New minimally invasive procedure for torn aorta repair

Dec 13 2007

Tears in the aorta which affect thousands of people each year coast to coast, may soon be treated with a much less invasive technique that could dramatically improve patients' chances of survival.

A national study being directed by a vascular surgeon at Thomas Jefferson University Hospital is exploring a new minimally invasive method that could spare patients the trauma and risk of open chest surgery.

Joseph V. Lombardi, M.D., Director of the Jefferson Aortic Center (www.jeffersonhosptal.org/aortic) is the National Principal Investigator (PI) in the U.S. Food and Drug Administration--approved clinical study assessing the safety and effectiveness of an endovascular stent-graft to treat aortic dissection, a condition that led to the sudden death of actor John Ritter.

“This pathology specific endovascular device has the potential to eliminate the need for highly invasive, open chest surgery to repair one of the most deadly aortic diseases in the U.S.,” said Dr. Lombardi, assistant professor of Surgery, Jefferson Medical College of Thomas Jefferson University. “In Philadelphia alone, up to 60 patients per year are treated for aortic dissection with emergency procedures, which have numerous risks, high mortalities and long recovery periods. This device could help limit our need for invasive procedures and save many lives.”

According to the American Heart Association, aortic dissection affects up to 10,000 people annually in the United States. Though the disease is rare among the country's population, its mortality rate is high, creating a need for new and innovative treatments.

Aortic dissection is a laceration of the aorta, the largest artery in the body and the primary transporter of blood away from the heart. A tear in this artery causes blood to flow between the layers of its wall, eventually splitting the layers apart. Blood then collects in these new channels, compressing blood vessels that feed vital organs. It is an extremely serious medical condition that can quickly result in death.

Dr. Lombardi is also responsible for a parallel clinical trial including eight European and two Australian sites. As the global principal investigator, Dr. Lombardi's role is to oversee all clinical aspects of both trials and making any necessary adjustments as it moves forward. He will continuously update the national and international medical community on the trial's progress and will prepare the results for submission to the FDA. Robert Larson, M.D., assistant professor of Surgery, Jefferson Medical College of Thomas Jefferson University, will be serving as the Site PI for Jefferson University Hospital. A multidisciplinary team of physicians, cardiothoracic surgeons, cardiologists and anesthesiologists will all be involved with Drs. Lombardi and Larson.

Aortic dissection can be treated in the emergency room or intensive care unit with medications to lower blood pressure and heart rate. In some cases, surgery is needed. Now, rather than opening the chest cavity and clamping off the aorta to implant a graft to treat the damaged section, physicians will insert a catheter loaded with a self-expanding, fabric-covered stent-graft through a small incision in the femoral artery. The catheter is guided through the patient's blood vessels under fluoroscopy (a technique for obtaining “live” x-ray images) until the device is positioned across the diseased or injured part of the aorta. The stent-graft expands upon deployment from the catheter to form a continuous tube through the aorta that carries the blood and reduces pressure on the damaged vessel, restoring normal blood flow. The second stent is placed to re-expand the compressed blood vessel and restore flow to all of the vital organs below.

By using less invasive techniques, surgeons reduce the health risks for their patients, especially for many older individuals who might suffer from other significant medical conditions such as diabetes or hypertension. Thoracic aortic dissection can occur in anyone, but is most often seen in men 40 to 70 years of age. The exact cause is unknown, but risks include high blood pressure, smoking, atherosclerosis (hardening of the arteries), trauma and Marfan's syndrome. Symptoms comprise sudden, severe chest pain, dizziness, decreased sensation in any location, profuse sweating and shortness of breath.

Any patient with aortic dissection may be a candidate for this trial, though certain factors will be taken into account, including whether the individual was treated with medical therapy; whether the patient has organ failure from lack of blood flow to these organs; and whether the patient has a rapidly expanding aorta (aneurysm).

The combination endovascular device has already been studied in Australia with some evidence of effectiveness. It restored blood flow to both legs and the left kidney of a 50-year-old patient admitted to Monash Medical Centre in Melbourne with crushing chest pain, saving both limbs and the organ.