Public Release: 

Drug-eluting stents may cause allergic reactions

Researchers from Northwestern Memorial recommend physicians be vigilant in looking for symptoms

Northwestern Memorial HealthCare

CHICAGO - Drug-eluting stents have greatly reduced the risk of repeat blockage of heart arteries, but researchers from Northwestern Memorial Hospital have found that in some patients, the stents can cause allergic reactions that can have serious consequences. They stress that physicians and their patients should be aware of this potential and know the symptoms. The findings have been published online will be published in the January 3rd issue of the Journal of the American College of Cardiology.

"This paper provides evidence for the first time that instances of allergic reactions, presumably to the polymer in the stent, can occur. In some instances, these events have serious consequences- including stent closure and subsequent death," says one of the study's authors, Charles Bennett, MD, an epidemiologist and oncologist at Northwestern Memorial Hospital and professor of medicine at Northwestern University's Feinberg School of Medicine. Dr. Bennett developed and directs the Research on Adverse Drug/Device Events And Reports (RADAR) Project, which compiles information from reports submitted to the U.S. Food and Drug Administration's (FDA) database as well as reports by drug companies and independent researchers throughout the world. RADAR has previously successfully identified a large number of serious drug reactions associated with 15 commonly used drugs.

For this study, RADAR investigators from 10 centers around the country reviewed 5,783 reports available from April 2003 through December 2004 for hypersensitivity-like reactions associated with drug-eluting stents. From these reports, researchers identified 17 cases of hypersensitivity reactions that were classified as probably or certainly caused the stent, four of which resulted in death. Symptoms included rash, difficulty breathing, hives, itching and fevers. They also concluded that the polymer coating on the stent itself is the most probable cause of hypersensitivity in the majority of cases rather than the medications the stent is coated with.

"It is important to keep the findings in perspective," says Charles J. Davidson, MD, an author on the paper and medical director of the Cardiac Catheterization Lab at the Bluhm Cardiovascular Institute of Northwestern Memorial Hospital and professor of Medicine at Northwestern University's Feinberg School of Medicine. "Drug-eluting stents are a life-saving advance used by hundreds of thousands of people that have greatly reduced the risk of restenosis. We are in no way recommending they be used less, but we do think that health professionals should be vigilant in watching for this problem."

Another concern, say the authors, is that in many instances, blame for the allergic symptoms is placed on other medications that treat their heart conditions, such as Plavix® and anti-platelet agents, and these are discontinued. Premature discontinuation of Plavix® can increase the risk of dangerous blood clots.

"Physicians should be cognizant that allergic reactions to the polymers in drug eluting stents can occur and all such events should be reported to the FDA. Six months after the approval of the first drug-eluting stent, the FDA issued a letter to physicians identifying 50 hypersensitivity cases associated with drug-eluting coronary artery stents, but retracted an assertion of causality a month later. That retraction may have been premature," says Dr. Bennett.

The paper also concludes that further research is warranted to better understand this risk and to develop a skin test to identify people who might be at high risk for hypersensitivity to drug eluting stents.

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This study was supported by grants from National Institutes of Health.

About Northwestern Memorial Hospital
Northwestern Memorial Hospital is one of the country's premier academic medical centers and is the primary teaching hospital of Northwestern University's Feinberg School of Medicine. Northwestern Memorial and its Prentice Women's Hospital and Stone Institute of Psychiatry have 744 beds and more than 1,200 affiliated physicians and 5,000 employees. Providing state-of-the-art care, Northwestern Memorial is recognized for its outstanding clinical and surgical advancements in such areas as cardiothoracic and vascular care, gastroenterology, neurology and neurosurgery, oncology, organ and bone marrow transplantation, and women's health.

Northwestern Memorial received the prestigious 2005 National Quality Health Care Award and is listed in eight specialties in this year's US News & World Report's issue of "America's Best Hospitals." The hospital is also cited as one of the "100 Best Companies for Working Mothers" by Working Mother magazine for the past 5 years and has been chosen by Chicagoans for a decade as their "most preferred hospital" in National Research Corporation's annual survey.

About the Bluhm Cardiovascular Institute
The Bluhm Cardiovascular Institute at Northwestern Memorial Hospital is a world-class heart program offering comprehensive services and state-of-the-art surgical treatments in all areas of cardiovascular care. Recently named by Solucient, an industry-leading healthcare information provider, as the only Chicago hospital on its list of the country's 100 Top Cardiovascular Hospitals, Northwestern Memorial Hospital offers a timely response to referrals and a multidisciplinary approach that joins physicians, nurses and a range of other medical specialists and caregivers from Cardiology, Cardiac Surgery, Vascular Surgery, Cardiovascular Anesthesiology and Radiology from evaluation to follow-up. Patients benefit from the latest minimally invasive surgical techniques and are offered the opportunity to participate in a range of clinical research trials.

Advanced Cardiovascular Care
Patients referred to the Bluhm Cardiovascular Institute experience a healthcare environment in which the most advanced diagnostic and treatment options are supported by state-of-the-art technology and a commitment to medical excellence through research. Expertise is available in all areas of cardiovascular care, including:

Cardiac Surgery

  • Valve repair and replacement
  • MAZE and atrial fibrillation ablation procedures
  • Coronary artery bypass with arterial conduits
  • LV and aortic aneurysm repair
  • Congestive heart failure surgery
  • Ventricular assist devices
  • Heart transplantation

Vascular Surgery

  • Thoracic and abdominal aortic aneurysm surgery
  • Carotid endarterectomy and stents
  • Endovascular surgery for aortic aneurysms and limb salvage
  • Lower extremity bypass procedures
  • Uncommon mesenteric and upper extremity revascularization
  • Supraaortic trunk revascularization

Cardiology

  • Primary and secondary prevention
  • Advanced diagnostic testing including echocardiography, nuclear cardiology, cardiac MRI and computed tomography
  • Cardiac electrophysiology, including diagnostic EP procedures, catheter ablation and pacemaker and ICD implantation
  • Heart failure management
  • Evaluation of heart valve disease
  • Acute coronary care
  • Diagnostic catheterization and interventional cardiology

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