Endovascular procedures, particularly those involving complex aortoiliac interventions, often require safe and reliable vascular access. However, access can be severely hindered by the presence of heavily calcified iliac arteries, which present a significant barrier to device advancement and sheath insertion. In recent years, Shockwave Intravascular Lithotripsy (IVL) has emerged as a transformative tool in addressing this clinical challenge.
Calcification within the iliac arteries, particularly in elderly patients or those with long-standing peripheral arterial disease (PAD), can significantly compromise the elasticity and compliance of the vessel wall. This stiff, non-yielding plaque increases the risk of procedural complications, including vessel dissection, rupture, and access failure. In the context of large-bore access, such as for transcatheter aortic valve replacement (TAVR), endovascular aneurysm repair (EVAR), or mechanical circulatory support, the inability to safely navigate through calcified iliac arteries can be a procedural endpoint.
Conventional methods to treat calcified vessels, including high-pressure balloon angioplasty and atherectomy, have limitations in safety and efficacy, particularly in the iliac territory. High-pressure inflation may result in vessel rupture, while atherectomy devices may not be suited for large, tortuous iliac arteries due to the risk of embolization or perforation.
Recently, Shockwave L6 was introduced to the European market, with the new catheter representing a novel approach that leverages sonic pressure waves to selectively target and fracture both intimal and medial calcium. The technology involves a semi-compliant balloon catheter that emits pulsatile acoustic energy upon inflation. These shockwaves create microfractures in the calcified plaque without damaging the surrounding soft tissue, thereby improving vessel compliance and facilitating the expansion of the vessel at low-pressure balloon inflation.
In the context of heavily calcified iliac arteries, IVL enables operators to prepare the access vessel for large sheath insertion safely. The technique can be particularly advantageous in pre-dilation of calcified iliac segments prior to sheath delivery in TAVR or EVAR, facilitating passage of large-bore devices when standard balloon angioplasty is inadequate, minimizing the risk of dissection or rupture in vessels that are heavily burdened with concentric or eccentric calcium.
IVL has a favourable safety profile, with a low incidence of vessel rupture, distal embolization, or no-reflow phenomena. Unlike atherectomy, IVL does not require the removal of calcific material, which reduces the risk of embolic events. Additionally, because IVL operates at low balloon pressures, the risk of barotrauma is minimized.
During the procedure, the IVL catheter is advanced to the target segment, typically under fluoroscopic guidance. After confirming adequate positioning, the balloon is inflated to appose the emitters to the vessel wall, and multiple cycles of lithotripsy pulses are delivered. The balloon is then inflated to low pressure (between 2 – 4 atmopheres) to attain vessel wall apposition and facilitate energy transfer. To optimize the luminal gain, it is very important to size the balloon 10% bigger than the reference vessel diameter. Following lithotripsy, operators often find a marked improvement in vessel compliance, allowing for successful advancement of large-caliber sheaths with reduced resistance and risk.
Early clinical data and real-world registries have demonstrated the safety and efficacy of IVL in treating calcified iliac arteries. In the Disrupt PAD III trial and subsequent sub-analyses, IVL showed a low rate of vascular complications and high procedural success when used in iliac and common femoral artery lesions. Furthermore, observational studies in the setting of TAVR and EVAR have shown that IVL can significantly improve procedural feasibility in patients who would otherwise be considered high-risk or ineligible for transfemoral access due to calcific burden. However, appropriate patient selection and anatomical assessment via pre-procedural CT angiography remain critical. Operators should be mindful of severely tortuous anatomy, extreme vessel stenosis that may impede catheter delivery, or thrombotic components that might predispose to embolization.
In conclusion, Shockwave Intravascular Lithotripsy and the new Shockwave L6 platform has revolutionized the approach to managing heavily calcified iliac arteries. By offering a safe, effective, and minimally traumatic method of calcium modification, IVL facilitates vascular access in complex endovascular procedures where conventional methods often fail. As experience with the technique grows, IVL is becoming an essential tool in the armamentarium for endovascular specialists tackling challenging iliac access.
