Only complicated or high risk STEMI, would require immediate anatomy based management. Please note, this population at worst is never beyond 20 % of all STEMI. Hence more than majority of patients can be managed effectively without CAG.
My reasoning tells me,though knowing the coronary anatomy appear vital , it is rather the physiological impact of those anatomical lesions that will determine the outcome. So,post STEMI, if at all , we need to investigate, it should be about the adequacy of the over all blood supply to left ventricle.This is done by a pre or post discharge sub maximal stress /nuclear test .If it’s negative with a good exercise tolerance CAG will never be required as any critical flow limiting lesion ( that would require intervention )is excluded with near 100% surety.
Postamble :Try asking any neurologist , how often they demand to know cerebral arterial anatomy for managing stroke ? You will get a real surprise answer !