When arteries become blocked, medical professionals must restore normal blood flow, typically using minimally invasive procedures. Intravascular Lithotripsy (IVL) is a specialized tool for treating blockages in both the coronary arteries of the heart and the peripheral arteries in the limbs. This technology adapts the medical principle of using acoustic energy to fracture hard material and applies it inside the vascular system. IVL is a precise method that prepares a hardened vessel for the successful placement of a stent, ensuring the artery remains open after the procedure.
The Clinical Need for IVL
Intravascular Lithotripsy was designed to address severely calcified atherosclerotic plaque, a major obstacle in interventional cardiology. Over time, fatty plaque within artery walls hardens into calcium deposits, making the artery stiff and unyielding. This calcification affects up to 30% of patients undergoing stenting and makes the artery resistant to traditional treatments.
Older methods, such as standard balloon angioplasty, often fail to fully expand a calcified vessel, preventing proper stent deployment or resulting in an incomplete opening. Incomplete expansion increases the risk of future blockages and the need for repeat procedures. Other techniques, like rotational or orbital atherectomy, scrape away calcium but are complex and primarily target only superficial layers. IVL modifies both superficial and deep calcium, increasing the vessel’s compliance before a stent is placed.
The Mechanism of Shockwave Delivery
The core principle of IVL is based on lithotripsy, a method used for decades to break up kidney stones using focused sound waves. The IVL system uses a specialized balloon catheter threaded to the site of the calcified blockage. Once positioned, the balloon is inflated to a low pressure (typically around four atmospheres) to ensure gentle contact with the artery wall.
Inside the fluid-filled balloon, tiny emitters generate high-speed sonic pressure waves, or shockwaves, via an electrical discharge that vaporizes the fluid. These waves travel through the soft tissue of the artery wall without causing damage because soft tissue is highly compliant. When the waves encounter dense, calcified plaque, they create significant mechanical energy, resulting in micro-fractures within the calcium deposits.
This selective nature allows shockwaves to interact strongly with hard calcium while safely passing through the surrounding elastic soft tissue. The resulting fractures increase the flexibility of the artery wall, improving vessel compliance. This modification allows the vessel to fully dilate under low pressure, preparing it optimally for subsequent stent placement.
Navigating the Treatment Process
The IVL procedure is performed in a catheterization laboratory. The physician gains access to the vascular system, usually through an artery in the wrist (radial access) or the groin (femoral access), by inserting a small tube called a sheath. Using X-ray imaging (fluoroscopy) as a guide, a wire is navigated through the blocked artery and past the calcified lesion.
The IVL catheter, containing the shockwave emitters, is advanced over the wire to the target area. Once positioned, the balloon is slightly inflated, and the physician activates the generator to deliver sonic pulses. Treatment involves delivering a set number of pulses, often in cycles, over a short period to fracture the calcium.
After shockwave delivery, the IVL balloon is deflated and removed. The vessel is then further expanded with a high-pressure balloon, and a permanent stent is deployed to maintain the restored opening. Intravascular imaging, such as Intravascular Ultrasound (IVUS), is often used afterward to confirm successful calcium fractures and full stent expansion.
Expected Patient Recovery
Patient recovery following Intravascular Lithotripsy is similar to a routine stenting procedure. Following the intervention, the patient is moved to a recovery area for monitoring, where nurses ensure there is no bleeding from the access site. Patients must lie flat for a period if the groin was used for access, though wrist access allows for earlier mobility. Patients undergoing peripheral artery procedures may be discharged the same day, while those with coronary artery interventions usually stay overnight for observation. Patients are advised to avoid strenuous activity, heavy lifting, or submerging the puncture site for several days to a week to allow the access artery to heal completely.