Clinical trial of newest technology to treat thoracic aortic aneurysms

Feb 16 2005

A clinical trial is underway at the Hospital of the University of Pennsylvania (HUP) to study the safety and effectiveness of an endovascular medical device to treat life-threatening thoracic aortic aneurysms. Ronald Fairman, MD, Chief of Vascular Surgery at HUP, is leading the study at Penn and is one of 35 principal investigators in North America to participate in this landmark trial.

Thoracic aortic aneurysms (TAAs) occur when a section of the aorta – the body's largest artery that carries blood out of the heart and into the organs of the body – weakens and bulges outward like a balloon in the section of the artery that runs down the chest. Each year, more than 20,000 patients in the United States are diagnosed with TAA. Aortic aneurysms – including thoracic and abdominal aortic aneurysms – remain the 13th major cause of death in this country, accounting for nearly 15,000 deaths annually.

"The STARZ-TX2 trial is groundbreaking and excellent news for patients diagnosed with descending thoracic aortic aneurysms," says Dr. Fairman. "Surgery can be life-threatening for many of these patients and a 'wait-and-see' approach is often not an option because patients are at an increased risk of an aortic rupture. A non-surgical approach to treating this life-threatening disease could benefit thousands of lives."

The clinical trial, called STARZ-TX2 (Study of Thoracic Aortic Aneurysm Repair with the Zenith® TX2™ Thoracic TAA Endovascular Graft), is open to patients diagnosed with a descending thoracic aortic aneurysm. STARZ-TX2 will compare the outcomes of patients treated with open surgery to patients treated with the Zenith TX2 Thoracic TAA Endovascular Graft, manufactured by Cook Incorporated.

Specifically, the trial will assess device performance, as well as patient survival and aneurysm rupture rates in the surgical and endovascular treatment groups, over a 12-month period.

The trial will enroll 275 patients at up to 35 medical institutions in the United States and Canada. Additional trial sites in Japan, Australia and Europe also will participate.

Currently, surgical repair is the standard of care for the treatment of TAAs. Surgical repair requires a surgeon to open the chest cavity, clamp off the aorta and sew a surgical graft in place to prevent an aneurysm from rupturing. Open surgical repairs carry high health risks for many older patients, who may also suffer from other significant medical conditions such as heart disease, lung disease, diabetes or hypertension.

The Zenith TX2 system requires an incision to insert the graft's hydrophilic, kink-resistant delivery system into the femoral artery in the leg. Once the system is guided into position through the patient's arteries under fluoroscopy, a one- or two-piece, fabric-covered, self-expanding stent graft is placed inside the weakened section of the thoracic aorta to relieve pressure on the aneurysm, helping to reduce the risk of rupture.

Endovascular treatment of aortic aneurysms has been a common practice for the past 10 years in the United States, Europe and Asia. During that time, significant improvements in treatment outcomes have been observed among patients treated with endovascular devices as compared with standard open surgery. Current endovascular treatments are marketed worldwide for the treatment of abdominal aortic aneurysms.

The major cause of thoracic aortic aneurysms is a hardening of the arteries, a condition in which fatty deposits adhere to the walls of the arteries, which become less elastic and weaker as a result. Major risk factors leading to a hardening of the arteries include smoking and high blood pressure as well as genetics. Other possible causes of TAA include trauma to the aorta and congenital diseases such as Marfan's syndrome.