August 31, 2010
Model Developed to Calculate Risk-Adjusted Stroke Outcome Benchmarks for CAS
September 1, 2010—In the Journal of Vascular Surgery, Jon S. Matsumura, MD, et al published risk-adjusted stroke outcome benchmarks for carotid artery stenting (CAS) with distal embolic protection from the CAPTURE 2 (Carotid RX Acculink/RX Accunet Postapproval Trial to Uncover Unanticipated or Rare Events, Phase 2) postapproval study of the RX Acculink/RX Accunet embolic protection system (Abbott Vascular, Santa Clara, CA) (2010;52:576–583).
According to the CAPTURE 2 investigators, many medical procedures undergo rapid evolution and process of care improvements after introduction. National outcome standards are useful to help physicians, institutions, and other stakeholders evaluate the quality of their programs and take action when suboptimal outcomes are identified. The purpose of this analysis was to derive contemporary risk-adjusted stroke rates from a large, contemporary, independently assessed outcome database within 30 days after CAS in the United States.
CAPTURE 2 is the second phase of the ongoing prospective, multicenter Acculink/Accunet postapproval clinical trial seeking to uncover rare events to assess CAS outcomes in the general practice setting after device approval for high-surgical-risk patients (symptomatic with > 50% stenosis or asymptomatic with > 80% stenosis).
As detailed in the Journal of Vascular Surgery, a neurologist examined the patients before the procedure and at 1 day and 30 days after CAS. The primary endpoint was a composite of death, any stroke, or myocardial infarction within the periprocedural period. Strokes and neurologic events suspected to be strokes were adjudicated by an independent clinical events adjudication committee. Logistic regression analysis including stepwise logistic and multivariable modeling was performed to determine clinical predictors of periprocedural stroke outcome and generate a parsimonious model that could be used for a clinical standard.
The investigators reported that 5,297 consecutive patients had CAS performed by 459 physicians at 186 sites before the data cutoff of January 10, 2009. The 30-day stroke rate was 2.7% (95% confidence interval [CI], 2.3–3.2). Multivariable predictors of periprocedural stroke included age, symptomatic status, and dwell time of the embolic protection device.
The investigators concluded that CAS outcomes in patients at high surgical risk have comparable periprocedural outcomes to published randomized trials of endarterectomy for patients at standard surgical risk. A model was presented for calculating a contemporary national standard for risk-adjusted stroke rates. The parsimonious model Pi = 1/(1+e −[−3.83 + 0.51 × (symptomatic) + 0.31 × (age ≥ 80) + 0.62 × (age ≥ 80 × symptomatic]), including symptomatic and octogenarian status and the term of the interaction of the two, was established based on consideration of clinical predictors, clinical interaction, and practicability. Quality improvement measures could be based on relative performance to this benchmark and could improve overall outcomes for patients undergoing CAS.