This is not the first claim regarding the potential dangers posed by drug-coated stents. At a scientific meeting in Barcelona in September, European investigators reported seeing a small but significant increase in the rate of death and heart attack among drug-coated stent recipients in long term follow-up trials. Similar findings were reported at a medical meeting in Atlanta in March.
Dr. Sanjay Kaul, a cardiologist at Cedars-Sinai Medical Center in Los Angeles and co-author of the recent editorial published on Cardiosource.com, examined both studies and several others published in the medical literature. He and co-author Dr. George Diamond found that an analysis of all the research so far suggests that drug-coated stents increase the risk of getting a clot by just over a half a percent when compared to patients with bare metal stents. Kaul and his colleague estimate the number of deaths associated with that higher risk could surpass 2000 patients a year in the U.S.
"If you do the math, if you assume a 45-percent case fatality rate and with 1 million interventions and you assume 80-percent of those are with drug-eluting stents, then it is possible that there may be an excess risk of death to the amount of 2160," he says.
Kaul is quick to point out, that number isn't based on actual deaths. He says a much larger study needs to be conducted to determine the real death rate and possible explanations for it. He speculates that one contributing factor has to do with the difference between real-world medicine and controlled clinical trials. Kaul thinks some patients have demanded the new technology. He says it appears physicians and hospitals have been too eager to give it to them.
"Perhaps we as physicians and patients got suckered in by the hype and now I think we are finding out that not all is hunky-dory with these devices and therefore we need to keep an open mind and be influenced and driven by the data. And if the data are telling us that there is some problems we need to recognize them and rectify them," he said.
Boston Scientific recently disclosed to the Food and Drug Administration that it too has found a slightly higher clotting risk on its Taxus drug-coated stent than its bare metal stents. But company spokesman Paul Donovan insists that discovery has not translated into increased deaths.
"We have observed a small increase in the rate of late-stent thrombosis also known more simply as blood-clotting. Our analysis of more than 3500 patients who received our drug-eluting stent has shown no clinically meaningful increase in heart attack or death when compared to bare metal stents," Donovan said.
Donovan wouldn't comment directly on Kaul and Diamond's editorial. But he did say he's confident the scrutiny will ultimately reveal the benefits of drug-coated stents far outweigh any risks.
"No therapy that has a benefit is without a risk and the risk here is very, very small."
Boston Scientific is the leader in the $6 billion a year stent market. The company develops and makes its stents in Maple Grove. Johnson & Johnson also markets a drug-coated stent.
The FDA says it will convene a panel before the end of the year to evaluate the studies presented in Atlanta and Barcelona. The agency says the data have raised important questions. But for now, the FDA believes the devices remain safe and effective.