Science/Medicine : Tubes Keep Arteries Open

Tiny, permanent metal tubes that can be snaked into clogged arteries to keep them open and thereby help prevent heart attacks are proving to be safe and effective in their first human trials, researchers said.

The devices, made of braided wire mesh so they can be compressed for insertion and then expanded inside clogged arteries, are intended to prevent the common problem of re-blockage of arteries that have been squeezed open with balloons, they said.

The balloon technique, called angioplasty, is done about 150,000 to 200,000 times a year in the United States, said Dr. Ronald Vlietstra of the Mayo Clinic.

Angioplasty can be done with a short hospital stay, at a cost of about $5,000, and has allowed many patients to forgo heart bypass surgery, which can cost about $20,000.

But in about 25% of angioplasty patients, their arteries have become re-clogged within two to six months, Vlietstra said.

The metal tubes, called stents, can be permanently inserted at the time of the angioplasty, and it appears they will keep the artery open by providing a kind of scaffolding that cannot be compressed again once it has been opened inside the artery.

“We’re making an already extremely valuable technique (angioplasty) even more valuable,” said Dr. Gary Roubin of Emory University. Use of stents might add $500 or $1,000 to the cost of angioplasty, he said.

One potential problem with stents is that, being foreign objects, they might encourage the formation of potentially dangerous blood clots.