High-sensitivity cardiac troponins in everyday clinical practice

High-sensitivity cardiac troponin(hs-cTn) assays are increasingly being used in many countries worldwide,however,a generally accepted definition of high-sen-sitivity is still pending.These assays enable cTn mea-surement with a high degree of analytical sensitivity with a low analytical imprecision at the low measuring range of cTn assays(coefficient of variation of < 10% at the 99th percentile upper reference limit).One of the most important advantages of these new assays is that they allow novel,more rapid approaches to rule in or rule out acute coronary syndromes(ACSs) than with previous cTn assay generations which are still more commonly used in practice worldwide.hs-cTn is also more sensitive for the detection of myocardial damage unrelated to acute myocardial ischemia.Therefore,the increase in early diagnostic sensitivity of hs-cTn assays for ACS comes at the cost of a reduced ACS specificity,because more patients with other causes of acute or chronic myocardial injury without overt myocardial isch-emia are detected than with previous cTn assays.As hs-cTn assays are increasingly being adopted in clinical practice and more hs-cTn assays are being developed,this review attempts to synthesize the available clinical data to make recommendations for their everyday clini-cal routine use.

An electrochemiluminescent magneto-immunosensor for ultrasensitive detection of hs-cTnI on a microfluidic chip

Sensitive detection and precise quantitation of trace-level crucial biomarkers in a complex sample matrix has become an important area of research.For example,the detection of high-sensitivity cardiac troponin I(hs-cTnI)is strongly recommended in clinical guidelines for early diagnosis of acute myocardial infarction.Based on the use of an electrode modified by single-walled carbon nanotubes(SWCNTs)and a Ru(bpy)32+-doped silica nanoparticle(Ru@SiO2)/tripropylamine(TPA)system,a novel type of electrochemiluminescent(ECL)magneto-immunosensor is developed for ultrasensitive detection of hs-cTnI.In this approach,a large amount of[Ru(bpy)3]2+is loaded in SiO2(silica nanoparticles)as luminophores with high luminescent efficiency and SWCNTs as electrode surface modification material with excellent elec-trooxidation ability for TPA.Subsequently,a hierarchical micropillar array of microstructures is fabricated with a magnet placed at each end to efficiently confine a single layer of immunomagnetic microbeads on the surface of the electrode and enable 7.5-fold signal enhancement.In particular,the use of transparent SWCNTs to modify a transparent ITO electrode provides a two-order-of-magnitude ECL signal amplifi-cation.A good linear calibration curve is developed for hs-cTnI concentrations over a wide range from 10 fg/ml to 10 ng/ml,with the limit of detection calculated as 8.720 fg/ml(S/N 3).This ultrasensitive immunosensor exhibits superior detection performance with remarkable sta-=bility,reproducibility,and selectivity.Satisfactory recoveries are obtained in the detection of hs-cTnI in human serum,providing a potential analysis protocol for clinical applications.

Elevated level of high-sensitivity cardiac troponin I as a predictor of adverse cardiovascular events in patients with heart failure with preserved ejection fraction

Background:The relationship between the elevation of cardiac troponin and the increase of mortality and hospitalization rate in patients with heart failure with reduced ejection fraction is clear.This study investigated the association between the extent of elevated levels of high-sensitivity cardiac troponin I(hs-cTnI)and the prognosis in heart failure with preserved ejection fraction patients.Methods:A retrospective cohort study consecutively enrolled 470 patients with heart failure with preserved ejection fraction from September 2014 to August 2017.According to the level of hs-cTnI,the patients were divided into the elevated level group(hs-cTnI>0.034 ng/mL in male and hs-cTnI>0.016 ng/mL in female)and the normal level group.All of the patients were followed up once every 6 months.Adverse cardiovascular events were cardiogenic death and heart failure hospitalization.Results:The mean follow-up period was 36.2±7.9 months.Cardiogenic mortality(18.6%[26/140]vs.1.5%[5/330],P<0.001)and heart failure(HF)hospitalization rate(74.3%[104/140]vs.43.6%[144/330],P<0.001)were significantly higher in the elevated level group.The Cox regression analysis showed that the elevated level of hs-cTnI was a predictor of cardiogenic death(hazard ratio[HR]:5.578,95%confidence interval[CI]:2.995-10.386,P<0.001)and HF hospitalization(HR:3.254,95%CI:2.698-3.923,P<0.001).The receiver operating characteristic curve demonstrated that a sensitivity of 72.6%and specificity of 88.8%for correct prediction of adverse cardiovascular events when a level of hs-cTnI of 0.1305 ng/mL in male and a sensitivity of 70.6%and specificity of 90.2%when a level of hs-cTnI of 0.0755 ng/mL in female were used as the cut-off value.Conclusion:Significant elevation of hs-cTnI(≥0.1305 ng/mL in male and≥0.0755 ng/mL in female)is an effective indicator of the increased risk of cardiogenic death and HF hospitalization in heart failure with preserved ejection fraction patients.