@chickenfeet7777 Welcome to Mayo Clinic Connect! Being in Stage 4 kidney disease is enough to deal with, let alone finding out you have stenosis on one kidney artery. Here is what Mayo Clinic has to say about that condition: https://www.mayoclinic.org/diseases-conditions/renal-artery-stenosis/symptoms-causes/syc-20352777 Is the stenosis the reason for your Stage 4, or do you have another underlying cause of kidney disease?

Does your medical team have you on any medications to address the stenosis, yet? Have they determined what caused it?

As far as if insurance would cover a renal angioplasty or stent, that is something you would need to ask your insurance provider about. It is not a question that we as members here could respond to. Also, I am not sure what you are referring to as far as stem cell - do you also have cancer?
Ginger