Arterial remodeling and hemodynamics in carotid stents: a prospective duplex ultrasound study over 2 years

AbstractObjectiveThis study was undertaken to study negative and positive arterial remodeling processes within self-expanding carotid stents, their interaction, and the resulting changes in hemodynamics over 2 years, with duplex ultrasound scanning.Subjects and methodsOne hundred twelve consecutive patients with 121 successfully stented carotid arteries were examined with color-coded duplex ultrasound scanning the day after the stent procedure and at 3, 6, 12, and 24 months of follow-up. The stent diameters at the proximal, middle, and distal regions, and the maximal neointimal thickness (B-mode) and hemodynamic parameters were recorded. Pre-interventional plaques were assigned to three types: soft, fibrous, and largely calcified.ResultsThe diameters of the self-expanding stents steadily increased over 2 years (positive arterial remodeling), from (mean ± SD) 5.80 ± 0.89 mm to 6.77 ± 0.98 mm in the proximal stent area, from 3.51 ± 0.76 mm to 4.92 ± 0.89 mm in the middle stent area, and from 3.7 ± 0.5 mm to 4.68 ± 0.61 mm in the distal stent area (P < .001). Stent expansion was most marked in the middle stent area, depending on the type of pre-interventional plaque. The extent in stent expansion was more in soft than in fibrous and calcified plaques (P < .001). Neointimal thickness increased up to 12 months, and stabilized thereafter. The mean (± SD) neointimal thickness at 3, 6, 12, and 24 months was 0.61 ± 0.28 mm, 0.97 ± 0.39 mm, 1.06 ± 0.36 mm, and 1.12 ± 0.38 mm, respectively. These complex interactions resulted in the dominance of negative remodeling secondary to neointimal proliferation, with an increased flow ratio during the first year, from 1.16 ± 0.37 at day 1 to 1.23 ± 0.46 at 3 months, 1.67 ± 1.37 at 6 months, and 1.57 ± 0.70 at 12 months (P < .001), followed by a tendency to decrease as a result of stent expansion thereafter (flow ratio at 24 months, 1.49 ± 0.70). Two of 121 stents (1.6%) had recurrent stenosis that required a secondary procedure.ConclusionsNeointimal proliferation or negative arterial remodeling prevails up to 12 months, and may give rise to rare stent recurrent stenosis. Stent expansion reduces this effect in the first year, and dominates in the second year. This might contribute to the good mid-term outcome of carotid stenting. Poor stent expansion in heavily calcified plaques calls for primary surgical management

Stent-induced flow disturbances in the ipsilateral external carotid artery following internal carotid artery stenting : a temporary cause of jaw claudication

Background We hypothesize that stenting of the internal carotid artery can immediately impede blood flow to the external carotid artery by either plaque shift or stent coverage of the ostium, and thereby cause ischemic symptoms like ipsilateral jaw claudication. Methods Thirty-three patients with high-grade asymptomatic stenosis of the internal carotid artery who underwent endovascular treatment were examined by ultrasound of the external carotid artery and performed an exercise test by chewing chewing gum synchronously to an electronic metronome for 3 min. Tests were performed before, the day after, and 1 week after the stenting procedure. Claudication time was defined as the timespan until occurrence of pain of the masseter muscle and/or chewing dyssynchrony to the metronome for more than 15 s. Ten patients with an isolated, atherosclerotic stenosis of the external carotid artery served as controls. Results A significantly reduced claudication time (in seconds) was recorded in patients who underwent carotid artery stenting compared to baseline values; median 89 (interquartile range, IQR, 57 to 124) vs. median 180 (IQR 153 to 180; p < 0.001). By categorization of the flow velocity at the external carotid artery into faster or slower as 200cm/sec, the effect was even accentuated. Stenting values showed improvement 1 week after but did not return to baseline levels. No respective changes were found in controls. Conclusion Stenting of the internal carotid artery lead to ipsilateral flow deterioration at the external carotid artery resulting in temporary jaw claudication. This impairment attenuated over the time and was significantly reduced after 1 week.(VLID)355041