This is according to an early-stage research trial involving UK and European patients and funded by the Medical Research Council (MRC).
The study, led by clinical researchers at Imperial College London and Imperial College Healthcare NHS Trust, is believed to be a world first for this non-invasive technique in TTTS.
TTTS
TTTS affects between 10% and 15% of identical twins that share a placenta, that’s between 300 and 400 pregnancies each year in the UK.
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.
First in-human study
Led by Professor Christoph Lees and published in the American Journal of Obstetrics and Gynaecology, this is the first in-human study of its type in early onset TTTS.
The procedure, involving 10 women from the UK and Europe, has been attempted in other related complications in identical twin pregnancies where the babies share a placenta.
While the researchers saw some early signs that this could be an effective treatment, they have not yet proved it could work clinically or that it could improve survival rates.
Current treatments
Currently, the best treatment for TTTS involves inserting a fetoscope, a small telescope like device, into the womb and amniotic fluid surrounding the twins.
Medics then use a laser to block blood flow in the shared blood vessels on the placenta’s surface.
While the procedure is often successful, because this procedure requires a small incision in the mother’s stomach, it can damage the amniotic sac causing the mother to miscarry.
Making a difference
Dr Adam Babbs, Associate Director of Translational Research at UKRI MRC, said:
Twin-to-twin transfusion syndrome is a life-threatening condition with very limited treatment options early in pregnancy.
This study provides important proof of concept that high intensity focused ultrasound (HIFU) could offer a non-invasive way to intervene earlier, with the potential to improve outcomes for affected babies.
Through the Developmental Pathway Funding Scheme (now MRC Proof of Concept), MRC supports researchers to de-risk innovative healthcare technologies and progress them towards patient benefit.
This project highlights the value of strong collaboration between academic researchers and industry partners and demonstrates how MRC investment is driving forward promising translational research with the potential to make a real difference to patients.”
Promising results
Professor Christoph Lees, head of fetal 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 to 100 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.
‘Doppler’ ultrasound
In this feasibility study, the team investigated whether non-invasive, ultrasound-guided HIFU is a viable and safe treatment between 12 and 17 weeks of pregnancy.
They used a type of ultrasound called Doppler to identify the tiny blood vessels in the placenta which connect the twins’ circulations, and which cause TTTS.
A beam of high energy sound waves, generated using a device outside the body, was then used to precisely heat the blood vessels and block blood flow through them.
This allows the blood flow between the two babies to become rebalanced.
Success rate
This new study found the procedure successfully blocked blood flow in 90% 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.
The treatment was received positively by women taking part.
Case study
Brioney Garrett, who lives in Cornwall, discovered she had advanced twin-to-twin transfusion syndrome at her 12 week scan in 2022.
After learning that laser treatment wouldn’t be an option, Brioney was referred to Queen Charlotte’s and Chelsea Hospital where she decided to take part in the HIFU research trial.
After successful treatment, she went on to give birth to her twin daughters Margo and Nancy later that year.
The twins are now almost four and are about to start primary school.
‘Much-needed hope’
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.
Researchers at the Institute of Cancer Research, London, University of Cambridge and the Centre of Trials Research at Cardiff University were also involved in the study.
Professor Lees and his team were awarded a £2.2 million grant by the MRC in 2017 to carry out this first in human trial of the ultrasound-guided HIFU technology.
Further research
As this study was not designed to test real world clinical efficacy, half of the women required further treatment, including laser ablation and sadly some babies did not survive.
The study could not confirm how effective the HIFU procedure was, but showed that HIFU could block blood flow in women with early onset twin-twin transfusion, without adverse side effects.
The team is now planning a larger study which will determine whether the procedure could ultimately reverse or improve TTTS, in the hope it could be offered routinely to patients.
Funding
Professor Lees and his team were awarded a £2.2 million grant by the MRC in 2017 to carry out this first in human trial of the ultrasound-guided HIFU technology.
The team has also received funding from The Wiseman Trust and Focused Ultrasound Foundation, with Canon Medical Systems acting as the the study’s commercial partner.
The team were also supported by patient support groups linked to the Twin-Twin Transfusion Foundation in the US, Multiple Births Foundation and Twins Trust in the UK.
Professor Lees is also supported by the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre, a translational research partnership between Imperial College Healthcare NHS Trust and Imperial College London.
Paper
‘Endothelial-erythrocyte glycocalyx exchange opens the door for ‘liquid biopsies’ of endothelial function’ by M Butler et al. in Nature Communications.
