Stroke, Death, and TIA Rates Significantly Reduced With Closed-Cell Carotid Stents

PARIS, May 21 /PRNewswire/ --

- Data From Multicentre Registry Show Significant Benefit With Closed-Cell Stents in the Treatment of Carotid Artery Stenosis

Boston Scientific Corporation (NYSE: BSX) welcomed results from a large independent registry confirming the benefit of closed-cell stents in patients with carotid artery stenosis. The results, published in the February 2007 issue of the European Journal of Vascular and Endovascular Surgery, show that symptomatic patients treated with closed-cell stents had significantly fewer complications after the stent was implanted than patients who received open-cell stents. In particular, the Carotid WALLSTENT(TM) was used in 66% of patients in the registry and had the lowest 30-day post-procedural event rate of 1.2% in symptomatic patients.(1)

The 3,179 patients with carotid artery stenosis (narrowing of the arteries in the neck supplying blood to the brain) included in the registry experienced significantly fewer strokes, deaths or transient ischaemic attacks (TIA) within 30 days of the procedure if they received a closed-cell stent (P = 0.002). These stents cover more of the artery wall than open-cell stents because they have overlapping or fully connecting struts, and have less space between struts (a smaller free cell area). A free cell area of less than 2.5 mm(2) was associated with a post-procedural complication rate of 1.2%, compared with 3.4% for a free cell area of more than 7.5 mm(2) (P = 0.006).(1)

The differences were even greater in patients with symptomatic disease who had already suffered a TIA or stroke and were at higher risk of having another event. In these patients, the post-procedural event rate was 1.3% for closed-cell stents (< 5 mm(2) free cell area), compared with 6.3% for open- cell stents (> 5 mm(2) free cell area) (P < 0.0001).(1) The post-procedural rates for free cell areas of < 2.5 mm(2) and > 7.5 mm(2) were 1.2% and 7.0%, respectively (P < 0.0001).(1)

Lead investigator Dr. Marc Bosiers, from the Department of Vascular Surgery, St Blasius Academic Hospital, Dendermonde, Belgium, explains the importance of these results: "After carotid angioplasty and stenting, patients are at risk for post-procedural complications within 30 days of the procedure. Closed-cell stents, with their smaller free cell area, provide better scaffolding and lesion coverage and were shown to reduce post-procedural adverse events in our study. In the symptomatic population, late complication rates were highest for the open-cell stents and increased with larger free cell area. For the time being, consideration should be given to the use of stents with a small free cell area, especially in symptomatic patients."

About 4-8% of the population has advanced carotid artery disease,(2) Which puts them at high risk of a TIA or stroke. TIAs involve stroke symptoms lasting only a few minutes or hours and provide an important clinical indicator for potential future stroke, with 10-20% of sufferers having a full-blown stroke within a month.(3) Approximately one-third of people who have had a stroke die within a month and one-third are left with disabilities.(4)

Carotid artery stenting is a minimally invasive procedure in which a stent is delivered to the site of the blockage and expanded to open the carotid artery and restore blood flow. Stents are tiny wire mesh tubes that are inserted into arteries to help keep the vessel open and therefore maintain blood flow. Closed-cell stents, such as the Carotid Wallstent(TM) and the NexStent(TM) Carotid Stent, have overlapping or fully connecting struts, so they have less free cell area and cover 5-10 times more of the artery wall than open-cell stents.

The registry recorded outcomes from carotid stenting using a range of closed- and open-cell stent devices at four centres in Belgium and Italy. The closed-cell stents included the Carotid WALLSTENT(TM) (1.08 mm(2) free cell area), Xact(R) (2.74 mm(2)) and NexStent(TM) (4.07 mm(2)). The open-cell stents included Precise(R) (5.89 mm(2)), Exponent(R) (6.51 mm(2_), Protégé(R) (10.71 mm(2)) and Acculink(R) (11.48 mm(2)).(x) The Carotid WALLSTENT(TM) was the most frequently used stent and was placed in 2,107 of the 3,179 patients.(1)

"As a leader in the field of cardiovascular device technology, Boston Scientific is delighted that this independent registry confirms the value of closed-cell stents, such as the Carotid WALLSTENT(TM) or the NexStent(TM), which provide excellent scaffolding and lesion coverage", said Jeff Goodman, President of Boston Scientific International. "Our Carotid stents offer a triple combination of benefits for the patient: optimal scaffolding, cell design and radial force."

Boston Scientific Corporation is a worldwide developer, manufacturer and marketer of medical devices whose products are used in a broad range of interventional medical specialties. For more information, please visit www.bostonscientific.com.

This press release contains forward-looking statements. Boston Scientific wishes to caution the reader of this press release that actual results may differ from those discussed in the forward-looking statements and may be adversely affected by, among other things, risks associated with new product development and commercialization, clinical trials, intellectual property, regulatory approvals, competitive offerings, Boston Scientific's overall business strategy, and other factors described in Boston Scientific's filings with the Securities and Exchange Commission.

References

(1) Bosiers M, de Donato G, Deloose K, et al. Does free cell area influence the outcome in carotid artery stenosis. Eur J Vasc Endovasc Surg 2007;33:135-141.

(2) Dodick DW, Meissner I, Meyer FB, Cloft HJ. Evaluation and management of asymptomatic carotid artery stenosis. Mayo Clin Proc 2004;79:937-944.

(3) The Stroke Association. Stroke statistics sheet R11 http://www.stroke.org.uk/information/our_publications/factsheets/r11_ stroke.html (last accessed 21 May 2007). (Due to the length of this URL, it may be necessary to copy and paste this hyperlink into your Internet browser's URL address field. Remove the space if one exists.)

(4) Global burden of stroke. WHO Atlas of Heart Disease and Stroke 2004. http://www.who.int/cardiovascular_diseases/en/cvd_atlas_15_burden_stroke.pdf (last accessed 21 May 2007).

(x)Carotid WALLSTENT and NexStent are trademarks of Boston Scientific Corporation. Xact and Acculink are trademarks of Abbot Laboratories. Precise is a trademark of Cordis Corp. Exponent is a trademark of Medtronic Vascular, Inc. Protégé is a trademark of ev3, Inc.