Intravascular Lithotripsy (IVL) is a minimally invasive medical technique designed to address hardened arteries. This procedure uses a specialized catheter to deliver acoustic pressure waves, known as shockwaves, directly into a blood vessel. IVL’s goal is to safely fracture calcified plaque within the artery walls, restoring the vessel’s flexibility and improving blood flow. Adapted from technology used to break up kidney stones, IVL is an effective treatment for severe arterial disease in both coronary and peripheral arteries.
Understanding Severe Arterial Calcification
Arterial calcification is a progressive disease where soft plaque transforms into hard, bone-like calcium deposits. This hardening makes the artery rigid and unyielding, severely compromising blood flow. Extensive, dense calcium predicts poor outcomes in traditional catheter-based interventions.
When physicians attempt to treat these calcified lesions with standard balloon angioplasty, the rigid artery often resists dilation, which can lead to suboptimal expansion of the vessel. The failure to fully open the artery means that any subsequently placed stent may not expand properly, a condition called stent underexpansion. Suboptimal stent placement is strongly associated with adverse events, including the long-term failure of the stent to remain open.
Applying excessive force with high-pressure balloons to overcome this resistance increases the risk of serious complications. These include tearing the delicate inner lining of the vessel wall, known as dissection, or causing a perforation. The rigidity caused by calcium creates a significant barrier to achieving successful revascularization using conventional tools.
The Mechanism of Action Using Sonic Waves
Intravascular Lithotripsy selectively targets and modifies brittle calcium within the artery. The system uses a specialized balloon catheter positioned across the blockage and inflated to a low pressure. Emitters built into the balloon generate electrical discharges that vaporize the liquid inside, creating a rapidly expanding and collapsing bubble.
This process generates a series of localized, pulsatile acoustic pressure waves, similar to the method used in urologic lithotripsy for kidney stones. These pressure waves travel through the soft, elastic tissue of the vessel wall and impact the dense, brittle calcium deposits.
The acoustic waves exert mechanical forces—including compression, shearing, and spallation—that cause the hard, inflexible calcium to fracture. The shockwave energy cracks the inelastic calcium but is absorbed by the more compliant, soft tissue without causing harm. These fractures, often visible as deep cracks in the plaque, restore the vessel’s compliance and flexibility. Fracturing the calcium renders the artery pliable, allowing for optimal expansion during subsequent balloon inflation or stent placement.
Patient Journey During the Procedure
The Intravascular Lithotripsy procedure is performed in a catheterization laboratory under fluoroscopy guidance, which provides live X-ray images. The patient usually receives conscious sedation, remaining awake but comfortable. Access to the arterial system is gained through a small puncture, most commonly in the femoral artery or the radial artery.
A guide wire is threaded through the artery to the site of the calcified blockage, and the IVL catheter is advanced over the wire. Once the specialized balloon is positioned, it is inflated to a low pressure, ensuring contact with the calcified wall before the shockwaves are delivered. A treatment cycle involves the delivery of multiple pulses of acoustic energy, with a typical coronary artery lesion receiving up to 80 pulses.
The physician monitors the procedure on the fluoroscopy screen to confirm the balloon expands fully following the shockwave delivery, a sign that the calcium has been successfully fractured. After the calcium modification is complete, the IVL catheter is removed. The artery is then treated with a standard balloon or, more commonly, a stent is placed to maintain the newly opened vessel. Since the procedure is minimally invasive, patients often experience a shorter recovery time and may be discharged the same day or the next day.