Plaque prolapse was higher with one stent than the other, but editorialists suggest the meaning of this finding may differ based on stent design.
Using optical coherence tomography (OCT), researchers have demonstrated similar rates of strut malapposition but differing rates of plaque prolapse after implantation of two new-generation mesh-covered stents into the carotid artery. The findings were published online ahead of print in EuroIntervention.
Tomoyuki Umemoto, MD (Tokyo Medical and Dental University, Tokyo, Japan), and colleagues obtained high-definition cross-sectional OCT images of 16 consecutive patients who underwent carotid artery stenting using either the CGuard Carotid Embolic Prevention System (InspireMD, Tel Aviv, Israel; n = 11) or the RoadSaver Carotid Artery Stent System (Terumo, Tokyo, Japan; n = 5). Proximal or distal embolization devices were used in all cases.
Both of these stents are different from conventional stents in that they possess micro-mesh. The CGuard micro-mesh is composed of polyethylene terephthalate (PET) and is positioned outside the widely open-cell-design stent frame. The RoadSaver has micro-mesh made of nitinol that is located inside the closed-cell-design stent frame. The RoadSaver has a smaller stent frame strut thickness than the CGuard, but its mesh has a larger strut size and pore size.
OCT revealed that rates of strut malapposition were similar for both stents, but plaque prolapse was more common with the RoadSaver.
Outcomes by Treatment type
|
|
CGuard (n = 11) |
RoadSaver (n = 6) |
P Value |
|
Strut Malapposition |
20.5% |
26.8% |
0.26 |
|
Plaque Prolapse |
10.8% |
20.7% |
0.05 |
None of the patients experienced any neurological complications, including stroke or transient ischemic attack, during the procedure or postprocedure.
“Taken in aggregate with our earlier work,” write the authors, the findings “indicate that mesh-covered stents have the potential to minimize plaque protrusion—a pathologic finding the presence of which is related to the risk of periprocedural and postprocedural adverse neurologic events.”
In an accompanying editorial, Piotr Musialek, MD, DPhil (John Paul II Hospital, Krakow, Poland), and Eugenio Stabile, MD, PhD (University of Naples “Federico II”, Naples, Italy), write that the findings “deserve further investigation” not only because they stem from a small study but also because “this work illustrates some fundamental limitations of the current definitions and techniques when used to evaluate the novel devices.”
Notably, strut malapposition can be minimized by optimizing postdilatation with an appropriately-sized open-cell stent such as the CGuard, they suggest, adding that this is more difficult to achieve with a stent that has a closed-cell design, such as the RoadSaver.
In addition, while plaque prolapse visualized via OCT following RoadSaver implantation can reliably be assumed not to be mesh-covered, the same cannot be said for the CGuard. “Mesh coverage of protruding plaque prevents embolism by ‘trapping’ the plaque in situ,” they write. “However, we cannot be absolutely sure that prolapsing plaque is mesh covered—the CGuard EPS mesh is made of PET fiber that is only 20 μm in diameter, which is too small to permit systematic visualization on conventional OCT.”
The editorialists stress that future research must both look at plaque prolapse predictors in these novel stents and “determine whether there is any definable unprotected (ie, not covered/ excluded by micromesh) plaque prolapse threshold for subclinical versus clinical cerebral embolism.”
Sources:
- Umemoto T, de Donato G, Pacchioni A, et al. Optical coherence tomography assessment of new generation mesh-covered stents after carotid stenting. EuroIntervention. 2017;Epub ahead of
- Musialek P, Stabile E. Residual plaque prolapse with novel dual-layer carotid stents: is it mesh-covered or not? EuroIntervention. 2017;Epub ahead of print.
Disclosure:
Umemoto, Musialek, and Stabile report no relevant conflicts of interest.
