Boston Scientific Announces Acquisition of TriVascular, Inc.
(April 18, 2005) -- Boston Scientific Corporation (NYSE: BSX) today announced that it has acquired TriVascular, Inc., a privately held company based in Santa Rosa, California. Boston Scientific exercised an exclusive option to acquire TriVascular that it obtained in December 2002. Terms of the acquisition were not disclosed.

TriVascular was founded in 1998 to develop less-invasive medical devices and procedures for treating abdominal aortic aneurysms (AAA). This life-threatening condition creates a weakening and bulging of the aorta - the body's main blood carrying vessel. Conventional treatment involves invasive surgery requiring a large abdominal incision to implant a fabric graft to replace the damaged aorta. More recently, physicians have been able to use catheters to deliver devices that combine graft material with metal stents inside the aneurysm. This allows blood to flow through the "stent-graft" and bypass the aneurysm.

TriVascular's innovative AAA stent-graft design reduces the size of the TriVascular device by replacing much of the metal stent assembly with a polymer that is injected into channels within the stent-graft during the procedure. The resulting device can be delivered into the patient through a narrower delivery system. These characteristics are intended to provide a treatment option for a broad range of patients, including those patients with unusual anatomies such as those who harbor narrow blood vessels and atypical sized aortic necks. These types of patients typically are not candidates for currently available stent-grafts.

TriVascular successfully completed its first human implant of its AAA stent-graft in 2002 and clinical experience to date on 78 patients has shown promising results in Phase I studies. The U.S. Phase II pivotal trial is planned to begin this year, and commercialization within the U.S. is expected in 2008. CE mark is also expected this year. In addition, TriVascular is in the early stages of developing a thoracic aortic stent-graft, built on the same platform as the AAA stent-graft.

"TriVascular has made tremendous progress in the development of a durable stent-graft that we believe will offer a new solution for both our surgical and interventional customers," said Paul LaViolette, Boston Scientific Chief Operating Officer. "The TriVascular AAA device reflects our commitment to bring more innovative products and add markets to our growing portfolio of cardiovascular solutions."

"Our team has overcome significant challenges in creating a unique, durable and minimally invasive treatment of aneurysms," said Michael Chobotov, Ph.D., President and Chief Executive Officer of TriVascular. "We believe our next-generation solution will address the significant unmet clinical need for a reliable, durable device that reduces patient trauma and the need for re-intervention."

The market for AAA stent-grafts was approximately $370 million in 2004. However, market evolution and penetration has been limited. Of the 1.7 million patients in the U.S. estimated to have aortic aneurysmal disease, only 360,000 patients (21 percent) are diagnosed and just 60,000 (3.5 percent) receive some form of treatment. Many believe the market could triple by 2008 with the introduction of a device that offers less-invasive placement and the improved durability required to decrease the incidence of re-intervention.

Non-surgical endovascular stent-grafts currently account for approximately one third of all aortic repair procedures performed. With the recent acquisition, Boston Scientific plans to increase its share in the overall market for AAA devices. Currently, the company holds a leading market share position for open surgical grafts with its Hemashield™ product line.

Boston Scientific 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:

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, integration of acquired companies, Boston Scientific's overall business strategy, and other factors described in Boston Scientific's filings with the Securities and Exchange Commission.