If creatinine is 1.8 can angio and stenting be done or is it unsafe? What is the safest level of creatinine if person had a heart attack 15 days ago?

HIgh creatinine . With a creatinine (c) of 1.8 mg/dl, you have some chronic kidney disease (ckd). There is some potential for you to have some temporary impairment of your kidney function (kf) due to the dye used in the angio procedure. Discuss your c level with your cardiologist to see how you should proceed and with what precautions. Any impairment of your kf will probably be temporary, if it occurs. Good luck.
Risk-benefit. It is not safe for a routine exam, however, depending on the severity / extent of the heart attack and how far along it is, much greater "risk" to the kidney is acceptable in order to preserve / restore blood flow and function of the heart. Even those w/worsened renal function from dye load often respond to hydration and temporary (<1month usually) dialysis.