Minimally invasive tool uses light for beating-heart repairs

Last year, cardiologists at Boston Children’s Hospital reported developing a groundbreaking adhesive patch for sealing holes in the heart. The patch guides the heart’s own tissue to grow over it, forming an organic bridge. Once the hole is sealed, the biodegradable patch dissolves, leaving no foreign material in the body.

As revolutionary as this device was, it still had one major drawback: implanting the patch required highly invasive open-heart surgery. But that may be about to change.

Researchers from the Wyss Institute, Brigham and Women’s Hospital, Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS) and Boston Children’s have jointly designed a radically different way to implant the patch without having to stop the heart, place patients on bypass or cut open their chests.

They created a flexible, UV light-guided catheter that can be inserted through a vein in the rib cage, and from there directed to the defect within the beating heart. Two positioning balloons, one on either side of the hole, open when the catheter is fully in place. One of the balloon’s surfaces has a mirror-reflecting quality that reveals areas of the heart that would otherwise be difficult to see without more invasive tactics.

After releasing the patch, the surgeon turns on the catheter’s UV light, which activates the patch’s adhesive coating. The two balloons are then deflated and withdrawn.

The new catheter/patch combo has been successfully used to close ventricular septal defects in animals both large and small. In the September 23rd issue of Science Translational Medicine, the research team reported successful patch placement in a live pig model—a major step towards demonstrating that the tool may work on a beating human heart without requiring bypass and open-heart surgery.

The Wyss Institute’s Ellen Roche, PhD, co-first author on the paper, explains that the animal studies were “proof of concept.” “We are looking forward to more animal studies that focus on a particular application,” she says.

Pedro del Nido, MD, chief of Cardiac Surgery at Boston Children’s, says the device would radically change how these kinds of cardiac defects are repaired. “In addition to avoiding open-heart surgery, this method also avoids suturing into the heart tissue, because we’re just attaching something to it,” he says.

Roche adds that the device was designed to be customizable. For instance, the rate at which the patch biodegrades within the body can be slowed or accelerated depending on how quickly the tissue around it grows. Further studies will reveal the appropriate length of time for different circumstances.

The glue’s unique ability to cure on cue—it only becomes sticky once the UV light is turned on—opens up a wide range of possible uses. “There are more applications than correcting heart defects,” says Roche. “The patch and the catheter can be used in a variety of situations, such as abdominal hernia repair or peptic ulcer closure.”

Learn more about Cardiac Surgery Research and Innovation at Boston Children’s Hospital.