Effects of Carotid Calcification on Restenosis After Carotid Artery Stenting: A Follow-Up Study with Computed Tomography Angiography

BACKGROUND: Carotid Doppler sonography has been used routinely in the screening for restenosis after carotid artery stenting (CAS) by applying the criteria of flow velocity; however, computed tomography angiography (CTA) enables us to detect restenosis directly and has some advantages that help to overcome the limitations of Carotid Doppler sonography. We aimed to investigate the incidence of restenosis with CTA and to identify factors related to restenosis after CAS. METHODS: We conducted a retrospective study of 225 patients (235 arteries, mean age of 71.9 +/- 7.7 years) who had undergone CTA of the neck for the evaluation of restenosis after CAS between July 2002 and June 2012. We assessed the cumulative incidence of restenosis (>50%) and the predictors of restenosis after CAS. RESULTS: During 1064.4 patient-years of follow-up (mean 4.5 years; range 1-9.7 years), the incidence of restenosis was 10.2% (24/ 235). The cumulative rate of freedom from restenosis was 94.1%, 88.8%, and 86.7% at 1, 3, and 5 years, respectively. The statistically significant factors associated with restenosis after CAS were residual stenosis (adjusted odds ratio 1.07, 95% confidence interval 1.03-1.11, P < 0.01) and high-grade (>50%) calcification (adjusted odds ratio 6.04, 95% confidence interval 1.29-28.36, P = 0.02) on multivariate analysis. CONCLUSIONS: This study revealed that carotid arteries with high-grade calcification were prone to develop restenosis after CAS. Regular follow-up should be performed for the monitoring of restenosis after CAS in patients with highly calcified carotid plaques.