MUSC first in state to monitor 'silent killer'MUSC has become the first medical facility in South Carolina to use a new microchip sensor device in patients suffering from an often deadly arterial condition, aortic abdominal aneurysms (AAA). The sensor device enables monitoring without the need of surgery or intravenous (IV) dyes.
MUSC vascular surgeon Bruce Elliott, M.D., and interventional radiologist Claudio Schonholz, M.D., also are the first in the state to implant an intraluminal pressure sensor device that allows the pressure inside a patient’s repaired aortic abdominal aneurysm to be monitored non-invasively.
“It’s absolutely ingenious,” said Elliott. “There
are no batteries, there’s no power supply. It’s simply a transducer
that’s commonly used in the automobile industry. It’s the same
sensor that detects the tire pressure in luxury cars.”
The key benefits of the procedure are that doctors can repeat monitoring more often than with a CT scan. The procedure also is safer and potentially less expensive that other methods.
By implanting a microchip with a graft into the aneurysm sac, doctors can monitor the pressure with a sensor device that looks like a “high-tech tennis racket,” Elliot said.
More than 200,000 Americans are diagnosed with AAA each year. AAA is a condition in which the body’s largest artery becomes weakened and balloons or bulges out from the arterial wall.
The condition often becomes a silent killer because patients typically show no symptoms until an aneurysm ruptures. A person suffering from a ruptured aneurysm has only a 10-percent to 20-percent chance of survival.
Treating the AAA condition prior to a rupture can reverse the 80-percent-to 90-percent fatality rate. As much as 98 percent of patients with AAA can be successfully treated and cured of the condition, Elliot said.
The cure rate for AAA patients and opportunites for interention have grown immensley, according to Elliott. “Left untreated, nearly all patients with aortic aneurysms will die from their aneurysm ultimately,” he said. “However, if treated, 95 percent will survive and can expect a near normal life expectancy. This is significantly better than we can say we are doing with many cancer survivals.”
The methods used to treat the condition have evolved through the years.
The first aortic aneurysm grafts were created in the early 1950s, literally using a shirt tail that was sewn to make a graft and implanted into a patient. These days, grafts are now made of strong manmade material, such as plastics and fabrics, and shaped to the size of the healthy aorta, Elliott said.
In the traditional open surgery to repair an AAA, a large incision is made in the abdominal wall from just below the patient’s breastbone to the top of the pubic bone. The aortic graft is sewn to the healthy aortic tissue above and below the weakened area so that, when finished, it functions as a bridge for the blood flow.
The less invasive procedure began about 15 years ago. It involves doctors implanting a stint graft intravascularly through the groin arteries. The stint provides support for the wall and also helps retain an opening in the aortic passage. During the early days using this procedure, stints would not work in everyone, and they sometimes failed and had to be re-implanted. However stint procedures have improved during the past six years. Medical advances have made stint grafts possible in about 60 percent to 70 percent of patients, and the early mortality rate has been cut in half, Elliott said.
“But there’s a downside,” Elliott said. “We’ve got to follow those patients treated with Endovascular Aneurysm Repair (EVAR) closely. They can’t just be operated on and dismissed from the practice.”
These patients, as long as the graft remains in place, are at some small but increased risk of complications of this aortic aneurysm, including graft leakage, migration, or aneurysm rupture.
Elliott explained that monitoring these repaired aneurysms usually requires the patient to undergo two IV-contrast CT scans a year—for life. This is not only costly, but the intravenous dye required for the CT scans can be toxic to the kidneys in some patients. The microchip method substantially reduces the concern for these issues.
The Catalyst Online
June 23, 2006
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