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.     

小剂量多巴酚丁胺超声心动图试验和双核素心肌显像检测急性心肌梗死后患者存活心肌比较

目的比较小剂量多巴酚丁胺超声心动图试验（LDDE）和^99mTc-甲氧基异丁腈（MIBI）／^18F-脱氧葡萄糖（FDG）双核素同时采集法（DISA）单光子发射型断层显像（SPECT）对急性心肌梗死早期存活心肌检出的准确性。方法对44例急性心肌梗死患者于发病后5～10天内行LDDE和DISA—SPECT,所有患者在LDDE和DISA检查后接受经皮冠状动脉介入术。两种方法均采用16节段半定量法分析图像。心肌梗死后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,比较两种方法检测存活心肌的敏感性和特异性。结果LDDE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77％、82％、79％、82％和77％。DISA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85％、62％、74％、71％和79％。LDDE和DISA两者对运动异常节段检出存活心肌的一致性为70％。对于运动减低节段,LDDE和DISA对存活心肌检出率差异无统计学意义（74．1％比77．6％,P〉0．05）;对于无运动节段,LDDE对存活心肌检出率低于DISA（29％比53％,P〈0．01）。结论对急性心肌梗死后的患者,DISA检出存活心肌的敏感性高于LDDE,而特异性低于LDDE,联合应用起互补作用,提高检测存活心肌的能力。     

腺苷负荷超声心动图识别存活心肌的应用研究

目的探讨腺苷超声心动图负荷试验(ATE)在识别存活心肌中的应用价值及安全性.方法59例心肌梗死后患者静脉注射腺苷,剂量为90 μg/min持续3 min,加量至110 μg/min持续3 min,检出二维超声室壁改善节段作为存活心肌节段,与治疗后随访结果--"金标准"比较,分析两者的符合率及试验中患者发生的不良反应的情况.结果腺苷负荷后,患者心率增加、血压下降,但幅度较小;ATE识别存活心肌的敏感性90.4%,特异性90.5%;未发生严重不良反应.结论ATE识别存活心肌是一种可靠、安全、有效的方法.     

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。     

腺苷超声心动图与腺苷负荷心肌灌注显像诊断冠心病的价值

目的探讨腺苷超声心动图负荷试验(ASF)与腺苷负荷~(99m)Tc心肌灌注显像(Ad-SPECT)诊断冠心病的价值。方法选择临床拟诊断为稳定性心绞痛的住院患者86例,同期行ASE和Ad-SPECT单项及联合试验,观察腺苷静脉滴注后心率、血压及其不良反应发生情况。结果 86倒患者接受冠状动脉造影检查,阳性62例,阴性24例。ASF诊断冠心病的敏感性、特异性和准确度分别为74%、79%和76%,Ad-SPECT分别为87%、62%和80%,ASE及Ad-SPECT的联合平行试验敏感性、特异性和准确度分别为97%、63%和87%,联合系列试验分别为65%、88%和80%。联合平行试验的敏感性与各单项试验敏感性之间、联合系列试验的特异性与各单项试验特异性之间差异有统计学意义(P<0.05)。结论腺苷负荷试验安全、可靠,ASE及Ad-SPECT诊断冠心病特异性、敏感性均较高,联合试验可进一步提高诊断冠心病的价值。     

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。     

药物负荷超声心动图与双核素心肌显像对比检测存活心肌

目的　比较99mTc 甲氧基异丁腈(MIBI) /18F 脱氧葡萄糖(FDG)双核素同时采集法(DISA)单光子发射型断层显像(SPECT)和药物负荷二维超声心动图(2DE)试验,识别冠心病左心室收缩功能严重减低患者[左室射血分数(LVEF)≤45% ]存活心肌的准确性。方法　陈旧性心肌梗死患者26例,平均LVEF(38. 6±4 .9 )%,在一周内分别进行小剂量多巴酚丁胺10μg·kg-1·min-1(Dob10μg)、亚硝酸异山梨酯合用Dob5μg·kg-1·min-1 (ISDN Dob5μg)的2DE试验,以及DISASPECT心肌显像。所有患者在冠状动脉血管重建(CRV)术后(6 .8±2 .9)个月完成了2DE复查。采用16节段半定量法分别分析图像,以CRV术后收缩功能改善节段为存活标准,比较两种方法检测存活心肌的敏感性、特异性和准确性。结果　26例患者272个运动异常节段中,术后156个( 57. 4% )有收缩运动改善。DISASPECT检测出72 .4% (134 /254)存活心肌节段,显著高于术后实际改善率(P<0 .001)。Dob10μg2DE的存活心肌检出率为65 5% (163 /249 ),ISDN Dob5μg2DE的为65 .7%(176 /268),均与术后实际改善率一致(P均>0 .05)。DISASPECT检测存活心肌的敏感性、特异性和准确性分别为93%, 55%和76. 8%;Dob10μg2DE的分别为88 .6%, 64 .2%和77. 9%,两种方法检测效果相当(P均>0 .05)。ISDN Dob5μg     

二维应变成像结合腺苷负荷超声心动图评价犬存活心肌

目的 探讨二维应变成像结合腺苷负荷超声心动图评价存活心肌的新方法.方法 15只健康杂种犬,结扎其冠状动脉前降支90 min后,恢复血流灌注120 min,建立急性心肌梗死再灌注模型.分别于基础状态下(结扎前)和再灌注后采集心尖三腔、两腔和短轴二尖瓣、乳头肌、心尖水平的图像.随后泵入腺苷并重复采集图像.以氯化三苯基四氮唑溶液(2,3,5-triphenyl tetrazolium chloride,TTC)染色结果测量梗死面积(SN)与该节段总面积(S)的百分比(SN/S),SN/S≤50%即为存活心肌.将前壁、前间壁各节段分为存活心肌和非存活心肌,运用二维应变成像技术定量评价犬不同状态下存活与非存活心肌径向、纵向及圆周的收缩期峰值应变(peak-systolic strain,Speak sys)并进行比较.结果 存活与非存活心肌分别为37和53个节段.(1)基础状态下:存活与非存活心肌的收缩期峰值径向应变(RSpeak sys)、纵向应变(LSpeak sys)及圆周应变(CSpeak sys)比较差异无统计学意义.(2)再灌注120 min后:存活与非存活心肌的RSpeak sys、LSpeak sys及CSpeak sys(绝对值)均低于基础状态,而存活心肌与非存活心肌组间差异无统计学意义.(3)腺肾负荷后:与再灌注120 min后相比,存活心肌的RSpeak sys、LSpeak sys显著升高(P<0.01或P<0.05),且存活心肌的RSpeak sys、LSpeak sys明显高于非存活心肌(P<0.01).(4)腺苷负荷后,RSpeak sys与SN/S呈负相关(r=-0.72,P<0.01),CSpeak sys及LSpeak sys与SN/S呈正相关(r值分别为0.40和0.67,P均<0.01).(5)将腺苷负荷前、后应变数值的变化率(△RSpeak sys和△LSpeak sys)作为研究对象,以△RSpeak sys≥13.5%作为判断心肌存活的最佳截断值,其识别存活心肌的敏感性和特异性分别为83.8%、83.0%;以△LSpeak sys≥11%作为最佳截断值,其敏感性和特异性分别为78.4%、88.7%;联合△RSpeak sys和△LSpeak sys两项指标,其敏感性和特异性分别为91.9%、79.2%.结论 二维应变成像技术结合腺苷负荷超声心动图能比较准确地区分存活心肌与非存活心肌.     

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。     

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。     

Dobutamine stress echocardiography for assessment of myocardial viability and ischemia in acute myocardial infarction treated with thrombolysis

To evaluate the role of dobutamine echocardiography for early assessment of myocardial viability and ischemia in acute myocardial infarction (MI), 59 patients with thrombolyzed acute MI underwent low- (5–10 μg/kg/min, 8 patients) and high-dose (20–40 μg/kg/min, 51 patients) dobutamlne echocardiography at a mean of 8 ± 4 days after acute MI. Myocardlal viability in the infarct zone was documented in 43 of 59 (73%) patients (group 1), in whom mean asynergy score index decreased from 1.6 ± 0.3 at baseline to 1.3 ± 0.2 (p < 0.001), after low-dose dobutamine. No viability was present in 16 of 59 (27%) patients (group 2). At follow-up, recovery of regional contractile function was observed in group 1 (asynergy score index decreased from 1.6 ± 0.3 to 1.4 ± 0.3; p < 0.001), but not in group 2 patients. Sensitivity, specificity, and negative and positive predictive values of low-dose dobutamine echocardiography in predicting spontaneous recovery of function were 79%, 68%, 50%, and 89%, respectively. Of the 51 patients who underwent high-dose dobutamine, 26 of 36 (72%) group 1 patients showed a deterioration of contractility in the infarct zone indicative of myocardlal ischemia compared with only 1 of 15 (7%) group 2 patients. At follow-up, recovery of regional function was greater in patients with no evidence of myocardlal ischemia at high doses than in those with an ischemic response. Thus, in patients with thrombolyzed acute MI, dobutamine echocardiography is a useful clinical tool for detection of myocardlal viability and ischemia in the infarct zone and for identification of patients with jeopardized myocardium in the area at risk who can benefit from myocardlal revascularlzation.     

Prognostic value of myocardial viability detected by myocardial contrast echocardiography early after acute myocardial infarction.

OBJECTIVES: This study sought to determine whether residual myocardial viability determined by myocardial contrast echocardiography (MCE) after acute myocardial infarction (AMI) can predict hard cardiac events. BACKGROUND: Myocardial viability detected by MCE has been shown to predict recovery of left ventricular (LV) function in patients with AMI. However, to date no study has shown its value in predicting major adverse outcomes in AMI patients after thrombolysis. METHODS: Accordingly, 99 stable patients underwent low-power MCE at 7 +/- 2 days after AMI. Contrast defect index (CDI) was obtained by adding contrast scores (1 = homogenous; 2 = reduced; 3 = minimal/absent opacification) in all 16 LV segments divided by 16. At discharge, 65 (68%) patients had either undergone or were scheduled for revascularization independent of the MCE result. The patients were subsequently followed up for cardiac death and nonfatal AMI. RESULTS: Of the 99 patients, 95 were available for follow-up. Of these, 86 (87%) underwent thrombolysis. During the follow-up time of 46 +/- 16 months, there were 15 (16%) events (8 cardiac deaths and 7 nonfatal AMIs). Among the clinical, biochemical, electrocardiographic, echocardiographic, and coronary arteriographic markers of prognosis, the extent of residual myocardial viability was an independent predictor of cardiac death (p = 0.01) and cardiac death or AMI (p = 0.002). A CDI of < or = 1.86 and < or = 1.67 predicted survival and survival or absence of recurrent AMI in 99% and 95% of the patients, respectively. CONCLUSIONS: The extent of residual myocardial viability predicted by MCE is a powerful independent predictor of hard cardiac events in patients after AMI.     

Comparison of low-dose dobutamine echocardiography and thallium-201 reinjection for the determination of myocardial viability in the early post myocardial infarction period

OBJECTIVE: Determination of viability in the infarction zone in the early post Ml period is an important parameter in clinical decision making. METHODS: In an attempt to compare the places of low-dose dobutamine echocardiography (LDDE) and thallium-201 reinjection SPECT (TI-SPECT) in the determination of viability in dyssynergic myocardial segments, 17 patients (mean age: 54.6 +/- 12.8 years, 16 male, 1 female) with a recent myocardial infarction and an uneventful early clinical course underwent both tests within 5-13 days of infarction. The 16-segment model was utilised to evaluate the left ventricular wall motion and each segment was graded as 1) normokinetic, 2) hypokinetic, 3) akinetic and 4) dyskinetic or aneurysmal on a 4-scale basis. A dyssynergic segment of myocardium was considered to be viable by LDDE if it showed an improvement in wall motion of at least one grade with low-dose dobutamine infusion (10 microg/kg/min). On the other hand, mild to moderate (< 50%) fixed perfusion defects and reversible (at least a 10% improvement in perfusion on either redistribution or reinjection images) severe (50% or more) perfusion defects were considered positive for viability by TI-SPECT. RESULTS: Of the 76 segments with resting dyssynergy (10 dyskinetic/aneurysmal, 33 akinetic, 33 hypokinetic), 51 (67%) were shown to be viable by LDDE and 61 (80%) by TI-SPECT. There was an agreement of 76% (p = 0.03, K = 0.63) between the two methods. CONCLUSION: This study disclosed a moderate degree of agreement between LDDE and TI-SPECT for the determination of viability in dyssynergic myocardial segments in the early post-myocardial infarction period.     

Preoperative cardiac risk assessment with adenosine stress dual-isotope myocardial single-photon emission computed tomography

Background: Previous studies have demonstrated that pharmacologic stress thallium-201(²⁰¹Tl) myocardial scintigraphy is a useful tool to evaluate preoperative cardiac risk. Hypothesis: The purpose of this study was to assess the utility of adenosine stress dual-isotope [rest ²⁰¹Tl/stress technetium-99m (^99mTc) sestamibi] myocardial single-photon emission computed tomography (SPECT) in predicting the risk of perioperative cardiac events (unstable angina, myocardial infarction, cardiac death) in patients undergoing major noncardiac surgery. Methods: We evaluated 43 consecutive patients (20 men, 23 women, mean age 64 years, range 30-83 years) within 8 weeks prior to major noncardiac surgery requiring general anesthesia. SPECT imaging was performed with 111 MBq (3 mCi)²⁰¹Tl at rest and 925 MBq (25 mCi)^99mTc sestamibi during adenosine stress. Results: Of the 43 patients, 15 (35%) had stress-induced ischemia and 28 (65%) did not. Perioperative cardiac events occurred in 4 (27%) of the 15 patients with stress-induced ischemia (2 unstable angina, 2 nonfatal myocardial infarctions) and in none of the 28 patients without inducible ischemia (p = 0.02). Conclusion: Adenosine stress dual-isotope myocardial SPECT is useful in determining the preoperative cardiac risk of patients undergoing major noncardiac surgery.     

Comparison of low-dose dobutamine stress echocardiography and echocardiography during glucose-insulin-potassium infusion for detection of myocardial viability after anterior myocardial infarction

BACKGROUND: Low-dose dobutamine stress echocardiography (LDDSE) is one of the methods most used to assess myocardial viability. Glucose-insulin-potassium (GIK) infusion has been shown to increase contraction of the ischemic zone. The aim of this study was to compare LDDSE and echocardiography during GIK infusion for detection of myocardial viability. METHODS: Thirty-two patients who had first anterior myocardial infarction (MI) without previous MI were included in the study. Echocardiographic evaluation was carried out on the 7th +/- 2 days after MI. During continuous electrocardiographic, blood pressure and echocardiographic monitoring, an intravenous infusion of dobutamine (3 microg/kg body weight/min) was started with an infusion pump, continued for 5 min and then increased to 5 microg/kg/min and 10 microg/kg/min for another 5 min. The GIK protocol consisted of a fixed dose of insulin (100 microU/kg/h intravenously) and a variable glucose/potassium infusion rate. GIK echocardiography was done at baseline and after 60 min of GIK. The detected viable myocardium was defined as one or two scores decreasing in at least two adjacent abnormal segments during LDDSE and GIK echocardiography. RESULTS: Under resting conditions 225 segments (44%) were normokinetic, 21 segments (4%) dyskinetic, 117 segments (23%) akinetic and 149 segments (29%) hypokinetic. Viability was detected in 20% (57 segments) of the asynergic segments at baseline with GIK echocardiography and in 22% (62 segments) of those segments with LDDSE (P < 0.05). Left ventricular wall motion score index at baseline was 1.87 and it decreased significantly indicating improvement in left ventricular systolic function during both LDDSE and GIK echocardiography (P < 0.001, versus 1.75 and 1.76 respectively). The agreement between LDDSE and GIK echocardiography for detection of myocardial viability was 96%. CONCLUSION: We have shown that GIK echocardiography is similar to LDDSE for detection of myocardial viability. With the support of further clinical studies GIK echocardiography could be used to detect myocardial viability after acute MI.     

Role of real-time myocardial contrast echocardiography in the assessment of viability after acute myocardial infarction and angioplasty.

OBJECTIVE: To assess the role of myocardial contrast echocardiography (MCE) in early identification of myocardial viability in patients with residual segmental dysfunction after myocardial infarction and primary angioplasty (PA), in comparison with dobutamine stress echocardiography (DSE), using late functional recovery as gold standard. DESIGN: Prospective study for comparison of the two methods. SETTING: Hospital. PATIENTS: 17 patients (11 male, 53 +/- 11 years old) were consecutively included, with a first myocardial infarction and PA, with residual segmental akinesis or dyskinesis and good echocardiographic window. METHODS: All patients underwent: a) baseline echocardiographic study, MCE, and DSE obtained at 4.0 +/- 1.2 days after PA; b) late echocardiographic study performed at 4.4 +/- 0.8 months after PA. MCE was performed with Optison, administered as a slow infusion via a peripheral vein and a modality of real-time perfusion imaging with power pulse inversion and flash and subsequent data acquisition of triggered end-systolic images. Segmental contractility and perfusion were assessed using a 16-segment model. Perfusion assessment was qualitative (three perfusion patterns) and quantitative (ratio of maximal intensity between dysfunctional segments and contralateral normal segments). The viability criterion for MCE was defined as homogenous enhancement in 50% of wall thickness in each segment. The standard criterion for myocardial viability was defined as late functional recovery. 6. RESULTS: Viability was present in 56 (63.6%, Group 1) of dysfunctional segments and was absent in the remaining 32 (36.4%, Group 2). The sensitivity of DSE for viability was 80.0%, while specificity was 86.5%. The positive and negative predictive values were, respectively, 91.8% and 69.6%. MCE yielded a sensitivity of 96.5% and specificity of 78.1%, while positive and negative predictive values were respectively 86.2% and 94.1%. With the two methods together, the positive predictive value was 90.3% and negative was 80.0%. The intensity ratio was higher for viable segments (Group 1) in comparison with non-viable ones (Group 2; p<0.005). 7. CONCLUSIONS: This study showed a potentially valuable role for MCE in assessing viability in patients with myocardial infarction and PA. In comparison with DSE, MCE yielded a higher negative predictive value as well as a high positive predictive value. The use of both methods together is promising as a useful tool for early assessment of viability after primary angioplasty.