BACKGROUND: Primary percutaneous coronary intervention (pPCI) is recommended in patients presenting with ST-elevation myocardial infarction (STEMI) within <12 h of symptom onset. However, patients-reported symptom duration is not always reliable. Cardiac specific troponin T (cTnT) and the endogenous stress marker copeptin have different temporal release patterns for myocardial infarction MI. We hypothesized that copeptin/troponin-ratio is associated to the duration of coronary occlusion and therefore inversely proportional to myocardial salvage.

METHOD: Patients older than 18 years with first time STEMI referred to pPCI were eligible. cTnT and copeptin values were measured at admission. A cardiac magnetic resonance scanning (CMR) was done during the index admission for assessment of area at risk (AAR), and later 3 months to assess final infarct size (FIS). Myocardial salvage index (MSI) was calculated based on these measurements.

RESULTS: A total of 468 patients were included. The median time from patient-reported onset of symptoms to pPCI was 192 min (IQR 150 min - 290 min). At presentation 416 (89%) patients had hs-cTnT values above the 99th percentile, median hs-cTnT was 53 ng/l (IQR 24 ng/l-146 ng/l) and 318 (68%) patients had copeptin values above the 99th percentile (18.9 pmol/l), median copeptin was 50 pmol/l (IQR 14 pmol/l-131 pmol/l). Symptom duration showed a weak but significant association with AAR (R2 = 0.02, p = .04), FIS (R2 = 0.03, p < .01) and MSI (R2 = 0.04, p < .01). Copeptin/troponin-ratio was significantly associated with symptom duration (R2 = 0.19, p < .01), but not AAR (R2 = 0.02, p = .19), FIS (R2 = 0.02, p = .12), or MSI (R2 = 0.01, p = .25).

CONCLUSION: Copeptin/troponin-ratio is associated with patient-reported symptom duration, but there was no association with area at risk, final infarct size or myocardial salvage index.