Carotid artery velocity characteristics after carotid artery angioplasty and stenting

ObjectiveCorrelation of carotid duplex ultrasound (DUS) flow velocities with carotid artery stenosis before and after carotid endarterectomy is well established. With the evolution of catheter-based techniques, carotid stenosis increasingly is being treated with angioplasty and stenting (CAS). CAS changes the physical properties of the arterial wall, which may alter blood flow velocities compared with the nonstented carotid. Opinions differ about whether DUS is a reliable tool to assess technical outcome and recurrent stenosis after CAS. This study correlated carotid DUS flow velocity findings with carotid arteriography after CAS.MethodsData from 77 pairs of carotid arteriograms with corresponding DUS after CAS in 68 patients were reviewed. Preintervention and postintervention DUS and carotid arteriogram data were evaluated for each patient. Peak systolic velocities (PSV), end-diastolic velocities (EDV), and internal carotid artery/common carotid artery ratios (ICA/CCA) were correlated with the post-CAS arteriogram.ResultsThe mean preintervention PSV was 390 ± 110 cm/s (range, 216 to 691 cm/s), and the average EDV was 134 ± 51 cm/s (range, 35 to 314 cm/s). Postintervention DUS was obtained a mean of 5 days after CAS (range, 1 to 30 days). Sixty (81%) post-CAS arteriograms were normal, and each corresponded to a normal postintervention DUS (PSV range, 30 to 118 cm/s; EDV range, 18 to 60 cm/s). In 14 arteries (19%), completion arteriograms revealed residual stenoses of 20% to 40% in 13, and 50% in one. The mean PSV was 175 cm/s (range, 137 to 195 cm/s), and the mean EDV was 44 cm/s (range, 20 to 62 cm/s). All velocities exceeded the threshold of a 50% stenosis by DUS criteria for a nonstented carotid artery. In three arteries (2 patients), high-grade recurrent stenoses detected by DUS developed that required reintervention during follow-up. This high-grade restenosis was confirmed by arteriography in each patient, providing an additional three correlations.ConclusionsNormal DUS imaging reliably identifies arteriographically normal carotid arteries after CAS. Carotid velocities are disproportionately elevated with mild and moderate degrees of stenoses, and velocity criteria for quantitating stenoses in these patients require modification. However, DUS appropriately identifies severe recurrent stenoses after CAS.