Authors' recommendations: High level evidence on the true effectiveness of EPDs remains scarce, with only one randomised trial comparing the clinical outcomes of CAS patients with or without embolic protection. The randomised trial suggests a lack of demonstrable benefit with the use of EPDs. Five of the seven comparative studies retrieved to determine the safety and effectiveness of EPDs supported this view, with several studies indicating that major and minor stroke rates remain comparable up to 30-days post-treatment. Only one comparative study indicated that significant reduction in peri-operative and post-operative stroke rates is possible. The one remaining comparative study observed a 79% reduction in stroke rates with EPDs, but this was not statistically significant.Utilising DWI, one study observed that the proportion of patients with new lesions was significantly lower with the use of EPDs. In contrast, the randomised trial highlighted that the occurrence of new DWI-detected lesions were comparable between protected or unprotected patients. One comparative study demonstrated that the number of microembolic signals and showers during each phase of the CAS procedure was significantly higher in protected patients compared to those without EPD. This raises doubt to the widely held perception that EPDs reduce embolic load. However, it is interesting to note that this higher microembolic load did not translate to higher stroke or death rates in EPD patients. It is postulated that macroembolus may be propelled into the filter and consequently disintegrated into smaller particles that passes the micropores of the filter. Alternatively, it is possible the filter EPDs do not adequately cover the entire internal carotid artery.Three studies demonstrated that there is virtually no difference in effectiveness between various filter EPDs and proximal or distal occlusion EPDs. However, subgroup analysis of symptomatic patients in another study suggested that eccentric filters perform better relative to concentric filters. One retrospective case series study has demonstrated that the use of patient specific EPDs, selected based on characteristics such as plaque characteristics and internal carotid artery tortuosity, results in very low in-hospital death or stroke rates which compare favourably to several trials that utilised one specific EPD for all CAS patients. This indicates that the “one size fits all” approach to EPDs in certain trials is not optimal and warrants further investigation.Overall, the evidence supporting the efficacy of EPDs remains controversial. The only randomised trial to date does not support the general view that EPDs are beneficial during CAS. Meanwhile, most of the comparative studies retrieved indicate that patients with EPDs experience similar stroke and death rates to those who underwent unprotected CAS. The observation that microembolic load may be higher in EPD recipients is of concern despite the fact that it does not have immediate neurological relevance. It is highly unlikely that new randomised controlled trials investigating the benefits of EPDs during CAS compared with unprotected CAS will be conducted in the near future. The only randomised trial to investigate the true effectiveness of filter EPDs did not achieve its target cohort as the FDA approval of EPDs and widespread consensus for mandatory protection during CAS severely impaired patient recruitment. Nevertheless, there is some evidence that EPDs (at least filter-type EPDs) may not be as beneficial as widely thought and might be a contributing factor to higher embolic load in patients while burdening the healthcare system with potentially unnecessary costs. Larger well-designed comparative studies are clearly warranted. It is likely that comparative studies with historical controls derived from registries will form the majority of future attempts to determine the effectiveness of EPDs. Additional research is also necessary to determine if all classes of EPDs are truly comparable.

Project Status: Completed

URL for project: http://www.horizonscanning.gov.au/internet/horizon/publishing.nsf/Content/211ABF81A69CA39DCA2575AD0080F3DC/$File/HSReport%20%20Embolic%20protection%20devices%20(ASERNIPS).pdf

Year Published: 2009

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Australia

Organisation Name: Australian Safety and Efficacy Register of New Interventional Procedures-Surgical

Contact Address: ASERNIP-S 24 King William Street, Kent Town SA 5067 Australia Tel: +61 8 8219 0900

Contact Name: racs.asernip@surgeons.org

Contact Email: racs.asernip@surgeons.org

Copyright: Australian Safety and Efficacy Register of New Interventional Procedures - Surgical (ASERNIP-S)