Intravascular lithotripsy (IVL) is an innovative treatment that uses sonic pressure waves, or shock waves, to break up calcified plaque deposits in the arteries. This makes IVL a critical tool for treating coronary artery disease (CAD) and peripheral arterial disease (PAD). But how does IVL work? In this article we explain the science and technology behind intravascular lithotripsy.

Overview of Intravascular Lithotripsy

Intravascular lithotripsy is a novel, catheter-based approach to treating plaque lesions in the peripheral and coronary arteries. The purpose of an IVL treatment is to fracture this hard, calcified plaque in order to optimize stent placement and improve blood flow. The procedure involves introducing a lithotripsy catheter equipped with an integrated angioplasty balloon into the artery. Emitters within this balloon produce sonic pressure waves that focus mechanical energy on the targeted lesion, causing the hard plaque to crack without affecting the surrounding soft tissues.(1)

As the artery is subjected to these pressure waves, the calcified deposits start to disintegrate. The increased blood flow, paving the way for subsequent interventional treatments and ensuring the best stent positioning. Intravascular imaging techniques employed during and post-treatment confirm the comprehensive disruption of the plaque. This article gives a background on how calcified plaque can accumulate in arteries and lead to CAD and PAD.

Applications of IVL: Treating Calcified Arteries in People with CAD and PAD

With over 5% of the adult population affected by CAD and PAD, IVL has emerged as a preferred treatment for those with arterial calcification, especially in instances where conventional treatments like angioplasty might be less effective.(2,3,4) This article goes into more detail about when IVL is used, and when IVL shouldn’t be used. 

Intravascular Lithotripsy Technology

IVL technology has its origins in a novel treatment for renal calculi, or kidney stones.(5) This was the first use case for mounting multiple lithotripsy emitters on a traditional catheter platform to deliver shock waves at a targeted lesion. Today this principle is used to treat calcified plaque in arteries. Modern IVL features a multi-faceted system that includes a lithotripsy catheter with an integrated angioplasty balloon that is connected to a generator. IVL equipment includes:

• IVL catheter: A single-use, sterile, disposable catheter with an integrated angioplasty balloon.

• Angioplasty balloon: Integrated within the IVL catheter, it contains lithotripsy emitters.

• Energy generator: The generator powers the emitters, which deliver sonic pressure waves, or shock waves.

The Use of Intravascular Imaging Techniques Before and After IVL Procedures

Medical professionals can use intravascular imaging techniques before and after the IVL procedure. These include intravascular ultrasound (IVUS) and optical coherence tomography (OCT), which help to assess and characterize severely calcified arteries.

IVL Works Against Calcified Plaque By Generating Sonic Pressure Waves

An IVL procedure generates a series of sonic pressure waves, or shock waves, inside a vessel with a plaque obstruction. These waves are specifically designed to generate mechanical energy that fragments superficial and deep-seated calcium deposits. Modifying these arterial calcium deposits makes it easier to deploy other vascular therapies like stents and drug-eluting technologies. 

The IVL catheter, integral to this process, is designed as a single-use, sterile, and disposable instrument, emphasizing patient safety and treatment efficacy. The catheter incorporates lithotripsy emitters set within an integrated balloon that produce sonic pressure waves.

The Precision of IVL: Procedures are Highly Selective, Targeting Plaque

IVL is highly selective. The energy from an IVL treatment creates cracks and fissures in hard plaque, while passing harmlessly through soft, fibroelastic tissues in the artery walls. IVL has proven to be an effective way to fracture plaque without harming the vessel.(1) This precision helps the artery to become more compliant, optimizing subsequent interventions like balloon inflations, which require significantly lower pressures than traditional methods.

What Happens During an IVL Procedure

The standard IVL procedure includes the following primary steps:

1. IVL catheter insertion: First, the catheter is inserted into the artery and navigated to the targeted calcified blockage. Clinicians utilize marker bands to ensure proper positioning to align the emitters adjacent to the calcified sections, thereby optimizing the therapeutic effect.

2. Device inflation: Next, the angioplasty balloon is inflated within the diseased artery.

3. Sound wave emission: Once the intravascular lithotripsy catheter is inflated, the generator powers the emitters to produce sound waves targeting the calcified plaque. The generator is designed to deliver consecutive pulses at a specified rate, which creates mechanical energy that fractures calcium deposits.

4. Device deflation: After targeting the plaque with a series of sound or shock waves, the balloon is deflated and the IVL catheter is removed.

5. Imaging evaluation: Post-treatment, the use of advanced intravascular imaging techniques help assess the effectiveness of the procedure. These techniques include both intravascular ultrasound and optical coherence tomography. These imaging techniques are used to detect calcium fractures in the plaque, helping the treating physician to determine what additional treatment is necessary.

This article goes into more detail about what happens during an IVL procedure.

The Patient Experience During an IVL Procedure

For most patients, IVL is a pain-free experience, with the only discomfort arising from the catheter insertion. The procedure, similar to other catheter-based treatments, can be performed either as an outpatient or inpatient procedure in a room equipped with imaging tools (X-ray or fluoroscopy machines).

Treatment procedures will vary from facility to facility, but in general a person undergoing an IVL treatment can expect the following steps:

1. IVL preparation: Before the procedure, the patient will undergo a thorough medical evaluation, and will be informed about the procedure's details, potential risks, and benefits.

2. Mild sedation and local anesthesia: Some IVL patients are given mild sedation to help them relax. Most patients remain awake during the procedure and can communicate with the medical team. Local anesthesia is often applied at the site where the catheter will be inserted.

3. Procedure: A nurse or physician will make a small puncture in the artery, typically in the groin (femoral artery). Through this entry point, a sheath is placed to allow catheters to be passed easily into the artery. Once the emitters begin to deliver sonic pressure waves, the patient may hear a faint clicking sound and feel a mild vibration. Additional treatments, like a stent placement, are typically used afterwards. The entire procedure may take anywhere from 30 minutes to several hours.

4. Post-procedure: Once an IVL procedure is complete, the catheter is removed, and the access site is closed, often with manual pressure or a vessel closure device. Patients are then monitored in a recovery area. They might be discharged the same day or might require a short hospital stay.

IVL Has an Excellent Safety Profile

IVL is mostly painless for patients, and peer-reviewed studies have also indicated that IVL has an excellent safety profile, with a low incidence of procedure-related complications.(3,4) You can dive deeper into IVL safety and potential complications in this article.