REN and myocardial ischemia: For example, patients with STEMI have a high risk of CIN, whereas those with CAD have a relatively lower risk.[30,31] On the other hand, natriuretic peptide levels are higher in myocardial ischemia patients, even without ventricular dilation.[32] Plasma BNP levels are elevated within 12 to 24 hours after acute myocardial infarction[33] and are indicators of ventricular pressure and renin-angiotensin-aldosterone system activated by myocardial infarction, which play a role in CIN development.