Thrombolytic or Angioplasty Therapy of Evolving Myocardial Infarction?

Journal of Thrombosis and Thrombolysis -     

Myocardial Contrast Echocardiography Versus Dobutamine Echocardiography for Predicting Functional Recovery After Acute Myocardial Infarction Treated With Primary Coronary Angioplasty

Objectives. We sought to compare myocardial contrast echocardiography with low dose dobutamine echocardiography for predicting 1-month recovery of ventricular function in acute myocardial infarction treated with primary coronary angioplasty.

Background. The relation between myocardial perfusion and contractile reserve in patients with acute myocardial infarction, in whom anterograde flow is fully restored without significant residual stenosis, is still unclear.

Methods. Thirty patients with acute myocardial infarction treated successfully with primary coronary angioplasty underwent intracoronary contrast echocardiography before and after angioplasty and dobutamine echocardiography 3 days after the index infarction. One month later, two-dimensional echocardiography and coronary angiography were repeated in all patients and contrast echocardiography in 18 patients.

Results. After coronary recanalization, 26 patients showed myocardial reperfusion within the risk area, although 4 did not. At 1-month follow-up, all patients had a patent infarct-related artery without significant restenosis. Both left ventricular ejection fraction and wall motion score index within the risk area significantly improved in the patients with reperfusion ([mean ± SD] 38 ± 8% vs. 48 ± 12%, p < 0.005; and 2.35 ± 0.5 vs. 2 ± 0.6, p < 0.001, respectively), but not in those with no reflow. Of the 72 nonperfused segments before angioplasty, 27 showed functional improvement at follow-up. Myocardial contrast echocardiography had a sensitivity and a negative predictive value similar to dobutamine echocardiography in predicting late functional recovery (96% vs. 89% and 89% vs. 93%, respectively), but a lower specificity (18% vs. 91%, p < 0.001), positive predictive value (41% vs. 86%, p < 0.001) and overall accuracy (47% vs. 90%, p < 0.001).

Conclusions. Microvascular integrity is a prerequisite for myocardial viability after acute myocardial infarction. However, contrast enhancement shortly after recanalization does not necessarily imply a late functional improvement. Thus, contractile reserve elicited by low dose dobutamine is a more accurate predictor of regional functional recovery after reperfused acute myocardial infarction than microvascular integrity.

(J Am Coll Cardiol 1996;28:1677–83)>     

Thrombolytic Therapy in Acute Myocardial Infarction

Thrombolytic trials in acute myocardial infarction have progressively increased in size, with the GUSTO study including over 40,000 patients. New thrombolytic drugs are unlikely to lead to further major reductions in fatality, and demonstrating small differences from existing compounds would require even larger trials to establish mortality benefits. New agents may, however, have advantages, such as a greater ease of administration or a reduced cost, and the problem is how to assess such new agents in the most efficient way. The concept of equivalence as a clinical trial endpoint is discussed, and the INJECT study, comparing reteplase and streptokinase in acute myocardial infarction, is described as a prototype equivalence trial.     

Randomized Comparison of Primary Coronary Angioplasty With Thrombolytic Therapy in Low Risk Patients With Acute Myocardial Infarction

Objectives. We sought to compare primary coronary angioplasty and thrombolysis as treatment for low risk patients with an acute myocardial infarction.Background. Primary coronary angioplasty is the most effective reperfusion therapy for patients with acute myocardial infarction; however, intravenous thrombolysis is easier to apply, more widely available and possibly more appropriate in low risk patients.Methods. We stratified 240 patients with acute myocardial infarction at admission according to risk. Low risk patients (n = 95) were randomized to primary angioplasty or thrombolytic therapy. The primary end point was death, nonfatal stroke or reinfarction during 6 months of follow-up. Left ventricular ejection fraction and medical charges were secondary end points. High risk patients (n = 145) were treated with primary angioplasty.Results. In low risk patients, the incidence of the primary clinical end point (4% vs. 20%, p < 0.02) was lower in the group with primary coronary angioplasty than in the group with thrombolysis, because of a higher rate of reinfarction in the latter group. Mortality and stroke rates were low in both treatment groups. There were no differences in left ventricular ejection fraction or total medical charges. High risk patients had a 14% incidence rate of the primary clinical end point.Conclusions. Simple clinical data can be used to risk-stratify patients during the initial admission for myocardial infarction. Even in low risk patients, primary coronary angioplasty results in a better clinical outcome at 6 months than does thrombolysis and does not increase total medical charges.(J Am Coll Cardiol 1997;29:908–12)© 1997 by the American College of Cardiology     

Underuse of Thrombolytic Therapy in Acute Myocardial Infarction and Left Bundle Branch Block

Thrombolytic therapy reduces mortality in patients with acute myocardial infarction (AMI) and left bundle branch block (LBBB). The difficulty in accurately diagnosing AMI in patients with LBBB, however, might result in their undertreatment. Among 3,890 patients hospitalized with chest pain, 241 (6.2%) had LBBB at presentation. The only variable independently associated with AMI among patients with LBBB was in‐hospital left ventricular failure (odds ratio [OR]: 4.32, 95% confidence interval [CI]: 1.95–9.57, p < 0.0005). Only 16 (29%) of the LBBB patients with AMI received thrombolytic therapy compared with 583 (78%) of the 747 patients with ST‐elevation AMI (p < 0.0005). A further 19 (10%) LBBB patients without AMI also received thrombolysis. Difficulty in making an accurate early diagnosis in patients with LBBB ensures that the majority of those with AMI fail to receive thrombolytic therapy while others without AMI are treated inappropriately. Improved diagnostic and therapeutic strategies are needed for patients with acute coronary syndromes and LBBB. Copyright © 2010 Wiley Periodicals, Inc.     

Recovery of Myocardial Perfusion in Acute Myocardial Infarction After Successful Balloon Angioplasty and Stent Placement in the Infarct-Related Coronary Artery

Objectives. This study sought to investigate changes in myocardial perfusion after direct percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (MI).Background. After initially successful recanalization of the infarct-related artery, coronary perfusion may deteriorate as a result of reocclusion, distal embolization of platelet aggregates formed at the dilated plaque or microvascular reperfusion injury. This change could offset the benefit from early intervention.Methods. The study included 19 patients in whom the infarct-related artery was successfully recanalized by PTCA with Palmaz-Schatz stent placement within 24 h after the onset of pain. Basal and papaverine-induced coronary blood flow were assessed by Doppler flow velocity measurements and quantitative coronary angiography. In addition, basal and adenosine-induced myocardial blood flow were measured by nitrogen-13 ammonia positron emission tomography (PET).Results. Immediately after completion of the intervention, the average coronary flow reserve (CR) in the recanalized vessel was 1.56 ± 0.51; it increased to 2.04 ± 0.65 at 1 h (p = 0.013) and to 2.66 ± 0.72 at 2 weeks after reperfusion (p = 0.008, n = 16). PET studies in 12 patients revealed that perfusion defect size and CR in the infarct region (2.19 ± 0.89 vs. 2.33 ± 0.86) did not change significantly between day 2 after recanalization and 2 weeks. However, we found significant (p < 0.03) increases in basal (by 26%) and adenosine-induced (by 40%) blood flow in the infarct region.Conclusions. Despite the persistence of a perfusion defect after successful recanalization of the occluded artery in acute MI, CR of the infarct region improves in most patients within 1 h and further improves within 2 weeks.     

直接经皮冠状动脉介入治疗与溶栓后即刻和补救经皮冠状动脉介入治疗对急性心肌梗死患者近期心功能的影响

目的评价直接经皮冠状动脉介入治疗(PCI)与小剂量重组组织型纤溶酶原激活物(rt-PA)溶栓后即刻和补救PCI对急性心肌梗死(AMI)患者的有效性和安全性,并观察其对近期左心室重构及功能的影响.方法对初次发病、发病6 h内且无溶栓禁忌证的AMI患者63例随机给予直接PCI(直接PCI组,32例)或小剂量rt-PA溶栓加即刻和补救PCI(溶栓加补救PCI组,31例)治疗,于术后3 d、30 d、90d行二维超声心动图检查并记录有关心脏事件.结果术后3 d、30 d、90d两组间左心室收缩末期容积指数(ESVI)、左心室舒张末期容积指数(EDSI)、左心室射血分数(EF)和室壁运动指数(WMSI)均无显著差异(P＞0.05);各组内30 d、90d与3 d比较均有显著差异;依据首次造影血流是否达心肌梗死溶栓治疗临床试验(TIMI)3级将所有患者再分为两组.首次造影达TIMI血流3级者与未达TIMI3级者30d、90d各指标均显著改善.结论直接PCI与小剂量rt-PA溶栓后即刻和补救PCI同样安全有效,改善左心室功能并降低心脏事件的发生.     

急性心肌梗死溶栓疗法临床分析

目的 分析溶栓疗法治疗急性心肌梗死的疗效.方法 选择发病在12h内的急性心肌梗死患者30例,在对症治疗的同时立即给予静脉滴注尿激酶100万U,分析患者的冠状动脉再通率情况.结果 30例患者中26例再通,再通率为86.67%,没有发生严重的不良反应.结论 心肌梗死后早期采用静滴尿激酶进行溶栓安全、有效,值得临床推广应用.     

Early Noninvasive Identification of Failed Reperfusion After Intravenous Thrombolytic Therapy in Acute Myocardial Infarction

Objectives. This study sought to evaluate a biochemical approach to the early noninvasive assessment of reperfusion.

Background. In patients with an acute myocardial infarction, a rapid noninvasive method of detecting failure of intravenous thrombolytic therapy to restore early Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow in the infarct-related artery (IRA) is needed.

Methods. Serial blood samples were collected to assay creatine kinase-MB fraction (CKMB mass), cardiac troponin T and myoglobin concentrations in 105 patients with a myocardial infarction who underwent early angiography after intravenous streptokinase. The ratios of the 60- and 90-min concentrations to prethrombolytic values were used to determine an index that could identify failure to achieve TIMI grade 3 flow in the IRA at 90 min.

Results. Significant increases in serum concentrations of markers at 60 min were more likely with TIMI grade 3 flow (59 patients) than with TIMI grade 0 to 2 flow (46 patients). Ratios ≤5 at 60 min after thrombolysis detected failure to achieve 90-min TIMI grade 3 flow with 92% to 97% sensitivity, 43% to 60% specificity and 63% to 76% positive and 86% to 94% negative predictive values. Ratios ≤10 at 90 min showed 88% to 95% sensitivity, 49% to 65% specificity and 61% to 69% positive and 86% to 94% negative predictive values for TIMI flow grade <3. The overall predictive values were thus similar for all three markers.

Conclusions. In acute myocardial infarction treated with intravenous streptokinase, a simple measurement of increased serum concentrations of CKMB mass, cardiac troponin T or myoglobin at 60 and 90 min can accurately predict failure to achieve TIMI grade 3 flow in the IRA at 90 min.     

Thrombolytic Therapy in Acute Myocardial Infarction: Management Algorithms

Journal of Thrombosis and Thrombolysis -     

急性心肌梗死早期溶栓治疗对QT离散度及恶性室性心律失常的影响

研究急性心肌梗死（ＡＭＩ）后溶栓治疗对ＱＴ离散度（ＱＴｄ）及恶性室性心律失常（ＭＶＡ）事件的影响。回顾性选择分析ＡＭＩ患者７５例（溶栓治疗组４３例、未溶栓组３２例）,通过测量入院时及入院后２４ｈ常规心电图计算ＱＴｄ、校正ＱＴｃ（ＱＴｃｄ）,并在入院后一周内心电监护观察ＭＶＡ事件发生情况。溶栓再通组ＱＴｄ、ＱＴｃｄ较溶栓前显著缩短（４２．６±１４．３ｍｓｖｓ７１．７±１６．９ｍｓ,４５．９±１７．４ｍｓｖｓ７４．８±１８．５ｍｓ,Ｐ均＜０．０１）;溶栓未通组、未溶栓组入院２４ｈ期间ＱＴｄ、ＱＴｃｄ无明显变化（Ｐ＞０．０５）。ＱＴｄ、ＱＴｃｄ≥９０ｍｓ者ＭＶＡ事件明显高于＜９０ｍｓ者（７０．６％ｖｓ１０．２％,Ｐ＜０．０１）,溶栓再通组ＭＶＡ事件与溶栓未通组比较趋于减少（１１％ｖｓ２８％）。结论：ＡＭＩ后成功的溶栓治疗可以缩短心室复极的ＱＴｄ,从而可能减少ＡＭＩ后早期ＭＶＡ的发生;无效的溶栓治疗对ＡＭＩ近期预后无任何影响。     

Left Ventricular Mural Thrombus after Acute Myocardial Infarction

Left ventricular mural thrombus is a well-recognized complication of acute myocardial infarction. In survivors of infarction, the incidence with which mural thrombus occurs is influenced by the location and magnitude of infarction, so that it occurs commonly in those with large anterior Q-wave infarctions, particularly in the presence of a left ventricular aneurysm. Echocardiography, radionuclide imaging with indium-111 labeled platelets, computerized tomography, and magnetic resonance imaging may be used to identify a left ventricular mural thrombus. Acute and chronic anticoagulation with heparin and warfarin, respectively, is given to prevent further thrombus formation and to reduce the incidence of systemic embolization.     

Routine Coronary Arteriography Following Thrombolytic Therapy for Acute Myocardial Infarction: An Unsettled Controversy

Although coronary artery disease remains the leading cause of death in industrialized countries, the management of patients recovering from acute myocardial infarction varies significantly. The issue of routine arteriography and revascularization following thrombolytic therapy remains controversial despite substantial evidence associating infarct-related artery patency with improved cardiac function and survival. Randomized trials of routine intervention after myocardial infarction have generally failed to demonstrate advantages of this invasive approach but methodological problems limit their application to current practice. High-risk patients should be referred for arteriography. While awaiting definitive trials addressing the influence of routine arteriography on patient survival and its cost effectiveness, the management of other patient groups must be individualized.