coronary flow assessment at the tissue level. AIM: To compare the value of intravenous contrast echocardiography (MCE) in detecting myocardial perfusion defects in patients with acute MI with (99m)Tc MIBI SPECT study. METHODS: Sixteen patients (11 males, 5 females, mean age 55.4+/-10.2 years) underwent primary coronary angioplasty or facilitated angioplasty (with reduced dose of a fibrinolytic drug and glycoprotein IIb/IIIa inhibitor) (PCI) for acute anterior MI. TIMI grade flow, TIMI Myocardial Perfusion Grade (TMPG), corrected TIMI frame count (cTFC), wall motion score index (WMSI) and segmental perfusion by myocardial contrast echocardiography (MCE) were estimated in real time before and immediately after PCI. MCE was repeated on the third day after PCI. All patients underwent (99m)Tc MIBI SPECT study (SPECT) while at rest on the third day after PCI. The area at risk was defined as the number of segments with no perfusion before angioplasty. Reflow was defined as an increase in contrast score in the same segments after angioplasty. RESULTS: Baseline MCE showed 95 segments with perfusion defects. Immediately after PCI, 77 segments were found with perfusion defect; in 10 patients improvement of myocardial perfusion was observed whereas in 6 patients perfusion defect remained unchanged. On the third day further improvement was observed in 8 patients. The number of segments with perfusion defect decreased to 53. SPECT detected perfusion defect in 54 segments. The agreement between MCE and SPECT for detecting perfusion abnormality was 98% (kappa 0.94). CONCLUSIONS: MCE is a safe technique for detecting myocardial perfusion in patients with acute MI. MCE proves that both primary and facilitated angioplasty improve myocardial perfusion in two thirds of patients with acute MI. Serial MCE allows identification of patients with both early and late improvement of myocardial perfusion. There is a very strong correlation between MCE and SPECT in the assessment of perfusion defects.     

Usefulness of myocardial contrast echocardiography in predicting collateral blood flow in the presence of a persistently occluded acute myocardial infarction-related coronary artery

Adequate collateral blood flow at rest can sustain myocardial viability despite persistent occlusion of the infarct-related artery (IRA) in acute myocardial infarction (AMI). This has therapeutic and prognostic implications. Studies addressing the value of intravenous myocardial contrast echocardiography (MCE) to detect collateral blood flow after AMI in humans are limited. Accordingly, 70 consecutive patients with AMI underwent low-power intravenous MCE using a Sonovue infusion 7 to 10 days after thrombolysis. Myocardial perfusion detected by MCE was analyzed (qualitatively and quantitatively) in the akinetic segments in 20 patients (29%) with an occluded IRA who subsequently underwent revascularization. Contractile reserve, which is a marker of myocardial viability, was assessed with low-dose dobutamine 12 weeks after mechanical revascularization. Of the 102 akinetic segments (32%), 37 (36%) showed contractile reserve. Contractile reserve was present in 24 of the 29 segments (83%) with homogenous contrast opacification and absent in 60 of the 73 segments (82%) with reduced/absent opacification. Quantitative peak contrast intensity, microbubble velocity, and myocardial blood flow were significantly higher (p <0.0001) in the segments with contractile reserve than in those without contractile reserve. Multiple logistic regression analysis using electrocardiographic, biochemical, and myocardial contrast echocardiographic markers of collateral blood flow showed that MCE (odds ratio 26.0, 95% confidence interval 6.3 to 108.0, p <0.001) was the only independent predictor of collateral blood flow as demonstrated by the presence of contractile reserve. MCE may thus be used as a reliable bedside technique for the accurate evaluation of collateral blood flow in the presence of an occluded IRA after AMI.     

Detection of myocardial viability by contrast echocardiography in acute infarction predicts recovery of resting function and contractile reserve

OBJECTIVES: We sought to determine whether myocardial contrast echocardiography (MCE) performed before and early after primary coronary stenting (PCS) in patients with acute myocardial infarction (AMI) could predict recovery of resting left ventricular systolic function and contractile reserve. BACKGROUND: Myocardial contrast echocardiography can be used to assess perfusion within the risk area before PCS and the extent of necrosis soon after PCS. METHODS: In 30 patients with AMI, MCE and two-dimensional echocardiography were performed before PCS and 3 to 5 days and 4 weeks after PCS. Contractile reserve was assessed by dobutamine echocardiography at four weeks in patients with persistent severe wall-motion abnormalities. RESULTS: Of segments without perfusion at 3 to 5 days, 95% had severe hypokinesis to akinesis at 4 weeks. Of segments with normal perfusion at 3 to 5 days, 90% had normal wall motion or mild hypokinesis at 4 weeks, whereas those with partial perfusion at 3 to 5 days were evenly divided between normal wall motion, hypokinesis, and akinesis. In segments with persistent severe wall-motion abnormalities at four weeks, contractile reserve was found in >80% of segments with perfusion, compared with only 10% of segments without detectable perfusion (p < 0.01). The presence of myocardial perfusion by MCE before PCS was associated with maintained or improved perfusion at 3 to 5 days and eventual recovery of resting wall motion. CONCLUSIONS: Myocardial contrast echocardiography performed early after PCS provides information on the extent of infarction, and hence the likelihood for recovery of resting systolic function or contractile reserve. The presence of perfusion before PCS, from either collateral or antegrade flow, predicts the maintenance of perfusion and recovery of systolic function.     

小剂量多巴酚丁胺超声心动图与硝酸甘油介入~(99m)Tc-MIBI的心肌灌注显像估测存活心肌

目的　探讨小剂量多巴酚丁胺超声心动图 (LDDE)与含服硝酸甘油 (NTG)介入99mTc 甲氧基异丁基异睛 (MIBI)的心肌灌注显像在心肌存活估测中的价值。方法　对 17例心肌梗死患者分别行静息 NTG介入99mTc MIBI和小剂量多巴酚丁胺超声心动图的检查 ,经皮冠状动脉腔内成形术或冠状动脉旁路移植术后一个月重复基础超声心动检查 ,并进行对比分析。结果　 17例患者于基础超声心动检查 ,共有 94个心肌节段运动异常 ,在其中 5 0个低动力心肌节段中 ,两种方法一致性节段 2 9个 (5 8% ,P >0 .0 5 ) ;在 44个无动力心肌节段中两种方法一致性节段 16个 (36 % ,P<0 .0 5 )。两种方法对低动力心肌节段功能恢复的预测差异无显著性意义 (P>0 .0 5 ) ;而对无动力心肌节段 ,LDDE较NTG介入 99m　Tc MIBI心肌灌注显像有较高的特异性 (90 .9%vs 6 4.7% ,P <0 .0 5 )和较低的敏感性 (6 3.6 %vs88.9% ,P <0 .0 5 )。对整个运动障碍节段功能恢复的预测 ,LDDE较NTG介入99mTc MIBI心肌灌注显像有较高的特异性 (87.2 %vs 6 8.2 % ,P <0 .0 5 )。结论　两种方法对低动力心肌节段的预测有良好的一致性 ,LDDE对整个运动障碍节段功能恢复的预测有较高的特异性。     

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.     

Early changes in myocardial perfusion patterns after myocardial infarction: relation with contractile reserve and functional recovery

Objectives. The purpose of this study was to assess early temporal changes in myocardial perfusion pattern by myocardial contrast echocardiography (MCE) and their relation to myocardial viability in patients with reperfused acute myocardial infarction (AMI).

Background. Myocardial contrast echocardiography no-reflow is associated with poor contractile recovery after AMI. However, little is known regarding early reversibility of microvascular dysfunction and its relation to myocardial viability.

Methods. Intracoronary MCE was performed immediately after reflow and 9 days later in 28 patients with a first AMI and successful coronary recanalization (Thrombolysis in Myocardial Infarction trial grade 3 flow). Semiquantitative contrast score and wall motion score (WMS) were assessed in each initially asynergic segment at initial and repeat MCE study. Low dose dobutamine echocardiography (DE) was performed at day 10, and follow-up (FU) rest echocardiography was performed 6 weeks later.

Results. Among 200 initially asynergic segments, 49% exhibited no or heterogeneous contrast enhancement at initial MCE versus 24% at restudy (p < 0.001). Three groups of segments were defined according to early changes in contrast pattern: group A, “sustained no-reflow” (n = 17); group B, improved contrast score (n = 68), and group C, “sustained reflow” (n = 112). Group A segments showed no improvement in WMS at FU. In contrast, group B segments showed significant improvement in WMS at FU (p < 0.0001), and exhibited more frequently contractile reserve at DE (36% vs. 6%, p = 0.02) and contractile recovery at FU (34% vs. 7%, p = 0.03) than group A segments. Group C segments exhibited contractile reserve and contractile recovery in 47% and 51% of segments respectively.

Conclusions. Improvement in MCE perfusion pattern may occur after initial no-reflow in the days following reperfused AMI and is associated with preservation of contractile reserve and gradual regional functional recovery.     

Myocardial viability after primary coronary angioplasty: low-dose dobutamine stress echocardiography versus myocardial contrast echocardiography.

BACKGROUND: Successful reperfusion therapy in patients with acute myocardial infarction (AMI) improves survival. Indeed, after AMI myocardial dysfunction may be reversible (hibernating or stunned myocardium). Low-dose dobutamine stress echocardiography (LDDSE) provides us with the possibility of evaluating viable myocardial segments, while myocardial contrast echocardiography (MCE) allows the study of the microcirculation in the same myocardial areas. The aim of our study was to compare LDDSE and MCE, in the prediction of the recovery of segments in patients with AMI who were submitted to primary coronary angioplasty (PTCA). METHODS: We studied 14 patients with AMI. Both LDDSE and MCE with Levovist were performed after primary PTCA. The viability gold standard was a recovery of contractility detected at echocardiography 2 months later. RESULTS: For LDDSE, the sensitivity was 91%, the specificity 71% and the positive and negative predictive values were 93 and 64% respectively. For MCE, the sensitivity was 94%, the specificity 44%, the positive predictive value 89%, and the negative predictive value 59%. Two tests agreed in 81% of the cases. Stress echocardiography and contrast echocardiography agreed in 81% of cases. CONCLUSIONS: LDDSE has a very good positive accuracy, it has an acceptable negative predictive value and is relatively cheap. On the other hand, MCE has a good positive accuracy, but a low negative accuracy and carries a high cost. The integration of these two tests, which are too expensive in clinical practice, could improve our comprehension of the post-PTCA pathophysiology.     

Assessment of myocardial viability with dobutamine stress echocardiography in patients with ischemic left ventricular dysfunction

The noninvasive assessment of myocardial viability has proved clinically useful for distinguishing hibernating and/or stunned myocardium from irreversibly injured myocardium in patients with chronic ischemic heart disease or recent myocardial infarction, with marked regional and/or global left ventricular (LV) dysfunction. Noninvasive techniques utilized for the detection of viability in asynergic myocardial regions include positron emission tomographic imaging of residual metabolic activity, single photon emission tomography (SPECT) of radioisotope uptake with thallium-201, low-dose dobutamine echocardiography assessment of inotropic reserve and myocardial contrast echocardiography for evaluation of microvascular integrity. Of these techniques, dobutamine stress echocardiography is a safe, widely available and relatively inexpensive modality for the identification of myocardial viability for risk stratification and prognosis. Low-dose dobutamine response can accurately predict improvement of dysfunctional yet viable myocardial regions, and thus identify a subset of patients whose LV function will improve following successful coronary revascularization.     

Quantitative intravenous myocardial contrast echocardiography predicts recovery of left ventricular function after revascularization in chronic coronary artery disease

BACKGROUND: Quantitative intravenous myocardial contrast echocardiography (MCE) has been shown to measure regional myocardial blood flow velocity noninvasively. PURPOSE: To determine whether quantitative intravenous MCE could be used clinically to predict functional recovery after revascularization in patients with chronic coronary artery disease. METHODS: Twenty-eight patients with chronic stable coronary artery disease and resting regional left ventricular dysfunction were included in this study. The study permits myocardial perfusion analysis by intravenous MCE before revascularization with continuous infusion of Levovist and intermittent ultrasonic exposure. Wall motion assessment by echocardiography at rest was repeated after long-term follow-up period (7 +/- 2 months). In dysfunctional segments, we analyzed myocardial perfusion quantitatively by fitting to an exponential function, Y = A(1 - e-betat) to obtain the rate of rise (beta) of background-subtracted intensity, which represented myocardial blood flow velocity. RESULTS: Of the 101 revascularized dysfunctional segments, MCE was adequately visualized in 91 (90%) segments, and wall motion was recovered in 45 (49%) segments. The value of beta in the recovery segments was significantly higher than that in nonrecovery segments (0.80 +/- 0.50 vs 0.39 +/- 0.24, P < 0.001). The value of beta > 0.5 predicted recovery of segmental function with a sensitivity of 71%, specificity of 78%. CONCLUSION: Quantitative intravenous MCE can predict functional recovery after revascularization in patients with chronic coronary artery disease.