Department of Clinical Chemistry, Maastricht University Medical Center (MUMC), Maastricht, the Netherlands.
Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center (MUMC), the Netherlands.
Clin Chem. 2016 Dec;62(12):1602-1611. doi: 10.1373/clinchem.2016.257485. Epub 2016 Oct 5.
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.
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.
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.
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.
急性心肌梗死（AMI）的诊断假设，连续的高敏心肌肌钙蛋白（hs-cTn）检测值是围绕个体的内稳态设定点随机波动的。本研究旨在挑战这一诊断概念。
研究 1 通过对 24 名近期无 AMI 病史的个体进行 24 小时的昼夜每小时采血，检测 hs-cTn 是否存在昼夜节律。研究 2 在一项前瞻性多中心诊断研究中，评估了 2782 例未经选择的急性胸痛患者就诊时 hs-cTnT 和 hs-cTnI 的清晨与傍晚的诊断准确性。
在研究 1 中，hs-cTnT 而不是 hs-cTnI 表现出昼夜节律，特征为白天浓度逐渐降低，夜间浓度升高，清晨浓度达到峰值（上午 8：30 时的平均浓度为 16.2ng/L，下午 7：30 时的平均浓度为 12.1ng/L）。在研究 2 中，hs-cTnT 节律通过与非心源性疾病诊断的傍晚就诊者相比，清晨就诊者的 hs-cTnT 浓度更高而得到证实。hs-cTnT 在就诊时、1 小时时以及绝对变化与就诊浓度相结合的诊断准确性（接受者操作特征曲线下面积[AUC]）非常高，且清晨就诊患者与傍晚就诊患者之间具有可比性（所有 AUC＞0.93）。hs-cTnI 没有昼夜节律，清晨就诊者和傍晚就诊者之间 AUC 无差异。
hs-cTnT 的节律性昼夜变化是一种普遍现象，hs-cTnI 不存在这种现象。虽然 hs-cTnT 的昼夜节律似乎不会影响 hs-cTnT 对 AMI 的诊断准确性，但在使用 hs-cTnT 进行筛查时应考虑这一点。
