Cracking Calcium in Arteries Using Sound Waves: Interview with Shockwave Medical’s Scott Shadiow

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Shockwave Medical, a medtech company based in California, has developed a technique called intravascular lithotripsy, which involves delivering sonic waves to calcified plaque in an artery in much the same way that sound waves have been used to treat kidney stones for many years. The idea is to safely crack the calcified deposits so that a stent can then be inserted to open the artery.

At present, calcified coronary arteries are typically treated using high pressure balloons, which can sometimes struggle to disrupt calcified deposits and the high pressure involved can pose safety issues. Other techniques include using small drills to chip the calcium away, but these are difficult to use safely and the small pieces of calcium that are dislodged can cause blockages elsewhere.

This latest technology, which has recently been FDA approved for use in the US, applies sonic waves to crack the calcium, allowing subsequent low-pressure expansion of the artery and stent placement. The company claims that the technique is safer and easier to use than many existing approaches, and has recently validated the safety and efficacy of the Shockwave Coronary IVL System in the DISRUPT CAD III study.

Medgadget had the opportunity to speak with Scott Shadiow, Senior Director at Shockwave Medical, about the technology. 

Conn Hastings, Medgadget: Please give us an overview of calcified coronary arteries and the issues they cause for patients.

Scott Shadiow, Shockwave Medical: As people with heart disease grow older and their disease progresses, plaque in the arteries can evolve into calcium deposits. These bone-like structures can narrow the artery and restrict blood flow, and may eventually cause a complete blockage. This obviously creates cause for concern as reduced blood flow prevents the heart from operating efficiently and results in chest pain for the patient. When this happens, physicians typically use stents to open the artery and restore blood. However, of the approximately one million U.S. patients that undergo stent procedures each year, up to 30 percent have calcified lesions that increase their risk for adverse events in the acute procedural setting and result in worse long-term clinical outcomes.

Medgadget: How is the condition currently treated? What are the drawbacks associated with these approaches?

Scott Shadiow: When hardened calcium presents within the plaque, physicians have conventionally relied on two treatment options prior to stent implantation to prepare the lesion – high pressure balloons or atherectomy – but both come with limitations and safety risks. High pressure balloons are the most common treatment method, and use high pressure to try to crack the calcium so that the vessel can expand with stent implantation. However, thick and circumferential calcium in an artery may be resistant to the high pressure, and it can damage the artery by tearing the soft tissue or even causing a perforation in the artery. The other treatment option is atherectomy, a technically demanding approach that uses a tiny drill spinning at over 125k RPM to ablate the calcium from the arterial wall so that the artery can expand. As expected, operating a small, high-speed drill within a patient’s artery is very difficult to master unless performed regularly. It can result in distal embolization of the calcium, as well as perforations. Despite the treatment being available for several decades, it isn’t used frequently (<5% of all stent procedures) due to its complexity and potential to result in adverse patient outcomes.

Medgadget: How does shockwave intravascular lithotripsy work? What are the benefits of this approach?

Scott Shadiow: Intravascular Lithotripsy, or IVL, is a novel adaptation of extracorporeal lithotripsy, an approach used for decades to safely break up kidney stones. It uses sonic pressure waves, also known as shockwaves, that pass through soft arterial tissue and preferentially disrupt calcified plaque by creating a series of fractures. After the calcium has been cracked, the artery can be safely expanded at very low pressure and a stent can be implanted to restore blood flow with minimal trauma to normal arterial tissue. What makes IVL unique is the fact that it offers physicians an intuitive treatment option that can modify the calcium in a safe manner, reducing the risk of perforations and distal embolization, all in a platform that they are very used to using in every case – a balloon catheter. 

Medgadget: Please give us an overview of the recent DISRUPT CAD III study.

Scott Shadiow: Our recent FDA approval (February 2021) for IVL in coronary arteries was largely supported by the results we observed in the DISRUPT CAD III study. It was a prospective, multicenter, single-arm, global IDE study designed to evaluate the safety and effectiveness of the Shockwave Coronary IVL System. The results were presented in a late-breaking clinical session at the virtual 2020 TCT conference last fall, and simultaneously published in the Journal of the American College of Cardiology (JACC). The study enrolled 384 patients around the globe who had severe coronary calcification and required modification for proper stent delivery and expansion. The study concluded that coronary IVL safely and effectively facilitated stent implantation in nearly all patients, resulting in a low risk of complications: perforation (0.3 percent), major dissection (0.3 percent), abrupt closure (0.3 percent), and slow flow/no reflow (0 percent) at the end of the procedure. Overall, the results surpassed expectations of investigators and the physician community as they eagerly anticipated FDA approval of IVL in the U.S. at the time. We look forward to presenting the one-year results at TCT later this year, as the patients will be followed out two years to complete the study.

Medgadget: Congratulations on your recent FDA approval. Where else has the technology been approved, and how has it been received by patients and clinicians to date?

Scott Shadiow: The coronary application of IVL has been widely adopted in Europe since launching it in mid-2018, with more than 30,000 patients having undergone a coronary procedure using Shockwave’s technology since then. We have also launched the technology in certain Middle East, South America and Asian Pacific countries. Our largest market is the U.S., where we just received our recent coronary FDA approval. This was a significant milestone for the benefit of both our physician customers and the patients they serve. Since the technology’s introduction, the response we’ve received from clinicians worldwide has been overwhelmingly positive, with their uptake of the technology exceeding our own expectations in each market we launch in. We feel like it’s once-in-a-career opportunity to introduce a technology that is truly novel, while also predictably safe and easily intuitive. Physicians can pick it up and be successful with it in their first case. It’s not every day that you have a technology with such a clear unmet clinical need that can be used by such a wide variety of physicians, regardless of their previous training or skill level.

Medgadget: How does the technology work in peripheral arterial disease (PAD)? Is it easier to access and treat calcified plaque in the arteries of the leg?

Scott Shadiow: Fundamentally the technology works the same in PAD as it does in coronary artery disease, as it’s the same mechanism of action for both arterial beds. In fact, we received peripheral approval a few years before we received our coronary approval. We have different versions of the product for each application to accommodate for the artery sizing and length, but the calcium – both superficial and deep – is similar in both vessel beds. From an access perspective, both peripheral and coronary applications can each be accessed by both transfemoral and trans radial routes, and similar challenges exist in both vessel beds from a treatment perspective. What’s different between the two treatments is that in the coronary, IVL is nearly always followed with a drug-eluting stent, while in the periphery, IVL can be used as a standalone treatment, or followed by a drug-coated below, or a stent. The technology really dovetails into the physician’s preferred algorithm when treating different anatomies.

Medgadget: What payment options are available to providers?

Scott Shadiow: For the coronary technology, given our approval as part of the Breakthrough Device Designation program, it qualified for the Centers for Medicare & Medicaid Services’ (CMS) outpatient Transitional Pass-Through (TPT) payment and inpatient New Technology Add On Payment (NTAP). Our TPT was effective on July 1st and our NTAP will start October 1st. These programs will allow hospitals to get reimbursed for at least part, if not all, of the technology’s costs, in addition to the base procedure. We applaud CMS for connecting these programs, which created a novel pathway to help increase access to innovative products to the patients who need them most. With each of these programs running for three years, Medicare will have the time needed to determine what the most appropriate long-term reimbursement should be based on their collection of data.

Link: Shockwave Medical company homepage…

Flashbacks: Shockwave’s Lithoplasty System Now Cleared in EU for Coronary Artery Disease Treatment; Shockwave PAD Balloon Catheters with Lithotripsy Technology CE Marked; Shockwave Lithoplasty for Peripheral Vascular Disease FDA Cleared; Shockwave’s S4 Catheter Shakes Calcified Plaque Off Peripheral Arteries

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