Minimally Invasive Stent Placement Can Fix Thoracic Aneurysms
The availability of a federally approved stent for aortic aneurysms in the upper chest is improving the quality of life for patients who otherwise would undergo a complicated open surgery or live a life of worry.
Ohio State University Medical Center is one of few centers in the state equipped to use the stent graft for thoracic aortic aneurysms because of the highly specialized training required to safely place the device.
"Our experience has been very good with this device," said Dr. Jean Starr, a vascular surgeon and director of endovascular services at Ohio State's Medical Center. "We have fixed people's aneurysms that couldn't have been fixed any other way."
The minimally invasive procedure enables aneurysm repair for some patients who are too sick or whose disease is too extensive for open surgery, Starr said. "This really has revolutionized the way we treat patients with thoracic aortic aneurysms," she said.
A thoracic aortic aneurysm is a widening or bulging of part of the wall of the aorta, the body's largest artery, in the area of the vessel closest to the heart. The most common cause of a thoracic aortic aneurysm is hardening of the arteries, but other risk factors include some connective tissue disorders, previous tears in the aorta wall, longtime high blood pressure and trauma, such as a fall or motor vehicle accident. Thoracic aortic aneurysms are diagnosed in approximately 15,000 people annually; the condition is generally believed to be underdiagnosed because most people with aneurysms have no clear symptoms.
The stent graft used to repair these defects at Ohio State is made of nitinol, a nickel titanium shape-memory alloy that expands when it's exposed to body temperature, and Gore-Tex. The device is initially crimped to fit inside a small tube that is inserted into the body via catheter through a small incision in the groin. A surgeon maneuvers the device through blood vessels until the stent is in the proper place in the aorta, and pulls a string to deploy the device. Fluoroscopy, or real-time X-ray imaging, allows surgeons to monitor the device's placement.
"Once it's there, there's no longer a danger of seepage. All of the blood stays inside the tube," Starr said.
People with thoracic aortic aneurysms are at high risk for rupture if the defect is not repaired, but smaller aneurysms sometimes are closely monitored to see how rapidly they grow because the risks associated with repair sometimes outweigh the risks of watchful waiting. Open surgical repair typically requires a week in the hospital and prolonged time on a ventilator. The minimally invasive procedure allows patients to return home more quickly and decreases or, in some cases, eliminates the need for rehabilitation.
One of the most devastating complications of open surgical repair is paralysis from the waist down. Starr said the stent manufacturer's studies of the device indicate the risk for paralysis is reduced from at least 14 percent to 3 percent in patients who undergo the minimally invasive repair.
The U.S. Food and Drug Administration approved the GORE TAG thoracic endoprosthesis, manufactured by W.L. Gore & Associates Inc., in March 2005. It is the only federally approved stent of its kind on the market.