The adoption of carotid stents for treatment of carotid stenosis was associated with increased rates of adverse clinical outcomes after carotid revascularization, according to a retrospective cohort study published July 23 in the Journal of Vascular Surgery.
Peter W. Groeneveld, MD, from the department of medicine at Philadelphia Veterans Affairs Medical Center, and colleagues said that the carotid arterial stent (CAS) systems are an alternative to carotid endarterectomy for the treatment of moderate to severe carotid stenosis, but the effectiveness of CAS compared to endarterectomy in preventing stroke and death is uncertain. This study's objective was to compare the clinical outcomes among Medicare beneficiaries undergoing carotid revascularization before and after CAS became widely available.
The researchers compared 46,784 patients undergoing carotid revascularization from August 2005 to March 2006 (the coverage era) to propensity-score-matched patients undergoing carotid revascularization between October 2002 and September 2004 (the pre-coverage era), before widespread Medicare coverage of CAS.
According to investigators, mortality was compared at 90 and 270 days after revascularization, as were the combined outcomes of periprocedural acute MI and any stroke or death within 90 and 270 days after revascularization, between the two eras. They also made comparisons between localities with higher (23 percent of carotid procedures being CAS) and lower (9 percent of carotid procedures being CAS) adoption rates of carotid stents during the coverage era.
Groeneveld and colleagues found that there were no significant differences in 90-day mortality (2.2 vs. 2.2 percent), 90-day combined outcomes (4.5 vs. 4.3 percent), or 270-day mortality (4.8 vs. 4.6 percent) between the coverage and pre-coverage eras, but there were more 270-day combined outcomes in the coverage era (7.7 vs. 7.3 percent).
In localities with higher adoption of carotid stents, the researchers found that there was higher 90-day mortality, 90-day combined outcomes, 270-day mortality, and 270-day combined outcomes in the coverage era. There were no differences in event rates between eras in areas with lower carotid stent adoption.
For the study's limitations, the researchers noted that the Medicare patients tended to be older than those in clinical trials, and they received treatment in a broad range of hospitals, not just major academic centers. The investigators said that the study used geographic variability in the adoption of stenting to try to replicate the effect of randomization in a clinical trial.
"The current study contributes to the [carotid stenting vs. endarterectomy] comparative effectiveness evidence base by reporting outcomes among a nationwide cohort of patients who received [stenting] or [surgery] under nonexperimental conditions," the authors wrote.