Kinetics of high-sensitivity cardiac troponin T and I differ in patients with ST-segment elevation myocardial infarction treated by primary coronary intervention.

Purpose: Cardiac biomarkers including troponins are the cornerstone of the biological definition of acute myocardial infarction. New high-sensitivity cardiac assays determining troponin T (hs-cTnT) as well as I ((hs-cTnI) from Abbott and s-cTnI from Siemens) raise concerns because of their unclear kinetics following the peak.

Aims: This study aims to compare kinetics of creatine kinases, hs-cTnT, hs-cTnI and s-cTnI in patients with ST-segment elevation myocardial infarction (STEMI) treated by percutaneous coronary intervention.

Methods: We prospectively studied 106 consecutive patients admitted in our institution for STEMI and treated by percutaneous coronary intervention. We evaluated for all the patients simultaneously kinetics of creatine kinases, hs-cTnT (Roche) and two different cTnIs (hs-cTnI from Abbott and s-cTnI from Siemens). Modelling of kinetics was realized using mixed effects with cubic splines.

Results: Kinetics of markers showed a first peak at 10.7h (8.0-12.0) for creatine kinases, 11.8h (10.4-13.3) for hs-cTnT (Roche); 11.8h (10.7-11.8) for hs-cTnI from Abbott and 10.2h (8.7-11.6) for s-cTnI from Siemens, respectively. This peak was followed by a nearly log linear decrease for hs-cTnI/s-cTnI and creatine kinases in contrast to hs-cTnT, which appeared with a biphasic shape curve marked by a second peak at 76.9h (69.5-82.8). The analysis of the decrease in percentage of the peak value at 77h showed that hs-cTnT follows a twice lower decrease than other markers.

Conclusion: Kinetics of hs-cTnT, hs-cTnI and s-cTnI differ significantly with a linear decrease regarding both cTnI assays contrasting with a biphasic shape curve for hs-cTnT. This is of importance for clinical management of patients in routine settings especially in follow-up after STEMI including the suspicion of reinfarction.