Flow velocities in the external carotid artery following carotid revascularization.

OBJECTIVE: To study the changes in peak systolic velocities of the ipsilateral external carotid artery (ECA) following carotid revascularization. METHODS: All patients randomized to carotid artery stenting (CAS) or carotid endarterectomy (CEA) in the International Carotid Stenting Study (ICSS; ISRCTN25337470) in our center were included. Peak systolic velocities (PSV) were assessed with duplex ultrasound (DUS) at baseline, at 30 days, and at 12 and 24 months after treatment. Our primary outcome measure was the change in blood flow velocities in the ECA (ΔPSVECA). Secondary outcome measure was the prevalence of post interventional ECA occlusion. RESULTS: Of 270 patients enrolled in ICSS at our center, 224 patients (mean age, 68.8 years; 154 males) were included in the present study (116 CAS, 108 CEA). Baseline PSV in the ipsilateral ECA was similar between the groups. Following CAS, PSV gradually increased during follow-up, whereas PSV remained relatively stable after CEA; mean difference of PSV between CAS and CEA: 23 cm/s (95% CI, -5 to 52), 58 cm/s (95% CI, 27-89), and 69 cm/s (95% CI, 31-107) at 30 days, 12 months, and 24 months. One new ECA occlusion occurred after CAS and two after CEA. CONCLUSION: Blood flow velocities in the ipsilateral ECA increase significantly after CAS but not after CEA. However, this does not lead to a higher rate of ECA occlusion in the first 2 years after revascularization. We conclude that CAS is not inferior to CEA in preserving the ECA as a possible potential collateral pathway for cerebral blood supply within 2 years following revascularization.

Interprocedural comparison of changes in natural flow velocity patterns in the internal carotid artery following CAS or CEA.

BACKGROUND AND PURPOSE: Different flow velocities have been reported after carotid angioplasty with stenting (CAS) than after carotid endarterectomy (CEA). We compared blood flow velocities following CAS and CEA in the International Carotid Stenting Study (ICSS; ISRCTN25337470). MATERIALS AND METHODS: In total, 254 patients (70% male; 129 CAS and 125 CEA) were included. Mean peak systolic velocities (PSVICA) were assessed at baseline, 30 days, 1 and 2 years. Following both treatments, restenosis ≥ 50% was defined as PSVmean >125 cm s(-1). RESULTS: CAS and CEA resulted in a similar reduction in PSVICA 1 month after treatment. Post-intervention analysis for each treatment separately revealed that PSVICA following CAS increased significantly during follow-up (30 days to 2 years; 22.4 cm s(-1); 95% confidence interval (CI), 14.3 to 30.5). On the contrary, PSVICA following CEA remained relatively stable during follow-up (4.7 cm s(-1); 95% CI, -6.5 to 15.9). When we analysed the increase in PSVICA between both treatments after 2 years of follow-up, no significant interprocedural difference was observed. The internal carotid artery/common carotid artery (ICA/CCA) PSV ratio increased after CAS but not after CEA: 1.2 vs. 1.1 (0.04, 95% CI; -0.16 to 0.25) at 30 days; 1.5 vs. 1.1 (0.39, 95% CI; 0.13 to 0.65) at 1 year; and 1.5 vs. 1.1 (0.36; 95% CI, 0.08 to 0.63) at 2 years. The rate of apparent ipsilateral ICA restenosis >50% was higher following CAS (hazard ratio 2.35; 95% CI, 1.35 to 4.09). CONCLUSION: Two years after carotid revascularisation, no significant interprocedural difference was observed in the increase of PSVICA between CAS and CEA. However, the ICA/CCA ratio increased more following CAS resulting in an apparent higher rate of restenosis following CAS.

The fate of the external carotid artery after carotid artery stenting. A follow-up study with duplex ultrasonography.

OBJECTIVE: To evaluate the long-term effect of carotid angioplasty and stenting (CAS) of the internal carotid artery (ICA) on the ipsilateral external carotid artery (ECA). SUBJECTS AND METHODS: We prospectively registered the pre- and post-interventional duplex scans obtained from 312 patients (mean age 70 years) who underwent CAS. Duplex scans were scheduled the day before CAS, 3 and 12 months post-procedurally and yearly thereafter, to study progression of obstructive disease in the ipsilateral ECA compared to the contralateral ECA. The duplex ultrasound criteria used to identify ECA stenosis >or=50% were Peak Systolic Velocities of >or=125 cm/s. RESULTS: Preprocedural evaluation of the ipsilateral ECA demonstrated >or=50% stenosis in 32.7% of cases vs 30% contralateral. Both ipsilateral and contralateral 3 (1%) ECA occlusions were noted. After stenting 5 (1.8%) occlusions were seen vs 1% contralateral. No additional ipsilateral occlusions and 2 additional contralateral occlusions were noted at extended follow-up. The prevalence of >or=50% stenosis of the ipsilateral ECA (Kaplan-Meier estimates) progressed from 49.1% at 3, to 56.4%, 64.7%, 78.2%, 72.3%, and 74% at 12, 24, 36, 48, and 60 months respectively. Contralateral prevalences were 31.3%, 37.7%, 41.7%, 43.1%, 46.0%, and 47.2% respectively (p<0.001). Progression of stenosis was more pronounced in 234 patients (75%) with overstenting of the carotid bifurcation (p=0.004). CONCLUSION: Our results show that significant progression of >or=50% stenosis in the ipsilateral ECA occurs after CAS. There was greater progression of disease in the ipsilateral compared with the contralateral ECA. Progression of disease in the ECA did not lead to the occurrence of occlusion during follow up.