Drug-Eluting Stents -- More Good Than Harm for Heart Patients?

Newswise — Clinical evidence suggests that drug-eluting stents in patients undergoing coronary artery revascularization procedures relieve obstructive coronary artery disease, provide durable mechanical results, and do more good than harm. This is the conclusion reached by Allen Jeremias, M.D., Assistant Professor of Medicine and Director, Vascular Medicine and Peripheral Intervention, Division of Cardiovascular Medicine at Stony Brook University Medical Center, in an article published online in the Annals of Internal Medicine (print edition: February 5, 2008).

The use of stents coated with drugs, which are slowly released to help keep blood vessels from reclosing, is one of the most recent advancements in interventional cardiology. This type of stent was developed to address the problem of the re-narrowing or blockage of an artery (restenosis) after bare-metal stent implementation. Yet, clinical reports of increased incidence of blood clot formation " defined as late stent thrombosis occurring more than 30 days after drug-eluting stent implementation " has raised concerns about the safety of the devices.

Dr. Jeremias and co-author Ajay Kirtane, M.D., Assistant Professor of Clinical Medicine, Center for Intervascular Therapy, Division of Cardiology at Columbia University Medical Center in New York, analyzed current clinical data to provide a perspective on the benefits and risks of drug-eluting stents compared to bare-metal stents in "Balancing Efficacy and Safety of Drug-Eluting Stents in Patients Undergoing Percutaneous Coronary Intervention."

"There appears to be a slightly higher risk with drug-eluting stents, namely late stent thrombosis, but our analysis of the clinical evidence suggests that the net clinical benefit of drug-eluting stents may outweigh their risks," says Dr. Jeremias, adding that studies show a remarkably consistent benefit of these devices in the reduction of repeat revascularization.

Drs. Jeremias and Kirtane write that a number of studies indicate that drug-eluting stents carry a small but increased risk of late stent thrombosis in patients compared to bare-metal stenting. They also point out that multiple studies indicate the single most important predictor of stent thrombosis in patients is the premature discontinuation of antiplatelet therapy. Therefore, they explain, it is critical for all patients with drug-eluting stents to be evaluated for their ability to continuously receive and tolerate dual antiplatelet therapy with aspirin and clopidogrel. The authors also point out that trials comparing the two types of stents had varying definitions of stent thrombosis, which is one reason for a lack of an association between possible increases in late stent thrombosis, and other end points, such as myocardial infarction (MI) or mortality rates, in certain trials. In addition, they question whether the true incidence of stent thrombosis with drug-eluting versus bare-metal stents can even be determined, largely because of the overall rarity of the event (less than 2 percent of patients).

Drs. Jeremias and Kirtane urge readers that much larger patient studies are necessary to address the issue of comparative stent thrombosis incidence. They add that larger studies designed to detect small differences in stent thrombosis, MI, and mortality rates after stent implantation are also necessary to address the benefits and risks of drug-eluting stents in a definitive manner.