Assessment of serum phenylalanine and tyrosine isomers in patients with ST‐segment elevation vs non‐ST‐segment elevation myocardial infarction

BackgroundUnder conditions of oxidative stress, hydroxyl radicals can oxidize phenylalanine (Phe) into various tyrosine (Tyr) isomers (meta‐, ortho‐, and para‐tyrosine; m‐, o‐, and p‐Tyr), depending on the location of the hydroxyl group on the oxidized benzyl ring. This study aimed to compare patients with ST‐segment elevation myocardial infarction (STEMI) and non‐STEMI (NSTEMI) and the serum levels of Phe and Tyr isomers at the aortic root and distal to the culprit lesion in both groups.MethodsForty‐four patients participated in the study: 23 with STEMI and 21 with NSTEMI. Arterial blood samples were taken from the aortic root through a guiding catheter and from the culprit vessel segment distal from the primary lesion with an aspiration catheter, during the percutaneous coronary intervention. Serum levels of Phe, p‐Tyr, m‐Tyr, and o‐Tyr were determined using reverse‐phase high‐performance liquid chromatography.ResultsSerum levels of Phe were significantly higher distal to the culprit lesion compared to the aortic root in patients with STEMI. Serum p‐Tyr/Phe and m‐Tyr/Phe concentration ratios were both lower distal to the culprit lesion than at the aortic root in patients with STEMI. There were no statistically significant differences with respect to changes in serum Phe and Tyr isomers distal to the culprit lesion compared to the aortic root in patients with NSTEMI.ConclusionOur data suggest that changes in serum levels of different Tyr isomers can mediate the effects of oxidative stress during myocardial infarction.     

Acute ST‐elevation myocardial infarction in a 24‐year‐old woman with atheromatous coronary artery disease

We report the case of a 24‐year‐old Torres Strait Islander woman who presented to a rural hospital ED with chest pain suspicious for myocardial ischaemia and was found to have an anterior ST‐elevation myocardial infarction. She was thrombolysed and transferred to a tertiary centre where subsequent angiography revealed atheromatous disease of the left anterior descending coronary artery. We believe this to be one of the youngest reported cases of myocardial infarction due to atheromatous coronary artery disease, and demonstrates important learning points regarding the demographics and risk factors of indigenous patients with chest pain.     

影响急性心肌梗死患者院前延迟时间的因素

目的探讨影响急性心肌梗死(AMI)患者院前延迟时间(PDT)的相关因素.方法收集461例AMI患者,剔除47例资料不全者,将入选414例分为PDT≤6小时组221例,PDT>6小时组193例.分析包括性别、年龄、高血压病史、糖尿病病史、高血脂、吸烟史、既往心绞痛史、发病时间、主要症状、入院时心功能、梗死部位等.结果① PDT＞6小时组较PDT≤6小时组年龄大,女性患者比例高,糖尿病病史者比例高,既往有心绞痛病史者多,夜间发病者比例高,两组相比差异均有统计学意义(P＜0.05～0.01).但典型胸痛症状和入院时心功能不全PDT＞6小时组较PDT≤6小时组比率低,两组差别均有统计学意义(P＜0.05～0.01).②多元逻辑回归分析显示年龄、糖尿病病史、既往心绞痛病病史、发病时间及入院时心功能不全为影响PDT的独立相关因素.结论年龄、糖尿病病史、心绞痛病史、发病时间及入院时心功能不全为影响AMI患者PDT的独立相关因素.     

The CD14++CD16+ monocyte subset and monocyte‐platelet interactions in patients with ST‐elevation myocardial infarction

Summary. Aim: Monocytes contribute to both myocardial damage and repair by virtue of subset heterogeneity. The dynamics and functional characteristics of the three human monocyte subsets, including the unique CD14++CD16+ subset, and their contributions to monocyte platelet aggregates (MPAs) following ST‐elevation myocardial infarction (STEMI) are unknown. We aimed to examine dynamic changes and relation to left ventricular ejection fraction (LVEF) of the three human monocyte subsets and their aggregates with platelets following STEMI. Methods: Three monocyte subsets, CD14++CD16?CCR2+ (‘classical’, Mon1), CD14++CD16+CCR2+ (‘intermediate’, Mon2) and CD14+CD16++CCR2? (‘non‐classical’, Mon3), and their contribution to MPAs were analyzed by flow cytometry in 50 patients with STEMI, 40 patients with stable coronary artery disease (CAD) and 40 healthy volunteers. Study parameters were measured within 24 h of primary percutaneous coronary intervention (PCI) (day1) and on days 3, 7 and 30. Monocyte activation was assessed by measuring the nuclear factor κB (NFκB) pathway. LVEF was assessed 6 weeks after STEMI. Correlations between monocyte subsets/MPAs and plasma cytokines and troponin were assessed. Results: We observed marked differences in subset dynamics, with a prominent increase in Mon2 (P < 0.0001) but no changes in Mon3. Significant increases in Mon2 CD14 (P = 0.002) and CCR2 (P < 0.0001) expression, and reduction in CD16 expression (P = 0.001) were seen. NFκB pathway activity increased most prominently in Mon2 (P = 0.007). Mon2 count correlated with peak troponin (r = 0.31, P = 0.04) and plasma interleukin (IL)‐6 (r = 0.65, P < 0.0001) and IL‐10 (r = 0.34, P = 0.017). Mon1 correlated with IL‐6 (r = 0.55, P < 0.0001). Reduced Mon2 expression of CD16 on day 1 was independently predictive of higher LVEF (β = ?0.37, P = 0.013). The increase in MPA count following STEMI persisted at 1 month. Conclusion: The Mon2 ‘intermediate’ subset has unique dynamic and functional characteristics following STEMI and significant correlations with troponin, plasma cytokines and convalescent left ventricular function. The persistent increase in MPA count 30 days after STEMI may affect monocyte subset functional activity.     

Acute and subacute stent thrombosis after primary percutaneous coronary intervention for ST‐segment elevation myocardial infarction: incidence,predictors and clinical outcome

Summary. Background: Early coronary stent thrombosis occurs most frequent after primary percutaneous coronary intervention (PCI) for ST‐segment elevation myocardial infarction (STEMI). Objectives: To identify the specific predictors of, respectively, acute and subacute stent thrombosis in patients after primary PCI for STEMI. Patients/Methods: Consecutive STEMI patients with angiographically confirmed early stent thrombosis were enrolled and compared in a 2 : 1 ratio with a matched control group. Clinical outcome was collected up to 1 year. Results: Of 5842 STEMI patients treated with primary PCI, 201 (3.5%) presented with a definite early stent thrombosis. Of these, 97 (1.7%) had acute stent thromboses and 104 (1.8%) had subacute stent thromboses. Postprocedurally discovered dissection, undersizing and smaller stent diameter were the strongest predictors for acute stent thrombosis. No glycoprotein IIb/IIIa therapy and the use of drug‐eluting stents were also associated with acute stent thrombosis. Lack of clopidogrel therapy in the first 30 days after the index PCI was the strongest predictor for subacute stent thrombosis. Mortality rates at 1‐year follow‐up were lower for acute stent thrombosis than for subacute stent thrombosis (8.3% vs. 13.2%, P = 0.294). The incidence of definite recurrent stent thrombosis at 1‐year follow up was significantly lower after a first definite acute stent thrombosis than after a first definite subacute stent thrombosis (6.4% vs. 19.3%, P = 0.007 at 1 year). Conclusions: The specific risk factors for, respectively, acute and subacute stent thrombosis after primary PCI vary greatly. Mortality rates are high for both categories of stent thrombosis. However, recurrent stent thrombosis occurs more frequently after subacute stent thrombosis.     

Association between serum hemoglobin and major cardiovascular adverse event in Chinese patients with ST‐segment elevation myocardial infarction after percutaneous coronary intervention

BackgroundST‐segment elevation myocardial infarction (STEMI) is a common clinical acute and severe disease, and it is of great significance to evaluate the prognosis of these patients. Hemoglobin levels are associated with a variety of diseases, but studies on Chinese patients with STEMI after percutaneous coronary intervention (PCI) have not been sufficient.MethodsThis was a secondary analysis based on a prospective cohort study of patients undergoing PCI in Taizhou, Zhejiang, China. We performed multivariable logistic regression to explore the association between the serum hemoglobin and the incidence of major cardiovascular adverse event (MACE) in patients after PCI. We also used a generalized additive model and smooth curve fitting to explain the nonlinear relationship after adjusting the potential confounders. Finally, the heterogeneity among specific groups was examined by subgroup analysis.ResultsOf all 462 patients enrolled in this study, 118 (25.54%) developed MACE. There was a negative correlation between serum hemoglobin and MACE in all three models (hazard ratio [HR] 0.82, 95% confidence interval [CI 0.72, 0.93], HR 0.86, 95% CI [0.76,0.98], and HR 0.87, 95% CI [0.74,0.98], respectively). In the subgroup analysis, the negative correlation existed between the patients who had myocardial infarction (MI) history (p for interaction = 0.0059) after adjusting covariates. However, no significant differences were found between age and sex groups (p for interaction = 0.1381, 0.4103, respectively).ConclusionOur results indicated that patients who received PCI with low preoperative hemoglobin were more likely to develop MACE, especially if they have already had a history of MI.     

Elevated levels of PAI‐1 activity and t‐PA antigen are associated with newly diagnosed abnormal glucose regulation in patients with ST‐elevation myocardial infarction

Summary. Background: Both Type 2 diabetes and cardiovascular disease have been associated with enhanced coagulation and suppressed fibrinolysis. Objectives: To investigate a possible relationship between selected hemostatic variables and abnormal glucose regulation (AGR) in patients with acute ST‐elevation myocardial infarction (STEMI) without known diabetes and to study changes in selected hemostatic variables from baseline to follow‐up in STEMI patients with or without AGR. Methods: Plasminogen activator inhibitor‐1 (PAI‐1) activity, tissue plasminogen activator (t‐PA) antigen, prothrombin fragment 1+2 (F₁₊₂) and von Willebrand factor (vWF) were measured in fasting blood samples from 199 STEMI patients 16.5 h (median time) after admission and 3 months later. All patients were classified into normal glucose regulation (NGR) or AGR based on an oral glucose tolerance test at follow‐up, according to the WHO criteria. Results: High PAI‐1 activity (≥ 75th percentile) measured in‐hospital was associated with AGR (n = 49) with an adjusted odds ratio of 2.2 (95% confidence interval, 1.1, 4.4). In addition, high levels of t‐PA antigen (≥ 75th percentile) were associated with AGR (adjusted odds ratio, 3.5; 95% confidence inteval, 1.5, 8.2), but only in men. Changes in the levels of F₁₊₂ were significantly more pronounced in patients with AGR compared with NGR (adjusted P = 0.04). Conclusion: Elevated levels of PAI‐1 activity and t‐PA antigen measured in‐hospital in STEMI patients were associated with AGR classified at 3‐month follow‐up. Additionally, changes in the levels of F₁₊₂ were more pronounced in patients with AGR compared with NGR. The data suggest an enhanced prothrombotic state after an acute STEMI in patients with AGR without known diabetes.     

急性非ST段抬高心肌梗死患者临床特点分析

目的 分析急性非ST段抬高心肌梗死(NSTEMI)患者的临床特点.方法 对211例NSTEMI和急性ST段抬高心肌梗死(STEMI)116例患者行冠状动脉造影、超声心动图检查,采集病史和症状特征进行分析.结果 与STEMI患者相比,NSTEMI患者危险因素较多,梗死后心绞痛常见,重度冠状动脉病变和三支病变多见,对心功能影响相对较小.结论 NSTEMI患者冠状动脉病变严重,梗死后心肌缺血常见,应重视对其治疗.     

The case for prehospital thrombolysis in acute myocardial infarction

Thrombolysis is of proven benefit in improving survival after acute myocardial infarction. The benefit decreases with time after the onset of pain; the first 2 h appear to be important. Reduction of thrombolysis times must be undertaken as a whole‐systems approach. Delays in the patient contacting assistance services are unavoidable, but once contact is made the system should ensure attendance of a qualified person within 8 min. In‐hospital delays should be decreased, aiming for a door‐to‐needle time of less than 30 min. Prehospital electrocardiographs are accurate and can help reduce in‐hospital delays. Some trials have shown that prehospital administration of thrombolysis can lead to reduced thrombolysis times. Angioplasty with or without stenting for those with contraindications to thrombolysis and as a rescue procedure needs to be considered in deciding the destination of AMI patients. More evidence is needed to support this aspect of care. Prehospital thrombolysis has an important role to play, especially when time to hospital may be prolonged.     

替格瑞洛在高龄急性非ST段抬高型心肌梗死患者早期介入治疗中的疗效及安全性

目的评价替格瑞洛在高龄(≥75岁)急性非ST段抬高型心肌梗死(NSTEMI)患者早期(发病24 h内)介入治疗(PCI)中的有效性及安全性。方法连续入选85例资料齐全行早期PCI的高龄NSTEMI的患者,随机分为替格瑞洛组和氯吡格雷组。随访6个月,比较2组患者术中无复流或慢血流的发生情况,发生典型心绞痛、非致死性心肌梗死、心力衰竭和心源性死亡等主要心脏不良事件(MACE)的发生率,出血、药物不良反应情况,以及左室舒张末期内径(LVDD)、左室射血分数(LVEF)等指标变化情况。结果替格瑞洛组术中发生梗死溶栓试验血流分级(TIMI)2级、TIMI心肌灌注分级(TMP)3级的比例显著低于氯吡格雷组(P0.05)。随访6个月,替格瑞洛组总MACE发生率显著低于氯吡格雷组(P0.05)。2组患者术后严重出血发生率无显著差异(P0.05)。2组发生呼吸困难等药物不良反应情况有显著差异(P0.05)。替格瑞洛组LVEF优于氯吡格雷组。结论对于高龄NSTEMI患者早期行PCI时,替格瑞洛可以获得更好的心肌水平再灌注,且不增加严重出血情况的发生,降低总心脏不良事件的发生。     

Initial experience with the Endicor X-sizer thrombectomy device in patients with ST segment elevation myocardial infarction

Summary We investigated 16 patients with ST segment elevation myocardial infarction who had an occluded coronary artery (TIMI 0) at initial angiogram. Instead of balloon angioplasty and stenting, patients were subjected to thrombectomy (Endicor X-sizer) and stenting. In 15/16 patients the occlusion could be crossed by the thrombectomy device resulting in TIMI flow 3 in all of them. Thereafter, stenting was performed. At final angiogram all 15 patients continued to show TIMI flow grade 3. Twelve-lead ECG was performed prior to and post-intervention. ST elevation was measured as the sum of eight leads for anterior infarction and of five leads for inferior infarction. In 13/15 patients, ECG analysis was possible (2 developed bundle branch block post-intervention). In all 13 patients, a >50% ST decrease of the initial amount of ST elevation was observed reaching a >70% reduction in 11 patients. Procedural complications were low (one coronary dissection after thrombectomy) and 30 days follow-up was uneventful. Thrombectomy using the Endicor X-Sizer device may become an attractive mechanical reperfusion strategy for patients with acute myocardial infarction. Received: 29 September 2001 Accepted: 5 December 2001     

Prehospital system delay in patients with ST-segment elevation myocardial infarction in Singapore

BACKGROUND: Timely reperfusion in ST-segment elevation myocardial infarction(STEMI)improves outcomes. System delay is that between first medical contact and reperfusion therapy,comprising prehospital and hospital components. This study aimed to characterize prehospital system delay in Singapore.METHODS: A retrospective chart review was performed for 462 consecutive STEMI patients presenting to a tertiary hospital from December 2006 to April 2008. Patients with cardiac arrest secondarily presented were excluded. For those who received emergency medical services(EMS),ambulance records were reviewed. Time intervals in the hospital were collected prospectively. The patients were divided into two equal groups of high/low prehospital system delay using visual binning technique.RESULTS: Of 462 patients, 76 received EMS and 52 of the 76 patients were analyzed. The median system delay was 125.5 minutes and the median prehospital system delay was 33.5minutes(interquartile range [IQR]=27.0, 42.0). Delay between call-received-by-ambulance and ambulance-dispatched was 2.48 minutes(IQR=1.47, 16.55); between ambulance-dispatch and arrival-at-patient-location was 8.07 minutes(IQR=1.30, 22.13); between arrival-at- and departurefrom-patient-location was 13.12 minutes(IQR=3.12, 32.2); and between leaving-patient-location to ED-registration was 9.90 minutes(IQR=1.62, 32.92). Comparing patients with prehospital system delay of less than 35.5 minutes versus more showed that the median delay between ambulancedispatch and arrival-at-patient-location was shorter(5.75 vs. 9.37 minutes, P0.01). The median delay between arrival-at-patient-location and leaving-patient-location was also shorter(10.78 vs.14.37 minutes, P0.01).CONCLUSION: Prehospital system delay in our patients was suboptimal. This is the first attempt at characterizing prehospital system delay in Singapore and forms the basis for improving efficiency of STEMI care.     

Fibrinolytic therapy in patients with ST-elevation myocardial infarction

ST-elevation myocardial infarction (STEMI) is related to acute occlusion of a coronary artery by a fibrin-rich thrombus. Early reperfusion in STEMI reduces infarct size and improves prognosis. Acute reperfusion may be achieved with percutaneous coronary intervention (PCI) and/or fibrinolytic agents. When performed in a timely manner, primary PCI is the preferred method of reperfusion; however, due to logistic reasons, including lack of PCI-capable hospitals and delay in the first medical contact-to-balloon time, this simplified approach lacks universal applicability. Due to clinical efficacy and the ease of administration, fibrinolysis is still an important reperfusion modality in patients with STEMI who cannot have primary PCI within guideline-recommended time. This review focuses on the role of fibrinolysis in patients with STEMI.