The aim of this study was to investigate acceleration time (AcT) in carotid ultrasonography for evaluation of severe restenosis after carotid artery stenting (CAS). Subjects comprised 49 consecutive patients (155 examinations) who underwent CAS. Peak systolic velocity (PSV) and AcT of the internal carotid artery (ICA-AcT) were measured using carotid ultrasonography in all patients. ICA-AcT was measured distal to the stent. The stenosis was measured by CT or digital angiography in 16 patients (22 examinations) using the NASCET method. Significant correlations were seen between PSV and ICA-AcT (p < 0.01; correlation coefficient, r = 0.346). ICA-AcT was significantly prolonged by contralateral ICA occlusion or severe stenosis (p < 0.01, standardized partial regression coefficient β = 0.322) and aging (p = 0.03, β = 0.164). In a receiver operating characteristic curve analysis, the sensitivity and specificity of ICA-AcT using 107.7 msec as a cut-off were 85.7% and 88.4%, respectively, for predicting PSV > 300 cm/sec, indicating severe restenosis after CAS. This cut-off is similar to that previously reported for a non-stented carotid artery. AcT in carotid ultrasonography is useful for evaluating restenosis after CAS.
