- Group C (control group). 15 prospectively enrolled patients with previous Type 1, 4a, 4b myocardial infarction (ST-segment elevation acute myocardial infarction [STEMI] and Non ST-segment elevation acute myocardial infarction [NSTEMI] acute coronary syndrome [ACS] with significant ≥70% coronary stenosis) at least six months after the event.