Rivaroxaban dosage.

[Geoff47]

As I suffer from AF, my cardiologist prescribed Rivaroxaban blood thinner to help prevent stroke. Dosage was 20mg daily. I've been on this for about two years. A couple of months ago I noticed that my dosage had been reduced to 15mg. I called my GP surgery and was advised that as my routine blood tests always show a borderline kidney function level, one of the GPs had reduced the dosage without telling me. A few days ago I had a routine consultation with my cardiologist. She was somewhat annoyed that my Rivaroxaban had been reduced and said she would write to my GP to have the dosage restored to 20mg. So now I have a predicament. Should I take 15mg and increase stroke risk or 20mg and increase kidney failure risk? I should also add that I was born with only one kidney which may complicate things.