Drug-eluting stents, bare metal stents similar in off-label use

Adverse event rates for death, MI lower in drug-eluting stents for off-label indications.

Issue: March 2008

Patients receiving drug-eluting stents showed no more risk for mortality or myocardial infarction than those receiving bare metal stents, according to new study results.

The researchers compared the safety and efficacy of drug-eluting stents with that of bare metal stents for off-label use in patients undergoing percutaneous coronary interventions. The drug-eluting stents not only demonstrated a comparable safety profile with that of bare metal stents but also achieved lower repeat revascularization rates at one-year follow-up. The results were published in The New England Journal of Medicine.

Off-label uses common

The researchers analyzed data from 6,551 patients in the National Heart, Lung and Blood Institute Dynamic Registry to determine the prevalence of off-label use for stents between 1997 and 2006. Off-label uses in the study were defined as use of the stents to treat restenotic lesions, lesions in a bypass graft, left main CAD or with occluded lesions.

Off-label use of both bare metal stents and drug-eluting stents was common in the patient population. The registry listed 2,110 of 3,858 (54.7%) patients with bare metal stents and 1,312 of 2,693 (48.7%) patients with drug-eluting stents as having off-label use. Patients with drug-eluting stents in the off-label groups had lower rates of death (3.7% vs. 6.4%; P<.001), MI (4.4% vs. 5.9%; P=.06) or death or MI (5.2% vs. 10.0%; P<.001) than those with bare metal stents. Although the data suggested that off-label use for both stent types was generally associated with worse clinical outcomes at one-year follow-up, the data also suggested that the use of drug-eluting stents is as safe, if not safer, than bare metal stents for off-label indications.

Some practitioners, however, cautioned about reading too heavily into the study findings.

“The key point is that drug-eluting stents have not been shown to be better than best medical therapy and are inferior to CABG,” Salim Yusuf, MD, professor of medicine at McMaster University, Ontario, Canada, told Cardiology Today. “The issue of on-label vs. off-label is less important; we should simply be reducing the number of people who undergo PCI irrespective of which stent is used. There is at best a small and short-lived improvement in symptoms at hugely increased cost, and that is the real issue.”

Limitations

Although the study used a large sample, the researchers did highlight several key limitations. The study was based on data from an observational registry and was not a randomized, controlled trial. The short follow-up period of one year was also cited as a limitation. The fact that many patients with bare metal stents, in most cases, had them implanted earlier than those patients with drug-eluting stents also became a factor. Patients who had the stents implanted more recently could have benefitted from adjustments in PCI and medical therapies that may have not been present in the earlier years of the registry data. - by Eric Raible

The broad use of drug-eluting stents in recent registries has shown no excess death or MI compared with the use of bare metal stents. The most complex patients who are in the group not studied in the FDA trials are called “off-label.” Of course, these patients have a less ideal outcome for either stent than the simple “on-label” cases, but in many incidences, the benefit of drug-eluting stents in reducing restenosis is greater in the more complex cases. Selective use of drug-eluting stents or bare metal stents based on a risk–benefit ratio has been associated with overall improved outcomes compared with the prior era when only bare metal stents were available. Some of this improvement may be due to the drug-eluting stents, and much may be due to improved technique and the expanded use of ancillary therapies, especially prolonged aspirin and clopidogrel use.

– Spencer B. King III, MD
Cardiology Today Section Editor,
Interventional Cardiology

For more information:

Marroquin OC, Selzer F, Mulukutla SR, et al. A comparison of bare metal and drug-eluting stents for off-label indications. N Engl J Med. 2008;358:342-352.