Reply

Abstract

We appreciate the astute and thoughtful comments regarding our study. As outlined, it is certainly clear that many factors contribute to the elastic modulus and compliance of the carotid artery after stenting, which result in changes in flow hemodynamics. Our data highlights the importance of stent design and its salient role in demonstrating elevated duplex velocities in the absence of angiographically demonstrable stenosis after carotid stenting. We do agree that the optimal timing of postoperative duplex ultrasound (DUS) after carotid stenting has not been established, but we doubt this is a real study limitation. Although initially we obtained duplex scans within 24 hours after stenting, the timing of the postoperative DUS was later postponed, primarily as a factor of study design. Many of the patients in our series were enrolled in post-marketing registries and clinical trials (eg, SAPPHIRE, CREST, EMPIRE), all of which require post-intervention DUS at one month. Because most randomized clinical trials assessing carotid stenting required postoperative DUS at one and six months and yearly thereafter, such protocols have been widely adopted in most centers. We believe that DUS at one month should serve as a baseline study and that changes in blood flow velocities related to stent design are validated at this time period. Obtaining DUS at one and 90 days, as suggested, may be unnecessary, cost-ineffective, and clinically impractical. Obviously, long-term changes in blood flow velocities related to stent design and incidence of in-stent restenosis need to be further investigated. In this regard, we are currently conducting studies to quantify to what extent stent design differences in carotid velocities may influence DUS criteria for precisely defining restenosis after carotid artery stenting. Regarding “Open-cell versus closed-cell stent design differences in blood flow velocities after carotid stenting”Journal of Vascular SurgeryVol. 50Issue 2PreviewAlthough several studies have suggested that stent placement in the carotid artery alters its biomechanical properties, leading to an increase in Duplex Ultrasound (DUS) velocities in the absence of residual stenosis, many uncertainties remain about the generalizability of these single-center results with small sample sizes.1 Recently, Pierce et al described disproportionately elevated velocities for closed cell design when comparing different types of stents.2 Surprisingly, the authors concluded that their results were related to the amount of free cell area between scaffolding components. Full-Text PDF Open Archive