Division of Nephrology, Lenox Hill Hospital, New York, NY, USA.
Nephrol Dial Transplant. 2011 Feb;26(2):665-70. doi: 10.1093/ndt/gfq442. Epub 2010 Jul 23.
Troponin I (TnI) is an effective marker for detecting myocardial injury, but the interpretation of levels in the setting of end-stage renal disease (ESRD) is still unclear. TnI levels have been noted to be increased in 5-18% of asymptomatic haemodialysis (HD) patients with standard assays, but newer-generation, high-sensitivity assays have not been examined. In addition, there is limited data on the variability of TnI levels in patients over time as well as the effect of HD on TnI levels. The aim of this study was to prospectively explore the incidence of TnI with a high-sensitivity assay, the variability of TnI levels over time and the effect of HD on levels.
We enrolled 51 asymptomatic HD patients and checked TnI levels using a high-sensitivity assay. Levels were drawn pre-HD monthly for three consecutive months. As per manufacturer guidelines, levels were considered normal up to 0.034 ng/mL, indeterminate elevation (IE) if between 0.035 and 0.120 ng/mL and consistent with myocardial infarction (MI) if >0.120 ng/mL. In the third month, post-HD TnI was also drawn to determine change with dialysis.
At baseline, median TnI level was 0.025 ng/mL (range, 0-0.461 ng/mL). Baseline TnI levels were normal in 63% and elevated (≥0.035 ng/mL) in 37%. Of those with elevations, 79% were in the IE range and 21% in the acute myocardial infarction range. Higher TnI levels at baseline were associated with a history of coronary artery disease, left ventricular hypertrophy, lower cardiac ejection fraction and higher serum phosphate levels. Average incidence of elevated TnI was 41% over the 3 months. Thirty-six patients had stable levels without a change in classification over 3 months. Twelve varied over time. Forty-five (94%) had no change in classification pre- and post-HD.
Using a new-generation, high-sensitivity assay, over a third of asymptomatic ESRD patients have an elevated TnI. The significance of these low-level elevations is unclear at this time. TnI levels remain stable over a 3-month period in most patients. HD treatment does not appear to affect the TnI level.
肌钙蛋白 I（TnI）是检测心肌损伤的有效标志物，但在终末期肾病（ESRD）患者中，其水平的解读仍不清楚。标准检测方法发现，5-18%的无症状血液透析（HD）患者的 TnI 水平升高，但尚未对新一代高敏检测方法进行检查。此外，关于 TnI 水平随时间的变化以及 HD 对 TnI 水平的影响，数据有限。本研究旨在前瞻性地探索高敏检测方法中 TnI 的发生率、TnI 水平随时间的变化以及 HD 对水平的影响。
我们纳入了 51 名无症状 HD 患者，使用高敏检测方法检测 TnI 水平。每月在 HD 前抽取一次连续三个月的样本。根据制造商的指南，TnI 水平<0.034ng/mL 被认为是正常的，0.035-0.120ng/mL 之间为不确定升高（IE），>0.120ng/mL 为符合心肌梗死（MI）。在第三个月，也在 HD 后抽取 TnI 样本以确定与透析的变化。
在基线时，中位 TnI 水平为 0.025ng/mL（范围，0-0.461ng/mL）。63%的患者 TnI 水平正常，37%的患者升高（≥0.035ng/mL）。在升高的患者中，79%处于 IE 范围，21%处于急性心肌梗死范围。较高的基线 TnI 水平与冠心病病史、左心室肥厚、较低的心脏射血分数和较高的血清磷水平相关。在 3 个月内，升高的 TnI 平均发生率为 41%。36 例患者在 3 个月内无变化，分类无变化。12 例患者随时间变化。45 例（94%）患者在 HD 前后无分类变化。
使用新一代高敏检测方法，超过三分之一的无症状 ESRD 患者 TnI 升高。目前尚不清楚这些低水平升高的意义。在大多数患者中，TnI 水平在 3 个月内保持稳定。HD 治疗似乎不会影响 TnI 水平。
