Recently developed procedure uses sonic waves to break up cholesterol buildup

Blocked or narrowed heart arteries is the top 3 killer disease in developed countries. The narrowing is caused by deposits of cholesterol in the walls of the arteries. These areas of cholesterol narrowing are known as ‘plaques.’ In the past, the treatment would have been a bypass operation. However, these days, the standard of care is ‘angioplasty’ commonly known as ‘stenting’ or ‘ballooning.’

This is a very low-risk procedure when a balloon is used to push aside the cholesterol and then a ‘stent’, a kind of metal tube, is placed to hold the artery opened.

This procedure may become a lot more complicated, however, for ‘hardened’ plaque, as Tan Chong Hiok, a cardiologist at Mount Elizabeth Hospital in Singapore, observed.

“Some patients may see a doctor late, for reasons like ignoring their symptoms, or not going for regular checkups,” Dr. Tan explained.

“Over time, say, three years or more, calcium gradually gets deposited onto this cholesterol plaque, making it rock hard. This ‘hardened’ plaque does not allow the balloon to expand.”

Previously, these cases would be treated by using a tiny drill. This is like a dentist’s drill spinning at high speed. It gradually drills away the calcium deposits. But the device can be cumbersome to use. The procedure also carries other risks such as tearing the blood vessels. “Because of these issues, some doctors may be hesitant to recommend this drill procedure or to perform it,” Dr. Tan said. The patient is recommended to undergo a bypass operation instead.

Technological development paved the way for a new medical procedure that offers a safer way to treat hardened plaques for these patients.

The procedure, called intravascular lithotripsy (IVL), involves using a balloon that delivers sonic pulses to break up the hardened plaque in the arteries.

Said Dr. Tan, who is among the first doctors to apply the technique in Singapore, IVL is a simpler and much lower risk device compared to the drill.

It is similar to angioplasty in that it also delivers a balloon to the site of narrowing. Instead of balloon just expanding and squeezes the plaque aside, it also sends out shock waves that crack the calcium like eggshell. This softens the plaque and allows a stent to be expanded.

Shock waves has been utilized since the 1980s to break up kidney stones into smaller fragments so that it can pass out in urine. In this way, patient does not need to undergo an open surgery.
This is exactly the same concept for IVL. Except that the shock wave is not delivered from outside the body. It is delivered inside the arteries when the calcium deposits are deposited.

As of December 2019, Dr. Tan has used the IVL device to treat eight patients. Other public hospitals in Singapore have also started offering the procedure.

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