Cardiac troponin I and electrocardiogram for estimation of infarct size and for risk stratification in patients with STelevation myocardial infarction treated with primary percutaneous coronary intervention
Background: Cardiac troponin and the electrocardiogram (ECG) are essential diagnostic tools in acute coronary syndrome. They are also important prognostic markers. Cardiac troponin reflects myocardial necrosis. Following reperfusion therapy for ST-elevation myocardial infarction (STEMI), ECG-derived measures of ST-segment recovery (STR) reflect tissue perfusion and are associated with clinical outcome.
Aims: In a population of STEMI patients receiving primary percutaneous coronary intervention (pPCI), to study the association of cardiac troponin I (TnI) with infarct size (IS), left-ventricular (LV) function and volumes and microvascular obstruction (MVO); and to study the association of 3 measures of STR with IS and LV function.
Methods: Post hoc analyses of the 227 patients enrolled in the overall negative FIRE (Efficacy of FX06 in the Prevention of Myocardial Reperfusion Injury) trial. cTnI sampled at 24 and 48 hours. STR calculated immediately following pPCI and at 90 minutes. The outcome measures (IS, MVO and LV function and volumes) were obtained by (late gadolinium enhanced) cardiac magnetic resonance (CMR) at 5-7 days and 4 months following the index event.
Results: cTnI was significantly correlated with IS, LV ejection fraction (LVEF) and LV volumes at both 5-7 days and 4 months. The associations between cTnI and these outcome measures at 4 months remained after adjustment for the early CMR evaluation. cTnI was associated with MVO independent of IS. All 3 STR algorithms were significantly associated with IS and LVEF at 4 months. The simple metric of worst-lead residual ST-segment deviation evaluated at 90 minutes post-intervention was comparable to the more complex STR algorithms.
Interpretation and conclusion: Both measurement of cTnI and calculation of STR provide useful information on IS and LV function and remodeling in STEMI patients treated with pPCI, and may allow for early and simple risk stratification of this patient population. The clinical utility of these findings for prognostic assessment awaits further prospective studies.
List of papers. Papers I-IV are removed from the thesis due to copyright restrictions.
Hallén J, Buser P, Schwitter J, Petzelbauer P, Geudelin B, Fagerland MW, Jaffe AS, Atar D.
Relation of cardiac troponin I measurements at 24 and 48 hours to magnetic resonancedetermined infarct size in patients with ST-elevation myocardial infarction.
Am J Cardiol. 2009;104(11):1472-7.
Hallén J, Jensen JK, Fagerland MW, Jaffe AS, Atar D.
Cardiac troponin I for the prediction of functional recovery and left ventricular remodeling following primary percutaneous coronary intervention for ST-elevation myocardial infarction.
Heart. 2010; 96(23):1892-7.
Hallén J, Jensen JK, Buser P, Jaffe AS, Atar D.
Relation of cardiac troponin I and microvascular obstruction following ST-elevation myocardial infarction.
Acute Cardiac Care. 2011; 13(1):48-51
Hallén J, Sejersten M, Johanson P, Atar D, Clemmensen PM.
Influence of ST-segment recovery on infarct size and ejection fraction in patients with ST-segment elevation myocardial infarction receiving primary percutaneous coronary intervention.
Am J Cardiol. 2010;105(9):1223-8.