Table 1_Prognostication in emergency room patients: comparing ultrasensitive and contemporary quantification of cardiac troponin levels below the 99th percentile.docx

IntroductionCardiac troponin levels below the 99th percentile improve the predictive efficacy for cardiovascular events when associated with relevant clinical variables. However, whether ultra-sensitive analytical methods improve this predictive efficacy over less sensitive or contemporary analytical methods remains unknown.
MethodsThis retrospective observational study involved consecutive patients who presented to the emergency department for suspected acute coronary syndrome and underwent measurement of ultra-sensitive cardiac troponin I (Singulex) and contemporary cardiac troponin I (Siemens) with levels below the 99th percentile. The clinical characteristics of these patients were analysed, and the efficacy of both analytical methods for predicting cardiovascular events over a 4-year follow-up period was compared.
ResultsIn total, 838 patients were analysed (mean age, 62.9 ± 16.6 years; 42.2% women). Their cumulative incidence of the composite cardiovascular event (death, readmission for myocardial infarction, and readmission for heart failure) was 25.9% over the 4-year follow-up. Both Singulex cardiac troponin I (analysed by quartiles) and Siemens cardiac troponin (analysed as detectable/undetectable) improved the predictive efficacy for the combined event over clinical variables [Harrell's C-index (95% confidence interval): 0.77 (0.74–0.80) vs. 0.79 (0.76–0.81) and 0.77 (0.74–0.80) vs. 0.78 (0.75–0.81), respectively; p = 0.018]. However, there were no statistically significant difference between the two predictive models that included the aforementioned troponin assays.
ConclusionsDetectable levels of cardiac troponin using a contemporary analytical method or those near the 99th percentile using an ultra-sensitive analytical method improve the predictive efficacy for cardiovascular events, with no differences between the two methods

引言：当心肌肌钙蛋白（cardiac troponin）水平低于第99百分位时，结合相关临床变量可提升心血管事件的预测效能。然而，相较于低敏检测方法或常规检测方法，超敏检测方法是否能进一步优化该预测效能，目前仍不明确。
方法：本项回顾性观察研究纳入了因疑似急性冠状动脉综合征就诊于急诊科，并接受了超敏心肌肌钙蛋白I（ultra-sensitive cardiac troponin I，Singulex）与常规心肌肌钙蛋白I（contemporary cardiac troponin I，Siemens）检测，且检测水平低于第99百分位的连续入组患者。研究分析了这些患者的临床特征，并对比了两种检测方法在4年随访期内对心血管事件的预测效能。
结果：最终共纳入838例患者进行分析（平均年龄62.9±16.6岁；女性占比42.2%）。在4年随访期内，复合心血管事件（包括死亡、心肌梗死再入院及心力衰竭再入院）的累积发生率为25.9%。以四分位数分层分析的Singulex超敏心肌肌钙蛋白I，以及以可检测/不可检测分层的Siemens常规心肌肌钙蛋白I，均能在临床变量基础上进一步提升复合事件的预测效能[Harrell一致性指数（Harrell's C-index，95%置信区间）：0.77（0.74~0.80） vs 0.79（0.76~0.81），以及0.77（0.74~0.80） vs 0.78（0.75~0.81），P=0.018]。不过，包含上述两种肌钙蛋白检测方法的两个预测模型之间，未观察到统计学显著性差异。
结论：采用常规检测方法可检出的心肌肌钙蛋白水平，或采用超敏检测方法测得的接近第99百分位的心肌肌钙蛋白水平，均能提升心血管事件的预测效能，且两种检测方法之间无显著差异。