The humble plastic bag is fast becoming indispensable to heart patients - for it helps them to pull on tight compression stockings, which they are required to wear after surgery.

Slipping a plastic bag over the foot helps the stocking to "glide" on easily - an improvisation that has helped 70 per cent of patients wear their stockings daily.

The plastic bag can be removed through a hole at the base of each stocking.

Everyone who has had open heart surgery has to wear anti-embolic compression stockings all day for four to six weeks. They help to improve blood circulation in the legs during a heart patient's convalescence.

But only 17 per cent stuck to the tedious routine after they returned home, according to a study done last year by the National Heart Centre Singapore (NHCS).

Its senior nurse manager, Ms Lee Chin Hian, said the sole of the foot tends to be dry, resulting in friction that can be uncomfortable for some patients when they wear the stockings.

"Their toes tend to get stuck in the stocking. It is also difficult for some patients to bend over because of their surgery wounds."

The plastic bag idea came about last April, when health-care staff at NHCS sought to find a way to ease the patients' leg discomfort.

A seven-man team, comprising mainly nurses, tried several ways such as using creams and powder before deciding on the plastic bag. They taught the method to hospitalised patients and their caregivers over a five-month pilot study last year.

The introduction of the method has resulted in more heart patients who were willing to wear the stockings, with seven in 10 of them now going through the routine daily.

Since last May, some 1,000 patients have been taught by NHCS staff to use plastic bags to wear compression stockings.

And the process now takes an average of four minutes, down from 10 minutes previously. The project won a regional innovation award earlier in July.

Former chauffeur Mohamed Ismail Bin Aziz, 65, said he and his wife found the method easy to learn.

He had a heart bypass operation two weeks ago at Singapore General Hospital, after suffering from chest pain.

"Once you get the hang of it, there are no difficulties," he said, adding that patients do not incur extra costs from using it.

"I think it is a good idea to introduce this to everyone."

Ms Lee said that any clean plastic bag that covers the foot, up to the ankles, will be suitable.

Cardiothoracic surgeon Loh Yee Jim said failure to wear compression stockings, as advised by doctors, can lead to a higher risk of deadly blood clots.

This includes deep vein thrombosis, where blood pools in the legs and forms a clot in the veins. Death can result when the clot dislodges and travels to the lungs.

"The stockings promote circulation in the legs by using pressure to push blood along," said Dr Loh, a visiting consultant at NHCS.

Meanwhile, Mr Mohamed Ismail found another advantage in the routine.

"With the stockings on, the cold air from the air-conditioner cannot penetrate my legs, so it helps me to stay warm," he said.