hi and welcome. angiography is an imaging modality for the coronaries( arteries of the heart that supplies the heart itself). angioplasty is the treatment modality for the narrowed arteries due to blockage complete or partial. well there are prerequisites for angiography that the patient must be well hydrated, kidney function optimal and blood hemoglobin normal or not very reduced. most important that there should be clear indication to under go this invasive procedure chartered by American heart association. the number of times for the procedure depends on nature of the disease and the duration of intervention after initial evaluation. not all blockages are directed to be opened by angioplasty. only cardiologist can decide whether the patient requires stent or bypass operation. take care