A 73-year old man had shortness of breath and severe cramps and pain in both legs whenever he walked. They would go away if he rested for a while.

He was examined for possible heart ailment since he had undergone coronary bypass surgery in 1995. But doctors found his heart was doing fine.

So, they decided to conduct peripheral intravascular ultrasound to check the condition of the arteries of his legs.

The man had an angioplasty in the legs in 2014 to gets stents implanted because of blocked arteries.

A specialised catheter with a camera at its tip was inserted through his left arm to capture the inside images of the vessels. Doctors found that significant fatty deposits along the entire length of the arteries had led to reduced blood flow - a condition known as peripheral arterial disease (PAD).

"About 20 to 30 per cent of cardiac patients suffer from peripheral arterial disease," said Rabin Chakraborty, director, Institute of Cardiac Sciences, Apollo Gleneagles Hospitals.

Chakraborty, who treated the 73-year-old, inserted a medicated balloon through the catheter, which restored the blood flow in the man's legs to normal levels.

Peripheral arterial disease occurs in the arteries that carry blood to the arms and legs.

A doctor said the peripheral arteries get narrow or blocked when plaque builds up inside the artery walls, similar to what happens with the coronary arteries. Since it reduces the blood flow, it can cause tissue death.

Plaque is made of excessive fat, cholesterol and other substances floating through the bloodstream.

"If left untreated, PAD can lead to amputation of limb/s because of the possibility of gangrene in the absence of blood supply," Chakraborty said.

Smokers, diabetics or those with a history of cardiac ailments run the risk of developing PAD, he said.

Initial symptoms are severe pain and cramps in the legs while walking, which go away after a period of rest. Also, the leg muscles can become numb or fatigued while walking. The disease can also result in dry skin because of restricted blood supply.

"Peripheral intravascular ultrasound produces better results since the camera captures precision images and doctors can measure the amount of blockage correctly," Chakraborty said.

Conventional methods like a Doppler ultrasound - a non-invasive test using high-frequency sound waves to estimate blood flow through vessels - cannot produce such precise images, he said.