Identification of patient characteristics that may improve procedure selection for the treatment of carotid stenosis.

Background: Carotid endarterectomy and carotid artery stenting are common procedures for the treatment of carotid artery stenosis. The aim of this study was to identify factors that modify the effect between type of treatment and outcome, and could thus be used to refine the selection of treatment procedure.

Methods: All patients who underwent either carotid endarterectomy or carotid artery stenting between 2012 and 2018 in German hospitals were included. The analysis of effect modification was focused on baseline patient characteristics. The outcome was a composite of any stroke or death until discharge from hospital. For multivariable analyses, a generalized linear mixed regression model was used.

Results: Some 221 282 patients were included, of whom 68% were male. In patients who underwent carotid endarterectomy or carotid artery stenting, the risk of any stroke or death was 2.3% and 3.7% respectively. Patient age was statistically significantly associated with a higher risk of a composite outcome of any stroke or death (main effect of age: adjusted OR 1.21 (95% c.i. 1.17 to 1.26), P < 0.001). The age effect was stronger in patients treated with carotid artery stenting (interaction effect: adjusted OR 1.29 (95% c.i. 1.20 to 1.38), P < 0.001). Statistically significant interaction effects were identified for side of treatment, ASA grade, contralateral degree of stenosis, and the time interval between the index event and treatment.

Conclusion: This analysis shows that carotid artery stenting may be particularly disadvantageous in older patients, in patients with right-sided stenosis, and in symptomatic patients treated within the first 2 days after the index event. In patients with contralateral occlusion, carotid artery stenting appears equivalent to carotid endarterectomy.