ST段早期恢复反映急性心肌梗死溶栓治疗后心肌再灌注

目的 比较溶栓再通后早期ST段恢复与未恢复者住院期间临床结局的差异，探讨ST段早期恢复在心肌再灌注中的作用。方法 108例溶栓经酶学等指标临床判定再通的急性心肌梗死（AMI）患者，按照有无早期（溶栓后2h)ST段恢复分为两组。连续测定血清肌酸激酶（CK）水平，了解心肌酶峰出现时间及峰值；放射性核素评估左心室功能。观察4周住院期间充血性心力衰竭（CHF）、室壁瘤、心肌梗死后心绞痛发生情况及病死率。结果 无论是前壁MI还是下壁MI，ST段早期恢复组左心室射血分数均高于未恢复组（P＜0．05）；CK峰值则低于未恢复组（P＜0．05）。住院期间ST段恢复组核素心肌显像充盈缺损、CHF及室壁瘤发生率低，心肌梗死后心绞痛发生率高（P值均小于0.05)。结论 同ST段未恢复组相比，溶栓再通后ST段早期恢复者临床预后好。心电图模式可以反映再灌注程度。     

High frequency qrs electrocardiography in the detection of reperfusion following thrombolytic therapy

The hypothesis that an increase in the amplitude (root-mean-square voltage) of the high frequency (150-250 Hz) components of the QRS complex occurs with successful reperfusion following thrombolytic therapy in acute myocardial infarction (AMI) and fails to occur when thrombolysis fails was tested. Clinical markers for successful or failed reperfusion following thrombolytic therapy for AMI are notoriously insensitive. The amplitude of the high-frequency components of the QRS complex decreases during ischemia and returns to normal with resolution of ischemia, but neither the variability in measurement of these potentials nor their patterns of change during the course of AMI have been described. In 32 control subjects, the average coefficient of variation for the amplitude of the highfrequency QRS complex was 10% or 0.3 uV. Based on these data, for the acute infarction population a significant change in this measurement was therefore defined as a change in amplitude > 20% or 0.6 uV on two consecutive recordings. In 30 patients with AMI treated with a thrombolytic agent, either cardiac catheterization, serial serum myoglobin, or complete resolution of ST-segment elevation were used to define successful or failed reperfusion. High-frequency QRS electrocardiograms were obtained at the start of treatment with a thrombolytic agent and for 3 h thereafter using a signal-averaging technique and digital filtering. Standard 12-lead electrocardiograms were obtained at the same time. In patients who reperfused successfully, the high-frequency QRS amplitude increased significantly (1.2 ± 0.9 uV above its nadir at 83 ± 36 min after initiation of thrombolytic therapy) in 23 of 25 patients. In contrast, the highfrequency QRS amplitude did not change or declined in all five patients who failed to reperfuse (-0.4 ± 0.4 uV, p < 0.05 compared with successful reperfusion). Traditional clinical markers such as resolution of chest pain and ST-segment elevation failed to distinguish successful and failed reperfusion. High-frequency QRS electrocardiography is a rapid, reliable bedside technique for discriminating between successful and failed reperfusion in patients treated with thrombolytic agents for AMI.     

Relationship between changes in ST segment elevation and patency of the infarct-related coronary artery in acute myocardial infarction

Forty-one patients with acute myocardial infarction and ST segment elevation were studied to determine the relationship between early changes in ST segment elevation, time to peak serum creatine kinase (CK), peak serum CK, left ventricular function, and patency of the infarct-related artery. ST segment elevation decreased by more than 40% within 8 hours of peak sigma ST in all patients with inferior infarction and in 10 of the 13 patients with anterior infarction and subtotal occlusion, but in none of the patients with anterior infarction and total occlusion (p = 0.003). The time to peak serum CK was related to the rate of decrease of ST segment elevation in patients with anterior (r = 0.59) and inferior (r = 0.71) infarction. In patients with anterior infarction, peak serum CK tended to be lower and left ventricular ejection fraction (EF) higher in those with rapid resolution of ST segment elevation than in those with persistent ST elevation (1721 +/- 1422 U/L vs 3285 +/- 1148 U/L, p less than 0.10, for peak CK; and 50.3 +/- 18.5% vs 41.2 +/- 12.8%, p = NS, for EF), but there was no difference in the patients with inferior infarction. Early resolution of ST segment elevation is an index of early spontaneous antegrade or collateral reperfusion in patients with acute myocardial infarction.     

Prognostic value of angiographic markers of myocardial reperfusion in patients treated with primary coronary angioplasty for anterior wall acute myocardial infarction

BACKGROUND: Modern therapy of acute myocardial infarction (AMI) is aimed at rapid and persisting restoration of blood flow in an infarct-related artery (IRA). However, in some patients myocardial reperfusion is not achieved in spite of effective IRA recanalisation. Myocardial Blush Grade (MBG) is one of the angiographic markers useful for the detection of this phenomenon. AIM: To assess the prognostic value of MBG in patients with anterior AMI treated with primary angioplasty. METHODS: The study group consisted of 104 patients (74 males, 30 females, mean age 62+/-13 years) treated with primary angioplasty due to anterior ST-segment elevation AMI. MBG was assessed after the procedure. The mortality and major cardiovascular event (MACE) rates were analysed one and six months after AMI. RESULTS: Patients with preserved myocardial reperfusion following angioplasty (MBG 2-3, n=64 (61.5%)) had a trend towards lower one-month mortality and significantly reduced six-month mortality compared with 40 (38.5%) patients with an impaired (MBG 0-1) myocardial reperfusion (3% vs 12.5%, NS; and 6.25% vs 20%, p<0.05, respectively). The rate of MACE was significantly lower in patients with rather than without reperfusion both after one and six months of follow-up (9.4% vs 27.5%, p=0.027 and 12.5% vs 42.5%, p<0.001, respectively). Compared with patients with a high MBG score, patients with altered reperfusion more frequently had diabetes (30% vs 12.5%, p=0.04), hypertension (67.5% vs 45%, p=0.043), longer time from the onset of symptoms to balloon inflation (355.9+/-199 min vs 215.5+/-113 min, p<0.001) and lower left ventricular ejection fraction, measured 3 days after AMI (43.3%+/-8 vs 47.4%+/-9, p=0.02). CONCLUSIONS: MBG has a significant prognostic value in patients with anterior AMI treated with primary angioplasty. Diabetes, hypertension and long delay of treatment are associated with the impairment of myocardial reperfusion.     

Transient increase in ST-segment elevation immediately after reperfusion in acute myocardial infarction]

The significance of transient increase in ST-segment elevation immediately after reperfusion in acute myocardial infarction (AMI) was assessed by 12-lead electrocardiography. The study population consisted of 18 patients with initial anterior AMI, whose totally-occluded left anterior descending arteries were reperfused within 6 hours after the onset of symptoms. The ST-segment elevation was defined as that of more than 0.2 mV in the V3 lead immediately after reperfusion. Collateral circulation, timing of reperfusion, CPK release, left ventricular ejection fraction and mean % 201Tl uptake in the infarct regions were compared between patients with and without ST elevation. Eleven patients (61%) had ST-segment elevation (0.61 +/- 0.29 mV). Well-developed collaterals were observed in 43% of patients without ST-segment elevation (p < 0.05) but not in those with ST elevation. ST-segment elevations were accompanied by delays in timing of reperfusion (3.7 +/- 1.2 hrs vs 2.5 +/- 0.9 hrs, p < 0.05), higher peak CPK values (6,190 +/- 3,156 IU/l vs 3,222 +/- 2,053 IU/l, p < 0.05) and lower mean % 201Tl uptake (54.2 +/- 11.4% vs 73.9 +/- 11.3%, p < 0.01). We concluded that transient increase in ST-segment elevation immediately after reperfusion may relate to poorly-developed collaterals and prolongation of ischemia; i.e., severe ischemia before reperfusion, and therefore may reflect myocardial reperfusion injuries.     

Reliability of resolution of ST-segment elevation after coronary reperfusion in predicting myocardial salvage in anterior wall acute myocardial infarction

Resolution of ST-segment elevation (ST resolution) after reperfusion therapy has been shown to correlate with improved left ventricular (LV) function in patients with acute myocardial infarction (AMI). However, not all patients with ST resolution have preserved LV function. We evaluated the clinical significance of ST resolution in 129 patients with anterior wall AMI who underwent successful coronary recanalization within 6 hours after symptom onset by studying the relation to myocardial blush grade, another angiographic marker of myocardial reperfusion. A reduction of > or =50% in ST-segment elevation after recanalization was defined as ST resolution. Ninety-eight patients had ST resolution and 31 patients did not. Patients with ST resolution were subdivided into 2 groups according to myocardial blush grade after recanalization: 67 patients with blush grade 2 or 3, and 31 with blush grade 0 or 1. The QRS score after recanalization was higher (5.9 +/- 1.9 vs 3.4 +/- 2.0, p <0.01) and predischarge LV ejection fraction was lower (39 +/- 8% vs 57 +/- 9%, p <0.01) in patients with blush grade 0 or 1 than in those with blush grade 2 or 3. However, the QRS score after recanalization and the predischarge LV ejection fraction were similar in patients who had ST resolution with blush grade 0 or 1 and in those without ST resolution. Our findings suggest that ST resolution after recanalization does not consistently predict myocardial salvage in patients with anterior AMI.     

急性前壁心肌梗死伴不同下壁导联ST段改变的临床特点

目的探讨ST段抬高急性前壁心肌梗死(简称心梗)伴不同下壁导联ST段改变患者的梗死相关血管以及梗死面积及心功能情况。方法73例急性前壁心梗患者,根据入院时心电图下壁导联ST段改变情况将患者分为3组:A组为Ⅱ、Ⅲ、aVF中至少两个导联ST段抬高;B组为Ⅱ、Ⅲ、aVF中至少两个导联ST段压低,C组为Ⅱ、Ⅲ、aVF中少于两个导联ST段有改变。比较三组CK最大值,左室射血分数以及梗死相关血管(IRCA)。结果CK最大值3组比较A组最低(1280±531IU/Lvs2034±911,1677±630IU/L,P<0.01);左室射血分数A组最高(0.54±0.09vs0.48±0.07,0.47±0.08,P<0.01);三组IRCAA组中85.7%的患者位于“绕过心尖的左前降支(LAD)”的中远段,有14.3%的患者位于右冠状动脉(RCA)的近段;B组的患者中全部为非“绕过心尖的LAD”,其中有70.4%的患者位于非“绕过心尖的LAD”的近段;C组中有96.7%的患者为非“绕过心尖的LAD”,其中有73.3%的患者位于非“绕过心尖的LAD”的近中段,三组比较差异有显著性(P<0.01)。结论IRCA为LAD的急性前壁心梗时下壁ST段改变可能与LAD长度和病变部位有关;前壁合并下壁ST段同时抬高的患者若IRCA为“绕过心尖的LAD”,其梗死面积较小,心功能较好。     

A correlative study of ECG and coronary arteriogram findings after acute myocardial infarction

To evaluate the electrocardiographic value in the prediction of reperfusion state of the infarct-related artery (IRA), serial changes in ST segment elevation were assessed in 38 patients with acute myocardial infarction (AMI). ST segment elevation decreased by 35% or more within 8 hours of peak sigma ST in 16 of the 20 patients with subtotal occlusion, but in none of the patients with total occlusion of the IRA (P less than 0.01). Myocardial infarct size estimated by peak serum CK-MB, sigma Q and QRS score was smaller and left ventricular function was better in patients with rapid resolution of ST segment elevation than in those with persistent ST elevation. The study indicates that a fall of ST segment elevation by 35% or more of the peak sigma ST within 8 hours of infarction may be a useful indicator of early reperfusion of the IRA in patients with AMI.     

急性心肌梗死急诊经皮冠状动脉介入治疗后 ST段变化与临床预后的关系

目的 研究急性心肌梗死(AMI)成功急性介入术后ST段变化与临床预后的关系。 方法 回顾分析45例AMI患者的临床及造影情况,记录住院时、急诊介入术后90分钟、6小时、12小时、24小时12导联心电图,化验心肌CK值。介入治疗后在90分钟内抬高ST段回落>50％,CK峰值在12小时内,24小时内T波反转作为灌注组,不符合上述条件者为无灌注组。 结果45例AMI患者中36例(80％)再灌注,无再灌注组9例(20％);前壁心肌梗死无灌注组7例、而心肌再灌注组下壁心肌梗死20例。充血性心力衰竭、死亡,灌注组5例,无灌注组5例。 结论 AMI成功急性介入术后ST段变化与微循环障碍及住院期间的临床预后密切相关。     

Acute Myocardial Infarction with Hyperoxemic Therapy (AMIHOT): a prospective, randomized trial of intracoronary hyperoxemic reperfusion after percutaneous coronary intervention.

OBJECTIVES: This study sought to determine whether hyperoxemic reperfusion with aqueous oxygen (AO) improves recovery of ventricular function after percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI). BACKGROUND: Hyperbaric oxygen reduces myocardial injury and improves ventricular function when administered during ischemia-reperfusion. METHODS: In a prospective, multicenter study, 269 patients with acute anterior or large inferior AMI undergoing primary or rescue PCI (<24 h from symptom onset) were randomly assigned after successful PCI to receive hyperoxemic reperfusion (treatment group) or normoxemic blood autoreperfusion (control group). Hyperoxemic reperfusion was performed for 90 min using intracoronary AO. The primary end points were final infarct size at 14 days, ST-segment resolution, and delta regional wall motion score index of the infarct zone at 3 months. RESULTS: At 30 days, the incidence of major adverse cardiac events was similar between the control and AO groups (5.2% vs. 6.7%, p = 0.62). There was no significant difference in the incidence of the primary end points between the study groups. In post-hoc analysis, anterior AMI patients reperfused <6 h who were treated with AO had a greater improvement in regional wall motion (delta wall motion score index = 0.54 in control group vs. 0.75 in AO group, p = 0.03), smaller infarct size (23% of left ventricle in control group vs. 9% of left ventricle in AO group, p = 0.04), and improved ST-segment resolution compared with normoxemic controls. CONCLUSIONS: Intracoronary hyperoxemic reperfusion was safe and well tolerated after PCI for AMI, but did not improve regional wall motion, ST-segment resolution, or final infarct size. A possible treatment effect was observed in anterior AMI patients reperfused <6 h of symptom onset.     

Significance of neutrophil counts after reperfusion therapy in patients with a first anterior wall acute myocardial infarction.

BACKGROUND: Previous studies have demonstrated that an elevated neutrophil count on admission is associated with a higher risk of adverse events after acute myocardial infarction (AMI). However, the significance of the neutrophil count after reperfusion therapy has not been elucidated. METHODS AND RESULTS: The association of the neutrophil count on admission and days 2 and 3 with peak creatine kinase (CK) concentration, ST-segment resolution (a marker of myocardial tissue-level reperfusion), and left ventricular (LV) function at predischarge were examined in 122 patients (102 men, 20 women, mean age 61+/-11 years) with a first anterior wall AMI. Neutrophil counts were increased on day 2 and decreased on day 3 compared with admission (8,768+/-3,005 mm3, 6,617+/-2,424 mm3, and 7,725+/-3,388 mm3, respectively). Patients with ST-segment resolution (n=52) had lower neutrophil counts on days 2 and 3 than those without it (n=70), but neutrophil counts on admission did not differ significantly between patients with and without ST-segment resolution. Neutrophil counts on admission and days 2 and 3 were weakly but significantly correlated with peak CK concentration (r=0.31, p=0.0004; r=0.43, p<0.0001; r=0.32, p=0.003, respectively) and with LV ejection fraction at predischarge (r=-0.18, p=0.04; r=-0.26, p=0.003; r=-0.27, p=0.003; respectively). CONCLUSION: The neutrophil count after reperfusion is weakly but significantly correlated with infarct size, myocardial tissue-level reperfusion, and LV function at predischarge in a first anterior wall AMI. These correlations were slightly stronger than the correlations with the neutrophil count on admission.     

Early peak creatine kinase activity is not always a marker of successful reperfusion with myocardial salvage in patients with reperfused anterior acute myocardial infarction

BACKGROUND: Although early peak creatine kinase activity (peak CK) is considered a reliable marker of coronary reperfusion in patients with acute myocardial infarction (AMI), whether early peak CK indicates good myocardial salvage is unclear. Moreover, some patients have late peak CK despite successful reperfusion, and its clinical implication remains to be elucidated. METHODS AND RESULTS: We examined the association of the time to peak CK with predischarge left ventricular function in 124 patients with a first AMI who had successful reperfusion within 6 hours from symptom onset. Patients were classified according to the time from reperfusion to peak CK: group A, 61 patients with peak CK < 6 hours; group B, 42 with peak CK from 6 to 12 hours; and group C, 21 with peak CK > 12 hours. There were no differences among the 3 groups in age, sex, method of reperfusion, time from symptom onset to reperfusion, collateral circulation, or the extent of risk area estimated by number of leads with ST-segment elevation. Left ventricular ejection fraction measured by predischarge left ventriculography was lowest in group A, followed by group B, and highest in group C (median values, 43%, 52%, and 60%, P < .01). Left ventricular dysfunction (left ventricular ejection fraction < or = 40%) occurred in 26 (43%) patients in group A, 8 (19%) in group B, and none in group C (P < .01). CONCLUSIONS: We conclude that compared with early peak CK, late peak CK consistently reflects good myocardial salvage in patients with anterior AMI who had successful reperfusion within 6 hours from symptom onset.     

Tissue-Type Plasminogen Activator Therapy Versus Primary Coronary Angioplasty: Impact on Myocardial Tissue Perfusion and Regional Function 1 Month After Uncomplicated Myocardial Infarction

Objectives. This study sought to compare the impact of primary coronary angioplasty and thrombolytic therapy for acute myocardial infarction (AMI) on 1-month infarct size and microvascular perfusion.Background. The effect of the reperfusion strategies of primary coronary angioplasty and thrombolytic therapy on microvascular integrity still remains to be determined.Methods. Sixty-two consecutive patients with a first AMI, undergoing intravenous tissue-type plasminogen activator (t-PA) therapy (32 patients, Group I) or primary angioplasty (30 patients, Group II), were studied. Only patients with 1-month Thrombolysis in Myocardial Infarction (TIMI) flow grade 2 or 3 were selected for the study. Patients in whom primary angioplasty was unsuccessful or those with clinical evidence of failed reperfusion were excluded. Microvascular perfusion was assessed at 1 month by intracoronary injection of sonicated microbubbles. Contrast score index (CSI) and wall motion score index (WMSI) were derived using qualitative methods.Results. At baseline there were no significant differences between groups for age, risk factors, time to hospital presentation, Killip class on admission, prevalence of multivessel disease or anterior infarct site, infarct area extension before reperfusion, peak creatine kinase levels and postinfarction treatment. Conversely, significant differences between groups were found at follow-up for percent residual infarct related-artery (IRA) stenosis (70 ± 12 vs 36 ± 14 [mean ± SD], p = 0.0001), CSI (1.02 ± 0.4 vs. 1.49 ± 0.5, p = 0.0003) and WMSI (1.67 ± 0.3 vs. 1.45 ± 0.3, p = 0.015). In particular, in the subset of patients with TIMI grade 3 flow, a perfusion defect occurred in one or more segments subtended by the IRA in 72% of Group I versus 31% of Group II patients (p < 0.00001) and in 27% of Group I versus 8% of Group II segments (p < 0.00001).Conclusions. The present study shows, in a highly selected cohort with successful IRA recanalization, that primary angioplasty is more effective than thrombolysis in preserving microvascular flow and preventing extension of myocardial damage at 1-month after AMI.     

Serial plasma catecholamine response early in the course of clinical acute myocardial infarction: Relationship to infarct extent and mortality

Clinical and experimental evidence suggest that sympathoadrenal activation contributes to mortality in patients with ischemic heart disease. To determine the level of sympathoadrenal activation in the very early phase of acute myocardial infarction (AMI) and to determine if location of infarction (anterior versus inferior) was related to sympathoadrenal activation, we studied norepinephrine (NE) and epinephrine (E) within 4 hours after the onset of symptoms and prior to any rise in plasma creatine kinase (CK). Mean (± SE) initial (NE = 591 ± 111 pg/ml and E = 73 ± 19 pg/ml), peak (NE = 1356 ± 178 and E ± 1098 ± 608) and average (NE = 815 ± 142 and E = 252 ± 68) plasma catecholamine concentrations were considerbly above normal (NE = 228 ± 10 and E = 34 ± 2 pg/ml, n 60) and values were similar for inferior and anterior infarctions. During an 18-month follow-up, three patients died in whom the AMI mean NE and E and peak CK were higher than in the eight late survivors. Thus the three AMI patients with peak EP values > 1000 died, whereas the eight AMI patients with peak EP values < 1000 survived (p < 0.01). The magnitude of sympathoadrenal activation early in the course of clinical AMI appeared related to the extent of myocardial damage and late mortality.     

探讨老年急性心肌梗死患者冠状动脉介入治疗后ST段与血糖和肌钙蛋白T的关系

目的探讨入院时血糖水平对老年急性心肌梗死(AMI)患者PCI术后ST段下降幅度(STR)和肌钙蛋白T峰值的影响。方法首次AMI的412例老年患者,根据其血糖水平分为3组:A组(血糖<7.0mmol/L)156例;B组(血糖7.0～11.1mmol/L)135例;C组(血糖>11.1mmol/L)121例;分析3组患者急诊PCI术后90minSTR与血浆肌钙蛋白T峰值的相关性。结果C组患者PCI术后90minSTR>70%较A组显著减少(17.96%vs51.49%,P<0.01),B组患者PCI术后90minSTR30%～70%与血糖水平的高低差异无统计学意义(P=0.061);PCI术后,STR>70%的患者肌钙蛋白T峰值低于STR<30%患者[(0.033±0.018)ng/Lvs(0.107±0.055)ng/L,P<0.05],差异有统计学意义;logistic回归分析显示,C组肌钙蛋白T峰值升高与血糖的相关性最为密切(r=0.399,P=0.001)。入院时血糖水平与肌钙蛋白T峰值呈显著正相关,入院时血糖水平越高,血清肌钙蛋白T峰值升高越明显。结论入院时血糖升高的老年AMI患者PCI术后,较好的控制血糖对于此类患者有效的心肌再灌注是十分重要的。     

Intracoronary ST segment evolution during primary coronary stenting predicts infarct zone recovery

In patients with acute myocardial infarction (AMI), early ST segment elevation resolution on ECG predicts myocardial reperfusion and LV recovery. Intracoronary ECG is more sensitive than surface ECG to detect regional ischemia. In patients undergoing primary percutaneous coronary intervention (PCI), we investigated if failed myocardial reperfusion, despite successful infarct vessel recanalization, could be rapidly and easily identified by intracoronary ST segment monitoring from guidewire recording. We recorded intracoronary and standard ECG during primary coronary stenting (PCI) in 50 patients with AMI (59 ± 11 years; anterior AMI in 66%). All patients had a successful PCI and underwent 2D echocardiography soon after PCI and 6 months later. Following PCI, intracoronary ST resolution ≥ 50% from baseline was documented in 39 patients (78%; group A; from 11 ± 8 to 1 ± 2 mm) but not in 11 (22%; group B; from 11 ± 8 to 8 ± 5 mm). Group A had slightly shorter ischemic time (202 ± 94 vs. 238 ± 112 min in B; P = 0.2) and smaller peak CK values (2,752 ± 2,038 vs. 4,802 ± 3,671 U/L in B; P = 0.02). After PCI, ST resolution was found on standard ECG in 34 (87%) group A and in 3 (27%) group B patients. At 6‐month follow‐up, left ventricular ejection fraction was greater in group A (47% ± 8% vs. 39% ± 8% in B; P < 0.001) with improved wall motion score index (from 2.2 ± 0.3 to 1.7 ± 0.3 in A; from 2.3 ± 0.4 to 2.1 ± 0.4 in B; P < 0.001). There were no significant differences between intracoronary and standard ECG for sensitivity (92% vs. 86%) and specificity (62% vs. 57%) to predict improved infarct zone recovery after 6 months. ST elevation resolution on intracoronary recording during PCI predicts infarct zone recovery. Monitoring ST segment evolution by intracoronary ECG allows prompt and inexpensive identification in the catheterization laboratory of those patients without myocardial reperfusion, who may require adjunctive therapeutic interventions after successful infarct vessel recanalization. Catheter Cardiovasc Interv 2005;64:53–60. © 2004 Wiley‐Liss, Inc.     

Coronary Circulatory Indexes in Non-Infarct-Related Vascular Territories in a Porcine Acute Myocardial Infarction Model

ObjectivesThe aim of this study was to evaluate temporal changes in coronary hemodynamic and physiological indexes in the non-infarct-related artery (IRA), which might be affected by adjacent infarcted myocardium, using an experimental animal model of acute myocardial infarction.BackgroundThere has been debate on the reliability of fractional flow reserve and resting pressure-derived indexes, including instantaneous wave-free ratio, in the non-IRA in patients with acute ST-segment elevation myocardial infarction.MethodsIn Yorkshire swine, acute myocardial infarction was simulated with selective balloon occlusion at the left circumflex coronary artery as the IRA for 30 min. Non-IRA stenosis was created using bare-metal stent implantation in the left anterior descending coronary artery 4 weeks before the experiments. Serial changes in systemic hemodynamic status, coronary pressure, and Doppler-derived coronary flow velocity were measured in a nonoccluded left anterior descending coronary artery as the non-IRA from baseline, balloon occlusion of the left circumflex coronary artery, and 15 min after reperfusion of the left circumflex coronary artery.ResultsAmong the 6 experimental subjects, the median diameter stenosis of the non-IRA was 33.9% (interquartile range: 21.7% to 46.1%). During balloon occlusion of the IRA, there were transient significant changes in both resting and hyperemic aortic pressure, distal coronary pressure, averaged peak velocity, transstenotic pressure gradient, and microvascular resistance of the non-IRA (p < 0.020 for all). After reperfusion of the IRA, the resting averaged peak velocity (p = 0.002) and resting transstenotic pressure gradient (p = 0.004) were significantly increased and resting microvascular resistance (p = 0.004) was significantly decreased compared with their values in the baseline phase. However, the hyperemic averaged peak velocity (p = 0.479), hyperemic transstenotic pressure gradient (p = 0.778), and hyperemic microvascular resistance (p = 0.816) were not significantly different compared with those in the baseline phase. After reperfusion, fractional flow reserve in the non-IRA was not significantly different (0.94 ± 0.01 vs. 0.93 ± 0.01; p = 0.353), while coronary flow reserve (1.93 ± 0.07 vs. 1.36 ± 0.07; p = 0.025) and instantaneous wave-free ratio (0.97 ± 0.01 vs. 0.93 ± 0.01; p = 0.001) were significantly lower than baseline values.ConclusionsIn a porcine model of acute myocardial infarction, occlusion of the IRA induced significant changes in systemic hemodynamic status and coronary circulatory indexes of the non-IRA. However, after reperfusion of the IRA, fractional flow reserve did not change significantly, whereas coronary flow reserve and instantaneous wave-free ratio showed significant changes compared with baseline values.     

急性心肌梗死再灌注心律失常的分布特征及其与自主神经失衡的关系

目的:观察急性ST段抬高型心肌梗死（STEMI）患者自主神经活性及再灌注心律失常（RA）特点，探讨自主神经在急性STEMI再灌注心律失常的作用及机制。方法:冠状动脉造影证实梗死血管完全闭塞的患者，12 h内完成急诊冠状动脉介入（PCI）治疗的108例，根据梗死相关动脉分组，以梗死后心率、血压情况，评估自主神经活性。分析RA分布特征及与自主神经失衡的关系。结果: RA总发生率为44%，右冠状动脉组RA发生率显著高于其他部位（65% vs. 35%和33%，P<0.01),距开通时间愈短RA发生率愈高(P<0.05,P<0.01)。前降支组交感神经过度激活者增多，右冠状动脉组迷走神经过度激活者增多，两组有显著性差异。结论:STEMI梗死再灌注RA总发生率为44%，右冠状动脉发生率显著高于其他部位，距开通时间愈短发生率愈高，且RA与自主神经失衡有关。     

Intracoronary thrombectomy improves myocardial reperfusion in patients undergoing direct angioplasty for acute myocardial infarction

OBJECTIVES: We sought to evaluate the effects of mechanical thrombectomy on myocardial reperfusion during direct angioplasty for acute myocardial infarction (AMI). BACKGROUND: Embolization of thrombus and plaque debris may occur during direct angioplasty for AMI. This may lead to distal vessel or side branch occlusion and to obstructions in the microvascular system, resulting in impaired myocardial reperfusion. Mechanical thrombectomy is used to reduce distal embolization. METHODS: Ninety-two patients with AMI and angiographic evidence of intraluminal thrombus were randomized to either intracoronary thrombectomy followed by stenting or to a conventional strategy of stenting. Thrombectomy was performed using the X-Sizer catheter (EndiCOR Inc., San Clemente, California). Myocardial reperfusion was assessed by myocardial blush and ST resolution. RESULTS: Postprocedure Thrombolysis in Myocardial Infarction-3 flow was not different between groups (93.5% vs. 95.7%, p = 0.39). Myocardial blush-3 was observed in 71.7% of patients undergoing thrombectomy and in 36.9% of patients undergoing conventional strategy (p = 0.006). ST-segment resolution >or=50% occurred more often in patients undergoing thrombectomy (82.6% vs. 52.2%, p = 0.001). By multivariate analysis, adjunctive thrombectomy was an independent predictor of blush-3 (odds ratio, 3.27; 95% confidence interval, 1.06 to 10.05; p = 0.039). CONCLUSIONS: Intracoronary thrombectomy as adjunct to stenting during direct angioplasty for AMI improves myocardial reperfusion as assessed by myocardial blush and ST resolution.     

Association of noninvasive markers of coronary artery reperfusion to assess microvascular obstruction in patients with acute myocardial infarction treated with primary angioplasty.

Early restoration of coronary artery patency through primary angioplasty limits infarct size and improves survival. Increasing evidence, however, suggests that microvascular obstruction is often present despite coronary artery recanalization. This may limit the benefits of reperfusion therapy. We studied the use of noninvasive markers of coronary artery reperfusion as indicators of microvascular obstruction and determinants of prognosis in 98 patients with acute myocardial infarction (AMI) who were successfully treated with primary angioplasty (Thrombolysis In Myocardial Infarction grade 3 flow and residual stenosis <30%). Plasma creatine kinase (CK) levels and 12-lead electrocardiograms were performed on admission, at 90 minutes, and at 6, 12, and 24 hours after treatment. We defined: (1) reperfusion as resolution of ST-segment elevation >50% at 90 minutes, with peak CK levels within 12 hours, and T-wave inversion within 24 hours; and (2) failed reperfusion, as the absence of these parameters. Of the 98 patients studied, 87 (88.8%) had reperfusion and 11 (11.2%) had failed reperfusion. Infarct location was anterior (versus inferior) in 9 patients in the failed reperfusion group (81.8%) compared with 41 patients in the reperfusion group (47.1%) (p <0.01). Congestive heart failure >24 hours after presentation or in-hospital death occurred in 11 patients (12.6%) in the reperfusion group versus 5 (45.5%) in the failed reperfusion group (p <0.01). One-year survival was 96.1% for the reperfusion group and 60.6% for the failed reperfusion group (p <0.0001). We conclude that the association of noninvasive markers of reperfusion better identifies patients with microvascular obstruction among those who had a "successful" primary angioplasty. Evidence of impaired microvascular reperfusion is associated with a poor in-hospital and 1-year outcome.