A poloxamer gel paired with a bioadhesive can be used to reconnect blood vessels during vascular surgery without the complications associated with needle-and-thread sutures, which have been used for the past 100 years. This advance is five times faster than sewing and works on blood vessels with diameters as small as 0.2 millimeters, according Stanford University Medical Center researchers.
“Numerous alternatives to sutures have been proposed, but none has proven superior,” the researchers write in their study published in Nature Medicine. “This new technology has potential for improving efficiency and outcomes in the surgical treatment of cardiovascular disease.”
Rebecca Boyle reports for Popular Science that one of the researchers was inspired to work on this problem a decade ago after he has reattached the severed finger of a year-old infant during a five-hour surgery. The blood vessels in a baby’s finger measure approximately 0.5 millimeters. The microsurgeon thought about a way to fill the lumen, the inner space of a blood vessel, so the ends would stay open at full diameter long enough to glue them together. Originally, he thought about using ice, but its properties weren’t practical.
Boyle explains that the microsurgeon later approached an engineering professor “about using some kind of biocompatible phase change material, which could easily turn from a liquid to a solid and back again.” The engineering professor knew about Poloxamer 407, a thermo-reversible polymer that was already approved by the Food and Drug Administration (FDA) for medical use.
Poloxamers have been used to deliver drugs, including chemotherapeutics, vaccines, and anti-viral therapies, and had been tested in “beating heart” surgeries. After teaming with materials scientists, they modified the poloxamer to become “solid and elastic when heated warmer than body temperature, and [to] dissolve into the bloodstream at body temperature,” Boyle writes.
The researchers have tested their technique on rat aortas. They heated the poloxamer gel with a halogen lamp, and used the gel to fill up the lumen. To glue the blood vessels back together, they used an available bioadhesive. Their results showed reduced inflammation and scarring two years later.
The researchers say in a press release from Stanford University Medical Center that further testing on large animals is needed before human trials can begin, but they note that all of the components used in the technique are already approved by the FDA, and suggest that “the technique has the potential to progress rapidly from the ‘bench to bedside’.”
Source: “New Phase-Changing Gel Method Repairs Severed Blood Vessels Better than Stitches,” Popular Science, 8/29/11
Source: “Stanford researchers invent sutureless method for joining blood vessels,” Stanford University Medical Center press release, 8/28/11
Source: “Vascular anastomosis using controlled phase transitions in poloxamer gels,” Nature Medicine, 8/28/11
Image by isafmedia, used under its Creative Commons license.
Rachel Petkewich is a freelance science writer and editor. She has worked as a research scientist in the chemical industry and spent eight years as a staff writer and editor at various science journals and magazines, including Chemical & Engineering News.