The presence of competing risks and overall lower levels of provider proficiency appeared to limit the benefits of carotid artery stenting in Medicare beneficiaries, according to the results of a large retrospective cohort study of the Centers for Medicare & Medicaid Services CAS database (2005-2009).
Periprocedural mortality was more than twice the rate in this patient population than in those earlier patients those involved in the pivotal CREST and SAPPHIRE clinical trials, according to a report published online Jan. 12 in JAMA Neurology [doi:10.1001/jamaneurol.2014.3638].
“The higher risk of periprocedural complications and the burden of competing risks owing to age and comorbidity burden must be carefully considered when deciding between carotid stenosis treatments for Medicare beneficiaries,” according to Jessica J. Jalbert, Ph.D., of Brigham and Women’s Hospital and Harvard Medical School, Boston, and her colleagues.
Over 22,000 patients were assessed in the study. The mean patient age was just over 76 years, 60.5% were men, and 94% were white. Approximately half were symptomatic, 91.2% were at high surgical risk, and 97.4% had carotid stenosis of at least 70%.
Almost 80% of the patients undergoing carotid artery stenting (CAS) met the SAPPHIRE trial indications and about half met at least one of the SAPPHIRE criteria for high surgical risk.
In the mean follow-up of approximately 2 years, mortality risks exceeded one-third for patients who were 80 years of age or older (41.5% mortality risk), symptomatic (37.3% risk), at high surgical risk with symptomatic carotid stenosis of at least 50% (37.3% risk), or admitted nonelectively (36.2% risk). In addition, among asymptomatic patients, mortality after the periprocedural period exceeded one-third for patients at least 80 years old.
Of particular concern, few of these Medicare beneficiaries undergoing CAS as per the National Coverage Determinations were treated by providers with proficiency levels similar to those required in the clinical trials. This is a potential problem because lower annual volume and early operator experience are associated with increased periprocedural mortality, the authors wrote.
CAS was performed primarily by male physicians (98.4%), specializing in cardiology (52.9%), practicing within a group (79.4%), and residing in the South (42.5%). The mean number of past-year CAS procedures performed was only 13.9 for physicians and 29.8 for hospitals. This translated to more than 80% of the physicians not meeting the minimum CAS volume requirements and/or minimum complication rates of the SAPPHIRE trial, and more than 90% not meeting the requirements of the CREST trial.
“Our results may support concerns about the limited generalizability of [randomized clinical trial] findings,” the researchers stated.
“Real-world observational studies comparing CAS, carotid endarterectomy, and medical management are needed to determine the performance of carotid stenosis treatment options for Medicare beneficiaries,” Dr. Jalbert and her colleagues concluded.
The authors reported no relevant disclosures. The study was funded by the Agency for Healthcare Research and Quality, U.S. Department of Health & Human Services.