People with several clogged heart arteries tend to fare better if they have bypass surgery rather than a less drastic procedure in which the blood vessels are propped open with tiny mesh cylinders called stents, a study of nearly 60,000 patients has found.

In the study, reported today in The New England Journal of Medicine, patients who had surgery were significantly more likely to survive and less likely to need repeat procedures.

Experts noted that the two techniques had improved so much since the study was conducted that more research might be needed to determine which method works best for which patient.

The study is among the largest to compare treatments for clogged arteries, a problem that can lead to a heart attack.

For an open-heart bypass, blood vessels are taken from another part of the body and grafted at the site of the problem to create detours around blockages. The less drastic option is angioplasty and stenting, in which the tubes are threaded into arteries to keep them flowing smoothly.

Angioplasty is often performed for people with just one or two blockages. Many studies suggest that no harm is done if it is tried first in an effort to avoid surgery in people with multiple blockages. The new research calls that into question.