Is it okay to get an angioplasty for cerebrovascular ischaemia ?

Complex answer: There are few approved indications for angioplasty for blockages in brain arteries above the carotid arteries(in the neck). That said there are situations where experts may recommend angioplasty but much more information is needed to answer your question.

↑Risk vs. Heart PTCA: Angioplasty, ptca, because of brute force stretching of diseased arteries, instantly increases odds of debris, also induction of clots, being shed & blocking blood flow downstream. While heart muscle is more tolerant of this damage than brain, detectable heart muscle damage occurs in 5 to >30% of heart angioplasty procedures. Such complications, strokes, are more obvious in the brain circulation.

Depends: On location of stenosis. Talk to your doctor. Maximize medical treatment. If this fails have your doctor send you to a neurointerventional radiologist or interventional radiologist who does these procedures. They will tell you if intervention needed and risks involved.