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Several recent studies have been released offering a bright outlook for the use of drug-eluting stents (DES).

Presentations at the Society for Cardiovascular Angiography and Interventions and American College of Cardiology Annual Scientific Summit (SCAI-ACCi2) in Chicago recently concluded, offering promising results.

Yaling Han, M.D. of Shenyang China presented results of a recent CREATE study with the Excel stent. The Excel (from JW Medical Systems) DES is coated with a biodegradable polymer and the drug Sirolimus. Over 2,000 patients in 59 international medical centers received the Excel DES implant. About 17 percent received the stent just after a heart attack. After a 12-month follow up, the outcomes proved auspicious to DES usage. Only 2.77 percent of patients suffered complications. The Excel DES patients were also prescribed Clopidogrel and aspirin as anticoagulants to assist in therapy. Due to the minimal cardiovascular complications, the Excel stent therapy has potential to reduce instances of restenosis and late stent thrombosis.

Another DES-favorable study outcome was presented by Patrick W. Serruys, M.D. from Rotterdam, The Netherlands. Dr. Serruys discussed his group's SPIRIT II study, which evaluated the safety and efficacy of the XIENCE V Everolimus-eluting stent compared with the TAXUS Paclitaxel-eluting stent. Dr. Serruys stated that analysis of the outcomes demonstrated the XIENCE V stent is superior to TAXUS. The Everolimus group showed a 98% success rate.

The 300 international patients recruited for the SPIRIT II study had de novo coronary lesions needing 1-2 stents. The XIENCE V stent's clinical outcomes at two years showed a nearly identical rate to TAXUS for in-stent late loss, a 40 % lower major adverse cardiac event (MACE) rate, a 49% higher reduction in heart attack rates and a 64% higher reduction in cardiac death over the Taxus stent. The study did note that there was no difference in blood clotting or stent thrombosis at the two-year outcome between the TAXUS and XIENCE stents, indicating that further long-term data regarding the stents' performance should be pursued.

Philips Healthcare was present at the Chicago ACC Scientific Summit, demonstrating its interventional tool StentBoost Subtract. StentBoost is an X-ray enhancing visualization that helps assess full stent expansion and apposition. StentBoost freezes and enhances the image around the stent. Clinicians benefit from the better view of stent deployment in coronary arteries by being able to take immediate corrective action, which can prevent additional procedures. Philips' work follows the Society for Cardiovascular Angiography and Interventions recommendation of DES and the resulting interest in better quality stent and lumen visualization.

DES vs. BMS

In further stent news, according to a new study in the Journal of American Medicine the use of DES rather than bare-metal stents (BMS) has been found to be more effective. Heart attack patients given DES implants are far less likely to suffer from MACE, the study by Marco Valgimgli, M.D., Ph.D., from the Cardiovascular Institute in the University of Ferrara, Italy concluded.

Dr. Valgimgli and associates studied patients who received anticoagulants Abciximab and Tirofiban within 90 minutes of angioplasty procedure. In the 745-patient study taking place between 2004 and 2007, researchers evaluated the effect of high-dose Tirofiban and Sirolimus-releasing stents compared with Abciximab infusion and BMS implantation. The researchers discovered the patients with the DES had fewer incidents of MACE. At 8-month follow-up, occurrence of MACE was approximately halved by DES, compared with BMS. Patients who received DES were found to also be less likely to require revascularization.

In a similar study, the Cardiovascular Research Foundation presented meta-analysis results of comparisons between BMS and DES at the Drug-Eluting Stent Revolution VII, meeting recently held in Chicago. Ajay J. Kirtane, M.D., of New York-Presbyterian Hospital/Columbia University Medical Center, and Gregg W. Stone, M.D., of Columbia University Medical Center provided conclusive analysis of over fifty studies involving nearly 200,000 patients. The study concerned mortality rates for DES usage compared with BMS. The studies demonstrated that DES in either on-label or off-label use were not harmful to patients, a finding that Dr. Kirtane said should be reassuring to both patients and physicians, and favorable for future DES usage. The DES in the studies showed reductions in death, MIs, and tricuspid valve replacement.

Finally, the U.S. Food and Drug Administration has announced issuance of draft guidelines to aid the development, testing and manufacture of DES devices. The concerns over long-term clot formation following implantation of DES led to the production of the FDA guidance document. The guide contains advice for approval applications and recommendations for clinical evaluation in the pre-market stage and also for studies of post-market follow-up. The use of DES combines device and drug technology, therefore the guide received input from both the Center for Devices and Radiological Health and the Center for Drug Evaluation and Research. The FDA document also provides guidance on incorporating studies of the toxicology of drug substances into evaluations. The guide and its companion document are to provide assistance in minimizing risks of DES devices while maintaining patient benefits, according to Daniel G. Schultz, M.D., director of FDA's Center for Devices and Radiological Health.