Use of the MemoSorb bioresorbable PFO device in an 11-year-old diver with phospholamban mutation and family hypertrophic cardiomyopathy
This case report describes the successful implantation of a bioresorbable Memosorb PFO device in an 11-year-old diver with a phospholamban mutation to enable future transseptal interventions, despite transient conduction abnormalities that were managed medically.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Deep beneath the ocean's surface, where pressure shifts with every meter, the human body faces a unique challenge. For divers, a small, usually harmless opening in the heart can become a dangerous gateway. This opening, called a patent foramen ovale, is a tiny tunnel between the upper chambers of the heart that fails to close after birth. In most people, it causes no trouble. But for a diver, bubbles of nitrogen that form in the blood during a rapid ascent can slip through this tunnel, bypassing the lungs' natural filter and traveling directly to the brain or other organs. This can lead to a painful and potentially life-threatening condition known as decompression sickness. While doctors often treat this by closing the hole with a permanent metal mesh, that solution carries its own risks, especially for children who might need different heart procedures decades from now. The question then becomes: is there a way to seal the hole temporarily, protecting the diver now without leaving a permanent metal scar that could complicate future care?
A team of doctors at Evelina London Children's Healthcare and Royal Brompton & Harefield NHS Hospital recently explored this question with an eleven-year-old boy who dreamed of becoming a marine biologist. The boy was healthy and active, but he carried a specific genetic mutation that put him at high risk of developing a thickening of the heart muscle later in life. Because of this genetic risk, the doctors wanted to avoid leaving any permanent metal inside his heart, as that could make future, necessary procedures more difficult. At the same time, his passion for diving made the patent foramen ovale a serious concern. The medical team decided to attempt a primary prevention strategy: closing the hole before any diving accident occurred, using a new type of device that would dissolve over time.
The procedure involved guiding a small, biodegradable patch through a vein in the leg and into the heart to seal the tunnel. The device, made from materials similar to dissolving surgical stitches, was designed to hold the hole shut while the body's own tissue grew over it, eventually leaving no foreign material behind. The first attempt used a thirty-four millimeter device, but it proved too large. It pressed against the heart's electrical system, causing the boy's heart rhythm to drop to a complete block momentarily, and it also pushed against a nearby valve. The doctors quickly removed this oversized patch, and the heart rhythm returned to a first-degree block, though it remained slightly sluggish. They then selected a smaller, twenty-eight millimeter device. This second attempt was successful; the patch was released and held the hole securely without pressing on the heart's electrical pathways.
The recovery process required careful monitoring. In the days following the procedure, the boy experienced intermittent pauses in his heart's electrical signals, a side effect of the initial pressure on the heart tissue. Doctors treated this with oral steroids, and within a few days, his heart rhythm stabilized completely. Over the next six months, follow-up tests confirmed that the device was sitting perfectly and that no blood was leaking through the hole. A bubble test, which checks for leaks by watching for tiny bubbles in the heart after an injection, came back negative. This result meant the seal was tight, and the boy was cleared to return to diving. The doctors plan to repeat this test in eighteen to twenty-four months, after the device has fully dissolved, to ensure the hole remains closed by the body's own tissue.
This case represents a rare and cautious application of a new technology. The doctors acknowledge that using this dissolving device for a child who has never had a diving accident is an off-label use, meaning it is not the standard, approved method for this specific situation. The decision was made only after a thorough discussion with the boy and his family, weighing the desire to protect his future career against the lack of long-term data on how these devices perform over many years. While the procedure was successful in this single instance, the authors emphasize that more studies are needed to confirm that these devices are safe and effective for everyone. The boy's story shows that it is possible to use a biodegradable patch to solve a complex problem, but it also highlights the importance of having a wide range of sizes available during surgery and the need for precise imaging to avoid complications. For now, the device has done its job, allowing a young diver to pursue his dreams while keeping his heart free of permanent metal.
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