What can cause restenosis after angioplasty?

Many: There are techinical causes. If the stent is too small or the lesion wasnt completely covered. Complex bifurcation lesions and long lesions are more likely to restenose. Using multiple stents and working on stents that have already stenosed before. There are patient related causes .Pts that smoke or have diabetes (especially if its poorly controlled) have higher rates of restenoses. High cholest.

Restenosis: Great question which is not adequately answered. Often due to same uncontrolled factors that caused arterial disease in the first place: smoking, diabetes, lipid abnormalities, lifestyle issues such as poor diet and no exercise, etc. In my practice hyperhomocystenemia is found in many if not most of my patients with in stent restenosis.