Patients may soon have access to new scan to identify those with curable hypertension

The new procedure involves the 11C-Metomidate PET/CT scan, which is being used to identify small growths in a patient's glands and reveal if they are producing too much of the hormone aldosterone.
The new procedure involves the 11C-Metomidate PET/CT scan, which is being used to identify small growths in a patient's glands and reveal if they are producing too much of the hormone aldosterone.ST PHOTO: KELVIN CHNG

SINGAPORE - While some patients with hypertension in the past have had to endure an invasive and difficult procedure to assess if they have a curable form of the disease, a new non-invasive procedure may provide not only relief but more accurate results.

The new procedure involves the 11C-Metomidate PET/CT scan, which is being used to identify small growths in a patient's glands and reveal if they are producing too much of the hormone aldosterone, which results in excess salt in the body, causing hypertension.

PET refers to the positron emission tomography imaging test, which uses radioactive tracers contained in a special dye, while CT refers to the X-ray computed tomography scanner, which produces a series of images of the body.

The new procedure is currently undergoing clinical trials at the Clinical Imaging Research Centre at the National University of Singapore's (NUS) Yong Loo Lin School of Medicine.

The researchers behind the trials - Professor Roger Foo of NUS and Adjunct Assistant Professor Troy Puar, who is with the Changi General Hospital - announced this on Friday (Sept 6).

One quarter of those aged 25 and above here have hypertension, which if left untreated, can lead to heart and kidney disease and stroke.

While most patients with hypertension have no underlying curable cause for their condition, about 5 per cent here have a potentially curable form called primary aldosteronism.


Deputy Prime Minister and Minister for Finance Heng Swee Keat at the NUHS Innovation Summit 2019 on Sept 6, 2019. ST PHOTO: KELVIN CHNG

In patients with this condition, two small glands above the kidneys, known as adrenal glands, produce too much of the hormone aldosterone.

In half of such patients, tiny growths occur in only one of the glands. Keyhole surgery to remove that abnormal gland can increase the chances of curing the patient's condition.

Currently, patients with such growths, who also have high hormone levels, are identified using an invasive procedure called adrenal vein sampling (AVS).

It involves the insertion of metal catheters into the patient's groin to reach the veins and draw blood samples. It is a difficult process that produces inconclusive results in half of the patients, and requires them to stay overnight in the hospital.

Dr Puar said with the scan, a patient is injected with a radioactive tracer and during the procedure, abnormal hormone production will be highlighted.

The scan can also identify small growths in a patient's glands and show if they are producing too much aldosterone - all in less than an hour, without the need for hospitalisation.

Hypertension patient Lim In Chong, 43, who has undergone both procedures, said: "The scan is a lot better, simple, non-invasive and quick."

In his case, the AVS procedure he had in July produced inconclusive results. Mr Lim, who was diagnosed with the disease while in his 20s, was told he was eligible to be a patient under the clinical trial.

He then went for the scan later that month, which confirmed that one of his glands was overproducing aldosterone. This was validated by a second AVS procedure in August.

Mr Lim intends to go for keyhole surgery before the end of the year. However, even if the surgery is successful, Mr Lim may still not be completely free from his condition.

Dr Puar said: "Some patients have had high blood pressure for many years... there is so much damage to the blood vessels that this cannot be completely reversed... but at least they can take the same medication with much lower blood pressure, or have the same blood pressure with much less medication."

 The technique was developed in Sweden, but Singapore is the first country in Asia with facilities that are able to carry out the scan.

Dr Puar said that only two other centres - in the United Kingdom and Finland - currently use the technique.

The trial in Singapore will need to undergo a larger patient cohort validation before being ready for clinical use here.

Currently, 24 patients have undergone the new procedure.

Prof Foo said the scan can be done in Singapore partly because of the capabilities of the medical experts and infrastructure here.

"It's not a small process, not a simple process."

The announcement was made on the sidelines of the inaugural National University Health System Innovation Summit.

At the event, Deputy Prime Minister and Minister for Finance Heng Swee Keat announced the establishment of a new mentorship programme - the Brenner Fellowship.

Established by NUS, the programme is named after molecular biologist Dr Sydney Brenner, widely regarded as the "father of biomedical sciences in Singapore".

Dr Brenner, who died earlier this year at the age of 92, came to Singapore in 1983 to advise the Republic on the development of its biotechnology sector.

Over the next few decades, he helped Singapore establish its key research and development institutions, and developed its education and research efforts in the life sciences.

The fellowship aims to nurture and support talented Singapore-based undergraduates who are keen to pursue research in biomedical sciences, by giving them opportunities to travel overseas to work under the mentorship of leading scientists.

Calling Dr Brenner "an old friend of Singapore", Mr Heng, who is also chairman of the National Research Foundation, said: "(The programme) will allow our Fellows to learn from the best, and build a network of relationships around the world."