Nearly 3% of carotid stenting procedures in a decade had plaque protrusion
Over 10 years of carotid artery stenting, Japanese hospitals saw nine cases (a 2.6% rate) of plaque protrusion, wherein plaque is found inside the stent during the procedure. Plaque protrusion involved open-cell stents in all cases. The complication occurred with unstable plaque in 8 out of 9 cases.
Stroke occurred by 30 days in 6 of the 9 patients who had plaque protrusion (1 major stroke, 5 minor strokes). In addition, ischemic lesions were found in 8 of the 9 cases on the treated side at 48 hours on diffusion-weighted imaging, Masashi Kotsugi, MD, of Ishinkai Yao General Hospital in Japan, and colleagues reported in the April 24, 2017 issue of JACC: Cardiovascular Interventions.
Their study included 328 consecutive patients with carotid atherosclerotic stenoses who underwent stenting with IVUS from 2007 to 2016. Operators used embolic protection devices in all cases.
"The present results suggest that the protective effect of an embolic protection device against stroke may be limited in cases of plaque protrusion and may indicate it is not the embolic protection device but rather avoiding plaque protrusion that is necessary to prevent periprocedural ischemic stroke," Kotsugi's group suggested.
And to that end, they urged, "carotid artery stenting should be performed using a stent with as small a free cell area as possible to prevent plaque protrusion."
"Our recent strategy is as follows: if plaque protrusion occurs, we perform IVUS and then check large-volume plaque protrusion to determine if it is convex. In a case of convex plaque protrusion, we perform stent-in-stent placement using closed-cell stents until the plaque protrusion disappears. In a case of nonconvex plaque protrusion, we observe for 5 to 10 min, and, then, if the plaque protrusion is not changed, careful clinical follow-up is considered within 30 days after carotid artery stenting. If the plaque protrusion enlarges, stent-in-stent placement is performed until plaque protrusion disappears."
"When the findings from this study are paired with the emerging data on apparent reductions in both plaque protrusion on optical coherence tomography and new DW-MRI abnormalities with the use of mesh-covered stents, the case begins to grow for such improvements in stent design," commented William Gray, MD, of Lakenau Heart Institute in Wynnewood, Pa.
In an accompanying editorial, he continued: "Toward that end, a U.S. trial [SCAFFOLD] evaluating a mesh-covered open-cell stent in patients at high surgical risk has already completed enrollment ... and two other similar trials using different mesh technologies are imminent. Inherent in these technologies is the hope that the stent can be transformed from a potential offender into a reliable protector during carotid artery stenting. This advance, once proved, along with others such as direct carotid access for flow reversal and double-filtration strategies, will thereby continue to chisel away at the causes of stroke in carotid artery stenting to patients' benefit."
Good options with mesh technologies include the closed-cell Roadsaver (Terumo) and the open-cell C-guard (inspireMD): "Expectations for micromesh stents are high," according to the study authors.
Plaque protrusion was confirmed on both angiography and intravascular ultrasound (IVUS) in their study.
IVUS alone would have detected more cases of plaque protrusion (7.8%), Kotsugi's group found.
"The investigators pre-defined plaque protrusion as having to occur in both modalities, which cut by two-thirds the incidence of IVUS plaque protrusion and which will clearly affect many of the subsequent associations and conclusions," Gray commented.
Other caveats, according to the editorialist: the lack of a core lab, diffusion-weighted MRI not routinely performed before and after stenting, unblinded assessors, stent use not protocol-directed, lack of routine independent neurological assessment, treating plaque prolapse with a second stent, and the difficult distinction between plaque protrusion and actual thrombus.
The retrospective study was further limited by the 30-day follow-up and small sample size.
Gray reported consulting for Medtronic, Boston Scientific, Contego, WL Gore, and Silk Road Medical.
- Reviewed by F. Perry Wilson, MD, MSCE Assistant Professor, Section of Nephrology, Yale School of Medicine and Dorothy Caputo, MA, BSN, RN, Nurse Planner
JACC: Cardiovascular InterventionsSource Reference: Kotsugi M, et al "Carotid artery stenting: investigation of plaque protrusion incidence and prognosis" JACC Cardiovasc Interv 2017; DOI: 10.1016/j.jcin.2017.01.029.
JACC: Cardiovascular InterventionsSource Reference: Gray WA "Blurred lines: assessing the stent as provocateur in carotid intervention" JACC Cardiovasc Interv 2017; DOI: 10.1016/j.jcin.2017.03.022.