What is a “full metal jacket”?

Ask the doctor

Q. I heard my cardiologist say to another doctor that I have a “full metal jacket.” What does that mean?

A. Cardiologists use the term “full metal jacket” to refer to a long series of stents in one of the heart’s three major arteries. Stents are tiny metal cylinders, often with drug coatings, that help prop open arteries to restore blood flow to the heart. They’re placed inside arteries during an angioplasty, in which a doctor snakes a thin, flexible tube (catheter) through the blood vessels to a narrowed section. A deflated balloon at the tip of the catheter then inflates, pushing fatty plaque against the artery wall and expanding the stent.

The average stent is 1/2 to one inch long. People typically receive one or two stents, most commonly in one artery but sometimes in several arteries or branches of arteries. But if a vessel has an especially long area of fatty plaque, the doctor may use three or more adjacent stents. This long, stented area is sometimes referred to as a full metal jacket.