Prediction of carotid artery in-stent restenosis by quantitative assessment of vulnerable plaque using computed tomography

SummaryBackground and purposeTo assess the relationship between plaque volume evaluated by multidetector computed tomographic angiography (MDCT) and in-stent restenosis (ISR) after carotid artery stenting (CAS).Materials and methodsFrom a retrospectively maintained database, data were collected for 52 patients with carotid artery stenosis treated with CAS between 2007 and 2012. We defined ISR of ≥ 50% as a peak systolic velocity ≥ 200 cm/s on echo-duplex scan. Carotid plaques were subdivided into four components according to radiodensity in Hounsfield units (HU) as follows: < 0, 0–60, 60–130, and > 600 HU. Risk factors that influenced ISR were compared using univariate and multivariate Cox regression analyses.ResultsDuring a median follow-up period of 36 months, ISR of ≥ 50% was detected in five patients (9.6%). In the univariate Cox proportional hazard regression analysis, renal insufficiency, coronary artery disease, total plaque volume, and plaque volumes with radiodensities < 0 and ≥ 600 HU increased the risk for ISR (P < 0.10). When the significant risk factors determined from the univariate analysis were subjected to a multivariate analysis, only the volumes of the plaque components with radiodensities < 0 HU independently predicted the development of ISR (hazard ratio: 1.041; 95% confidence interval: 1.006–1.078; P = 0.021).ConclusionOur data suggest that the high volume of the plaque components with radiodensities < 0 HU was independently associated with the increased risk of ISR after CAS. Quantitative and qualitative tissue characterizations of carotid plaques using MDCT might be a useful predictive tool of the development of ISR.