Cardiology Department, Vaudois University Hospital, Rue du Bugnon 46, 1011, Lausanne, Switzerland.
Department of Internal Medicine, Vaudois University Hospital, Lausanne, Switzerland.
Clin Res Cardiol. 2017 Dec;106(12):1026-1032. doi: 10.1007/s00392-017-1152-8. Epub 2017 Aug 30.
High-sensitivity cardiac troponin assays have significantly improved the sensitivity of myocardial infarction detection by using cutoff values and early absolute changes. However, variation in repeated measures also depends on biological variability. This study aimed to assess the potential circadian component of this biological variability.
17 healthy volunteers were recruited, and standardized conditions for physical activity, meals, exposure to light and duration of sleep were imposed. Blood samples were collected every 4 h and high-sensitivity troponin T assay with a limit of detection of 3 ng/l and a 99th percentile of 14 ng/l were used. Circadian variations were analyzed using the cosinor method.
Statistically significant circadian variations were observed for body temperature, heart rate, and systolic/diastolic arterial blood pressures (p < 0.01 using both a non-adjusted cosinor model and a gender- and BMI-adjusted cosinor model). The amplitudes of the circadian variations were 18.93, 6, 15.35, and 1.92%, respectively. A statistically significant circadian biological variation of troponin blood concentrations was evidenced (p < 0.01 in both the non-adjusted cosinor model and the gender- and BMI-adjusted cosinor), with an amplitude of 20.5% (average: 4.39 ng/l; amplitude: 0.9 ng/l; peak at 06:00 and nadir at 18:00).
This study demonstrates a circadian biological variation in blood troponin concentration in a healthy population. The amplitude of this variation challenges the cutoff value for instant rule-out of the rapid rule-in/rule-out of the recent European guidelines for the management of acute coronary syndromes. These findings deserve further investigation in a population at risk of myocardial infarction.
高敏心肌肌钙蛋白检测通过使用临界值和早期绝对变化显著提高了心肌梗死检测的灵敏度。然而，重复测量的变化也取决于生物学变异性。本研究旨在评估这种生物学变异性的潜在昼夜变化成分。
招募了 17 名健康志愿者，并对其进行了身体活动、用餐、光照暴露和睡眠时间的标准化。每 4 小时采集一次血样，并使用检测限为 3ng/l 和第 99 百分位数为 14ng/l 的高敏肌钙蛋白 T 检测方法。使用余弦法分析昼夜变化。
观察到体温、心率和收缩/舒张压的统计学显著昼夜变化（使用未经调整的余弦模型和性别及 BMI 调整的余弦模型，p<0.01）。昼夜变化的振幅分别为 18.93%、6%、15.35%和 1.92%。证据表明，肌钙蛋白血液浓度存在统计学显著的昼夜生物学变异性（未经调整的余弦模型和性别及 BMI 调整的余弦模型中均为 p<0.01），振幅为 20.5%（平均值：4.39ng/l；振幅：0.9ng/l；峰值在 06:00，谷值在 18:00）。
本研究在健康人群中证明了血液肌钙蛋白浓度的昼夜生物学变化。这种变化的振幅挑战了即时排除快速排除近期欧洲急性冠状动脉综合征管理指南的规则。这些发现值得在心肌梗死风险人群中进一步研究。
