Portal de Periódicos da CAPES

Diurnal Rhythm of Cardiac Troponin: Consequences for the Diagnosis of Acute Myocardial Infarction

2016; American Association for Clinical Chemistry; Volume: 62; Issue: 12 Linguagem: Inglês

10.1373/clinchem.2016.257485

1530-8561

Lieke J.J. Klinkenberg, Karin Wildi, Noreen van der Linden, Imre W. K. Kouw, Marijke Niens, Raphael Twerenbold, María Rubini Giménez, Christian Puelacher, Jean Daniel Neuhaus, Petra Hillinger, Thomas Nestelberger, Jasper Boeddinghaus, Karin Grimm, Zaid Sabti, Judith Bons, Jeroen D.E. van Suijlen, Frans E. S. Tan, Joop ten Kate, Otto Bekers, Luc J. C. van Loon, Marja P. van Dieijen‐Visser, Christian Mueller, Steven J.R. Meex,

ECG Monitoring and Analysis

Abstract BACKGROUND Interpretation of serial high-sensitivity cardiac troponin (hs-cTn) measurements for the diagnosis of acute myocardial infarction (AMI) assumes random fluctuation of hs-cTn around an individual's homeostatic set point. The aim of this study was to challenge this diagnostic concept. METHODS Study 1 examined the presence of a diurnal hs-cTn rhythm by hourly blood sampling, day and night, in 24 individuals without a recent history of AMI. Study 2 assessed morning vs evening diagnostic accuracy of hs-cTnT and hs-cTnI in a prospective multicenter diagnostic study of 2782 unselected patients, presenting to the emergency department with acute chest pain. RESULTS In study 1, hs-cTnT, but not hs-cTnI, exhibited a diurnal rhythm, characterized by gradually decreasing concentrations throughout daytime, rising concentrations during nighttime, to peak concentrations in the morning (mean 16.2 ng/L at 8:30 AM and 12.1 ng/L at 7:30 PM). In study 2, the hs-cTnT rhythm was confirmed by higher hs-cTnT concentrations in early-morning presenters compared to evening presenters with an adjudicated diagnosis of noncardiac disease. The diagnostic accuracy [area under the receiver-operation characteristics curve (AUC)] of hs-cTnT at presentation, 1 h, and for the combination of absolute changes with presenting concentration, were very high and comparable among patients presenting early morning as compared to evening (all AUC >0.93). hs-cTnI exhibited no diurnal rhythm with no differences in AUC among early-morning and evening presenters. CONCLUSIONS Rhythmic diurnal variation of hs-cTnT is a general phenomenon that is not seen with hs-cTnI. While the diurnal hs-cTnT rhythm does not seem to affect the diagnostic accuracy of hs-cTnT for AMI, it should be considered when using hs-cTnT for screening purposes. Clinical Trial Registration 1. Circadian Variation of Cardiac Troponin, NCT02091427, www.clinicaltrials.gov/ct2/show/NCT02091427. 2. Advantageous Predictors of Acute Coronary Syndrome Evaluation (APACE) Study, NCT00470587, www.clinicaltrials.gov/ct2/show/NCT00470587.