A novel treatment developed by UCSF vascular surgeons has been used in a first-of-its-kind operation to repair a life-threatening aneurysm in the patient’s aortic arch, which carries blood from the heart.
In an aortic aneurysm the walls of the aorta, the primary blood vessels leading away from the heart, bulge out like a filling water balloon. Eventually it bursts, usually causing a fatal bleeding episode.
Using a wire-thin catheter, the UCSF team inserted a specially designed graft through the right carotid artery on the side of the neck. The graft, a fabric tube that incorporates metallic threads (to offer structural support), was then guided into the arched part of the aorta, which carries blood to the head and body from the heart. Once in place, this specially designed structure, also called a stentgraft, expanded to reinforce and reline the interior walls of the arch.
“While stentgrafts are now commonly used to treat aneurysms of the aorta within the abdomen, using stentgrafts to treat aneurysms of the aortic arch has presented special problems because of its large size, curved shape and its critical branches that supply blood flow to the brain,” said Darren Schneider, MD, a vascular surgeon at UCSF Medical Center and lead author of a paper which appears in the October issue of the Journal of Vascular Surgery.
“In particular, we had to develop a device capable of repairing the aorta without hampering the blood flow through blood vessels that branch out from the aortic arch to supply blood to the brain and arms.” The aortic arch repair represents the first time a U.S. patient’s entire aortic arch has been successfully repaired using a minimally invasive branched stentgraft technique. A surgeon from Japan first reported an endovascular stentgraft repair of the entire aortic arch in 1999 using a complex technique that has not been replicated, according to Schneider.
In the UCSF procedure, the team—led by Tim Chuter, MD, associate professor of surgery and Schneider, MD, assistant professor of surgery and radiology—created a stentgraft that included a main tube and a branch that extended into the innominate artery, one of three main arteries that branch off the aortic arch. The innominate artery directs blood flow to the right side of the brain and the right arm. Once the stentgraft was placed, surgeons completed a bypass to restore blood flow to areas supplied by the two additional arteries that branch off the aortic arch - the left carotid artery and the left subclavian artery. The left carotid supplies blood to the left side of the brain. The left subclavian supplies blood to the right arm.
Related experimental branched stentgraft devices previously have been used at UCSF Medical Center to repair aneurysms in the aorta (those lower in the chest and abdomen). Chuter completed the first catheter-delivered branched stentgraft for abdominal aneurysms in 2000. Since then, Chuter and his colleagues have completed eight such aneurysm repairs.
Chuter has long been at the cutting edge of design and placement of these aortic stentgrafts. He designed, built and used the first Y-shaped, or bifurcated stentgraft, which spans part of the main aorta and extends into the main arteries supplying each leg. Today, many stentgrafts are modeled on this Y-shaped graft and are used to treat abdominal aortic aneurysms.
Other investigational stentgrafts contain fenestrations (or holes) to accommodate arteries that lead from the aorta to the kidneys - a development pioneered by vascular surgeons in Australia. Chuter and Schneider have also used fenestrated stengrafts at UCSF to treat aortic aneurysms that involve the portion of the aorta next to the kidney arteries.
Chuter has an investigational device exception from the FDA that enables him to used non-approved devices to treat increasingly complex aortic aneurysms that cannot be treated with commercially available stentgrafts. Many of these aneurysms involve parts of the aorta that have branches to critical body organs.
Because of severe heart and lung disease, the patient presented in this paper was not a candidate for a traditional open aortic arch repair. In the traditional repair, the sternum is opened and the patient is placed on a bypass machine. Surgeons remove the abnormal part of the arch and replace it with a graft. Because these patients undergo a procedure involving a large chest incision, heart-lung bypass, circulatory arrest and body cooling, serious complications and death are not uncommon, according to Schneider.
The endovascular stentgraft technique minimizes these complications. In addition to a lower risk of death or complications, the stentgraft patient spent only three to four days in the hospital, compared to seven or more days for traditional graft surgery, he said.
Schneider is the first graduate of an integrated fellowship program in vascular surgery and interventional radiology being pioneered at UCSF Medical Center. The fellowship offers a year-long accredited fellowship in interventional radiology. This is followed by an additional year-long fellowship in vascular surgery.
“As more and more vascular surgery procedures are performed with minimally invasive radiological techniques, it’s critical to integrate training in both disciplines,” said Schneider.
UCSF’s vascular surgery program continues to be a national leader in stentgraft aneurysm repair. Chuter has performed more than 500 stentgraft procedures at UCSF Medical Center since 1996.
Aortic aneurysms are now the tenth leading cause of death among American men and the thirteenth leading cause of death in women. It is unclear why aneurysms are becoming more common, even what causes them, although diet and genetics are likely contributing factors, according to Schneider.
The UCSF Pacific Vascular Research Laboratory - funded by the Pacific Research Foundation and the Wayne and Gladys Valley Foundations - represents a collaboration between scientists and physicians working to answer those questions and generate and transfer knowledge about vascular diseases into safer and more effective treatments.