Strokes Linked to CA Stenting Occur Post Procedure

BY SHERRY BOSCHERT

SEATTLE -- The majority of strokes associated with carotid artery stenting occur after the patients leave the procedure room, and 18% occur in vessels that physicians hadn't manipulated, Dr. Rodney D. Raabe reported at the annual meeting of the Society for Interventional Radiology.

These unexpected findings from his retrospective ad hoc analysis of 3,500 patients in the CAPTURE Registry (Carotid Acculink/Accunet Post-Approval Trial to Uncover Unanticipated or Rare Events) suggest that there is "something going on in the arch or in the carotid that we're destabilizing," he said.

The rate of nonipsilateral stroke is much higher than medical histories suggest it should be. Approximately 5% of patients had a stroke either during the procedure or within 30 days after the procedure. Among the 170 strokes in 168 patients, 82% were ipsilateral and 18% were nonipsilateral

The 31 nonipsilateral strokes mean that nearly 1% of all patients who underwent carotid artery stenting developed nonipsilateral strokes.

"That's huge" and hard to explain, he said. "

With this number of strokes occurring outside the range of our procedure, there's great potential to reduce stroke in this already very safe procedure. We have a huge amount of work to do to figure this out. When we do, this will become an even safer procedure."

Two percent of all patients had major strokes, and 3% had minor ones. Major and minor strokes occurred at similar rates in patients who had ipsilateral strokes, but patients with nonipsilateral strokes were more likely to have minor strokes than major ones.

"Which is good, because if they're occurring in an area where we're not even manipulating, perhaps they're not going to be bad" strokes, said Dr. Raabe of Sacred Heart Medical Center, Spokane, Wash.

Among all strokes, approximately 23% were reported during the procedure. "I would have thought that would be 90%," he commented. Another 58% were reported after the procedure, and 20% were detected after the patient was discharged from the hospital. (The percentages were rounded off.)

To make sure the findings weren't being biased by patients stroking on gurneys during transport to a room immediately after the procedure, he reanalyzed the data. Even then, 38% of strokes occurred 24 hours or more after the last manipulation of the carotid.

"You'd think they would be stable by then," Dr. Raabe said.

Strokes occurring 24 hours or more after the procedure accounted for 48% of ipsilateral strokes and 36% of nonipsilateral strokes, but this difference was not statistically significant. None of the nonipsilateral strokes were reported during the procedure.

The incidence of strokes in patients 80 years of age or older was 7%, compared with 4% for younger patients. The difference was not statistically significant.

Symptomatic patients who underwent the procedure had a higher risk of stroke (9%) than did asymptomatic patients (5%), a risk factor seen in previous studies as well.

"We're starting to wonder if there's something different about the plaque morphology, or about the fragility or stability of plaque, or the stability of plaque" that makes symptomatic patients more vulnerable to stroke, he said. "We don't know."

The technical equipment used or stent design also might factor into the high rate of nonipsilateral strokes and postprocedure strokes.

"There's something we can work on, or something that needs to be evaluated" in all these areas, he suggested.

Dr. Raabe has been a paid consultant to companies including Abbott, owner of Guidant, the company that makes the stent and filter used in the study.