Coated stents' blood-clot risk may be higher than thought

MINNEAPOLIS -- Patients whose arteries are propped open with drug-coated stents made by Johnson & Johnson and Boston Scientific Corp. may be twice as likely to develop lethal blood clots as previously thought.

A study, appearing in today's Journal of the American Medical Association, tracked 2,229 patients in Italy and Germany who got the tiny mesh tubes after an artery-clearing procedure. After nine months, 1.3 percent developed clots, compared with 0.4 percent to 0.6 percent in earlier trials. Almost half died.

This trial looked at high- and low-risk patients to provide a more realistic look at outcomes in the general population, researchers said. The results underscore the need for doctors to evaluate people individually and for stent recipients to take anticlotting medication such as aspirin faithfully, they said.

Boston Scientific's Taxus device was linked to more clots than Johnson & Johnson's Cypher, though it wasn't large enough to prove one is better than the other, said the study's senior author, Dr. Antonio Colombo of Milan. A trial directly comparing the two devices should be done soon, he said.

Natick-based Boston Scientific did not return calls seeking comment. A spokesman for Johnson & Johnson said the study highlights the growing number of patients with complex conditions and the need for patients to take medicine to prevent clots.

The drug coatings on Cypher and Taxus are designed to prevent scar tissues from reclogging the artery.

It wasn't clear if drug-eluting stents were more likely to trigger blood clots than older, bare-metal ones.