Proximal May Be Preferred Form of Embolic Protection in Carotid Stenting

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A proximal protection device can be successfully and safely used as the first choice for embolic protection during most carotid artery stenting (CAS) procedures, according to findings from a case series published online July 18, 2014, ahead of print in EuroIntervention

Notably, proximal protection enables a much lower neurologic complication rate than has been seen in randomized trials of CAS using distal protection, Horst Sievert, MD, of CardioVascular Center Frankfurt (Frankfurt, Germany), and colleagues say in the paper. The difference, they assert, “suggests that the merit of carotid stenting when compared with carotid endarterectomy should be reevaluated using proximal protection.”

Investigators led by Dr. Sievert evaluated proximal embolic protection in 124 consecutive patients undergoing CAS at their institution. The Gore Flow Reversal System (WL Gore; Flagstaff, AZ) was used in the first 92 patients and after that device became unavailable, the Mo.Ma Ultra device (Medtronic; Minneapolis, MN) was used.
All patients received 100 mg of aspirin within 24 hours of the procedure and either 75 mg of clopidogrel daily for ≥ 3 days before the intervention or a 300-mg loading dose the day before. During the procedure, IV heparin was administered to maintain an activated clotting time of ≥ 250 seconds. After stenting, all patients were prescribed ≥ 100 mg of aspirin indefinitely and 75 mg of clopidogrel daily for ≥ 30 days.
Average patient age was 71.9 years, 75% were male, and 21% had symptomatic stenosis. Occlusion of the contralateral internal carotid artery was found in 5.6%, and 17% had type II or III aortic arches. Mean time between the index neurological event and stenting was 50.5 days. Mean diameter stenosis at baseline was 80.1%, with no difference between those with symptomatic or asymptomatic disease.
Procedure time was 61.2 ± 25.9 minutes with a fluoroscopy time of 13.9 ± 8.6 minutes. Predilation before crossing was performed in 33.1% of the stenoses. The most commonly implanted stents were the Protege (ev3 Endovascular; Plymouth, MN; 56.5%) and Xact (Abbott Vascular; Santa Clara, CA; 24.2%) devices.

High Technical, Clinical Success

The composite of new TIA or minor or major stroke within 30 days (primary endpoint) occurred in 1 patient. A 74-year-old asymptomatic male who received a Protege stent under embolic protection with the Mo.Ma Ultra device had no procedural complications but suffered a major stroke due to thrombotic stent occlusion 9 days after discharge.

Technical success—delivery and placement of the protection device with establishment of reverse flow and then retrieval of the balloon sheath and wire—was achieved in all but 2 patients (98.4%), with no intraprocedural complications. Clinical success—application of the protection device in the absence of death or stroke—was reached in all patients. 

Temporary neurological symptoms due to intolerance of antegrade flow interruption during balloon occlusion occurred in 10 patients (8.1%), but they resolved promptly with complete recovery once flow was reestablished.

In the 2 cases of technical failure, both involving the Gore system, a distal protection device was deployed and the procedure was completed without complications. In addition, there were 5 cases of minor technical problems that were resolved easily. 

Few Complications 

None of the patients in whom proximal protection was technically unsuccessful or associated with technical problems experienced neurological or other complications. 

“This case series shows that proximal embolic protection devices can be used as the first choice for embolic protection during carotid stenting with high rates of technical and clinical success as well as a very low incidence of cerebral ischemic events,” the authors conclude. 

Furthermore, they say, the results are similar to those of a meta-analysis (Bersin RM, et al. Catheter Cardiovasc Interv. 2012;80:1072-1078) showing that patient risk stratification may not be necessary for CAS using proximal protection. 

Indeed, the rate of neurologic complications with proximal protection in both the meta-analysis and the current series is “substantially lower” than reported in most trials comparing CAS with distal protection to endarterectomy, Dr. Sievert and colleagues note, and comes in under the neurological complication threshold for performing CAS established by the American Heart Association and American Stroke Association for both asymptomatic (< 3%) and symptomatic (< 6%) patients. 

Putative reasons for the superiority of proximal to distal protection, they say, include lesion manipulation only after embolic protection and more complete protection with flow reversal. 

The authors acknowledge that the study represents the experience of a single operator and thus may not be “completely transferable to other centers.” 

Done Right, Proximal Protection Shores Up CAS Safety

In a telephone interview with TCTMD, L. Nelson Hopkins, MD, of University at Buffalo Neurosurgery (Buffalo, NY), agreed that Dr. Sievert is “a very good operator” and characterized the stroke rate of 0.08% as “pretty amazing.”

Moreover, Dr. Sievert is “very meticulous” in ensuring that, once the proximal protective device is in place, all antegrade flow in the carotid artery has been shut down, he said, noting, “A lot of [operators] don’t do that, but when proximal embolic protection is done properly, it provides a real benefit, particularly in symptomatic patients.

“One single-center experience never [provides] the complete answer, but when you add this to all the other literature that’s accumulating on proximal embolic protection, it makes you realize that it’s a very important technology for carotid stenting,” Dr. Hopkins observed. In fact, in Europe, where carotid stenting is more routine, it is the preferred mode of embolic protection in many major centers, he added. 

Intolerance of the procedure is fairly rare; for example, the rate was less than 5% in other studies of both of the devices used in this series, he reported. Moreover, the occlusion time is typically no more than about 7 minutes—far shorter than the average 32 minutes with endarterectomy—and if intolerance does occur, management is straightforward, he noted. 

Also, the learning curve for device placement is “not major,” Dr. Hopkins said. He acknowledged that there are variations in vascular anatomy but added that “when you cannot make proximal protection work technically, in most cases you can change to distal protection.” So even though proximal protection should be the first choice, “I wouldn’t say to stop using distal filters, but rather both are important arrows in the quiver of interventionalists performing carotid stenting,” he commented. 


Hornung M, Bertog SC, Franke J, et al. Evaluation of proximal protection devices during carotid artery stenting as the first choice for embolic protection. EuroIntervention. 2014;Epub ahead of print.

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Proximal May Be Preferred Form of Embolic Protection in Carotid Stenting

  • Dr. Sievert reports having ownership interest in and receiving research support and consulting fees from multiple device companies.
  • Dr. Hopkins reports no relevant conflicts of interest.