“Is putting a heart stent major surgery?”

No, it is a minimally invasive procedure done through a catheter either from the groin or from the arm

no

Any procedure performed on the heart should be considered major, especially psychologically. The actual procedure is not particularly invasive of technically difficult. Most patients are discharged either later in the evening or the next day. They are not given general anesthesia and the heart is not stopped for the procedure. However, patients may feel quite anxious before and have a period of depression after. Both are normal.