ATLANTA -(Dow Jones)- Longer-term data from a study examining stents placed in a crucial artery that fuels the heart's main pumping chamber continued to show a similar impact on patient survival as bypass surgery, but also greater odds of stent patients needing more procedures.

Cardiologists typically pick bypass surgery when patients have a clog in the heart's "left main" artery, while less-invasive stent procedures are reserved for less dangerous locations. But the "Main-Compare" study from Korea, which tracked results from 2,240 patients treated at 12 centers, sought to determine if stents are also an option.

The five-year results were presented Sunday at the American College of Cardiology's annual conference. It is a registry-style study that broadly includes patients but doesn't have the same rigor as a randomized trial set up to make comparisons.

Three-year results presented at ACC in 2008 also showed similar safety for stent and bypass patients, but a higher likelihood of repeat procedures for stent patients. That data didn't jolt the market for stents, where Abbott Laboratories (ABT) and Boston Scientific (BSX) are big manufacturers these days, suggesting the latest batch will not have a big impact, either.

This time around, the combined risk of death, heart attacks and strokes were similar among stent and bypass patients at five years. The risk of death alone was also similar. But as at three years, stent patients once again had higher rates of repeat procedures in the problem artery.

Both bare-metal and drug-coated stents, which include medication to fight renarrowing in arteries that can prompt another procedure, were tracked in the study. But both types of stents led to higher rates of retreatment in the problem artery than bypass.

Seung-Jung Park, the study's main researcher and director of interventional cardiology at Asan Medical Center in Seoul, said in an ACC release that results suggest stenting is a good alternative for a "selected population" with a left-main artery clog.

The study was sponsored by the Korean Society of Interventional Cardiology, and without any industry involvement.

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