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Original Investigation
March 2015

Outcomes After Carotid Artery Stenting in Medicare Beneficiaries, 2005 to 2009

Author Affiliations
  • 1Division of Pharmacoepidemiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
  • 2LASER ANALYTICA, New York, New York
  • 3Division of Vascular and Endovascular Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
  • 4Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
  • 5Division of Cardiovascular Medicine, Massachusetts General Hospital, Boston
  • 6Ochsner Clinical School, Ochsner Medical Center, New Orleans, Louisiana
  • 7OptumInsight Epidemiology, Waltham, Massachusetts
  • 8Division of Cardiology, Denver Veterans Affairs Medical Center, University of Colorado, Denver
  • 9Division of Cardiovascular Medicine, St Joseph Mercy Ann Arbor, Ann Arbor, Michigan
  • 10Global Health Outcomes, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana
  • 11Department of Neurology, Mayo Clinic, Jacksonville, Florida
  • 12Department of Medicine, Duke Clinical Research Institute, Durham, North Carolina
JAMA Neurol. 2015;72(3):276-286. doi:10.1001/jamaneurol.2014.3638

Importance  Despite increased carotid artery stenting (CAS) dissemination following the 2005 National Coverage Determination, to our knowledge, periprocedural and long-term outcomes have not been described among Medicare beneficiaries.

Objective  To describe the incidence of outcomes during and after the periprocedural period among Medicare beneficiaries undergoing CAS.

Design, Setting, and Participants  Observational study with a mean follow-up time of approximately 2 years among 22 516 fee-for-service Medicare beneficiaries at least 66 years old undergoing CAS (2005-2009) who were linked to the Centers for Medicare & Medicaid Services’ CAS database. Database procedure dates were required to fall during a Medicare hospitalization for CAS.

Main Outcomes and Measures  Periprocedural (30-day) and long-term risks of mortality and stroke or transient ischemic attack, as well as periprocedural myocardial infarction. Subgroups were based on sociodemographic, clinical, and center-level factors, as well as the Stenting and Angioplasty With Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial or Carotid Revascularization Endarterectomy vs Stenting Trial (CREST) enrollment criteria.

Results  The mean patient age was 76.3 years, 60.5% were male, 93.8% were of white race, 91.2% were at high surgical risk, 47.4% were symptomatic, and 97.4% had carotid stenosis of at least 70%. Crude 30-day mortality, stroke or transient ischemic attack, and myocardial infarction risks were 1.7% (95% CI, 1.5%-1.8%), 3.3% (95% CI, 3.0%-3.5%), and 2.5% (95% CI, 2.3%-2.7%), respectively. Mortality during a mean follow-up time of 2 years was 32.0% (95% CI, 31.0%-33.0%), with rates of 37.3% (95% CI, 35.8%-38.7%) among symptomatic patients and 27.7% (95% CI, 26.4%-28.9%) among asymptomatic patients. Older age, symptomatic carotid stenosis, and nonelective hospital admission were associated with increased adjusted hazards of mortality and stroke or transient ischemic attack during and after the periprocedural period. The presence of a stroke center, government ownership, and a hospital bed capacity of 500 or more were associated with increased adjusted hazards of periprocedural mortality and stroke or transient ischemic attack. Few patients met the SAPPHIRE trial or CREST enrollment criteria primarily because physicians did not meet proficiency requirements either due to exceeding periprocedural complication trial thresholds or not meeting minimum CAS volume requirements.

Conclusions and Relevance  Competing risks may limit the benefits of CAS in certain Medicare beneficiaries, particularly among older and symptomatic patients who have higher periprocedural and long-term mortality risks. The generalizability of trials like the SAPPHIRE or CREST to the Medicare population may be limited, underscoring the need to evaluate real-world effectiveness of carotid stenosis treatments.