Evidence is growing that stents with certain drugs helps them do a better job of keeping blood vessels open after these vessels have been cleared surgically. But a new report suggests not all drugs work equally well. Researchers found that stents coated with a derivative of the cancer drug paclitaxel - which inhibits cell division - failed to keep blood vessels open in the majority of a small group of patients, resulting in heart attacks in 3 cases.
In angioplasty, a balloon-tipped catheter is threaded into a blocked artery and inflated, flattening fatty plaques against the artery wall. More than half of arteries cleared in this way eventually become blocked or narrowed again, so doctors may insert stents - sometimes coated with drugs - in order to keep them open. After receiving a new stent, many patients experience restenosis, during which cells from inside the vessel grow around the stent, partially obstructing the vessel and putting patients at risk of a heart attack.
The stents used in his experiment had a relatively thick plastic sleeve. The body's cells may have attacked the plastic, thinking it was a foreign body, leading to an accumulation of cells. The reblockage of the vessels could be a reaction to the plastic sleeve, and not necessarily a failure of the drug.