Intracardiac septal defects are the most common congenital defects in the young. The gold standard treatment is suture-based surgical closure, requiring cardiopulmonary bypass, which can increase the risk of pump-related complications, such as brain injury from inadequate cerebral perfusion. Open surgery has been the standard approach for internal heart defects, however, minimally invasive therapy is a potentially safer alternative with less surgical time and faster recovery periods.
Now, researchers led by Harvard University have designed a UV-light enabled catheter which fixes holes in the heart without invasive surgery. The team states that the catheter has been utilised successfully in animal studies to facilitate hole closure without the need for open heart surgery. The opensource study is published in Science Translational Medicine.
Previous studies have shown the feasibility to adhere an elastic biodegradable patch and hydrophobic, light-activated adhesive to an intact septum for quick and effective, atraumatic defect closure in heart tissue and vessels. Successful attachment and similar cardiac output was shown as compared to a suture-based patch attachment at 3 months in a small animal model. Such a biodegradable occluder could act as a temporary scaffold to facilitate the ingrowth of fibrous connective tissue and endothelialization, whereas the patch and glue are gradually absorbed and replaced by native tissue. However, advancing the clinical translation of this approach requires the engineering of minimally invasive tools to deliver the adhesives with optional accompanying materials for closure reinforcement.
An earlier study from the team introduced an unique adhesive patch, representing a large step forward in the quest to reduce complications associated with heart defect repair. While medical devices that remain in the body may be jostled out of place or fail to cover the hole as the body grows, results showed that the patch allowed for heart tissue to create its own closure and then dissolves. The current study sought a way to deliver the patch without open heart surgery.
The current study used a newly designed catheter device which utilizes UV light technology and can be used to place the patch in a beating heart. The team explain that the catheter is inserted through a vein in the neck or groin and directed to the defect within the heart. They go on to add that once the catheter is in place the clinician opens two positioning balloons, one around the front end of the catheter passing through the hole, and one on the other side of the heart wall.
Results show that when the clinician deploys 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. The lab observed that as the glue cures, pressure from the positioning balloons on either side of the patch help secure it in place. The clinician deflates both balloons and withdraws the catheter. Data findings show that over time normal tissue growth resumes and heart tissue grows over the patch; the patch itself dissolves when it is no longer needed.
The group state that the device is designed to be customizable, adding that the rate at which the patch biodegrades can be slowed or accelerated depending on how quickly the surrounding tissue grows over it. The lab note that further studies will reveal the appropriate lengths of time for different circumstances, with Gecko Biomedical also testing the glue product in humans later this year.
The team surmise that this really is a completely new platform for closing wounds or holes anywhere in the body. They go on to conclude that the device is a minimally invasive way to deliver a patch and then activate it using UV light, all within a matter of five minutes and in an atraumatic way that doesn’t require a separate incision. For the future the team state that this will enable a wide range of cardiac procedures.
Source: Wyss Institute for Biologically Inspired Engineering at Harvard University
