DALLAS -

New research raises serious questions about a very common medical procedure -- placing a stent to prop open a narrowed kidney artery.

A study found that people treated with these stents plus various heart drugs fared no better than people treated with medicines alone.

Stents are tiny mesh scaffolds pushed into narrowed, hardened arteries to help keep them open. They are widely used to treat clogged heart arteries, but their value for other types of blood vessels is less clear.

As many as 7 percent of people over age 65 have narrowed kidney arteries that can make high blood pressure worse. The new study means medicines may be enough to treat the condition.

Results were discussed Monday at an American Heart Association conference in Dallas.