Age Effect and Carotid Stenting
What are the factors contributing to higher stroke risk in elderly patients treated with carotid artery stenting (CAS)?
Mediation analysis of selected patient (hypertension, diabetes mellitus, and dyslipidemia) and arterial characteristics assessed at the clinical sites and the core laboratory (plaque length, eccentric plaque, ulcerated plaque, percent stenosis, peak systolic velocity, and location) was performed in 1,123 CAS-treated patients in the CREST (Carotid Revascularization Endarterectomy Versus Stenting Trial) study. The investigator assessed the association of age with these characteristics, the association of these characteristics with stroke risk, and the amount of mediation of the association of age on the combined risk of periprocedural stroke or death (S+D) with adjustment for these factors.
Only plaque length as measured at the sites increased with age, was associated with increased S+D risk, and significantly mediated the association of age on S+D risk. However, adjustment for plaque length attenuated the increased risk per 10 years of age from 1.72 (95% confidence interval, 1.26-2.37) to 1.66 (95% confidence interval, 1.20-2.29), accounting for only 8% of the increased risk.
The authors concluded that plaque length seems to be in the pathway between older age and higher risk of stroke or death among CAS-treated patients.
This study reports that plaque length seems to be a mediator between older age and higher risk of stroke or death among CAS-treated patients. However, it mediated only 8% of the age effect excess risk of CAS in CREST. This implies that other factors and mechanisms underlying the age effect need to be identified. This study could not determine whether there are intrinsic characteristics central to older age or other factors potentially in the pathway that was not considered in this analysis. Current evidence suggests that CAS should be used cautiously in the elderly regardless of patient or arterial characteristics.
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