5-Year Clinical and Ultrasound Outcomes in CARENET Prospective Multicenter Trial of CGuard MicroNET-Covered Carotid Stent

Next-generation transcarotid artery revascularization: TransCarotid flOw Reversal Cerebral Protection And CGUARD MicroNET-Covered Embolic Prevention Stent System To Reduce Strokes - TOPGUARD Study

BACKGROUND

Stent-assisted carotid artery revascularization employing surgical cutdown for transcervical access and dynamic flow reversal (TCAR) is gaining popularity. TCAR, despite maximized intra-procedural cerebral protection, shows a marked excess of 30-day neurologic complications in symptomatic vs. asymptomatic stenoses. The TCAR conventional single-layer stent (free-cell area 5.89mm2) inability to seal embologenic lesions may be particularly relevant after the flow reversal neuroprotection is terminated.

METHODS

We evaluated peri-procedural and 30-day major adverse cerebral and cardiac events (MACCE) of TCAR (ENROUTE, SilkRoad Medical) paired with MicroNET-covered neuroprotective stent (CGuard, InspireMD) in consecutive patients at elevated risk of complications with transfemoral/transradial filter-protected stenting (increased lesion-related and/or access-related risk). CGuard (MicroNET free cell area ≈0.02-0.03 mm2) has level-1 evidence for reducing intra- and abolishing post-procedural lesion-related cerebral embolism.

RESULTS

One hundred and six increased-risk patients (age 72 [61-76] years, median [Q1-Q3]; 60.4% symptomatic, 49.1% diabetic, 36.8% women, 61.3% left-sided index lesion) were enrolled in three vascular surgery centers. Angiographic stenosis severity was 81 (75-91)%, lesion length 21 (15-26)mm, increased-risk lesional characteristics 87.7%. Study stent use was 100% (no other stent types). 74.5% lesions were predilated; post-dilatation rate was 90.6%. Flow reversal duration was 8 (5-11)min. One stroke (0.9%) occurred in an asymptomatic patient prior to establishing neuroprotection (index lesion disruption with the sheath insertion wire); there were no other peri-procedural MACCE. No further adverse events occurred by 30-days. 30-day stent patency was 100% with normal velocities and absence of any in-stent material by Duplex Doppler.

CONCLUSIONS

Despite a high proportion of increased-risk lesions and clinically symptomatic patients in this study, TCAR employing the MicroNET-covered anti-embolic stent showed 30-day MACCE rate <1%. This suggests a clinical role for combining maximized intra-procedural prevention of cerebral embolism by dynamic flow reversal with anti-embolic stent prevention of peri- and post-procedural cerebral embolism (TOPGUARD NCT04547387).

Vascular surgery study of the CGuard MicroNet-covered stent in patients with indication to carotid revascularization: POLGUARD

BACKGROUND

In a recent randomized study, MicroNet-covered stent (CGuard) significantly reduced procedural and post-procedural cerebral embolism in relation to a single-layer CREST study carotid stent, but real-life clinical practice data are limited. The aim is to prospectively assess clinical outcomes of CGuard as a routine revascularization tool for patients with indication to carotid revascularization.

METHODS

From April 2019 to November 2021, 204 elective patients (age 71.0±7.1years, 69.6% males, 21.7% symptomatic) were enrolled.

RESULTS

Mean basal peak-systolic velocity was 251.41±91.85 cm/s with angiographic diameter stenosis 89.7±8.46%. About 34.4% lesions were severely calcified, 6.8% were angulated, and 4.4% showed significant access tortuosity. Access was femoral, with 100% protection device (filter) use. Two hundred and three lesions in 203 patients were treated (1 cross-over to surgery for lack of effective access, no cross-over to other devices); in most cases (66.9%) the stent was placed directly. For pre-dilated lesions, mean balloon diameter was 3.36±0.34mm. Mean nominal stent diameter was 7.64±0.5 mm; length was 37.19±4.5 mm. All stents were post-dilated (balloon diameter 5.2±0.25 mm). Residual stenosis was <30% in all (3.77±6.91%). By discharge, there were 2 minor strokes (0.9%) and one transient ischemic attack. By 30-days, one other minor stroke occurred in relation to de-novo atrial fibrillation. With no deaths or myocardial infarctions, 30-day total death/stroke/myocardial infarction rate was 1.48%. No in-stent thrombosis or patency loss occurred by 30-days. In-stent peak-systolic velocity was 55.49±22.73 cm/s.

CONCLUSIONS

Thirty-day results from POLGUARD study indicate safety and a low complication rate of the MicroNet-covered carotid stent use in every-day vascular surgery practice of carotid revascularization. Long-term observation is underway.

Procedural embolic protection strategies for carotid artery stenting: current status and future prospects

INTRODUCTION

Carotid artery angioplasty and stenting (CAS) is an established procedure to treat carotid artery stenosis for either primary or secondary prevention of stroke. Randomized clinical trials have shown an increased risk of periprocedural cerebrovascular events with CAS compared with carotid endarterectomy (CEA). Several strategies have been proposed to mitigate this risk, including alternative vascular access site, proximal/distal embolic protection devices, and dual-layer stents, among others.

AREAS COVERED

This review provides a general overview of current embolic protection strategies for CAS. The phases of the procedure which can affect the early risk of stroke and how to reduce it with novel techniques and devices have been discussed.

EXPERT OPINION

Innovations in device technologies have dramatically improved the safety and efficacy of CAS. To minimize the gap with surgery, a thorough, patient-oriented approach should be pursued. Endovascular technologies and techniques should be selected on an individual basis to address unique lesion characteristics and vascular anatomies. Meticulous pre-procedural planning, both clinical and anatomical, is needed to assess the embolic risk of each procedure. Only by having an in-depth understanding of the wide range of available endovascular devices and techniques, the operator will choose the most appropriate strategy to optimize CAS results.

Shear-Mediated Platelet Microparticles Demonstrate Phenotypic Heterogeneity as to Morphology, Receptor Distribution, and Hemostatic Function

Objective

Implantable cardiovascular therapeutic devices (CTD) including stents, percutaneous heart valves and ventricular assist devices, while lifesaving, impart supraphysiologic shear stress to platelets resulting in thrombotic and bleeding device-related coagulopathy. We previously demonstrated that shear-mediated platelet dysfunction is associated with downregulation of platelet GPIb-IX-V and αIIbβ3 receptors via generation of platelet-derived microparticles (PDMPs). Here, we test the hypothesis that shear-generated PDMPs manifest phenotypical heterogeneity of their morphology and surface expression of platelet receptors, and modulate platelet hemostatic function.

Approach and Results

Human gel-filtered platelets were exposed to continuous shear stress and sonication. Alterations of platelet morphology were visualized using transmission electron microscopy. Surface expression of platelet receptors and PDMP generation were quantified by flow cytometry. Thrombin generation was quantified spectrophotometrically, and platelet aggregation in plasma was measured by optical aggregometry. We demonstrate that platelet exposure to shear stress promotes notable alterations in platelet morphology and ejection of several distinctive types of PDMPs. Shear-mediated microvesiculation is associated with the differential remodeling of platelet receptors with PDMPs expressing significantly higher levels of both adhesion (α _IIb β ₃ , GPIX, PECAM-1, P-selectin, and PSGL-1) and agonist-evoked receptors (P ₂ Y ₁₂ & PAR1). Shear-mediated PDMPs have a bidirectional effect on platelet hemostatic function, promoting thrombin generation and inhibiting platelet aggregation induced by collagen and ADP.

Conclusions

Shear-generated PDMPs demonstrate phenotypic heterogeneity as to morphologic features and defined patterns of surface receptor alteration, and impose a bidirectional effect on platelet hemostatic function. PDMP heterogeneity suggests that a range of mechanisms are operative in the microvesiculation process, contributing to CTD coagulopathy and posing opportunities for therapeutic manipulation.