Doctors at Singapore General Hospital carrying out the non-surgical procedure on a patient. PHOTO: SINGAPORE GENERAL HOSPITAL
SINGAPORE - Patients with end-stage kidney failure may soon no longer have to undergo surgery before beginning dialysis, thanks to a new procedure being piloted by Singapore General Hospital (SGH).
Associate Professor Tan Chieh Suai, head and senior consultant at SGH's department of renal medicine, announced this on Tuesday (June 28) and said that in 2020, 7,125 such patients - about three in four - chose to go for a form of dialysis known as haemodialysis, up from 4,270 in 2011.
Haemodialysis involves using a dialysis machine and an artificial kidney to clean the blood of kidney patients.
In order for the blood to be extracted from patients, however, an access point needs to be created in their body.
Prof Tan said the best way of doing this is through the creation of what is known as an arteriovenous fistula (AVF), which involves joining a vein and an artery together and causing blood from the artery to flow through the vein.
This increases blood flow in the vein, allowing blood to be extracted from it, explained Professor Tay Kiang Hiong, head and senior consultant at SGH's department of vascular and interventional radiology, who was also at Tuesday's media briefing.
Traditionally, an AVF would have to be created through a surgical procedure on the patient's arm.
However, about 80 per cent of patients with end-stage kidney failure here choose to put off such procedures for various reasons, including fear of surgery, being unable to accept their diagnosis, and worry about the scars left behind by the procedure, said Prof Tan.
This results in many of them having to be admitted for emergency dialysis using a catheter.
But this increases the risk of patients getting infected, as well as internal bleeding, said Prof Tan, adding that eventually, an AVF has to be created anyway in these patients.
The method piloted by SGH is much less invasive. Known as endovascular AVF (endoAVF), the non-surgical procedure can be done in either of two ways.
A needle is inserted in the vein under the skin and guided into an artery using ultrasound. A specially designed catheter with a clip is later inserted to link the vein and artery.
Alternatively, needles are inserted into the vein and artery, allowing two catheters - both of which have magnets attached - to be inserted as well.
The magnets will be attracted to each other, pulling the artery and vein together. An electrical current is then passed through the catheters, burning a hole between the artery and vein.
The method used depends on several factors, including the size of the patient's veins.
Prof Tan said overseas studies have shown that the endoAVF has a high success rate of 90 per cent, compared with the 78 per cent success rate of the traditional method used so far in Singapore.
It is faster, taking around 15 minutes at best, as compared with 45 to 90 minutes when done the traditional way. EndoAVF also leaves no scars, whereas the traditional method typically leaves scars of between 3cm and 10cm on patients' arms.
Also, while patients getting an AVF through surgery require up to three procedures of balloon angioplasty a year to maintain their AVFs, those who undergo endoAVF need to do this only once every two years.
Associate Professor Chong Tze Tec, head and senior consultant at SGH's department of vascular surgery, said that because the traditional method involves moving veins around, the surrounding tissues will be disrupted, resulting in the vein which blood is extracted from becoming narrower as well. The endoAVF method does not cause this problem.
Prof Tan said that a previous pilot programme launched by SGH in October 2021 with 13 patients had already produced encouraging results, with a 90 per cent success rate.
Speaking to the media at the briefing, one of the patients from the pilot, 70-year-old Choong Yit Lin, said he had initially been reluctant to go for surgery to create an AVF, as he was concerned about the risks.
Mr Choong, who works in the construction industry, said in Mandarin that despite developing severe headaches in July last year due to end-stage kidney failure, he put off any procedure until November that year, when his condition worsened and he had to use a catheter for emergency dialysis. At that point, he had no choice but to opt for a procedure to create an AVF.
He was found to be suitable for endoAVF and underwent the procedure in December.
"I feel better every day," he said, adding that he is glad he underwent endoAVF after he noticed the scars on other patients who went for the traditional procedure.
By the end of the year, SGH will launch a three-year pilot programme to offer endoAVF to 200 eligible patients from SGH, Changi General Hospital, Sengkang General Hospital and National University Hospital.
Prof Tay said: "Rather than just keeping (the procedure) to ourselves, we're involving more hospitals because we see that the potential benefits are tremendous. But we have to prove it first."
Prof Chong said the suitability of a patient for endoAVF depends on many technical considerations, including the position of their veins and arteries, as well as the size of their veins.
But he added that he hoped the pilot would allow doctors to adjust the procedure so it could be offered to more patients in the future.
Prof Tan said SGH is partnering community dialysis service providers such as the National Kidney Foundation and Fresenius Medical Care Singapore so that nurses can be trained to conduct dialysis on patients who have undergone the new procedure as well.
"The aim of all this is to shift care from the tertiary institutions to the community by reducing the need for these patients to come to the hospital. We do this by creating (AVF) that have high success rates and low maintenance rates. Overall, the whole country will benefit from lower healthcare costs," he said.
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