Cardiac Troponin I as Compared to Troponin T for the Detection of Myocardial Damage in Horses

Abstract

BackgroundDifferent cardiac troponin I (cTnI) assays give different results. Only 1 manufacturer has marketed troponin T (cTnT) assays. Therefore, cTnT often is preferred for detection of myocardial infarction in human patients. Studies of cTnT in horses are limited.ObjectivesTo compare a cTnI and a high‐sensitive cTnT assay (hs‐cTnT) in horses.AnimalsCardiac troponin I and cTnT were determined in 35 healthy horses (group 1), 23 horses suspected to have primary myocardial damage (group 2a), and 41 horses with secondary myocardial damage caused by structural heart disease (group 2b).MethodsAll cTnI samples were analyzed at laboratory A (limit of detection [LOD]: 0.03 ng/mL), whereas cTnT samples were analyzed at 2 laboratories with the same hs‐cTnT assay (laboratory B, LOD: 10.0 pg/mL; laboratory C, LOD: 4.0 pg/mL).ResultsThe median cTnI concentration in group 2a (0.90 ng/mL; range, 0.03–58.27 ng/mL) was significantly higher (P < .001) than in group 1 (0.03 ng/mL; range, 0.03–0.09 ng/mL) or group 2b (0.05 ng/mL; range, 0.03–30.92 ng/mL), and the optimal cut‐off for detection of primary myocardial damage was 0.095 ng/mL (sensitivity: 90.5%, specificity: 100%). Using an LOD of 10.0 pg/mL for all cTnT samples, a cut‐off value of 10.5 pg/mL was found, but sensitivity was low (42.9%). When only samples analyzed at laboratory C (n = 58) were included, a cut‐off of 6.6 pg/mL was found (sensitivity: 81%, specificity: 100%).Conclusions and Clinical ImportanceDespite large quantitative differences, cTnI and cTnT are both useful for detection of myocardial damage in horses.

24‐Hour Kinetics of Cardiac Troponin‐T Using a “High‐Sensitivity” Assay in Thoroughbred Chuckwagon Racing Geldings after Race and Associated Clinical Sampling Guidelines

“…Because there are many different cTn assays available, the specific value of the hscTnT assay is described below. The median peak cTnT of 8.0 ng/L in the study population of healthy horses demonstrates that a cTnT cut-off point of 6.6 ng/L, as recently suggested to differentiate between normal horses at rest and those diagnosed with primary myocardial disease, 6 would not be applicable postracing. Cardiac troponin release from the myocardium in response to exercise is not well understood but has clinical implications in the differentiation between cTn concentrations postrace in healthy horses and those with myocardial damage, as discussed below.…”

“…Seven research studies in horses have evaluated cTn concentrations in normal horses after nonendurance exercise. None of these studies identified significant increases in cTn concentrations partly as a consequence of the study population sizes (15,28,6,24,26, and 15 horses, respectively) [13][14][15][34][35][36] but also as a result of the use of older generation, 11 conventional sensitivity assays that have a higher LoD. 37,38 We identified significant increases in cTn, using the hscTnT assay, in horses after high-intensity, short-duration racing exercise.…”

“…5 Upper reference limits (URL) for the 95th and 99th population distribution percentiles have been defined for apparently healthy horses and Thoroughbred Chuckwagon racing geldings 5 and plasma concentrations have been described in 2 populations of horses with cardiac damage. 6 In numerous studies of healthy humans, in laboratory rodents, in sled-dogs, as well as a few studies of horses, increases in cTn concentrations have been identified after exercise. [7][8][9][10][11][12][13][14][15] After myocardial injury in humans, loss of cell membrane integrity results in 2 phases of cTn release: a "high-sensitivity" cardiac troponin-T IQR interquartile range LoD limit of detection LoQ limit of quantitation NACB National Academy of Clinical Biochemistry ROC receiver operating characteristic TP total protein URL upper reference limit mild-to-moderate increase within 1-to 2-hour postinjury, and a more substantial increase 4-to 6-hour postinjury which may persist for 7-14 days.…”

Measurement of Biomarkers Troponin I, NT Pro BNP and ANP Between Horses with Signs of Respiratory Disease and Apparently Healthy Group

“…al. (2015) [26] demonstrated that despite large quantitative differences, cTnI and cTnT are both useful for detection of myocardial damage in horses but this finding is not in parallel with the findings of Gehlen and et. al.…”

Horse: anaesthetic management for open castration of a Belgian draught horse with interventricular septum defect, aortic regurgitation and ventricular premature depolarisations

“…The next morning, a clinical examination and a more extensive cardiac workup was performed. Serum cardiac troponin I was <0.03 ng/ml (reference range 0.03–0.09 ng/ml) (Van Der Vekens and others 2015). Echocardiography revealed an interventricular septum defect (2.4×3.3 cm on a long axis view), with a shunt velocity of 5.23 m/s, which corresponds to a pressure gradient of 109 mm Hg (P=4v 2 ; where P is the pressure gradient and v is the velocity).…”