缺血修饰白蛋白对急性心肌缺血早期诊断价值的探讨

目的探讨缺血修饰白蛋白（IMA）测定对急性心肌缺血的早期诊断价值。方法采用白蛋白钴结合试验检测830例健康体检者（健康对照组）、492例急性冠状动脉综合征患者（ACS组）、74例单纯性高血压病患者（高血压组）、78例病毒性心肌炎患者（病毒性心肌炎组）、395例急性胸痛者（急性胸痛组,包括急诊ACS患者133例与随诊胸痛患者262例）和68例接受经皮冠状动脉介入治疗术患者（PCI组）血清或血浆IMA水平,并对其中急诊ACS患者进行IMA水平动态观察及血清肌钙蛋白I（cTnI）和心电图检测。结果根据ROC曲线,当临界值为0．45时综合评价最佳。ACS组和病毒性心肌炎组IMA水平分别为（0．55±0．11）吸光度单位（ABSU）和（0．38±0．11）ABSU,高于健康对照组[（0．34±0．08）ABSU,P〈0．05],且ACS组和病毒性心肌炎组之间IMA差异有统计学意义（P〈0．05）。急性胸痛组中急诊ACS患者IMA水平及阳性率分别为（0．54±0．12）ABSU和77．4％,高于随诊者的（0．44±0．12）ABSU和39．3％（P〈0．01）。在133例急诊ACS患者中,首诊1h内IMA阳性率为82．O％,高于同期cTnI阳性率40．6％（P〈0．01）,就诊后6—24hIMA与cTnI水平及阳性率较首诊1h内显著升高（P〈0．01）。在72例急性胸痛发作3h内入院且cTnI均为阴性的ACS患者中,首诊IMA阳性率为86．1％,心电图阳性率为72．2％,两者联合测定阳性率为93．1％。PCI术后即刻患者动脉血浆IMA水平较术前IMA明显升高（P〈0．05）。首诊ACS患者IMA水平高于临界值,于入院1天达峰值,且持续升高,后缓慢下降,入院14天IMA均值接近正常水平。结论IMA早期诊断急性心肌缺血具有临床应用价值。     

A superior early myocardial infarction marker. Human heart-type fatty acid-binding protein

Human heart-type fatty acid-binding protein (FABP) has a high potential as an early marker for myocardial infarction (MI) being more specific than myoglobin. FABP is a low molecular mass cytoplasmic protein (15 kDa) that is released early after the onset of ischemia and it may be useful for rapid confirmation or exclusion of acute myocardial infarction (AMI). Immunochemically assayed FABP, cardiac troponin I (cTnI) and enzymatically assayed creatine phosphokinase (CPK) were determined serially in plasma and serum samples from 218 patients presenting with chest pain and suspected MI. In the 94 patients with confirmed MI, FABP rose to a maximum level (577.6 +/- 43.8 microg/L) 3 hours after the onset of symptoms and returned to normal within 30 hours. The FABP level peaked 7-9 hours earlier than CPK (2288 +/- 131 U/L) and cTnI (357.1 +/- 23.9 microg/L). CPK took 50-70 hours to return to normal level and cTnI returned to normal level over 70 hours. The areas under the receiver operating characteristic (ROC) curves for FABP were calculated as 0.871 at admission and 0.995 one hour after admission, whereas for CPK the areas were 0.711 and 0.856 and for cTnI the areas were 0.677 and 0.845, indicating that the FABP test gave a better diagnostic classification at the early stage being reached by cTnI (0.995) only 8 hours after admission. For FABP, both sensitivity and negative predictive value (NPV) increased quickly to 100% for samples monitored just one hour after admission. By using only two samples, one at admission and one 1 hour post admission, sequential FABP monitoring can reliably diagnose AMI patients 1 hour after admission and 100% of non-AMI patients can be excluded with no false negative results. The late markers cTnI and CPK have the similar diagnostic performance only 7 hours later. Thus measurement of FABP in plasma or serum allows the earliest immunochemical confirmation or exclusion of AMI.     

Ischemia Modified Albumin for the assessment of patients presenting to the emergency department with acute chest pain but normal or non-diagnostic 12-lead electrocardiograms and negative cardiac troponin T

BACKGROUND: The diagnosis of myocardial ischemia in patients with acute chest pain at rest but non-diagnostic electrocardiograms (ECG) is problematic. Ischemia Modified Albumin (IMA) is a new biochemical marker of ischemia, which may be useful to characterise acute coronary syndrome (ACS) patients. METHODS: We studied 131 patients (mean age 58.5 years; 95 male) presenting to the emergency department with symptoms suggestive of ACS but with normal or non-diagnostic ECGs. Cardiac troponin T (cTnT) and IMA were measured within 3 h of last chest pain episode. Based on hospital diagnostic test results, patients were classified as having ACS or non-ischemic chest pain (NICP), by two independent cardiologists unaware of IMA results. RESULTS: Mean IMA levels (U/ml) were higher in patients with ACS (98.3+/-11) compared to patients with NICP (85.5+/-15); p<0.0001. IMA levels >93.5 U/ml demonstrated a sensitivity and specificity of 75% for the diagnosis of ACS; area under the receiver operator characteristic curve 0.78 (95% CI: 0.70-0.85). If we applied the manufacturer cutoff point of 85 U/ml, the sensitivity of IMA increased to 90.6% with a specificity of 49.3% (negative predictive value=84.6%). In combination with cTnT (6-12 h) (>0.05 ng/ml), the sensitivity increased to 92.2%. After multivariate analysis, IMA levels >85 U/ml (odds ratio=14.6 [95% CI 4.4-48.4]; p<0.0001), age and prior myocardial infarction were independent predictors of ACS. CONCLUSION: IMA may be a useful biomarker for the identification of ACS in patients presenting with typical acute chest pain but normal or non-diagnostic ECGs.     

The Erlanger chest pain evaluation protocol: a one-year experience with serial 12-lead ECG monitoring,two-hour delta serum marker measurements,and selective nuclear stress testing to identify and exclude acute coronary syndromes

STUDY OBJECTIVE: We determine the overall use of a 6-step accelerated chest pain protocol to identify and exclude acute coronary syndrome (ACS) and to confirm previous findings of the use of serial 12-lead ECG monitoring (SECG) in conjunction with 2-hour delta serum marker measurements to identify and exclude acute myocardial infarction (AMI). METHODS: A prospective observational study was conducted over a 1-year period from January 1, 1999, through December 31, 1999, in 2,074 consecutive patients with chest pain who underwent our accelerated evaluation protocol, which includes 2-hour delta serum marker determinations in conjunction with automated SECG for the early identification and exclusion of AMI and selective nuclear stress testing for identification and exclusion of ACS. In patients not undergoing emergency reperfusion therapy, physician judgment was used to determine patient disposition at the completion of the 2-hour evaluation period: admit for ACS, discharge or admit for non-ACS condition, or immediate emergency department nuclear stress scan for possible ACS. A positive protocol was defined as a positive result in 1 or more of the 6 incremental steps in our chest pain evaluation protocol: (1) initial ECG diagnostic of acute injury or reciprocal injury; (2) baseline creatine kinase (CK)-MB level of 10 ng/mL or greater and index of 5% or greater or cardiac troponin I level of 2 ng/mL or greater; (3) new/evolving injury or new/evolving ischemia on SECG; (4) increase in CK-MB level of +1.5 ng/mL or greater or cardiac troponin I level of +0.2 ng/mL or greater in 2 hours; (5) clinical diagnosis of ACS despite a negative 2-hour evaluation; and (6) reversible perfusion defect on stress scan compared with on resting scan. All patients were followed up for 30-day ACS, which was defined as myocardial infarction (MI), percutaneous coronary intervention/coronary artery bypass grafting, coronary arteriography revealing stenosis of major coronary artery of 70% or greater not amenable to percutaneous coronary intervention/coronary artery bypass grafting, life-threatening complication, or cardiac death within 30 days of ED presentation. RESULTS: Discharge diagnosis in the 2,074 study patients consisted of 179 (8.6%) patients with AMI, 26 (1.3%) patients with recent AMI (decreasing curve of CK-MB), and 327 (15.8%) patients with 30-day ACS. At 2 hours, sensitivity and specificity for MI (AMI or recent AMI) of SECG plus delta serum marker measurements was 93.2% and 93.9%, respectively (positive likelihood ratio 15.3; negative likelihood ratio 0.07). At the completion of the full ED evaluation protocol (positive result in >or=1 of the 6 incremental steps), sensitivity and specificity for 30-day ACS was 99.1% and 87.4%, respectively (positive likelihood ratio 7.9; negative likelihood ratio 0.01). CONCLUSION: An accelerated chest pain evaluation strategy consisting of SECG, 2-hour delta serum marker measurements, and selective nuclear stress testing in conjunction with physician judgment identifies and excludes MI and 30-day ACS during the initial evaluation of patients with chest pain.     

Diversity of the elevation of serum cardiac troponin I levels in patients during their first visit to the emergency room.

BACKGROUND: Although measurement of serum creatine kinase levels, as well as myoglobin levels, has been used for screening patients with acute coronary syndrome (ACS), the specificity of both is low. Measurement of cardiac troponin levels is now extensively used for the diagnosis of ACS because of their superior cardiac specificity. However, troponin levels are reportedly elevated not only in patients with ACS but also in those with other diseases. METHODS AND RESULTS: The clinical characteristics of 1,023 patients (mean age: 63.5+/-16.3 years; males: 665, females: 358) whose serum cardiac troponin I (cTnI) levels had been measured at the initial visit to the emergency room of Toyota Memorial Hospital between April 2004 and March 2005 were retrospectively analyzed. A positive elevation of cTnI was defined as cTnI > or =0.03 ng/ml. There were 432 patients (42.2%) with positive cTnI levels. The cTnI levels (8.48+/-2.64 ng/ml) in patients with acute myocardial infarction (AMI) were greater than those (0.25+/-0.07 ng/ml) in patients with unstable angina pectoris (AP), as well as those (0.04+/-0.01 ng/ml) in patients with stable AP. In terms of the diagnosis of AMI, the sensitivity was high enough (94.6%), but its specificity was relatively low (61.9%). Furthermore, the differentiation between AMI and unstable AP by the cTnI value alone was impossible. The cTnI levels were elevated in patients with a variety of diseases other than ACS, including heart failure, cardiomyopathies, myocarditis, renal failure, tachyarrhythmias, and pulmonary embolism. CONCLUSIONS: Elevation of the cTnI level is frequently observed in patients in the emergency room with common diseases other than ACS.     

Differentiating ischemic from non-ischemic chest pain using white blood cell-surface inflammatory and coagulation markers

Chest pain is one of the most common complaints seen in emergency departments (ED), up to 5-8 % of all ED visits. About 50-60 % of chest pain patients presenting to the ED are hospitalized. Seventy percentage of those patients not discharged from the ED are subsequently shown to not have acute cardiac disease. It has been estimated that emergency physician miss 2-6 % of acute coronary syndrome (ACS) that present to ED. While admitting a non-ACS patient is a financial burden on the medical system, releasing to home an undiagnosed ACS patient has life-threatening consequences. This study used flow cytometry to evaluate a panel of mononuclear cells, neutrophils, cytokines and fibrinolytic activation markers in patients presenting in ED with acute chest pain. The goal was to add diagnostic tools to the differentiation between true ischemic cardiac and non-ischemic chest pain in the process of triage. The study population consisted of 74 consecutive patients presenting with acute chest pain to the emergency department of Ziv Medical Center and were admitted to Intensive Cardiac Care Unit or Internal Wards of our hospital during the period September 2009 to February 2010. ACS has been clearly associated with a decrease in CD89+/CD62L+ population, an increase in percentage of cytotoxic T-cell subset, and an increase in platelet marker. Differences in thrombin receptor surface expression were also noted. The combination of multiple biomarkers may help to enhance diagnostic accuracy.     

Cardiac troponin I for stratification of early outcomes and the efficacy of enoxaparin in unstable angina: a TIMI-11B substudy

OBJECTIVES: We sought to evaluate cardiac troponin I (cTnI) for predicting early clinical outcomes and the efficacy of enoxaparin among patients with non-ST segment elevation acute coronary syndrome (ACS) and negative creatine kinase, MB fraction (CK-MB) levels. BACKGROUND: Cardiac TnI identifies patients with unstable angina who are at higher risk of death or myocardial infarction (MI) by 30 days. The utility of cTnI for predicting very early clinical events, including recurrent ischemia, and the efficacy of enoxaparin are not yet established. METHODS: At baseline and 12 h to 24 h after enrollment in the Thrombolysis in Myocardial Infarction (TIMI)-11B trial, samples were collected for cTnI determination. RESULTS: Among 359 patients with negative serial CK-MB values, 50.1% had a cTnI result > or =0.1 ng/ml within the first 24 h. Patients with elevated cTnI were at higher risk of death or MI at 48 h (3.9 vs. 0%, p = 0.01) and 14 days (13.9 vs. 2.2%, p<0.0001). Elevated cTnI also correlated with higher risk of recurrent ischemia requiring urgent revascularization by 48 h (10.0 vs. 1.7%, p = 0.001) and 14 days (20.6 vs. 5.6%, p< or =0.0001). Enoxaparin had a greater benefit among patients with elevated vs. normal cTnI (p = 0.03), achieving a 47% reduction in the risk of death, MI or urgent revascularization by 14 days in cTnI-positive patients (p = 0.007). CONCLUSIONS: Elevation of cTnI among patients with non-ST segment elevation ACS and negative levels of CK-MB identifies those at higher risk for very early adverse outcomes, including severe recurrent ischemia. Treatment with enoxaparin reduces the risk associated with elevated cTnI.     

急性冠状动脉综合征血清缺血修饰白蛋白的动态变化

目的:探讨血清缺血修饰白蛋白(IMA)对急性冠状动脉综合征早期的诊断价值。方法:将56例急性冠状动脉综合征患者分为三组,不稳定性心绞痛组(n=25),ST抬高心肌梗死组(n=20),非ST抬高心肌梗死组(n=11),另选50例健康体检者为正常对照组。分别于胸痛发作2、4、6、12及24 h抽血检测56例急性冠状动脉综合征患者的血清缺血修饰白蛋白、肌钙蛋白Ⅰ(cTnI)、肌酸激酶MB同工酶(CK-MB),分析缺血修饰白蛋白对急性冠状动脉综合征的诊断价值。结果:在急性冠状动脉综合征患者中缺血修饰白蛋白水平于胸痛发作2小时已明显增高并达高峰,4小时仍持续增高,明显高于正常对照组(P<0．01),6小时降至正常。而CK-MB、cTnI水平在胸痛发作4小时开始增高,6小时明显增高,以后逐步递增并在24小时达高峰。不稳定型心绞痛、ST抬高的心肌梗死、非ST抬高的心肌梗死三组中,缺血修饰白蛋白水平升高以不稳定型心绞痛组最明显。结论:缺血修饰白蛋白是诊断急性冠状动脉综合征的早期敏感指标,是目前唯一的诊断心肌缺血的生化标志物。     

Chest pain in the emergency room. Importance of a systematic approach

OBJECTIVE: To evaluate the efficiency of a systematic diagnostic approach in patients with chest pain in the emergency room in relation to the diagnosis of acute coronary syndrome (ACS) and the rate of hospitalization in high-cost units. METHODS: One thousand and three consecutive patients with chest pain were screened according to a pre-established process of diagnostic investigation based on the pre-test probability of ACS determinate by chest pain type and ECG changes. RESULTS: Of the 1003 patients, 224 were immediately discharged home because of no suspicion of ACS (route 5) and 119 were immediately transferred to the coronary care united because of ST elevation or left bundle-branch block (LBBB) (route 1) (74% of these had a final diagnosis of acute myocardial infarction [AMI]). Of the 660 patients that remained in the emergency room under observation, 77 (12%) had AMI without ST segment elevation and 202 (31%) had unstable angina (UA). In route 2 (high probability of ACS) 17% of patients had AMI and 43% had UA, whereas in route 3 (low probability) 2% had AMI and 7 % had UA. The admission ECG has been confirmed as a poor sensitivity test for the diagnosis of AMI ( 49%), with a positive predictive value considered only satisfactory (79%). CONCLUSION: A systematic diagnostic strategy, as used in this study, is essential in managing patients with chest pain in the emergency room in order to obtain high diagnostic accuracy, lower cost, and optimization of the use of coronary care unit beds.     

A comparative study of markers of inflammation for the assessment of cardiovascular risk in patients presenting to the emergency department with acute chest pain suggestive of acute coronary syndrome

BACKGROUND: The role of inflammation in the pathogenesis of acute coronary syndrome (ACS) is established. Little is known however, regarding the use of inflammatory markers as predictors of future cardiovascular events in patients presenting to the emergency department (ED) with suspected ACS. HYPOTHESIS: To assess whether biomarkers that predict cardiovascular risk in apparently healthy individuals and coronary artery disease patients are useful predictors of future cardiovascular events in patients presenting to the ED with chest pain suggestive of ACS. METHODS: We compared the abilities of serum C-reactive protein (hs-CRP), albumin and leukocyte count to identify subjects with ACS and those who are at high risk of developing events during a 30-day follow-up. RESULTS: 144 patients (mean age 62+/-13 years, 45 female) presenting to the ED <3 h after the onset of symptoms suggestive of ACS were evaluated. Final hospital diagnoses were non-ischemic chest pain in 43 (30%) and ACS in 101 (70%) patients. Patients with ACS had significantly higher leukocyte count (p<0.0001) and hs-CRP levels (p<0.02) and lower albumin concentrations, compared to patients with NICP (p<0.0001). Lower albumin concentrations (p=0.03) and hs-CRP (p=0.049) were predictors of recurrent events at 30 days. On multivariate analysis, however, only leukocyte count was a predictor of ACS (OR 20.9; 95% CI: 3.7-19.5; p=0.01) and high hs-CRP levels were a predictor of clinical outcome (OR 2.8; 95% CI: 1.5-5.2; p=0.001). CONCLUSIONS: Leukocyte count is an independent predictor of ACS in patients presenting to the ED with chest pain suggestive of ACS and high hs-CRP levels are an independent predictor of clinical outcome in ACS patients.     

急性冠状动脉综合征患者血清超敏C-反应蛋白水平变化及其影响因素

目的 探讨急性冠状动脉综合征(ACS)患者血清超敏C-反应蛋白(hsCRP)和心肌肌钙蛋白I(cTnI)变化及其影响因素.方法 ①采用化学发光免疫分析法检测50例ACS患者、20例OMI患者和20名健康人的hsCRP和cTnI含量.②以hsCRP为因变量,以年龄、性别、高血压史、糖尿病史、吸烟史、cTnI、甘油三酯(TG)、胆固醇(CHO)、载脂蛋白A(APOA)、载脂蛋白B(APOB)、血糖(GLU)、高密度脂蛋白胆固醇(HDL-C)、尿酸(URI)为自变量进行多元逐步回归分析.结果 ①ACS组的hsCRP、cTnI均高于OMI组和对照组(P＜0.05);OMI组的hsCRP、cTnI水平与对照组相比有升高趋势,但差别无统计学意义(P＞0.05).②以hsCRP作为因变量的多元逐步回归方程式为:hsCRP=-3.362 0.02446X7 1.097X9(X7为cTnI,X9为CHO,X7、X9显著性均为P＜0.01).结论 ACS患者血清hsCRP、cTnI水平明显升高;血清hsCRP水平和cTnI、CHO呈正相关.     

The prognostic value of serum myoglobin in patients with non-ST-segment elevation acute coronary syndromes. Results from the TIMI 11B and TACTICS-TIMI 18 studies

OBJECTIVES: The goal of this study was to define the prognostic value of serum myoglobin in patients with non-ST-elevation acute coronary syndromes (ACS). BACKGROUND: While myoglobin is useful for the early diagnosis of myocardial infarction (MI), its role in the early risk-stratification of patients with ACS has not been established. METHODS: Myoglobin, creatine kinase-MB subfraction (CK-MB) and troponin I (cTnI) were measured at randomization in 616 patients from the Thrombolysis In Myocardial Ischemia/Infarction (TIMI) 11B study and 1,841 patients from the Treat Angina with Aggrastat and Determine Cost of Therapy with an Invasive or Conservative Therapy-Thrombolysis In Myocardial Ischemia/Infarction (TACTICS-TIMI) 18 study. The risks for death and nonfatal MI through six months of follow-up were compared between patients with and without myoglobin elevation (>110 microg/l) in each study and in a dataset combining all eligible patients from both studies (n = 2,457). RESULTS: In a multivariate model adjusting for baseline characteristics, ST changes and CK-MB and cTnI levels, an elevated baseline myoglobin was associated with increased six-month mortality in TIMI 11B (adjusted odds ratio [OR] 2.9 [95% confidence interval [CI] 1.2 to 7.1]), TACTICS-TIMI 18 (adjusted OR 3.0 [95% CI 1.5 to 5.9]) and the combined dataset (adjusted OR 3.0 [95% CI 1.8 to 5.0]). In contrast, there was no significant association between myoglobin elevation and nonfatal MI (combined dataset adjusted OR 1.55, 95% CI 0.9 to 2.6). In TACTICS-TIMI 18, patients with versus those without myoglobin elevation were more likely to have an occluded culprit artery (28% vs. 10%; p < 0.0001) and visible thrombus (49% vs. 34%; p = 0.006) and less likely to have TIMI 3 flow (53% vs. 68%; p = 0.009). CONCLUSIONS: A serum concentration of myoglobin above the MI detection threshold (>110 microg/l) is associated with an increased risk of six-month mortality, independent of baseline clinical characteristics, electrocardiographic changes and elevation in CK-MB and cTnI. These findings suggest that myoglobin may be a useful addition to cardiac biomarker panels for early risk-stratification in ACS.     

Urinary thromboxane A2 metabolites in patients presenting in the emergency room with acute chest pain

Abstract. Objectives . The diagnosis of acute myocardial infarction (MI) is difficult in emergency rooms where large groups of patients present with chest pain. Confirmation of the diagnosis of MI based on the myocardial band of creatine phosphokinase may take a day. A more rapid diagnostic screening procedure is desirable and for this reason we evaluated urine thromboxane. Design . The study consisted of patients presenting with chest pain. Urine samples were obtained in the emergency room and on the following 5 days for those patients who were admitted to the hospital. The urine samples were used to determine the levels of immunoreactive 11-dehydro-thromboxane B₂ (i-11-dehydro-TXB₂) and 2,3-dinor-thromboxane B₂ (i-2,3-dinor-TXB₂). Myocardial infarction was defined as an increase in the myocardial band fraction of plasma creatine phosphokinase (> 5% of the total) and changes in the electrocardiogram. The patients' diagnoses were retrospectively correlated with thromboxane metabolite levels. Setting . The present study took place in the emergency rooms of two major hospitals: Georgetown University Medical Center. Washington DC, and Fairfax Hospital, Virginia, USA. Subjects . The study comprised 369 patients presenting with acute chest pain and consisted of 247 men and 122 women aged 30–94 years. Main outcome measures . The outcome measure of this study was the predictive value of i-11-dehydro TXB₂ and i-2,3-dinor-TXB₂, for the diagnosis of MI, in patients presenting in the emergency room with chest pain. Results . Patients undergoing an MI had significantly higher levels of both thromboxane metabolites in their urine in the emergency room, when compared to patients undergoing a cardiac event other than an MI or to patients with unstable angina. Thromboxane metabolite levels rapidly returned to normal on the days following admission to the hospital. Aspirin intake appeared to significantly decrease the levels of i-11-dehydro-TXB₂, but not that of i-2,3-dinor-TXB₂. Conclusions . The measurement of thromboxane metabolites in the urine may provide a more rapid, accurate and cost-effective means of diagnosing MIs in patients presenting with chest pain.     

Impact of the troponin standard on the prevalence of acute myocardial infarction

Background

Recent recommendations are that troponin should replace creatine kinase (CK)-MB as the diagnostic standard for myocardial infarction (MI). The impact of this change has not been well described. Our objective was to determine the impact of a troponin standard on the prevalence of acute non-ST-elevation MI.

Methods

The current study was a retrospective analysis of consecutive patients without ST-segment elevation admitted for exclusion of myocardial ischemia to an inner city urban tertiary care center. All patients underwent serial marker sampling (CK, CK-MB, and cardiac troponin I [cTnI]). Patients with ST elevation consistent with acute MI (n = 130) or who did not have an 8 hour cTnI (n = 124) were excluded. The impact of 3 different cTnI diagnostic values were examined in 2181 patients: the lower limit of detectability (LLD); an optimal diagnostic value (OPT), chosen using receiver operator characteristic curve analysis; and the manufacturer's suggested upper reference level (URL), when compared to a gold standard CK-MB MI definition. In addition, MI prevalence was assessed using different CK-MB MI definitions and evaluated in patients with ischemic changes only.

Results

The prevalence CK-MB MI was 7.8%. Using the various cTnI diagnostic values, the incidence of MI increased the prevalence by 28% to 195%. Using the optimal diagnostic value for cTnI, patients with cTnI elevations not meeting CK-MB MI criteria had an intermediate 30-day mortality (5.4%) compared to those with CK-MB MI (7.1%). Grouping the cTnI positive, CK-MB MI negative patients with the CK-MB MI patients rather than the non-CK-MB MI patients reduced mortality for both the MI (to 5.9%) and non-MI groups (from 1.9% to 1.6%).

Conclusions

Changing to a troponin standard will have a substantial impact on the number of patients diagnosed with MI. The revised definition for MI will have important clinical and health care implications.     

联合测定缺血修饰白蛋白等生化标志物对急性冠脉综合征早期诊断的价值（英文）

目的：探讨生化标志物联合检测对急性冠脉综合征（ACS）的早期诊断价值。方法：对156例因胸痛4 h就诊患者,以冠状动脉造影（CAG）为诊断依据,分为ACS组（112例）和非缺血性胸痛（NICP）组（44例）。在胸痛〈4 h和4~8 h分别抽血测定缺血修饰白蛋白（IMA）,乳酸脱氢酶（LDH）,肌酸激酶（CK）,肌酸激酶同工酶（CK-MB）及心脏肌钙蛋白I（cTnI）等心脏生化标志物,并结合CAG检查结果进行综合分析。结果：在发病4h内对ACS诊断敏感性最高的是IMA（87.50%）,特异性最高的是cTnI达95.45%,准确性最高的是IMA达80.77%;4~8h对ACS诊断敏感性最高的是IMA,达91.07%,特异性最高的是cTnI（97.73%）,准确性最高的是CK和IMA,二者分别为85.90%,85.25%,无显著差异,并列第一。综合判断,无论是〈4h,还是4~8h,敏感性和准确性最高的是IMA,特异性最高的是cTnI。4 h内IMA等5项指标联合检测可提高敏感性达89.28%,特异性达95.45%,准确性达91.02%,均为最高水平。结论：对于诊断急性冠脉综合征,IMA的敏感性和准确性最高,cTnI的特异性最高,IMA等5种指标联合检测可将其诊断提高到最高水平     

The relative utility of cardiac troponin I,creatine kinase-MBmass,and myosin light chain-1 in the long-term risk stratification of patients with chest pain

BACKGROUND: Sensitive and specific cardiac markers convey important short-term prognostic information about patients with an acute coronary syndrome. There are, however, few data assessing their value as long-term predictors. HYPOTHESIS: The aim of the current study was to assess the relative value of three such markers and clinical characteristics in determining the long-term prognosis of patients with chest pain. METHODS: Cardiac troponin I (cTnI), myosin light chain-(MLC-1), and creatine kinase-MBmass levels were obtained on admission (0 h) and at 4, 8, 16, and 24 h in 208 patients with chest pain. Eligible subjects were determined, at the time of hospital admission, to be at >7% risk of acute myocardial infarction (MI), but without new ST-segment elevation on their presenting electrocardiogram. Follow-up was performed a median of 28 (range 1-46) months later. The primary study endpoint was death or nonfatal MI, subsequent to the index admission. RESULTS: Cardiac TnI levels > or = 0.2 ng/ml (odds ratio [OR] 1.93, 95% confidence interval [CI] 1.09-3.40) and MLC-1 levels > or = 1 ng/ml (OR 3.24, 95% CI 1.83-5.73) were both significant predictors of death or MI during long-term follow-up; MLC-1 was, however, the only independent biochemical predictor (OR 2.11,95% CI 1.14-3.93). CONCLUSIONS: Both cTnl and MLC-1 predict the long-term outcome of patients with chest pain, but, in this cohort, MLC-1 proved to be a better predictor of mortality and nonfatal acute MI.     

Ninety-minute accelerated critical pathway for chest pain evaluation

Rapid, efficient, and accurate evaluation of chest pain patients in the emergency department optimizes patient care from public health, economic, and liability perspectives. To evaluate the performance of an accelerated critical pathway for patients with suspected coronary ischemia that utilizes clinical history, electrocardiographic findings, and triple cardiac marker testing (cardiac troponin I [cTnI], myoglobin, and creatine kinase-MB [CK-MB]), we performed an observational study of a chest pain critical pathway in the setting of a large Emergency Department at the Veterans Affairs Medical Center in 1,285 consecutive patients with signs and symptoms of cardiac ischemia. The accelerated critical pathway for chest pain evaluation was analyzed for: (1) accuracy in triaging of patients within 90 minutes of presentation, (2) sensitivity, specificity, positive predictive value, and negative predictive value of cTnI, myoglobin, and CK-MB in diagnosing acute myocardial infarction (MI) within 90 minutes, and (3) impact on Coronary Care Unit (CCU) admissions. All MIs were diagnosed within 90 minutes of presentation (sensitivity 100%, specificity 94%, positive predictive value 47%, negative predictive value 100%). CCU admissions decreased by 40%. Ninety percent of patients with negative cardiac markers and a negative electrocardiogram at 90 minutes were discharged home with 1 patient returning with an MI (0.2%) within the next 30 days. Thus, a simple, inexpensive, yet aggressive critical pathway that utilizes high-risk features from clinical history, electrocardiographic changes, and rapid point-of-care testing of 3 cardiac markers allows for accurate triaging of chest pain patients within 90 minutes of presenting to the emergency department.     

BNP对于ACS的早期诊断价值及其与心肌坏死标志物的相关性

目的：探讨血清脑利钠肽（BNP）对于急性冠脉综合征（ACs）患者的早期诊断价值以及与心肌坏死标志物的相关性。方法：入选ACS患者63例（ACS组）,健康体检者22例（健康对照组）。ACS组被分为急性心肌梗死（AMI）组（25例）和不稳定型心绞痛（UAP）组（38例）;根据累及冠状动脉病变血管数量将其中45例ACS患者分为单支病变组（10例）、双支病变组（14例）、三支及以上病变组（21例）。检测各组BNP、肌钙蛋白I（cT—nI）、肌酸激酶-同工酶（CK—MB）水平。结果：（1）与健康对照组比较,UAP组和AMI组BNP水平明显升高[（27．68±7．54）pg／ml比（48．59±146．30）pg／ml比（277．99±179．57）pg／ml,P〈0．013;ACS患者多支病变组BNP水平明显高于双支及单支病变组[（308．17±178．94）pg／ml比（187．35±156．27）pg／ml比（68．36±47．76）pg／ml,P〈0．05-〈0．013,双支病变组BNP水平明显高于单支病变组（P〈0．05）;（2）ACS患者胸痛发作6h内,BNP、CK—MB水平明显高于健康对照组（P〈0．01）,而cTnI无显著变化（P〉0．05）;胸痛发作6～24h内,与健康对照组比较,ACS组BNP[（27．68±7．54）pg／ml比（280．45±155．27）pg／ml]、cTnI[（0．05±0．03）ng／ml比（10．45±4．01）ng／ml]、CK—MBE（6．79±1．42）U／L比（64．64±37．05）U／L]水平均明显升高（P〈0．01）;直线相关分析显示BNP与eTnI、CK—MB呈正相关性（r=0．517,P=0．000;r=0．483,P=0．001）。结论：血清脑利钠肽水平与心肌缺血损伤严重程度及冠脉病变支数相关,对于急性冠脉综合征的早期诊断有临床应用价值。     

High-Risk Plaque Detected on Coronary CT Angiography Predicts Acute Coronary Syndromes Independent of Significant Stenosis in Acute Chest Pain : Results From the ROMICAT-II Trial

Background

It is not known whether high-risk plaque, as detected by coronary computed tomography angiography (CTA), permits improved early diagnosis of acute coronary syndromes (ACS) independently to the presence of significant coronary artery disease (CAD) in patients with acute chest pain.

Objectives

The primary aim of this study was to determine whether high-risk plaque features, as detected by CTA in the emergency department (ED), may improve diagnostic certainty of ACS independently and incrementally to the presence of significant CAD and clinical risk assessment in patients with acute chest pain but without objective evidence of myocardial ischemia or myocardial infarction (MI).

Methods

We included patients randomized to the coronary CTA arm of the ROMICAT-II (Rule Out Myocardial Infarction/Ischemia Using Computer-Assisted Tomography II) trial. Readers assessed coronary CTA qualitatively for the presence of nonobstructive CAD (1% to 49% stenosis), significant CAD (≥50% or ≥70% stenosis), and the presence of at least 1 of the high-risk plaque features (positive remodeling, low <30 Hounsfield units plaque, napkin-ring sign, spotty calcium). In logistic regression analysis, we determined the association of high-risk plaque with ACS (MI or unstable angina pectoris) during the index hospitalization and whether this was independent of significant CAD and clinical risk assessment.

Results

Overall, 37 of 472 patients who underwent coronary CTA with diagnostic image quality (mean age 53.9 ± 8.0 years; 52.8% men) had ACS (7.8%; MI n = 5; unstable angina pectoris n = 32). CAD was present in 262 patients (55.5%; nonobstructive CAD in 217 patients [46.0%] and significant CAD with ≥50% stenosis in 45 patients [9.5%]). High-risk plaques were more frequent in patients with ACS and remained a significant predictor of ACS (odds ratio [OR]: 8.9; 95% CI: 1.8 to 43.3; p = 0.006) after adjustment for ≥50% stenosis (OR: 38.6; 95% CI: 14.2 to 104.7; p < 0.001) and clinical risk assessment (age, sex, number of cardiovascular risk factors). Similar results were observed after adjustment for ≥70% stenosis.

Conclusions

In patients presenting to the ED with acute chest pain but negative initial electrocardiogram and troponin, presence of high-risk plaques on coronary CTA increased the likelihood of ACS independent of significant CAD and clinical risk assessment (age, sex, and number of cardiovascular risk factors). (Multicenter Study to Rule Out Myocardial Infarction by Cardiac Computed Tomography [ROMICAT-II]; NCT01084239)     

Hypomagnesemia is a frequent finding in the emergency department in patients with chest pain

STUDY OBJECTIVE--To evaluate the frequency of low blood levels of total and ultrafilterable magnesium (total and ultrafilterable hypomagnesemia) in patients with chest pain in the emergency department, and to determine if hypomagnesemia is associated with other clinically important diagnostic and outcome variables in cardiac care. SETTING--An emergency department of a university teaching hospital. DESIGN--Prospective study of extracellular magnesium homeostasis in patients with chest pain in the emergency department and a cohort of patients without chest pain with a clinical indication for blood sampling. PATIENTS--During a 4-month period, 147 patients presenting to the emergency department were studied: 67 patients (mean +/- SD age, 61.4 +/- 13 years) with a chief complaint of chest pain (study group) and 80 patients (55.6 +/- 19 years) with other diagnoses (control group). RESULTS--Total and ultrafilterable hypomagnesemia occurred more frequently in patients with chest pain (20/67 [30%] and 9/67 [13%]) than in the control group (12/80 [15%] and 3/80 [4%]). Patients with a chief complaint of chest pain who were receiving diuretic medications were hypomagnesemic more frequently (9/16 [56%]) than patients not receiving diuretics (12/51 [23%]). In patients with chest pain admitted to the hospital with a diagnosis of "rule out" myocardial infarction, the frequency of hypokalemia was greater among hypomagnesemic patients (6/14 [43%]) than normomagnesemic patients (3/31 [10%]). A similar frequency of hypomagnesemia was noted in patients with a final diagnosis of myocardial infarction (4/15 [27%]) when compared with other patients admitted with chest pain (10/31 [32%]) in whom myocardial infarction was excluded. No association was noted among hypomagnesemia and length of hospital stay or the occurrence of hypotension or dysrhythmias. CONCLUSIONS--Total and ultrafilterable hypomagnesemia are frequent occurrences in patients with and without chest pain in the emergency department. Diuretic use is associated with hypomagnesemia in patients presenting with chest pain in the emergency department. These results support the concept that hypomagnesemia is common in patients with chest pain in the emergency department and is associated with hypokalemia but is not predictive of whether the patient with chest pain has had an acute myocardial infarction.