IVL is safe and effective across all calcium morphologies, new research confirms
The use of coronary intravascular lithotripsy (IVL) in treating various calcium morphologies has been a topic of discussion in interventional cardiology in recent years. Two recent studies presented at the Transcatheter Cardiovascular Therapeutics (TCT) 2023 meeting showed safety and efficacy in both nodular and eccentric calcium.
"What we know from the past is that patients who have a calcified nodule, who undergo rotational atherectomy actually have a threefold worse clinical outcome. But when we looked at the two-year clinical data for patients with IVL treatment, there was no difference whether or not you had a nodule in the clinical outcomes of those patients. So taken together, what it really shows is that IVL is an effective modality to treat calcified nodules and all types of calcified lesions," explained Ziad Ali, MD, DPhil, who was the first author of both studies.[1,2] He is also director of the DeMatteis Cardiovascular Institute, director of investigational interventional cardiology and director of the cardio-renal program at St. Francis Hospital and Heart Center in Roslyn, New York, and director of the angiographic core laboratory at the Cardiovascular Research Foundation (CRF).
He spoke with Cardiovascular Business in a video interview at TCT.
Since IVL has been released, Ali said it is universally seen as an excellent tool for concentric calcification. But different types of calcification can impact the acute procedural result and potentially the long-term clinical result, and there was still concern about calcified nodules and eccentric calcification.
Ali said the two studies he presented looked specifically at the patient subgroups for these patients.
Redefining treatment strategies for nodular calcification
The first study was an examination of calcified nodules, and it revealed promising outcomes with IVL. The study, analyzing 54 nodules within 248 lesions, demonstrated IVL's high effectiveness in modifying calcified nodules pre-stent implantation. Surprisingly, there were no significant disparities in stent area, expansion, or major procedural complications between lesions with and without calcific nodules treated with IVL. This finding indicates IVL's ability to safely and effectively handle calcified nodules, an encouraging revelation that could potentially redefine strategies in treating this specific calcium morphology.
Eccentric Calcification: A New Dimension of Treatment
The second study focused on eccentric calcification, a challenging area for traditional treatment methods due to potential missed areas during procedures. Ali said IVL's prowess in modifying eccentric calcium was underscored by the study's findings, showcasing consistent stent expansion and area across different degrees of calcium eccentricity. Unlike other modalities where the minimal stent area might deviate due to eccentricity, IVL demonstrated uniform modification regardless of the calcification's location within the vessel, mitigating the risk of incomplete treatment.
"We learned that irrespective of your arc of calcification, you got the same stent expansion and the same stent area. And what that teaches us is that if you modify even eccentric calcium, you don't end up potentially with a minimal stent area because of eccentricity.
Safety at the forefront of using IVL vs. other calcium busting modalities
A critical distinction surfaced when comparing IVL's safety profile with other devices like high-pressure balloons or atherectomy tools: IVL exhibited an exceptional safety profile, evident even in less calcified areas, without creating perforations or dissections. In contrast, Ali said alternative devices showed higher risks of procedural complications, including dissections and perforations, emphasizing IVL's superior safety measures.
"The mechanism by which IVL works is it actually breaks the nodule into smaller pieces, sort of transforming a marble into pebbles. And what that does, that forming of the gravel, allows it to be a lot more compressible and a lot more deformable allowing you to push it out of the way of the way," Ali explained.
Since the calcium is contained in the adventitia layer of the vessel wall, these fragments are contained and are prevented from embolizing. Ali said this is different than atherectomy, where grinding can cause micro-emboli and vessel trauma. High pressure balloon angioplasty is less effective at breaking the calcium and pushing it out of the way and often causes barotrauma that can lead to vessel dissection.
"One of the nice things about IVL is that multiple studies have shown, even if you use in areas that are less calcified, it doesn't create any perforations and dissections. The thing that's been a differentiator for Shockwave all along compared to atherectomy is its incredible safety profile, and that safety profile has now been extended into both nodular calcification and eccentric calcification. On the converse, when you use other devices like non-compliant balloons, which are really pressure and barometric pressure based, they create a lot of dissections," Ali said.