Relationship of Age and Outcomes in CREST Studied

December 1, 2011—Data from an investigation of the relationship of age and outcomes in the CREST (Carotid Revascularization Endarterectomy Versus Stenting Trial) study were published by Jenifer H. Voeks, PhD, et al in Stroke (2011;42:3484–3490).

According to the CREST investigators, high stroke event rates among patients treated with carotid artery stenting (CAS) in the CREST lead-in registry generated an a priori hypothesis that age may modify the relative efficacy of CAS versus carotid endarterectomy (CEA).

In the primary CREST report, there was found to be significant effect modification by age. This investigation was extended by examining the relative efficacy of the components of the primary endpoint, the treatment-specific impact of age, and contributors to the increasing risk in CAS-treated patients at older ages.

As detailed in Stroke, among 2,502 CREST patients with high-grade carotid stenosis, the investigators used proportional hazards models to examine the impact of age on the CAS-to-CEA relative efficacy, and the impact of age on risk within CAS-treated and CEA-treated patients. Age acted as a treatment effect modifier for the primary endpoint (P interaction = .02), with the efficacy of CAS and CEA approximately equal at age 70 years. For CAS, risk for the primary endpoint increased with age (P < .0001) by 1.77 times (95% confidence interval, 1.38–2.28) per 10-year increment; however, there was no evidence of increased risk for CEA-treated patients (P = .27). Stroke events were the primary contributor to the overall effect modification (P interaction = .033), with equal risk at approximately 64 years. The treatment-by-age interaction for CAS and CEA was not altered by symptomatic status (P = .96) or by sex (P = .45), reported the investigators.

The investigators found that outcomes after CAS versus CEA were related to patient age, attributable to increasing risk for stroke after CAS at older ages, and concluded that patient age should be an important consideration when choosing between the two procedures for treating carotid stenosis.