There are obvious advantages of this system compared with filters:¹⁴

• lesion-crossing is protected;
• there is no need for either a distal landing zone or a ‘mechanical’ device in the distal ICA;
• microbubbles in the stent delivery system can be aspirated; and
• vulnerable lesions with thrombus may be treated.

The disadvantages of the Gore NPS is the large profile sheath that is compatible with 9 French (Fr), which clearly requires the use of a closure device. This has to be offset against the fact that a filter-protected CAS procedure requires only a 6Fr sheath. There is undoubtedly a learning curve when using the system. The rate of intolerance to flow reversal is around 5%, and this would suggest that other CPDs should be available. The importance of a low origin of the superior thyroid and/or ascending pharyngeal artery is yet to be determined. In our experience, this does not seem to influence the achievement of flow reversal. The possibility of vessel wall damage caused by the occlusion balloons has to be considered and it is important not to overinflate the balloons, although these are compliant elastomeric balloons that are formulated for use against delicate intima.

Summary
CAS and CEA are procedures that have prophylactic intent, i.e. they should prevent subsequent stroke and stroke death. However, any potential benefit of these interventions has to be weighed against procedural risk of stroke. We have two methods that complement each other, but to date only CEA has been proved to be both efficient and safe.

It must be borne in mind that there are no embolic protection devices on the market today that protect the brain from the manipulations needed to gain access to the supra-aortic vessels, and hence there is no such thing as ‘total protection’.

Our view of the Gore NPS from a strict ‘user perspective’ is optimistic, and we believe that it could have significant advantages over other protection devices. It would seem to control not only procedural macroembolisation, but also microembolisation. There are additional factors that are important in keeping complication rates low, including careful patient selection, optimised medical treatment and meticulous technique.

The surgical and endovascular community (both interventional radiology and cardiology) should join forces in an attempt to establish the relative roles of CAS and CEA in the future. As Professor Naylor stated: “CEA and CAS will inevitably have a complementary role. It is therefore imperative that we support the two remaining trials that are randomising recently symptomatic patients, the International Carotid Stenting Study (ICSS) in Europe and Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) in North America.”¹⁵