New Sutureless Method for Joining Blood Vessels Developed by Scientists

Posted on Monday, August 29, 2011 by Unknown

Infant Blood Vessel Cross Section

For the past couple of decades medicine has advanced considerably with new techniques and methods being developed for nearly all areas of expertise in medicine thus increasing life expectancy. But one of the most commonly used practice of joining severed blood vessels have mostly remained the same way today- with sutures, as it was 100 years ago, when the French surgeon Alexis Carrel won a Nobel Prize for advancing the technique. Now, a team of researchers at the Stanford University School of Medicine has developed a sutureless method that appears to be a faster, safer and easier alternative.

In animal studies, a team led by Stanford microsurgeon Geoffrey Gurtner, MD, used a poloxamer gel and bioadhesive rather than a needle and thread to join together blood vessels, a procedure called "vascular anastomosis".

The problem with sutures as explained by Gurtner is that they are difficult to use on blood vessels less than 1 millimeter wide, which he faced when attempting to reattach the digit of a 10 month old infant in 2002

"We struggled with reattaching the digit because the blood vessels were so small — maybe half a millimeter. The surgery took more than five hours, and at the end we were only able to get in three sutures." told Gurtner "Everything turned out OK in that case," he continued. "But what struck me was how the whole paradigm of sewing with a needle and thread kind of falls apart at that level of smallness."

Sutures can lead to complications, such as intimal hyperplasia, in which cells respond to the trauma of the needle and thread by proliferating on the inside wall of the blood vessel, causing it to narrow at that point. Thus increasing the likely hood of production of blood clot which then may cause obstruction of blood flow. Sutures can also trigger an immune response causing inflammation and thus increased chances of a blockage.

So shortly after arriving at Stanford in 2005, Gurtner approached fellow faculty member Gerald Fuller, PhD, professor of chemical engineering and the Fletcher Jones II Professor in the School of Engineering, about whether they knew of a substance that could be turned easily from a liquid to a solid and back to a liquid again, and that would also be safe to use in vascular surgery. Fuller immediately suggested a FDA approved thermoreversible poloxamer called Poloxamer 407.

Fuller teamed up with Jayakumar Rajadas, PhD, director of the Stanford Biomaterials and Advanced Drug Delivery Laboratory, to modify the poloxamer so that it would become solid and elastic when heated above body temperature but dissolve harmlessly into the bloodstream when cooled. The poloxamer then was used to distend both openings of a severed blood vessel, allowing researchers to glue them together precisely.

In tests on animals, the technique was found to be five times faster than the traditional hand-sewn method, with considerably less inflammation and scarring after two years. The method even worked on extremely thin vessels only 0.2 mm wide.

Dermabond, a surgical sealant, was used to attach the ends of the blood vessels together.

Although further testing on large animals is required before human trials can begin, they note that all of the components used in the technique are already approved by the FDA.