A Comparative Quantitative Analysis of Embolic Filter Debris Load During Carotid Artery Stenting, Between Open Cell, Closed Cell And Micromesh Stents

Abstract

Introduction: The design of the stent used in carotid artery stenting (CAS) may influence the amount of embolized material during the procedure, responsible of perioperative neurological complication. The aim of the study was to compare the quantity of embolized material captured by filters during CAS, using different types of stent design (open/closed cell and micromesh). Methods: All patients with carotid stenosis >70% undergoing CAS between 2010 and 2018 were included in a prospective database. Stents were classified according to their design as micromesh (MMS), open-cell (OCS) and closed-cell stents (CCS). A distal filter protection was used in all patients; at the end of the procedure, the filter was fixed in formalin and then analyzed with a stereo-microscope. Morphometric analysis was performed with Image-Pro Plus software (Media Cybernetics). Embolic filter debris load (EFD) load, defined as the ratio of the filter area covered by particulate material to the total area of the filter membrane, was quantified as percentage and compared between different types of stents. Also thirty-days neurological complication, as stroke and transient ischemic attack (TIA), were compared. Results: 275 consecutive CAS were included in the analysis; a MMS was used in 43 cases (15.6%), an OCS in 168 (61.0%), and a CCS in 64 (23.2%). No perioperative deaths were reported. Overall, perioperative stroke was 2.5% (MMS: n=1, 2.3%; OCS: n=4, 2.4%; CCS: n=2, 3.1%; P=.489), while TIA rate was 3.6% (MMS: n=1, 2.3%; OCS: n=7, 4.1%; CCS: n=2, 1%; P=.873), without differences between subgroups. The filters quantitative analysis revealed that any quantity of EFD was present in 70.5% of cases; filters of patients receiving MMS were more likely to be free from embolized material compared to other subgroups (MMS: n=20, 46.5%; OCS/CCS: n=52, 23.3%; P=.003). The overall mean EFD load was 8.9±13.7%, with a significantly lower quantity reported in the MMS subgroup (MMS: 5.8±9.9%, OCS: 8.5±12.9%, CCS: 11.3±17.2%; P=.048). Compared to other types of stents, MMS had a significantly lower EFD load in particular in cases with hypoechogenic plaque (MMS: 7.6±7.0%; OCS/OCC: 20.7±21.6%; P=< .001) and in patients with preoperative ipsilateral asymptomatic ischemic lesion at the cerebral CT (MMS: 7.9±12.1%; OCS/OCC: 13.4±18.7%; P=.015), while there were no significant differences in case of plaque length >15mm (MMS: 8.4±14.7%; OCS/OCC: 9.5±13.0%; P=.598), kinking/coiling (MMS: 10.7±16.2%; OCS/OCC: 9.5±10.0%; P=.621), and carotid restenosis (MMS: 5.9±13.2%; OCS/OCC: 6.8±11.3%; P=.641). Conclusion: The use of MMS seems to be associated to a significantly lower embolization rate and EFD load, especially in cases of hypoechogenic plaque and preoperative evidence of asymptomatic ischemic cerebral lesion; however the use of MMS did not resulted in a reduction of the overall 30-day neurological complication rate. Disclosure: Nothing to disclose