Older patients with clogged heart arteries may face a little lower death risk over time if they have bypass operations instead of angioplasty and stents to fix the problem.

Researchers compared these approaches using Medicare records on 190,000 patients, the largest study ever of this issue. Death rates were similar one year after either treatment, but lower after four years among those who had bypass surgery.

Doctors say differences in the overall health of people referred to surgery versus the less drastic procedure could account for some of the results. They say angioplasty remains a good and safe option for many people.

Results were discussed Tuesday at a cardiology conference in Chicago.