What is intravascular lithotripsy?
Over many years, calcium can build up in the wall of an artery and make it as hard as a pipe lined with limescale. Such an artery is difficult to open, and a stent placed into it may not expand properly. Intravascular lithotripsy uses the same principle as the machine that breaks up kidney stones: a balloon catheter containing tiny emitters is placed inside the narrowing and delivers pulses of sound energy. These shock waves pass harmlessly through the soft tissue but crack the hard calcium in the wall, so that the artery becomes flexible enough to be opened and stented properly.
Why is it done?
It is used when a coronary artery is so heavily calcified that an ordinary balloon cannot open it or a stent will not expand fully. Treating a hard, calcified artery without preparing it is one of the main reasons stents fail later, so modifying the calcium first improves both the immediate result and the long-term outcome. Your cardiologist decides on lithotripsy from the appearance of the artery on the angiogram and, often, on intravascular ultrasound, sometimes choosing it instead of drilling the calcium away with a rotating burr.
What happens on the day?
Lithotripsy is done as part of an angiogram or stent procedure, in the catheterisation laboratory. You are awake and the wrist or groin is numbed with local anaesthetic. A fine wire is passed across the narrowing, the lithotripsy balloon is positioned across the calcified segment and inflated gently, and then a series of pulses is delivered, usually in bursts of ten. You may hear a soft ticking sound and feel a mild fluttering or brief chest discomfort while the pulses are given. The artery is then dilated and a stent is normally placed and fully expanded.
What to expect afterwards
Aftercare is the same as for any stent procedure. If the wrist was used, a compression band stays on for a few hours and if the groin was used, you lie flat for a while. Most patients go home the next morning.
Possible complications
Lithotripsy is well tolerated, but it forms part of a coronary intervention and carries the same risks. Bruising or bleeding at the access site is the most common. During pulse delivery the heart rhythm may be briefly disturbed by extra or paced beats, which usually settles immediately afterwards.
This information does not replace a consultation. Please discuss your own risks and options with your cardiologist.