Abdominal aortic aneurysms (AAA) can develop over many years and their rupture is fatal in the large majority of these cases. AAAs are known as "silent" killers because they typically present no initial symptoms. Most of the victims are men, often simply dying in their sleep.

In the last decade, treatment of AAAs has been equally split between open surgery and a less invasive procedure. Now, use of the minimally invasive type of surgery can be expanded with FDA approval of Medtronic's (Minneapolis) Talent Abdominal Stent Graft on the CoilTrac Delivery System.

Presenting as an abnormal bulge in the wall of the aorta, the body's largest artery, AAAs are present in an estimated 1.2 million people and responsible for about 15,000 deaths annually in the U.S.

The company says that the Talent system makes the minimally invasive type of surgery, endovascular repair (EVAR), accessible to an additional 20% of AAA patients, because featuring a proximal aortic neck length requirement of only 10 mm.

"That means you can go into aneurysms that are much closer to renal arteries," Daniel Beach, director of communication for Medtronic Cardiovascular told Medical Device Daily. "That gives us the 20% expansion of patients that can be treated with EVAR."

About 60,000 AAA surgeries are performed each year in the U.S., split equally between EVAR and open surgery, the latter requiring a large abdominal incision.

The Talent system consists of a woven polyester membrane supported by a tubular metal lattice. It's available in diameters of up to 36 mm, as well as flared and tapered iliac limbs of 8 mm to 24 mm. It has radiopaque markers for visual guidance during deployment and follow up, and the delivery system uses a single-step release mechanism for smooth deployment and a coiled rod for enhanced trackability and flexibility.

A Medtronic-sponsored clinical study of the Talent system enrolled 166 patients at 13 medical centers between February 2002 and April 2003.

All 166 patients received a Talent. Their outcomes were compared to those of 243 patients from the Surgical Control Group of the Society of Vascular Surgery (SVS) at 30 days and one year post-implant.

The study demonstrated that the Talent exceeded the SVS Control in freedom from major adverse events at 30 days, with a statistically significant difference between the two groups: Talent, 89.2%; SVS Control, 44%.

Although patients receiving the Talent Abdominal Stent Graft were older and had a higher baseline rate of co-morbidities, at 30 days post-implant they experienced lower rates of major adverse events compared with subjects treated with open surgery.

No aneurysm ruptures and no conversions to open surgery were reported in the Talent group up to 12 months after device implantation.

In previous studies, EVAR has been shown to be an effective therapy for AAA, with fewer postoperative complications and shorter recovery times than open surgical repair, according to Medtronic. Results from a U.S. study published in The New England Journal of Medicine in January, for example, indicate that perioperative mortality was significantly lower after EVAR than after open repair: 1.2% vs. 4.8%.

"As compared with open repair, endovascular repair of abdominal aortic aneurysm is associated with lower short-term rates of death and complications," the study authors concluded. "The survival advantage is more durable among older patients. Late reinterventions related to abdominal aortic aneurysm are more common after endovascular repair but are balanced by an increase in laparotomy-related reinterventions and hospitalizations after open surgery."

"It is landmark data such as this that has led to the dramatic uptake of EVAR," Beach said. "Talent eliminates technical limitations of the minimally invasive procedures so that even more of the aortic aneurysm population can benefit from EVAR."

In 2006, Medtronic paid Edwards Lifesciences (Irvine, California) and Endogad Research (Sydney, Australia) $37.5 million in a patent infringement settlement related to modular or multi-part endovascular grafts especially suited for treatment of various types of aneurysms, including AAA. In exchange, Medtronic was granted non-exclusive licenses to the patents involved in the litigation, as well as to other patents relating to endovascular AAA grafts and delivery systems (Medical Device Daily, Jan. 24, 2006).

Medtronic reported the European market launch of the Talent Abdominal Stent Graft earlier this year (MDD, March 14, 2008).

Ruptured AAAs are currently the 10th leading cause of death among U.S. men over age 55, with fewer than 20% of people surviving a rupture. But early detection through ultrasound screening and EVAR have historically shown a significant improvement in the survival rate for all ages.