What should be the Optimal Carotid Stent Opening Rate Without Post-Dilation?
Introduction
Atherosclerotic stenosis of the carotid bifurcations and adjacent segments causes 10-20% of all ischemic strokes.1,2 Carotid endarterectomy (CEA) and carotid artery stenting (CAS) are two main treatment strategies for stenosis in this region. CEA remains the gold standard for treating symptomatic carotid stenosis. CAS is usually recommended for patients with high risk for CEA, radiation-induced stenosis, or restenosis after CEA.3 CAS has some other advantages over CEA, such as its less invasive nature and shorter length of hospital stay.4
The periprocedural risk of vascular events and the long-term risk of in-stent restenosis (ISR) are two major concerns related to the safety and efficacy of CAS. Periprocedural strokes can be reduced by using embolic protection devices (EPD)5 Numerous transcranial Doppler studies demonstrated the presence of emboli with each passage across a stenosis with a guidewire, EPD, balloon, or stent, with the highest potential risk for embolization occurring during poststent dilation when the balloon pushes the stent struts against the atheromatous plaque.6, 7–8 In a study of 550 patients authored by Ackerstaff et al. multiple micro emboli (>5 showers) at post-dilation were independently found to be associated with cerebral deficits.9 Additionally, they postulated that most emboli are produced by post-dilation, with the balloon squeezing the stent struts against the atheromatous material.10 Many potential risk factors have been defined for ISR after CAS.11 One of them may be the post-procedural carotid stent opening rate (CSOR). According to expert consensus, the goal of CAS is to passivate the lesion and reduce the risk of stroke. An expanding stent with undersized angioplasty balloon is recommended, and moderate residual stenosis is acceptable.12 There is lacking data regarding the optimal CSOR without post-dilation. In this study, we measured CSOR without post-dilation in a high number of patients and aimed to evaluate the association between CSOR and ISR and related outcomes.
Section snippets
Patient population
This is a single center retrospective study. The study protocol and written informed consent were approved by the institutional review board, and all patients or their legal representatives signed the consent forms. We retrospectively evaluated the clinical and radiological data of patients who underwent CAS.
Between January 2010 and May 2016, a total of 1236 consecutive patients with atherosclerotic carotid artery stenotic lesions underwent CAS at the Kartal Kosuyolu Training and Research
Results
Baseline characteristics of the patients were shown in Table 1. The mean post-stent dilation rate was 0.71 ± 0.05 in the first group and 0.87 ± 0.05 in the second group (P<0.001). Age, gender, prevalence of hypertension, diabetes mellitus and smoking were similar between the groups. The frequency of hyperlipidemia was higher in the first group (P = 0.006) whereas the frequencies of previous MI, coronary intervention and coronary artery bypass grafting were similar between the groups
Discussion
This study showed that CSOR of the patients after carotid stenting without post-dilation had similar in-hospital and long-term results in 50% ≤ Post-SD<80% and 80% ≤ Post-SD ≤ 100% group. It also showed that 3-year carotid stent restenosis rates after the stenting were similar between the groups.
Traditional CAS technique includes initial predilation with a small balloon by which an EPD or a stent is accessible distal to the stenosis, placement of an EPD, followed by deployment of a stent
Limitations
Our study has several limitations. Firstly, the data arise from a nonrandomized registry. Secondly, no direct comparison was made between post-dilation group and those without post-dilation. Because post-dilation was one of the exclusion criteria and patients who underwent post-dilation were not enrolled to the study. Thirdly, however pre-dilation might influence the outcomes, we did not perform a regression analysis to reveal its’ relationship with the outcomes. Because the rate of
Conclusions
Based on this study, post-dilation may not be required to treat all carotid stenting procedures and CSOR > 50% may be enough in most patients. Post-dilation should be performed selectively and with caution. Deployment of self-expandable stent may widen CSOR with chronic outward force over time.
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