Mesh-covered carotid stent associated with low 30-day stroke rates

Patients treated for carotid stenosis with a new mesh-covered stent demonstrated stroke rates of 1.1 percent at 30 days, suggesting the device could help overcome one of the previously reported weaknesses of carotid artery stenting (CAS).

In the randomized CREST and ACT I trials comparing CAS and carotid endarterectomy (CEA) in standard-risk patients, rates of minor stroke were 1 to 1.5 percent higher in CAS patients—although the 30-day composite of MI, stroke and death was similar between groups, wrote lead author Peter A. Schneider, MD, and colleagues in JACC: Cardiovascular Interventions. The authors said plaque protrusion through the wall of the stent has been singled out as a likely factor in many post-procedure stroke events in CAS.

“A novel, dedicated stent that can better cover the plaque while still conforming to the native anatomy and maintaining flow in the external carotid when placed at the carotid bifurcation may be useful in reducing plaque protrusion, and thus contribute to stroke reduction in CAS,” wrote Schneider, with Hawaii Permanente Medical Group and Kaiser Foundation Hospital in Honolulu, and coauthors.

The investigators performed the first in-human study of a new-generation carotid stent from W.L. Gore & Associates (Flagstaff, Arizona), which funded the single-arm trial.

A total of 312 patients with severe carotid artery stenosis—asymptomatic stenosis above 80 percent or symptomatic stenosis above 50 percent—were enrolled and treated with a 100 percent implantation success rate. However, only 265 were included in the primary analysis after exclusions for protocol violations.

Three percent of those patients met the primary endpoint of any stroke, MI or death at 30 days. Strokes occurred in three patients (1.1 percent), including two major ischemic strokes within 30 minutes of the procedure and one major hemorrhagic stroke six days later. There were two deaths unrelated to stroke and four patients (1.5 percent) experienced MI.

Schneider et al. said the mesh-covered stent is intended to reduce late stroke events, so they came away encouraged by the study results.

“In the SCAFFOLD trial, the low rate of 30-day major adverse outcomes in properly selected patients and the absence of embolic stroke events post-procedure appear to validate the approach to the construction of the (stent) that employs an open-cell flexible nitinol platform covered with a 500-μm (expanded polytetrafluoroethylene) mesh covering to minimize plaque protrusion,” they wrote.

The investigators plan to collect follow-up data at one, two and three years post-procedure, and will add ipsilateral stroke outcomes to their future reports. Limitations of the current analysis include the trial’s single-arm design and the low number of patients and events in some subgroups.

In a related editorial, two cardiologists from Munich noted the complexity of the study population was an important strength. The patients were older on average and more had diabetes than in randomized trials of carotid stenting, reflecting a more “real-world” patient mix.

“The markedly higher stroke rate in the intention-to-treat analysis (2.9% compared with 1.1% in the primary analysis population) including anatomic high-risk features for CAS such as tortuous vessel anatomy and severe lesion calcification underlines that patient selection is of great importance to achieve high procedural safety,” wrote Harald Mudra, MD, and Jakob Ledwoch, MD.

“The study shows that consequent use of a protection device, appropriate patient selection, and implantation of novel mesh-covered stents can reduce the 30-day stroke rate down to 1.1%, which is lower than both the CAS and CEA groups in the large randomized trials despite higher patient comorbidity.”

However, the editorialists pointed out longer-term follow-up is necessary to fully evaluate the safety of the Gore stent. They also believe future randomized trials should compare mesh-covered stents both to conventional CAS devices and to CEA.

“If such trials can confirm the results of the current studies, this novel stent technology will really represent a new milestone in CAS,” Mudra and Ledwoch wrote.