Assessment of reverse flow as a means of cerebral protection during carotid artery stent placement with diffusion-weighted and transcranial Doppler imaging

Lessons From ACST-2

The recent 130-center, international, second ACST trial (Asymptomatic Carotid Surgery Trial) involving 3625 patients found that regardless of whether a patient underwent stenting or endarterectomy, the periprocedural risk of disabling or fatal stroke was about 1% and the 5-year estimated risk of nonprocedural disabling or fatal stroke was 2.5%. With advances in technique, technology, and patient selection, stenting done by appropriately trained and experienced operators can achieve safety and efficacy comparable to endarterectomy for asymptomatic patients. The ongoing CREST-2 trial (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial) will clarify whether revascularization, by either stenting or endarterectomy, remains an important therapeutic goal in the setting of modern intensive medical therapy.

Transcervical access, reversal of flow and mesh-covered stents: New options in the armamentarium of carotid artery stenting

In the last 25 years, the very existence of carotid artery stenting (CAS) has been threatened on a number of occasions. The initial disappointing results that even lead to the discontinuation of an early randomized controlled trial have improved considerably with time. Novel devices, advanced stent and equipment technology, alternative types of access and several types of filters/emboli protecting devices have been reported to reduce stroke/death rates during/after CAS and improve CAS outcomes. The present review will provide a description of the various technology advances in the field that aim to reduce stroke and death rates associated with CAS. Transcervical access, reversal of flow and mesh-covered stents are currently the most promising tools in the armamentarium of CAS.

Results of the ROADSTER multicenter trial of transcarotid stenting with dynamic flow reversal

OBJECTIVE

This report presents the 30-day results of the Safety and Efficacy Study for Reverse Flow Used During Carotid Artery Stenting Procedure (ROADSTER) multicenter trial and evaluates the safety and efficacy of ENROUTE Transcarotid NPS (Silk Road Medical Inc, Sunnyvale, Calif), a novel transcarotid neuroprotection system that provides direct surgical common carotid access and cerebral embolic protection via high-rate flow reversal during carotid artery stenting (CAS).

METHODS

A prospective, single-arm, multicenter clinical trial was performed to evaluate the use of the ENROUTE Transcarotid NPS during CAS procedures performed in patients considered to be at high risk for complications from carotid endarterectomy. Symptomatic patients with ≥50% stenosis and asymptomatic patients with ≥70% stenosis were eligible to be treated with any U.S. Food and Drug Administration-approved carotid artery stent. The primary end point was the composite of all stroke, myocardial infarction (MI), and death at 30 days postprocedure as defined in the Food and Drug Administration-approved study protocol. Secondary end points included cranial nerve injury; 30-day stroke, death, stroke/death, and MI; acute device, technical, and procedural success; and access site complications. All major adverse events were adjudicated by an independent clinical events committee.

RESULTS

Between November 2012 and July 2014, 208 patients were enrolled at 18 sites. Sixty-seven patients were enrolled as lead-in cases, and 141 were enrolled in the pivotal phase. In the pivotal cohort, 26% were symptomatic and 75% were asymptomatic. Acute device and technical success were 99% (140 of 141). By hierarchical analysis, the all-stroke rate in the pivotal group was 1.4% (2 of 141), stroke and death was 2.8% (4 of 141), and stroke, death and MI was 3.5% (5 of 141). One patient (0.7%) experienced postoperative hoarseness from potential Xth cranial nerve injury, which completely resolved at the 6-month follow-up visit.

CONCLUSIONS

The results of the ROADSTER trial demonstrate that the use of the ENROUTE Transcarotid NPS is safe and effective at preventing stroke during CAS. The overall stroke rate of 1.4% is the lowest reported to date for any prospective, multicenter clinical trial of CAS.

Endovascular treatment of traumatic internal carotid artery pseudoaneurysm

INTRODUCTION

Traumatic internal carotid artery pseudoaneurysm (TICAP) is the most common cause of stroke in young adults. The treatment of TICAP with open surgery poses excess risk, thus during last decade endovascular treatment strategies have been applied.

AIM

To assess the efficacy and the existing experience of endovascular treatment of TICAP.

METHODOLOGY

A systematic review of the literature was undertaken to identify all reported cases of endovascular treatment of TICAP from 1998 to 2015 in MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials.

RESULTS

A total of 193 patients (139 males, 75%) with mean age of 30.8±2.2 years in 23 case studies, were treated for their TICAP with endovascular treatment. The main causes of TICAP were road traffic accidents 51%, assaults 12%, fall from height 8% and other miscellaneous causes were 29%. In 8/23 studies, the patients were operated emergently, in 9/23 at least 1 month after the carotid injury, and in 6/23 the time between the injury and the operation was not reported. The total success rate of pseudoaneurysm occlusion was 84% (162/193). The reported peri-procedural morbidity rate was 6% (11/185; 3 TIA, 7 strokes and 1 subclavian artery dissection), and the peri-operative mortality rate was 1.2% (2/162). Most patients received post-operatively antiplatelet therapy (either single or dual) and the duration of the administration ranged from 3 months to long term. During their follow up (ranging from 4 days to 13 years) only 6 patients required re-intervention, and this was undertaken with endovascular approach.

CONCLUSION

Endovascular therapy tends to be an effective option for the treatment of TICAP with low morbidity and mortality rates.

Transcervical Carotid Stenting With Dynamic Flow Reversal Demonstrates Embolization Rates Comparable to Carotid Endarterectomy

PURPOSE

To evaluate a series of patients treated electively with carotid endarterectomy (CEA), transfemoral carotid artery stenting with distal filter protection (CASdp), and transcervical carotid stenting with dynamic flow reversal (CASfr) monitored continuously with transcranial Doppler (TCD) during the procedure to detect intraoperative embolization rates.

METHODS

Thirty-four patients (mean age 67.6 years; 24 men) with significant carotid stenosis underwent successful TCD monitoring during the revascularization procedure (10 CEA, 8 CASdp, and 16 CASfr). Ipsilateral microembolic signals were segregated into 3 phases: preprotection (until internal carotid artery cross-shunted or clamped if no shunt was used, filter deployed, or flow reversal established), protection (until clamp/shunt was removed, filter retrieved, or antegrade flow reestablished), and postprotection (after clamp/shunt or filter removal or restoration of normal flow).

RESULTS

CASdp showed higher embolization rates than CEA or CASfr in the preprotection phase (p<0.001). In the protection phase, CASdp was again associated with more embolization compared with CEA and CASfr (p<0.001). In the postprotection phase, no differences between the revascularization therapies were observed. CASfr and CEA did not show significant differences in intraoperative embolization during any of the phases.

CONCLUSION

TCD recordings demonstrated a significant reduction in embolization to the brain during transcervical carotid artery stent placement with the use of dynamic flow reversal compared to transfemoral CAS using distal filters. No significant differences in microembolization could be detected between CEA and CASfr. The observed lower embolization rates and lack of adverse events suggest that transcervical CAS with dynamic flow reversal is a promising technique and may be the preferred method when performing CAS.

Selecting an appropriate surgical treatment instead of carotid artery stenting alone according to the patient's risk factors contributes to reduced perioperative complications in patients with internal carotid stenosis: a single institutional retrospective analysis

This retrospective study was aimed to compare the perioperative complications for internal carotid artery stenosis (ICS) in a Japanese single institute between the use of carotid artery stenting (CAS) alone or the use of an appropriate individualized treatment method allowing either carotid endarterectomy (CEA) or CAS based on patient risk factors. Based on the policy at our hospital, only CAS was performed on patients (n = 33) between January 2005 and November 2009. From December 2009 to December 2012, either CEA or CAS (tailored treatment) was selected for patients (n = 61) based on individual patient risk factors. CEA was considered the first-line treatment in all cases. In high-risk CEA cases, CAS was performed instead (n = 11), whereas in low-risk CEA cases, CEA was performed (n = 19). Further, in moderate-risk CEA cases based on own criteria, CAS was considered first, whereas for high-risk CAS cases, CEA was performed (n = 17). For low-risk CAS cases, CAS was performed (n = 9). Perioperative clinical complications (any stroke, myocardial infarction, or death within 30 days) were compared between both periods. Significantly reduced perioperative complications were observed during the tailored period (4/61 sites, 6.6%) as compared with the CAS period (8/33 sites, 24.2%) [Fisher’s exact test p = 0.022; odds ratio, 4.56 (CAS/tailored); 95% confidence interval, 1.26–16.5]. Selecting an appropriate individualized treatment method according to patient risk factors, as opposed to adhering to a single treatment approach such as CAS, may contribute to improved overall outcomes in patients with ICS.

Carotid artery stenting: current and emerging options

Carotid artery stenting technologies are rapidly evolving. Options for endovascular surgeons and interventionists who treat occlusive carotid disease continue to expand. We here present an update and overview of carotid stenting devices. Evidence supporting carotid stenting includes randomized controlled trials that compare endovascular stenting to open surgical endarterectomy. Carotid technologies addressed include the carotid stents themselves as well as adjunct neuroprotective devices. Aspects of stent technology include bare-metal versus covered stents, stent tapering, and free-cell area. Drug-eluting and cutting balloon indications are described. Embolization protection options and new direct carotid access strategies are reviewed. Adjunct technologies, such as intravascular ultrasound imaging and risk stratification algorithms, are discussed. Bare-metal and covered stents provide unique advantages and disadvantages. Stent tapering may allow for a more fitted contour to the caliber decrement between the common carotid and internal carotid arteries but also introduces new technical challenges. Studies regarding free-cell area are conflicting with respect to benefits and associated risk; clinical relevance of associated adverse effects associated with either type is unclear. Embolization protection strategies include distal filter protection and flow reversal. Though flow reversal was initially met with some skepticism, it has gained wider acceptance and may provide the advantage of not crossing the carotid lesion before protection is established. New direct carotid access techniques address difficult anatomy and incorporate sophisticated flow-reversal embolization protection techniques. Carotid stenting is a new and exciting field with rapidly advancing technologies. Embolization protection, low-risk deployment, and lesion assessment and stratification are active areas of research. Ample room remains for further innovations and developments.

Asymptomatic carotid stenosis: What we can learn from the next generation of randomized clinical trials

Stroke remains an exceedingly incident and prevalent public health burden across the globe, with an estimated 16 million new strokes per annum and prevalence over 60 million, and extracranial internal carotid artery atherosclerotic disease is an important risk factor for stroke. Randomized trials of surgical treatment were conducted (North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial) and demonstrated efficacy of carotid endarterectomy for secondary prevention of stroke in patients with cerebrovascular events (e.g. ipsilateral stroke, transient ischemic attack, and/or amaurosis fugax) attributable to a diseased artery with 50–99% stenosis. Therapeutic clarity, however, proved elusive with asymptomatic carotid artery disease. Asymptomatic Carotid Atherosclerosis Study (ACAS), Asymptomatic Carotid Surgery Trial, and Veterans Affairs Cooperative Study (VACS) suggested only modest benefit from surgical intervention for primary stroke prevention and the best medical therapy at the time of these trials is not comparable to modern medical therapy. ACT-1, Asymptomatic Carotid Surgery Trial-2, Stent-Protected Angioplasty in asymptomatic Carotid artery stenosis versus Endarterectomy Trial-2, European Carotid Surgery Trial-2, Carotid Revascularization Endarterectomy Versus Stenting Trial-2 are trials that are recent, ongoing, or in development that include diverse populations across Europe and North America, complementary trial designs, and a collaborative spirit that should provide clinicians with evidence that informs best clinical practice for asymptomatic carotid artery disease.