Comparative effectiveness of carotid arterial stenting versus endarterectomy

Growth in carotid arterial stent utilization among Medicare beneficiaries, 2002-2006. The bars indicate the number of carotid arterial stent (CAS) procedures performed per month. The light gray background indicates the “pre-coverage era.” The dark gray background indicates the “coverage era.” The black arrow indicates the date that widespread Medicare coverage of CAS was implemented.

Geographic differences in carotid arterial stent utilization, 2005-2006. The 306 U.S. hospital referral regions are shaded based on the relative utilization rates of carotid arterial stent (CAS). The top 20% of hospital referral regions for CAS use are shaded in black, with progressively lighter gray colors indicating progressively lower quintiles of CAS use, with white indicating the lowest CAS-utilization quintile.

Adjusted odds ratios for clinical outcomes of carotid procedures comparing the rate of adverse outcomes in the carotid arterial stent (CAS) coverage era to the rate of adverse outcomes in the pre-coverage era, with odds ratios greater than 1 indicating more frequent adverse outcomes during the CAS coverage era. The “Top 20%” dots and error bars refer to the adjusted odds ratios and 95% confidence intervals for clinical outcomes among patients in the geographic areas with the highest adoption rates of carotid arterial stents (ie, the top quintile). The “Lower 80%” dots and error bars refer to the adjusted odds ratios and 95% confidence intervals for clinical outcomes among patients located in geographic areas that were not in the top 20% for CAS adoption. *Indicates combined clinical outcomes of any peri-procedural myocardial infarction, any stroke, or any death.

Distribution of the propensity scores for all Medicare beneficiaries receiving carotid endarterectomy (gray bars) or carotid stents (black bars) during the carotid arterial stent (CAS) coverage era (August 1, 2005 - March 31, 2006). The propensity score was calculated from a logistic regression model predicting CAS receipt that included multiple demographic, clinical, and hospital-level covariates. The x-axis indicates the propensity score, expressed in units of logit (probability) = log (probability/[1-probability]). The y-axis indicates the percentage of observations in each propensity score interval.