Introduction Trials describe a risk of stroke of about 6% following carotid artery stenting (CAS). Stent cell design has been implicated as a potential factor in these risks. The small free cell area between the struts of a closed-cell stent theoretically provides better scaffolding of the vessel wall and superior plaque stabilization compared to the larger uncovered gaps in open-cell stents. No comparison between stent designs, and their relative effects on clinical outcome compared with carotid endarterectomy, has yet been published in the literature.
Materials and Methods This is an exploratory meta-analysis of randomized control trials (RCTs) comparing carotid endarterectomy (CEA) to CAS stratified by the stent cell design. A comprehensive literature search was conducted on major scholar search engines until July 2010. The primary outcome was a composite of the 30-day risk of stroke or death. A Mantel-Hansel random-effects model was used to calculate OR and 95% CIs.
Results Nine RCTs (4949 patients) were included in the final analysis. Closed-cell stent design was used in 807 patients and open-cell stents in 1657 patients, while 2485 patients were treated with CEA. The primary outcome was significantly lower in the CEA arm compared to CAS using open-cell design arm (OR 1.84, 95% CI 1.23 to 2.75; p=0.003). However, there was no significant difference in the primary outcome between CEA and CAS using closed-cell design, although a trend favoring CEA was noted (OR 1.54; 95% CI 0.69 to 3.47; p=0.29), Abstract O-007 figure 1. If only the 30-day stroke rate was considered, the difference between CEA and CAS in the closed-cell stents is still non-significant (OR 2.92; 95% CI 0.52 to 16.21; p=0.22), compared to open-cell stents which continued to be inferior to CEA (OR 1.97; 95% CI 1.33 to 2.92; p=0.0007).
Conclusion In this meta-analysis of nine RCTs, CEA was not superior to CAS in trials using closed-cell stents. While these results may suggest better outcomes of CAS using the closed-cell stents, trials included in this analysis did not randomize patients to open- vs closed-cell stents. Furthermore, trials using the closed design recruited fewer patients than those using open-cell stents. Further assessment of a potential modification of CAS outcomes by stent design is underway with a meta-analysis of prospective CAS cohorts and registries to directly compare open- vs closed-cell stents.
Competing interests None.
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