As a vascular surgeon who operates on people with advanced peripheral artery disease (PAD), Leigh Ann O’Banion, M.D.† knows firsthand how frustrating it can be when you can’t treat them using minimally invasive tools.
PAD—in which plaque accumulates in the arteries and reduces blood flow to the limbs—affects roughly 200 million people worldwide, with many showing no symptoms.1 But a small subset develops chronic limb-threatening ischemia (CLTI), in which heavy plaque build-up causes a severe reduction of blood flow, extensive tissue damage and severe pain in the limbs.
In an ideal world, you could go into the affected artery and revascularize it to restore blood flow. “But, sometimes, we just can’t get through the plaque to deliver treatment,” Dr. O’Banion says. Not only is that disappointing for clinicians, but it can be devastating for patients who may wind up needing a major amputation.
More people die within five years of being diagnosed with CLTI than from any type of cancer, excluding lung cancer.2 Left untreated, more than 20% of those with CLTI lose a lower extremity.3 “Patients are falling victim to it every single day. We’re facing an epidemic of CLTI,” Dr. O’Banion says.
There’s an urgent need for alternative treatment methods that can prevent amputations and save lives. Dr. O’Banion recently served as a site principal investigator for a clinical trial evaluating a novel, first-of-its-kind Forward Intravascular Lithotripsy (IVL) Platform called the ShockwaveTM Javelin Peripheral IVL Catheter. It has a single distal emitter, positioned 3mm from the catheter tip, to enable cracking of calcium and assist in both modifying and crossing calcific disease prior to final treatment.
We sat down with Dr. O’Banion to learn more about how this new technology is helping transform the lives of people with PAD.
Why can advanced PAD be difficult to treat?
LO: PAD is caused by atherosclerosis, a build-up of plaque within the arteries. While everyone has some amount of plaque sneaking around, certain risk factors, including older age, smoking, diabetes, and high cholesterol, can accelerate this process.4 Over time, that plaque accumulation may cause the arteries to become stiff and narrow, leading to PAD.5 As a result, the limbs—mainly the legs and feet—do not get enough blood and oxygen.
Advanced PAD—or CLTI—is, in some ways, like stage three or four vascular cancer. People with CLTI typically experience rest pain (severe pain in the legs and feet when you’re not moving) and tissue loss. Without intervention, there’s also a high risk of limb loss. Like most cancer, there is no cure, only remission, thus patients with CLTI require lifelong surveillance and management.
In recent years, vascular surgeons, myself included, have seen an influx of patients who are living longer, healthier lives largely due to the availability of life-saving medications like statins and anticoagulants.6 And because those patients are living longer, many patients with CLTI are older and frail with multiple comorbidities. As such, they may no longer be good candidates for open bypass surgery, the gold-standard approach that creates new routes for blood to flow around blocked arteries.
For these individuals, bypass—and prolonged anesthesia—is too risky as they may lead to lengthy hospital stays and increased complication rates.7 But without it, they may lose a limb. There’s a growing need to expand the CLTI treatment toolbox.
How is CLTI currently treated, and what are the limitations?
LO: The majority of patients with CLTI also have diabetes or end-stage renal disease on dialysis.8,9 They also tend to be heavy smokers. Together, these conditions dramatically increase the risk of calcified atherosclerotic disease, or a severe build-up of calcified plaque in the arteries within the lower extremities.
There are multiple traditional technologies to treat this issue, including various types of catheters, atherectomy devices, stents and drug-coated balloon angioplasty.
But the limitations of these treatments increase when the disease is present below the knee and ankle, which is often the case with CLTI. In these locations, you see smaller vessels that are clogged with, for example, medial arterial calcification and eccentric or concentric calcium (i.e., the proverbial "boulders" in the arteries).10 In simple terms, these calcium deposits block and narrow the arteries, preventing blood from flowing through.
As a result, crossability, or the ability to move wires and catheters through narrowed blood vessels, becomes more limited. Traditional technologies cannot get by these challenging lesions because they’re just too heavily calcified. And when that happens, treatment cannot be delivered. You’re stuck—you can either bail and perform a high-risk bypass or, if that’s not an option due to the patient’s age and or comorbidities, amputate a limb.
How can Javelin address this treatment gap?
LO: We need tools that are capable of modifying these lesions. The Shockwave Javelin IVL emitter has a spherical sonic output, similar to traditional balloon-based IVL devices. Due to the emitter’s proximity to the distal tip, the emitter’s spherical sonic output extends beyond the tip of the catheter, closer to the calcium than balloon-based platforms.11 Those shockwaves effectively modify the calcium, or make it more compliant, by creating tiny fractures in the plaque.
Once the lesion has been modified to be more compliant, you can administer your treatment of choice—whether that be inserting an implant such as a drug-eluting scaffold, atherectomy device or balloon angioplasty. It is the only intravascular lithotripsy tool of its kind.
With CLTI, the first procedure—whether it’s a bypass or another endovascular intervention—has the greatest impact on patient outcomes. The more successful the first procedure is, the greater the chance the patient will achieve long-term patency (when their vessels remain open and free of significant blockage) and avoid the need to be re-treated or have a limb amputated.
How do you determine when to use Javelin?
LO: You can typically identify calcium on imaging tests that evaluate blood vessels. In the operating room (OR), you can also use intravascular ultrasound (IVUS) to locate calcium—this will inform where you should deliver the technology in your patients.
If the lesion is crossable, standard intravascular lithotripsy, like ShockwaveTM E8, is still my go-to option as it will most effectively modify the plaque so you can deliver your treatment.
That said, you don’t really know how crossable a lesion is until you are in there with a wire. Sometimes, you get lucky and the wire flies through; other times, you think you will be able to move the wire through the vessel, but it will get stuck. Then you need to change course.
This is exactly why it’s so crucial to have Shockwave Javelin in your toolkit. Though it still requires a guide wire, its forward tip emitter offers a potential solution for patients with lesions that are challenging to cross. For me, it’s been most effective with distal tibial and below-the-ankle disease.
What are the trickle-down effects of having more effective treatment options?
LO: Healthcare systems are currently stretched very thin. In certain hospitals, for example, there are 200 or more people sitting in the emergency room at any given time, waiting for a bed. That’s a dire situation to be in—there aren’t enough physicians and there aren’t enough beds for patients.
If there’s a way to quickly revascularize CLTI patients and get them back home, you can reduce some of that strain on the healthcare system. Providers can see more patients, and they can treat them faster. Nothing bad can come from having a successful revascularization.
We went into this field to help people. Saving someone’s life is the most important thing when it comes to job satisfaction. If there’s a new tool that can give my patients a better outcome, I’m going to take it.
References:
† Dr. Leigh Ann O'Banion, M.D. is a paid Shockwave Medical consultant. The views expressed are of her own opinion and do not necessarily represent Shockwave Medical.
[1] https://www.ahajournals.org/doi/10.1161/CIR.0000000000001153
[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC10531516/
[3] https://www.sciencedirect.com/science/article/pii/S2772930323004179
[4] https://www.nhlbi.nih.gov/health/peripheral-artery-disease/causes
[5] https://medlineplus.gov/ency/article/000170.htm
[6] https://www.nhlbi.nih.gov/health/peripheral-artery-disease/treatment
[7] https://www.ncbi.nlm.nih.gov/books/NBK572137/
[8] https://pmc.ncbi.nlm.nih.gov/articles/PMC9408142/
[9] https://pmc.ncbi.nlm.nih.gov/articles/PMC4254470/
[10] https://pmc.ncbi.nlm.nih.gov/articles/PMC9909396/
[11] https://www.ncbi.nlm.nih.gov/books/NBK560548/
Not for use in coronary, carotid, or cerebral vasculature. Additionally, not for use in pulmonary vasculature in the US and New Zealand.
Please contact your local Shockwave representative for specific country availability.
In the United States: Rx only.
Indications for Use—The Shockwave Medical Intravascular Lithotripsy (IVL) System is intended for lithotripsy-enhanced balloon dilatation of lesions, including calcified lesions, in the peripheral vasculature, including the iliac, femoral, ilio-femoral, popliteal, and infrapopliteal arteries. Not for use in the coronary, carotid or cerebral vasculature. Peripheral IVL is also indicated for use in renal arteries in certain jurisdictions, including the United States. Please reference Instructions For Use for country specific information.
Contraindications—Do not use if unable to pass 0.014" (M5, M5+, S4, E8) or 0.018" (L6) guidewire across the lesion-Not intended for treatment of in-stent restenosis or in coronary, carotid, or cerebrovascular arteries.
Warnings—Only to be used by physicians who are familiar with interventional vascular procedures—Physicians must be trained prior to use of the device— Use the generator in accordance with recommended settings as stated in the Operator’s Manual.
Precautions—use only the recommended balloon inflation medium—Appropriate anticoagulant therapy should be administered by the physician— Decision regarding use of distal protection should be made based on physician assessment of treatment lesion morphology.
Adverse effects–Possible adverse effects consistent with standard angioplasty include–Access site complications –Allergy to contrast or blood thinner– Arterial bypass surgery—Bleeding complications—Death— Fracture of guidewire or device—Hypertension/Hypotension— Infection/sepsis—Placement of a stent—renal failure—Shock/pulmonary edema—target vessel stenosis or occlusion— Vascular complications. Risks unique to the device and its use— Allergy to catheter material(s)— Device malfunction or failure— Excess heat at target site.
Prior to use, please reference the Instructions for Use for more information on indications, contraindications, warnings, precautions and adverse events. www.shockwavemedical.com/IFU
Please contact your local Shockwave representative for specific country availability.
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