Dagnone E, Collier C, Pickett W, Ali N, Miller M, Tod D, Morton R
Department of Emergency Medicine, Faculty of Health Sciences, Queen's University, Kingston, Ont.
CMAJ. 2000 May 30;162(11):1561-6.
Early detection of acute myocardial infarction (AMI) may save lives. In the emergency setting, it is unclear whether the early use of certain cardiac markers (myoglobin and cardiac troponin I [cTnI]) assists in making appropriate decisions whether to admit or discharge patients with chest pain of possible ischemic cause who have nondiagnostic electrocardiograms (ECGs). We performed a study to determine whether the addition of new cardiac markers in the emergency department results in improved clinical decisions.
A single-blind randomized controlled trial was conducted between June 1997 and June 1998 in a tertiary care emergency department in Kingston, Ont. Of 296 patients aged 30 years or more who presented to the emergency department with chest pain and nondiagnostic ECGs, 146 were randomly assigned to the intervention group (determination of baseline creatine kinase [CK] level, CK MB fraction and cTnI level, and myoglobin level at baseline and at 2 hours) and 150 to the control group (determination of baseline CK level and CK MB fraction). Outcome measures included the rate of admission to the inpatient cardiology service and length of stay in the emergency department.
Of the 296 patients, 34 (11.5%) received a diagnosis of AMI in the emergency department, and 92 (31.1%) had chest pain of noncardiac cause. Patients in the intervention group were less likely than those in the control group to be admitted to the cardiology service (67 [45.9%] v. 81 [54.0%]). The absolute difference in the proportion (8.1% [95% confidence interval -3.3 to 19.5]), although potentially important clinically, was not statistically significant. The length of stay in the emergency department was essentially the same in the 2 study groups. At 30 days, the proportions of patients with a diagnosis of recurrent angina (58.2% in the intervention group and 58.0% in the control group) and AMI (12.3% and 14.7%) were also similar.
The optimal cardiac marker panel to be used in the emergency department remains unknown. The addition of serial testing of myoglobin with cTnI confirmation to the standard panel did not substantially change the clinical management or outcomes of patients presenting with chest pain and nondiagnostic ECGs.
急性心肌梗死（AMI）的早期检测可能挽救生命。在急诊情况下，尚不清楚早期使用某些心脏标志物（肌红蛋白和心肌肌钙蛋白I [cTnI]）是否有助于做出适当决策，以确定对心电图（ECG）无诊断意义但可能因缺血导致胸痛的患者是收住入院还是出院。我们进行了一项研究，以确定在急诊科添加新的心脏标志物是否能改善临床决策。
1997年6月至1998年6月在安大略省金斯敦的一家三级护理急诊科进行了一项单盲随机对照试验。296例年龄30岁及以上因胸痛且心电图无诊断意义而就诊于急诊科的患者中，146例被随机分配至干预组（测定基线肌酸激酶[CK]水平、CK同工酶MB分数和cTnI水平，以及基线和2小时时的肌红蛋白水平），150例被分配至对照组（测定基线CK水平和CK同工酶MB分数）。观察指标包括入住心内科病房的比例和在急诊科的停留时间。
296例患者中，34例（11.5%）在急诊科被诊断为AMI，92例（31.1%）有非心脏原因的胸痛。干预组患者入住心内科病房的可能性低于对照组（67例[45.9%]对81例[54.0%]）。比例的绝对差异为8.1%（95%置信区间 -3.3至19.5），尽管在临床上可能很重要，但无统计学意义。两个研究组在急诊科的停留时间基本相同。在30天时，诊断为复发性心绞痛的患者比例（干预组为58.2%，对照组为58.0%）和AMI的患者比例（分别为12.3%和14.7%）也相似。
急诊科使用的最佳心脏标志物组合仍不明确。在标准检测组合中增加肌红蛋白的系列检测并结合cTnI确认，并未显著改变胸痛且心电图无诊断意义患者的临床管理或结局。
