What is intravascular lithotripsy?

What is intravascular lithotripsy?

Intravascular lithotripsy (IVL) delivers acoustic pressure waves using specialized balloon catheters into blocks within blood vessels to modify the calcium present in them. It is used when the blocks in blood vessels have large amount of calcium so that they cannot be removed by the usual balloon catheters used for coronary angioplasty. Coronary angioplasty is the process of removing blocks in blood vessels of the heart using balloon catheters. Balloon catheters are thin tubes with sturdy balloons attached to the tip. They are guided to the blood vessels of the heart using continuous X-ray imaging.

When there is a lot of calcium deposits in the blocks in blood vessels of the heart, usual balloon catheters may rupture while attempting to enlarge them at high pressure. Even if the balloon does not rupture, the expansion will be incomplete so that adequate removal of the block is not possible. Only if the block is removed well, can the vessel be further supported by inserting tiny metallic structures known as stents. Stents are inserted in blood vessels after balloon angioplasty and expanded using balloon catheters on which stents are mounted.

If the stents cannot be expanded well, it will not permit good flow through the blood vessel. An under expanded stent can promote the formation of clots within it, known as stent thrombosis. Stent thrombosis is a real nightmare as it can cause sudden worsening with chest pain and more. To modify the blocks with a lot of calcium, intravascular lithotripsy is very useful. It works in the same way as a similar procedure which has been in use for a long time for pulverizing kidney stones using external shock waves. But in case of blood vessels of the heart, the shock waves are delivered within the blood vessels using specialized balloons attached to thin tubes.

Intravascular lithotripsy is not confined to the blood vessels of the heart. It can be used in blood vessels of the limbs, and intestines when needed. It is also used to enlarge blood vessel of the groin to facilitate other procedures. In elderly persons, aortic valve may need to be replaced through tubes introduced through blood vessels of the groin. That procedure is known as transcatheter aortic valve implantation or TAVI. The procedure requires a relatively large device to be introduced through the blood vessel of the groin. In elderly, very often the blood vessel of the groin or in the route of the device may have large calcium deposits. These can be modified by using intravascular lithotripsy to facilitate TAVI.