Gene therapy given after treatment to unblock clogged-up arteries could help them stay clear, according to research.

Narrowing of blood vessels can increase the chance of heart attack or stroke, and one treatment is to insert and inflate a balloon in the affected section, then put in a metal tube to stop it closing again.

However, the insertion of the tube, called a stent, can actually trigger a reaction in some patients which leads to rapid re-blocking of the blood vessel.

Researchers at the University of Kuoppio in Finland believe they understand why the stent causes this process.

They also think they can halt this reaction by introducing an extra gene into the blood vessel.