Peri-procedural risk of events seems to be higher in women who have carotid artery stenting than those who have carotid endarterectomy, whereas there is little difference in men, according to a substudy of the CREST trial published May 6 in Lancet Neurology.
In the randomized CREST (Carotid Revascularization Endarterectomy versus Stenting Trial), the primary endpoint did not differ between carotid artery stenting and carotid endarterectomy in patients with symptomatic and asymptomatic stenosis. Virginia J. Howard, PhD, department of epidemiology, School of Public Health at University of Alabama at Birmingham, Ala., and colleagues undertook this substudy with the pre-specified secondary aim to examine differences by sex.
The CREST researchers enrolled patients who were asymptomatic or who had a stroke or transient ischemic attack within 180 days before random allocation at 117 clinical centers in the U.S. and Canada.
The primary outcome was the composite of stroke, MI or death during the peri-procedural period or ipsilateral stroke within four years. They used standard survival methods including Kaplan-Meier survival curves and sex-by-treatment interaction term to assess the relation between patient factors and risk of reaching the primary outcome.
Between Dec. 21, 2000, and July 18, 2008, the researchers randomly assigned 2,502 patients to recieve carotid endarterectomy (1,240) or carotid artery stenting (1,262)—34.9 percent of whom were women.
The rates of the primary endpoint for carotid artery stenting compared with carotid endarterectomy were 6.2 percent vs. 6.8 percent in men, and 8.9 percent vs. 6.7 percent in women.
There was no significant interaction in the primary endpoint between sexes, Howard and colleagues reported. Peri-procedural events occurred in 4.3 percent of the 807 men assigned to carotid artery stenting compared with 4.9 percent of the 823 assigned to carotid endarterectomy and 6.8 percent of the 455 women assigned to carotid artery stenting compared with 3.8 percent of the 417 assigned to carotid endarterectomy.
"Although there was no evidence of a relative difference in the four-year primary composite outcome by sex, the peri-procedural stroke risk for women in the carotid artery stenting group was more than twice the risk of those in the carotid endarterectomy group, whereas there was little difference in men," the authors pointed out
They concluded: "This study adds to previous findings by showing a higher periprocedural risk from carotid artery stenting in women …This additional information supports that the sex of the patients should be taken into account in decisions for treatment of carotid disease."
Howard et al also noted that additional data are needed to confirm whether this differential risk should be taken into account in decisions for treatment of carotid disease in women.
In an accompanying Lancet commentary, Martin Brown, MD, and Rosalind Raine, MBBS, PhD, from University College London, cautioned that any “differential effects of treatment by sex are unlikely to be explained by differences in sex chromosomes. Far more likely is that other patient characteristics are the true determinants of risk difference."
They added: "The choice of treatment between the sexes therefore requires better understanding of the various predictors of risk. Future work needs to concentrate on identifying these risk factors to select which of carotid stenting, carotid endarterectomy or optimized medical therapy are most appropriate for which women and which men."
The National Institute of Neurological Disorders and Stroke and Abbott Vascular funded the study.