ATLANTA — Carotid stenting of asymptomatic, high-risk patients who were less than 80 years old had a 4.2% rate of death, myocardial infarction, or stroke during 30 days of follow-up in more than 1,700 registry patients.
This rate “compares favorably” with the complication rate for low-risk patients who have had carotid endarterectomy during the past 10 years, and “approaches the 3% goal set by the American Heart Association for all endarterectomy patients, and we're doing it in a high-risk population,” Dr. William A. Gray said at the annual meeting of the American College of Cardiology.
“Based on the results [of the registry], especially in asymptomatic patients, we anticipate approaching the Center for Medicare and Medicaid Services to reopen [its] decision on reimbursing for [carotid stent placement in] asymptomatic, high-risk patients,” Dr. Gray said.
In the registry overall, which included 30-day outcome results for 2,500 patients who underwent carotid stenting with the Acculink stent and its corresponding filter system following approval by the Food and Drug Administration in August 2004, the rate of death, stroke, or myocardial infarction was 5.7%. This rate was significantly better than the 8.3% rate that had been seen in the trial that led to approval of the Acculink stent, said Dr. Gray, director of endovascular services at the Center for Interventional Vascular Therapy at New York-Presbyterian Hospital.
The registry was mandated by the FDA when it approved the Acculink stent; the registry was sponsored by Guidant Corp., which markets this stent. Dr. Gray is a consultant to and receives research support from Guidant.
The first 2,500 patients received their implants at 137 hospitals, with a maximum of 40 patients at any single hospital. All patients underwent a neurologic examination by an independent neurologist at baseline and at 24 hours and 30 days post treatment.
The primary end point evaluated with the registry's data was the combined incidence of death, stroke, and MI during 30 days of follow-up. The registry patients were, on average, 2.5 years older than were those in the approval trial.
Results of the study highlighted the marked increased risk faced by patients with symptoms of carotid stenosis and by older patients. The 233 symptomatic patients in the registry had a combined event rate of 14.2%, compared with a 4.9% rate among asymptomatic patients. Among the 594 patients aged 80 or older, the combined event rate was 8.2%, compared with a 4.9% rate among younger patients.
Another major focus of the analysis was to assess event rates relative to the experience of physicians who performed the carotid stenting procedure.
Physicians were classified as highly experienced if, when the registry began, they had previously been the primary operator for placing at least five Acculink stents and corresponding embolic protection devices.
Physicians were classified as having a medium experience level if they had previously placed at least 10 carotid stents of any type as the primary operator. And physicians classified as having a low level of experience had previously done at least 25 carotid angiograms, 10 peripheral procedures with self-expanding stents, and 10 procedures using a drug system.
For the purposes of this analysis, physicians retained their baseline rating even if they qualified for another category based on the number of stenting procedures that they performed during the registry period.
Physicians who had a medium level of experience were in the majority, at 71% of operators in the registry. Low-experienced physicians composed 20% of the total, and the remaining 9% were rated as high-experienced physicians.
Categorized by specialty, 55% of the physicians placing the carotid stents were interventional cardiologists, 22% were vascular surgeons, 15% were interventional radiologists, and the remaining 8% were equally divided between neurosurgeons and interventional neuroradiologists.
The rate of patient death, MI, or stroke was similar for all physicians regardless of their level of experience, ranging from a 5.4% rate in low-experienced physicians to 6.2% in high-experienced physicians. The carotid-stenting training program “appears to have eliminated the influence of previous experience on outcomes,” Dr. Gray said. He and his associates have not yet analyzed outcomes by physician specialties.
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