Minimally invasive tool uses light-activated patch for beating-heart repairs

Last year, cardiac surgeons at Boston Children’s Hospital reported developing a groundbreaking adhesive patch for sealing holes in the heart. The patch, which is biodegradable, dissolves once heart tissue has naturally grown over it to form an organic bridge. No foreign material remains in the body.

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

Researchers from the Wyss InstituteBrigham and Women’s Hospital and Boston Children’s Hospital have jointly designed a specialized catheter that can implant the patch while the heart is still beating. This method has the potential to eliminate the need for open heart surgery for certain defects.

How it works

The catheter is inserted through a vein in the rib cage and directed to the defect within the beating heart. Once it’s in place, two positioning balloons open up: one around the front end of the catheter, poking through the hole, and one on the other side of the heart wall.

The operator then releases the patch and turns on the catheter’s UV light. The light reflects off of the balloon’s shiny interior and activates the patch’s adhesive coating. As the glue cures, pressure from the positioning balloons on either side of the patch help secure it in place.

Finally, both balloons are deflated and the catheter is withdrawn. Over time, normal tissue growth resumes and heart tissue grows over the patch. When it is no longer needed, the patch itself dissolves.

Animal studies and looking ahead

The new catheter/patch combo has successfully closed tissue and heart 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 to correct a ventricular septal defect — the most common congenital heart defect.  This was 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, joint first author on the paper with Assunta Fabozzo, MD, 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 represents a radical change in the way 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.”

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

The glue’s unique ability to cure on cue — it only adheres when 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.”