HOLLYWOOD, FLA. — The design and composition of carotid stents can have a major effect on their clinical impact, based on results from two separate studies.
Treatment with open-cell and large-cell carotid stents was linked to a substantial increase in the rate of periprocedural adverse events in symptomatic patients in a multicenter registry with more than 3,000 patients, Dr. Koen Deloose, department of vascular surgery, A-Z St.-Blasius, Dendermonde, Belgium, reported at the 19th International Symposium on Endovascular Therapy. His report expanded on similar findings from about 700 patients reported last year.
In addition, treatment with a self-expanding, nitinol carotid stent was linked with a twofold increase in the rate of periprocedural hypotension in a single-center review of 172 patients, Dr. Barry T. Katzen, medical director, Baptist Cardiac and Vascular Institute, Miami, reported at the same meeting.
A carotid stent's cells are the open sections on its surface that are formed by the wires of the stent. Cells can range in size from the 1.05-mm
Dr. Deloose reported on 3,179 consecutive patients who received a carotid stent at one of four collaborating hospitals in Belgium and Italy during 1997–2006. About 96% were also treated with an embolic protection device. The most common stent used was the small-cell, closed-cell Wallstent, in 66% of patients. Next was the large-cell, open-cell Acculink stent, in 13% of patients. A total of seven stent types were used. There were no significant differences in baseline clinical factors among patients who received different stents.
The analysis correlated stent-cell size and design with the incidence of transient ischemic attacks, strokes, and deaths that occurred either during stenting or the first 30 days following treatment. An effect from cell size or design was only seen in symptomatic patients (patients with a history of transient ischemic attacks or minor strokes before treatment) but not in asymptomatic patients.
Among symptomatic patients, those who received stents with a cell size that was 5.0–7.0 mm
The impact of stent-cell size was also limited to late events—about two-thirds of events occurred after the stent was in place. In the subgroup of symptomatic patients who had late events, the rate was more than fourfold higher among patients who received stents with cells that were 5.0–7.0 mm
Reduced adverse events were also found in patients who received closed-cell stents, compared with those who got open-stent designs.
Although a prospective, randomized study is needed to confirm a role for cell size and design on outcomes, “for the time being stents with a small free-cell area should be used in symptomatic patients,” concluded Dr. Deloose.
The impact of stent design and composition on the incidence of periprocedural hypotension was examined in a review of 172 patients who received a carotid stent to treat a new lesion during January 1996-October 2006 at the Baptist Cardiac and Vascular Institute. The group included 31 patients who received a balloon-expandable, braided stent—the Wallstent—and 142 who received a self-expanding, nitinol stent. For this review, hypotension was defined as an episode of reduced blood pressure that required treatment with fluids or medications.
In the series, the incidence of all hypotensive episodes was about 40% in patients treated with nitinol stents, and about 19% in those who received a Wallstent, a statistically significant difference, reported Dr. Katzen.
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