Interpreting Changes in Troponin Clinical Judgment Is Essential

Summary

DOI: 10.1373/clinchem.2011.173138

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.

Student Discussion

Student Discussion Document (pdf)

Hugo A. Katus,¹ Evangelos Giannitsis,¹ and Allan S. Jaffe^2*

¹Medizinische Klinik, Abteilung für Innere Medizin III, Universitätsklinikum Heidelberg, Heidelberg, Germany; ²Mayo Clinic and Mayo College of Medicine, Rochester, MN.
*Address correspondence to this author at: Cardiovascular Division, Department of Internal Medicine, and Division of Core Clinical Laboratory Services, Department of Laboratory Medicine and Pathology, Mayo Clinic and Medical School, 200 First St. S.W., Rochester, MN 55905. Fax 507-266-0228; e-mail [email protected].

Case Descriptions

Case 1

A 51-year-old woman with a history of mild hypertension and mild hyperlipidemia 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 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.

Case 2

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 evaluation was <0.01 μg/L (99th-percentile upper reference limit, <0.01 μg/L). A cTnT concentration measured with a high-sensitivity cTnT assay of the same sample was mildly increased (15 ng/L; 99th-percentile value for women, 10 ng/L).

Questions to Consider

How should acute myocardial infarction (AMI) be diagnosed according to the “universal MI” definition?
Define the 2 subtypes of “spontaneous” MI.
What additional testing might be performed for each patient?
What change in cardiac troponin should be considered clinically important?

Final Publication and Comments

The final published version with discussion and comments from the experts appears in the January 2012 issue of Clinical Chemistry, approximately 3-4 weeks after the Student Discussion is posted.

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