I'm not sure exactly what an angioplasty is for but i know they blow up a balloon similar to what i had done in my valve, which was called a valvuloplasty, where they opened 3 balloons trying to open my bicuspid aortic valve. I know that with the valvuloplasty they said they had to use a dye to track the catheter with the balloon going through my artery, and that the dye is very hard on a person's kidneys. They made me drink this really bad tasting liquid medicine for 3 days to get the dye out of my body as fast as possible before it damaged my kidneys. I would think they would have to track the catheter with the same type of dye for an angioplasty since they said it is a very similar procedure, so it could affect the kidneys. I know they told me that with some people it wrecks their kidneys to the point they have to be on dialysis afterwards. I'm not sure about it causing a nosebleed though.