Interpreting Changes in Troponin—Clinical Judgment Is Essential

[摘要] A 51-year-old woman with a history of mild hypertension and mild hyperlipidemia had presented with a 2-h episode of substernal chest discomfort for the first time. She was receiving a statin but refused treatment for hypertension. She was an avid runner and had never had chest discomfort previously. The discomfort occurred at rest and radiated to her arms and her neck. Her electrocardiogram (ECG)3 revealed minor ST-segment and T-wave changes in the inferior and lateral leads. Her initial cardiac troponin T (cTnT) concentration was 0.04 μg/L (99th-percentile upper reference limit, <0.01 μg/L) but increased to 0.32 μg/L and then to 0.76 μg/L. An emergent coronary angiogram was interpreted as normal with the exception of slow flow in the circumflex coronary artery. An echocardiogram was normal.A 62-year-old woman was referred for evaluation of atypical chest pain and an equivocal stress test result. She had a history of hypertension and smoking for >25 years. Her chest discomfort was mild and radiated to the right shoulder. It occurred at rest and during exercise but had not changed in intensity or duration for >2 months. Her ECG was normal, and the cTnT concentration measured with the fourth-generation assay on the day of a computed tomography (CT) angiography evaluation was <0.01 μg/L (99th-percentile upper reference limit, <0.01 μg/L). A cTnT concentration measured with a high-sensitivity cTnT (hs-cTnT) assay of the same sample was mildly increased (15 ng/L; 99th-percentile value for women, 10 ng/L).### QUESTIONS TO CONSIDER1. How should acute myocardial infarction (AMI) be diagnosed according to the “universal MI” definition?2. Define the 2 subtypes of “spontaneous” MI.3. What additional testing might be performed for each patient?4. What change in cardiac troponin should be considered clinically important?Cardiac troponin is the preferred biomarker for the diagnosis of myocardial necrosis because it is the most sensitive and specific …

[学科分类] 过敏症与临床免疫学