Overview of coronary stents

Tiny, expandable mesh tubes - or stents - which help prop open clogged arteries are among the most commonly used medical devices.

The June issue of Mayo Clinic Health Letter offers an overview of this treatment, including an update on recent research that raised some questions about stent use.

In angioplasty, doctors insert a flexible tube (catheter) into a leg or arm and thread it toward a blocked heart artery. In the early days of this procedure, a balloon at the end of the catheter was inflated to stretch open the artery. About 30 to 40 percent of the time, the stretched vessel would narrow again. In the mid-1990s, the Food and Drug Administration approved the routine use of stents, which are expanded into place using balloon angioplasty and left within the artery to help keep it open. This procedure helps about 1 million Americans each year.

Recently, a large study suggested that angioplasty may not be necessary in people who have regular, predictable chest pain due to partially blocked arteries. However, if medication and lifestyle changes don't relieve pain, or if there is a change in the usual pattern of chest pain, stents may still be the best treatment.

Other research found an increased risk of blood clots in the newest type of stents, called drug-eluting stents. These devices are coated with a drug that is released over about 30 days to inhibit inflammation and scar tissue growth. This risk is low when patients take recommended medications.

Stents aren't risk free, but they've allowed millions of Americans to avoid far more extensive heart bypass surgery to open critical blockages in arteries leading to the heart. For patients without other significant risk factors, the risk of major complications related to angioplasty - such as heart attack, death or stroke - is less than 3 percent.