Cardiac troponin I degradation in STEMI patients revealed intact cTnI and a single degradation product as early as 90 minutes post-symptom onset, correlating with higher cTnI levels (P<0.001).
RCT (n=26)
Randomized
What is the time course of cardiac troponin I degradation in patients with acute STEMI?
Cardiac troponin I degradation begins as early as 90 minutes after STEMI symptom onset, with the extent of degradation correlating with infarct size and time to treatment.
Although measurement of troponin is widely used for diagnosing acute myocardial infarction (AMI), its diagnostic potential may be increased by a more complete characterization of its molecular appearance and degradation in the blood. The aim of this study was to define the time course of cardiac troponin I (cTnI) degradation in patients with acute ST-elevation myocardial infarction (STEMI). In the ASSENT-2 substudy, 26 males hospitalized with STEMI were randomized to 2 different thrombolytic drugs within 6 hours after onset of symptoms. Blood samples were obtained just before initiation of thrombolysis and at 30 minutes intervals (7 samples per patient). Western blot analysis was performed using anti-cTnI antibodies and compared with serum concentrations of cTnI. All patients exceeded the cTnI cutoff for AMI during the sampling period; at initiation of therapy, 23 had elevated cTnI values. All patients demonstrated 2 bands on immunoblot: intact cTnI and a single degradation product as early as 90 minutes after onset of symptoms. On subsequent samples, 15 of 26 patients showed multiple degradation products with up to 7 degradation bands. The appearance of fragments was correlated with higher levels of cTnI (P<0.001) and time to initiation of treatment (P=0.058). This study defines for the first time the initial time course of cTnI degradation in STEMI. Intact cTnI and a single degradation product were detectable on immunoblot as early as 90 minutes after onset of symptoms with further degradation after 165 minutes. Infarct size and time to initiation of treatment was the major determinant for degradation.
Madsen et al. (Fri,) conducted a rct in Acute ST-elevation myocardial infarction (STEMI) (n=26). Thrombolytic drugs was evaluated on Time course of cardiac troponin I (cTnI) degradation. Cardiac troponin I degradation in STEMI patients revealed intact cTnI and a single degradation product as early as 90 minutes post-symptom onset, correlating with higher cTnI levels (P<0.001).
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