Refined Techniques Improve Stenting Outcomes

By Mitchel L. Zoler  

HOLLYWOOD, FLA. -- The safety of carotid stenting in high-risk patients is enhanced by improved stenting techniques and patient management, Dr. Jay S. Yadav said at the 19th International Symposium on Endovascular Therapy.

Improved strategies for placing carotid stents are critical, especially when treating elderly or symptomatic patients, said Dr. Yadav, who is cofounder and CEO of a medical device company in Atlanta and formerly director of endovascular services at Piedmont Hospital, also in Atlanta.

Dr. Yadav reviewed several of the steps that he believes can boost the safety of carotid artery stenting.

Although access through the aortic arch poses a major risk for causing strokes, the risk can be reduced by using alternative access routes and better equipment.

Dr. Yadav recommended using an Ansel sheath as well as a hooked Simmons catheter in order to navigate more easily through a stenotic arch.

These tools can be introduced from either a brachial or femoral artery approach, and they can be used to reach either the left or right carotid artery.

Another tip is to be sure the embolic protection device is properly positioned--in a straight segment of the distal carotid artery. If the device is placed in a curved region, debris might slip by the outside of the device. In a straight segment, it's easier to fit the device snugly in the vessel.

Embolic filters can also slow or arrest blood flow, especially when filters are distal to large, soft plaque.

In such cases, the column of blood that's trapped proximal to the filter should be aspirated before the filter is collapsed and withdrawn.

If such stagnant blood isn't removed, trapped particles can embolize when the filter is withdrawn, Dr. Yadav said.

Another tip is to minimize the duration of filter deployment. Once an embolic protection device is deployed, stenting should proceed immediately and finish within 5 minutes.

In a recent study, patients with a filter in place for more than 20 minutes had double the risk of stroke, compared with patients with shorter dwell times.

In certain highly challenging cases with very stenotic vessels, the deployment of two distal protection devices can help to ensure that all of the embolic material is trapped.

Proper medical management can also improve outcomes.

Dr. Yadav recommended starting treatment with clopidogrel a week before the stenting procedure, rather than relying on a loading bolus.

During the procedure, patients should receive heparin or bivalirudin, with a target activated clotting time of 275-300 seconds. After stenting is complete, patients should received clopidogrel and aspirin for 3-4 weeks.

When asked to comment upon this article, Dr. Ronald Fairman stated: "Reviewing these data from the CAPTURE registry of 3,500 patients who have undergone carotid artery stenting with the use of distal protection demonstrates that almost one-fifth of the periprocedural strokes were nonipsilateral and the absolute rate of nonipsilateral stroke was 1% regardless of patient age or symptomatic status." Dr. Fairman is the chief of the division of vascular surgery, Hospital of the University of Pennsylvania, in Philadelphia.

"If one equally distributes this incidence to the ipsilateral side, the conclusion is that a significant number of strokes, up to perhaps 40%, associated with carotid stenting are access related.

"Clearly we should be focusing our efforts on alternative techniques to reduce the risk of access-related strokes," Dr. Fairman concluded.