Michael Megaly, MD, MS, FACC, FSCAI
Interventional Cardiologist
Complex Coronary and CTO PCI & Limb Salvage Specialist | Oklahoma City
Coronary Artery Calcium Modification: Atherectomy and Intravascular Lithotripsy
What is Coronary Artery Calcification?
Calcium buildup inside the coronary arteries is one of the most significant technical challenges in interventional cardiology. When calcium deposits become severe, they can prevent a stent from expanding fully and sitting properly against the artery wall.
A stent that is not fully expanded is more likely to fail over time, through either re-narrowing (restenosis) or clot formation (stent thrombosis). For this reason, treating the calcium itself, before placing a stent, is often a necessary step in severely calcified coronary artery disease. This process is known as calcium modification. It does not remove all of the calcium from the artery. Instead, it changes the structure of the calcium enough to allow the artery to expand and a stent to seat properly. Several technologies are available to accomplish this, and each works through a different mechanism.
Rotational atherectomy
Rotational atherectomy uses a diamond-coated burr that rotates at high speed, sanding away the hardest, most superficial layer of calcium and creating a smoother channel through the artery.
It is particularly useful for very tight, heavily calcified narrowings that a balloon or stent cannot initially cross. Because the burr works by differential cutting, removing hard calcified tissue while sparing more elastic, healthy tissue, it is well suited to lesions where the calcium is concentrated and superficial.
Orbital atherectomy
Orbital atherectomy uses an eccentrically mounted crown that orbits within the artery, and its sanding diameter increases as rotational speed increases.
This allows a single device to treat a range of vessel sizes and provides continuous blood flow around the crown during treatment, which can reduce the risk of ischemia during the procedure. Orbital atherectomy tends to be favored in lesions with more diffuse or circumferential calcification, and in vessels where preserving flow during treatment is a priority.
Intravascular Lithotripsy
Intravascular lithotripsy (IVL) uses localized, pulsed sonic pressure wave, similar in principle to the technology used to break up kidney stones, delivered through a balloon catheter positioned at the site of calcification.
The sonic waves create microfractures in both superficial and deep calcium, including calcium embedded within the vessel wall that atherectomy devices cannot reach. Because IVL works through a balloon rather than a rotating or orbiting device, it does not require a wire that crosses through the calcified segment in the same way atherectomy does, and it carries a distinct risk and technical profile.
Combination Therapy
In some of the most severely calcified lesions, no single technology is sufficient on its own. Superficial, concentric calcium may respond well to atherectomy, while deeper or circumferential calcium may require the fracturing effect of lithotripsy to allow full vessel expansion.
In these cases, atherectomy and intravascular lithotripsy are sometimes used in combination, in a specific sequence, to address different components of the same calcified segment. This combined approach is used selectively in lesions where imaging and procedural findings indicate that a single technology would not adequately prepare the vessel for stenting.
Why the Strategy Matters More Than the Device
None of these technologies is inherently superior to the others. Each addresses calcium differently, and each has lesions it is best suited for and lesions where it is not the right choice. The clinical decision that determines outcomes is not which device is used, but how the lesion is assessed, often with intravascular imaging such as intravascular ultrasound (IVUS) or optical coherence tomography (OCT), to determine the location, depth, and distribution of calcium, and which technology, or combination of technologies, is best matched to that specific pattern of disease.
Choosing the correct strategy for the specific lesion, rather than defaulting to a single familiar tool, is what separates adequate vessel preparation from inadequate vessel preparation, and it is central to achieving a well-expanded stent and a durable long-term result.