Authors maintain that using distal embolic protection has been handed down as a directive despite lack of adequate evidence of benefit or efficacy.
A small, single-center study suggests that carotid artery stenting (CAS) can be safely performed without use of distal embolic protection to reduce the risk of embolization. While outcomes were good and complications low, experts pointed out several flaws and limitations of the study to Neurovascular Exchange, which call into question the validity of the results.
While distal embolic protection devices have disadvantages, include increasing the duration and complexity of the procedure as well as the number of potential failures, “not using some form of embolic protection is very unusual,” said Christopher White, MD (Ochsner Medical Center, New Orleans, LA), in an email.
Similarly, Jad Omran, MD (University of Missouri-Columbia, Columbia, MO) pointed out in an email that use of embolic protection in CAS has been endorsed by all major guidelines and that the procedure is not reimbursed by Medicare unless a protection device is used. “Most of the places I have surveyed during prior studies used protection devices [regardless of] the level of experience they had,” he added.
But in a paper published online March 20, 2017 ahead of print in Neurosurgery, Mandy J. Binning, MD (Drexel Neurosciences Institute, Philadelphia, PA), and colleagues argue that “the use of distal filter embolic protection devices for CAS has been handed down as a directive despite the lack of adequate evidence as to their benefit and efficacy. However, there is doubt regarding the efficacy of [embolic protection] in preventing thromboembolic complications during carotid stenting procedures,” they write, adding that many institutions and studies have shown that unprotected CAS can be performed safely and effectively.
To examine the issue, Binning and colleagues performed a retrospective chart review of CAS procedures performed at their institution from 2008 to 2014 in 166 patients without use of distal protection devices or post-stent angioplasty.
Overall, 78% of stents were placed in symptomatic patients and 22% in asymptomatic patients with internal carotid artery stenosis. The degree of stenosis was ≥ 80% in 75% of patients and ≥ 90% in 55% of patients.
Rates of complications were low, with no patients having transient ischemic attack, intracranial hemorrhage, or ischemic stroke at 24 hours or 30 days. Rate of perioperative non-STEMI was 2%, and the rates of retreatment for either > 80% restenosis or symptomatic restenosis were 2.8% and 0.6%, respectively.
The authors conclude that, “carotid artery stenting without the use of embolic protection devices and without postangioplasty stenting, in experienced hands, can be performed safely.” Furthermore, they say it “does not result in a higher degree of in-stent restenosis than series in which poststenting angioplasty is performed.”
No Comparison Group, Operator Experience Questioned
But White pointed out that the study is too small to be informative. In addition, “there was no comparison group to justify their conclusion,” he noted, adding that it also was retrospective, and thus underdetection of minor stroke was likely.
“They are low-volume, inexperienced operators with fewer than one CAS per week [and] less than 30 per year among several operators [in the study],” White observed. He also pointed out that the authors used general anesthesia for elective CAS, a rare practice that indicates that they are operating outside of mainstream protocol.
Omran pointed out an additional limitation: lack of postprocedure DW-MRI data to determine more conclusively if new lesions arose.
A more useful analysis, White concluded, would be a study comparing the effectiveness of different types of embolic protection devices.
According to Omran, more research is needed on operator experience and learning curve. “We recently have shown in a systematic review that no difference between [proximal and distal] methods was noted in terms of protection,” he said. “That makes the operator experience and the learning curve a main key player in this procedure.”
Sources:
Binning MJ, Maxwell CR, Stofko D, et al. Carotid artery angioplasty and stenting without distal embolic protection devices. Neurosurg. 2017;Epub ahead of print.
Disclosures:
- Binning and Omran report no relevant conflicts of interest.
- White reports being a member of the interventional management committee of the CREST-2 NIH trial.
Related Stories:
- Meta-analysis: Proximal, Distal Protection Devices Equivalent for CAS
- Double Embolic Protection Feasible During Carotid Artery Stenting
