Georgia Tech Researchers Developing Biomechanic Device To Grow Arteries for Bypass Surgery Patients

Biomedical engineers at the Georgia Institute of Technology (Georgia Tech) are testing a device that, when implanted, mechanically lengthens an existing artery in patients preparing for coronary artery bypass surgery (CABG). The lengthened artery, when harvested and used as a graft, has the potential to greatly improve the long-term outcomes of bypass patients.

Designed to stimulate growth in the gastroepiploic artery – a small, disease-free artery about 3-7 mm diameters in size and located below the stomach – the device has shown to be effective in lengthening arterial tissue in pigs by as much as 30 cm – enough for a patient to undergo at least two CABG procedures, researchers say.

The patented process has been coined “distraction angiogenesis” by lead scientist Ray Vito, a professor at Georgia Tech who holds dual appointments in the Woodruff School of Mechanical Engineering and the Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.

Vito is president and CEO of Medanoia Medical Inc., a company he formed in February 2001, along with Jack Griffis, COO, to develop, manufacture and market the device. The process is similar to distraction osteogenesis – a process that has been used clinically since the 1950’s to lengthen bones, especially in the legs and face.

“The long-term outcome of coronary bypass surgery is critically dependent on the graft that is used,” Vito said. “The consensus among surgeons and cardiologists is that arterial grafts are preferable to venous grafts (veins) because they stay open much longer. However, the human body has a very limited supply of arterial tissue that can be harvested without consequence to the patient. Distraction angiogenesis increases the supply of arterial tissue suitable for use as grafts.”

Coronary artery bypass surgery is among the most common operations performed in the world to bypass a blockage. Clogged arteries are often caused by a buildup of fat, plaque or cholesterol. According to American Heart Association statistics, 336,000 people underwent coronary artery bypass surgery in the United States in 1998.

Traditionally the surgery requires opening the chest and taking blood vessels from either the calf (saphenous vein) or chest (internal mammary artery) and detouring them around, or “bypassing,” the clogged arteries to improve the supply of blood and oxygen to the heart.

However, many patients cannot use either because the tissue is unsuitable for grafting or it has already been harvesting for a previous surgery. Up to 35 percent of patients lack saphenous veins or other suitable conduits. These types of patients are the ones being targeted for the new device, Vito said.

The device, when fully developed, is intended for endoscopic implantation about 30 days prior to a patient’s bypass surgery. After it is implanted, the device is autonomous and continuously distends the gastroepiploic artery, gradually increasing its length. Distraction angiogenesis uses mechanical forces to stimulate the body’s own adaptive processes to produce additional artery.

The engineered artery and device are harvested endoscopically at the time of CABG surgery. The residual artery may be surgically repaired by an end-to-end anastamosis (joining) so that normal blood flow is restored.

“The evidence supporting the superiority of arteries as conduits for CABG procedures is overwhelming,” Vito said. “Distraction angiogenesis is a relatively simple way of increasing the supply of autologous arterial tissue without compromising the perfusion of healthy tissue. An all arterial revascularization is cost effective and could dramatically reduce the need for further treatment.”

Vito and Griffis plan to continue testing and improving the device during the next year, followed by clinical trials. The team hopes to receive FDA approval and bring the product to market within five years or less.

The work recently caught the attention of the Wallace H. Coulter Foundation, which will award Vito with the 2002 Coulter Award for Innovation and Entrepreneurship on Nov. 1. The award recognizes a technical achievement likely to have a significant impact on healthcare delivery and comes with a $100,000 grant to assist his company in bringing the technology to market.

The Georgia Institute of Technology is one of the world's premier research universities. Ranked seventh among U.S. News & World Report's top public universities and the eighth best engineering and information technology university in the world by Shanghai Jiao Tong University's Academic Ranking of World Universities, Georgia Tech’s more than 20,000 students are enrolled in its Colleges of Architecture, Computing, Engineering, Liberal Arts, Management and Sciences. Tech is among the nation's top producers of women and minority engineers. The Institute offers research opportunities to both undergraduate and graduate students and is home to more than 100 interdisciplinary units plus the Georgia Tech Research Institute.