An innovative experimental procedure which uses high energy soundwaves to treat a rare and serious condition in pregnancy called twin-twin transfusion syndrome (TTTS) is safe, according to an early-stage research trial involving UK and European patients.
In the first study of its kind, research led by Imperial College London and Imperial College Healthcare NHS Trust, and involving the Institute of Cancer Research, the Cardiff University Centre for Trials Research, the University of Cambridge, and the University Hospitals Leuven, investigated a non-invasive alternative to current treatments for twin‑twin transfusion syndrome.
Twin-twin transfusion syndrome affects between 10 and 15 per cent of identical twins that share a placenta. Blood flow between the babies is unbalanced, resulting in one twin receiving too much blood and the other receiving too little - this can harm both babies, even causing organ failure for both twins if left untreated. In the most serious cases, one or both babies can die.
The current treatment for TTTS involves inserting a small telescope-like device into the womb and amniotic fluid surrounding the twins before using a laser to block blood flow in the shared blood vessels on the placenta's surface. While the procedure is often successful, this procedure requires a small incision in the mother's stomach, it can risk damage the amniotic sac causing the mother to miscarry.
In this trial, researchers explored a new, non-invasive alternative using high-intensity focused ultrasound. This technique uses carefully targeted sound waves from outside the body to block the problematic blood vessels. This method aims to treat the condition without needing surgery, making it potentially safer for both the mother and the babies.
The study involved ten pregnant women with early-stage twin‑twin transfusion syndrome. Using ultrasound imaging, doctors first identified the blood vessels connecting the twins' circulations. They then used high-intensity focused ultrasound to target and attempt to close these vessels. The researchers focused on whether the treatment was safe and whether it was effective at closing the targeted vessels.
Professor Christoph Lees, head of foetal medicine at Imperial College Healthcare NHS Trust and professor of obstetrics at Imperial College London, said: "This is very promising research, confirming for the first time that this non-invasive procedure can be used safely in twin-twin transfusion syndrome. That's really encouraging, because at present we are only able to treat this condition by using a more invasive method which has its own risks.
"We hope to follow this study with a bigger clinical trial with 50 to100 women, so we can determine if it can successfully treat TTTS and understand whether this procedure could be a less risky and equally or more effective option for women and their twin babies."
This new study found the procedure successfully blocked blood flow in 90 per cent of the placental blood vessels treated. Those women taking part, and their unborn twins, experienced no adverse side effects and 18 out of 20 of the pregnancies were still healthy two weeks after treatment.
Our results were promising. About 90% of the targeted blood vessels were successfully blocked using high-intensity focused ultrasound. Also, importantly, we saw no significant side effects.
Brioney said: "It was such a tough time for us, being diagnosed with such an advanced form of TTTS. We had such limited options with laser treatment not possible and were facing the very real prospect of losing one of my babies. I feel so blessed that our consultant knew about the research trial and was able to put us in touch with the team at Queen Charlotte's and Chelsea Hospital. This gave us some much-needed hope and, with minimum risk, we jumped at the chance.
"The procedure itself took about 15 minutes, with a few follow-up scans over the next few weeks. It was such a relief to find out that the treatment had worked a couple of weeks later and that both twins were OK. There were a couple of wider complications in the pregnancy related to the syndrome itself. But otherwise the pregnancy progressed well. My daughters Margo and Nancy are thriving now and are about to start primary school."
I'm so grateful to the hospital team and to everyone involved in the research. They saved my girls' lives. It really means the world to me to have been part of the trial - not just for my family but for other women and babies who may be able to benefit from this in the future
While the study could not formally confirm how effective the HIFU procedure was, it showed that HIFU could successfully block blood flow in women with early onset twin-twin transfusion, without adverse side effects.
The study now needs to be expanded, to include a larger number of participants, to understand how effective this new technique could be in terms of a safe, non-invasive way to treat twin‑twin transfusion syndrome in the future.
The research, Ultrasound guided High Intensity Focused Ultrasound is technically feasible and safe in occluding placental vessels in early onset twin-twin transfusion syndrome , was published in the American Journal of Obstetrics and Gynecology
