Aim: We investigated dynamics of high-sensitivity troponin I (cTnI) and associated extent of myocardial injury in out-of-hospital cardiac arrest (OHCA) patients with different extent of coronary artery disease.
Methods: 159 consecutive patients undergoing immediate coronary angiography after OHCA were included and divided into groups with acute culprit lesion (A), stable obstructive coronary disease (B) and non-obstructive or absent coronary disease (C). Serial measurements of cTnI were obtained at admission and 3, 6, 12, 18, 24, 36 and 48 hours later. Area under cTnI curve was calculated and optimal cut-off value predicting acute coronary lesion was determined.
Results: ST-elevation myocardial infarction (STEMI) was documented in 65 % in group A, 26 % in group B, and 11 % in group C (p < 0.001). cTnI, which was 0,88 ng/mL, 0,44 ng/mL and 0,19 ng/mL in groups A, B and C on admission (p < 0.001), increased to a maximum of 63,96 ng/mL, 10,00 ng/mL and 2,35 ng/mL, respectively (p < 0.001). Within the group A, cTnI was significantly larger in patients with acute occlusion than in patients with spontaneous reperfusion at initial angiography. Within groups B and C, peak cTnI correlated with duration of resuscitation, number of defibrillations and cumulative epinephrine dose. If admission cTnI exceeded 0,46 ng/mL, sensitivity for detection of acute culprit lesion was 64 % and specificity 60 %.
Conclusions: Significant myocardial injury associated with highest cTnI levels in OHCA patients occurs in the presence of acute culprit lesion, particularly if the infarct-related coronary artery is still occluded at the time of coronary angiography. Extent of myocardial injury in stable or absent coronary disease is significantly smaller and correlates with the duration and intensity of cardiac resuscitation. Admission cTnI have insufficient accuracy to securely predict presence of acute culprit lesion.