Is it possible if i have high blood pressure i could have developed peripheral arterial disease undetected and could this lead to an ankle fx nonunion?

Possible: Although anything is possible, peripheral vascular disease can have numerous causes, but for nonunions, sometimes there isn't a "good" reason. Because you haven't had a diagnosis of pad, it's unlikely you had that during your recovery. From your previous posts, i'd recommend getting results from previous vascular exam by ur surgeon prior to surgery (foot pulses, cft, etc). Hope this helps.

Unlikely: A non union fx is probably not related to HTN and pad. It is easy to test for circulation. Non union fx is often related to too much movement at the fracture site. If it's been more than 6 weeks you may need a bone stimulator. ( note this is advice only. You must contact your primary care physician or podiatrist for an examination).

Yes: High blood pressure is a risk factor for peripheral vascular disease. Also, peripheral vascular disease is a potential cause of fracture nonunion. However, it is only one of many potential causes.