The very next day if the angiogram doesn’t show significant coronary artery disease.
No it is not considered as a major surgery.Its classified as minimally invasive diagnostic procedure.
Angio in Latin means vessels , So a graph or image of the vessel is angiography. It’s a test just like a CT scan or MRI it is not a therapy. After the angiogram the cardiology ascertains whether to keep the patient on medical management, do and angioplasty or send for bypass surgery to the surgeon.
In short an angiogram is a test to detect the narrowing of arteries supplying the heart,whereas angioplasty is a procedure to expand these arteries.