Edinburgh Imaging

MSc projects 0910 002

Carotid stent restenosis; imaging follow-up & reported restenosis rates.

  • Introduction: Endovascular carotid artery stenting has been proposed & practiced as an an alternative method of revascularisation to operative management, carotid endarterectomy. However uncertainties remain regarding the safety & relative efficacy of carotid artery stenting. Recent trials of carotid stenting have raised concerns about its peri-procedural morbidity.
  • Methods: We sought published journal papers in the English language, which had details of imaging follow-up of extracranial carotid artery stents. Papers had to include imaging follow-up which addressed the presence & degree of carotid stent restenosis & included details on how measurement of the degree of stenosis was performed for the specific imaging modality or modalities being used. We searched published literature in MEDLINE & EMBASE databases from January 1966 (MEDLINE) & January 1980 (EMBASE) up to the 12th of December 2009.
  • Results: We found 688 publications using MEDLINE & 1481 using EMBASE. Following exclusions, we reviewed the full text of 159 papers. 107 papers did not include a description of the methods used to calculate the degree of restenosis for the imaging modality used; 52 papers did. Of these 52, 18 were published in 2004 or earlier, which left 34 papers for the final analysis. 32 of 34 studies used duplex ultrasound to evaluate stented vessels. CT angiography was performed in 5 studies, one of which compared the two imaging methods. Contrast-enhanced MR angiography was used in one small study. Cerebral angiography was used in addition to a non-invasive imaging modality in 17 of 34 papers. The majority of studies used ultrasound velocity criteria to calculate restenosis. 34 papers satisfied the inclusion criteria containing sufficient information on imaging methods. These 34 papers contained details of 5222 patients (5413 stenoses/vessels) in whom carotid stenting was successfully performed & follow-up imaging was available. Information on the duration of follow-up was available from 16 papers. There was insufficient information on the time to restenosis for individual cases to plot cumulative incidence over time.
  • Discussion: Restenosis rates ranged from 0% to 23.8%, while the mean duration of follow-up ranged from 45 months, to 5 months. When the duration of follow-up was plotted against restenosis rates for studies with this information available, there was no clear correlation between the duration of follow-up & rates of in-stent restenosis. This may, in part, be accounted for by the different thresholds & criteria for calculating restenosis in-use across studies.
  • Conclusion: There continues to be deficiencies in the adequate reporting of imaging follow-up of carotid stents. The heterogeneity in restenosis thresholds & ultrasound velocity criteria lead to difficulties in estimating the true prevalence & incidence of carotid stent restenosis. Future studies in this area should ideally ensure that both the index imaging test & a gold standard reference test are performed in a large sample size, & that the criteria used to calculate the degree of restenosis have been validated for use in carotid artery stents.
Project type:
  • Systematic review

  • Meta-analysis

Imaging keywords:
Application / disease keywords:
  • Carotid stent restenosis
  • Endovascular carotid artery stenting
  • 09-10