Welcome to HCM,
I can understand difficulty you are facing with Ischemic heart disease
and on to of it unfortunately developed CIN or Contrast induced Nephropathy.
I am sure he is in hospital and must be receiving treatment for CIN like hydration and volume expansion , NAC, Furosemide
with judicious use of medications and taking care of his heart condition.
I hope he responds well and fully recovers from AKI ( Acute Kidney Injury
Please do not worry in most of cases it can be treated by various modalities and in worse case by HD hemodilysis( may not be required)
Please take very good care of him.
I wish him good luck and speedy recovery .
please update about progress