AVP and ST Elevation Myocardial Infarction: Patients with non-ST-elevation myocardial infarction (NSTEMI) had a significantly lower level of copeptin than those with ST-elevation myocardial infarction (STEMI) but a higher level than those with unstable angina, indicating that copeptin levels were strongly associated with the extent of myocardial necrosis (67).