Orbital Atherectomy and Radial Access: Revolutionizing Peripheral Disease Treatment

Can you tell us about your practice?

I am an interventional cardiologist by profession and came to realize that many patients in Louisiana experience extensive problems from peripheral arterial disease. As a result, my practice has slowly transitioned from a mostly coronary practice to a predominantly peripheral interventional practice. I treat a variety of peripheral disease patients, often via radial access. Traditional groin access can be a very painful process for the patient, from removing the sheath and applying manual pressure, and is associated with a large number of complications. I had experience with radial access from my coronary work and saw the benefits to my patients. Therefore, today we treat most of our peripheral lesions through radial access.

A lack of appropriate device length has been one of the traditional limitations of radial access for peripheral vascular disease. Has that changed?

Yes, one of the main problems was that devices were not long enough to go from the radial artery to the legs. That has now significantly changed. Terumo Medical Corporation came out with a long sheath called the Destination sheath. Traditional femoral sheaths range from 45 cm, 65 cm, to at the most 90 cm, but the Destination sheaths range from 119 cm to 149 cm, which means that we can now reach all the way to the leg from the radial artery. Long shaft balloons with a shaft length of 200 cm have also come onto the market and can be delivered from the wrist down into the legs. Traditional balloons used from the femoral approach have a 135 cm shaft length. These newer balloons can cover the entire superficial femoral artery (SFA), and easily include below-knee vessels, proximal and mid-level. The third device that really changed the field was CSI’s Diamondback 360˚ peripheral orbital atherectomy system, which is a long, 200 cm shaft device that can reach all the way to the infrapopliteal vessels from the wrist. Everything is moving toward radial access. And now we also have a long stent available on the market. It is a 200 cm shaft length Misago stent by Terumo Medical Corporation. Now we have most of the devices and lengths necessary to do both simple and complicated peripheral intervention cases via radial access. 

Did you first learn radial access for coronary interventions?

Yes. As an interventional cardiologist, my training was very radial focused, including ST-elevation myocardial infarction and complicated percutaneous coronary interventions. Moving on to do peripheral intervention via a radial approach was second nature. It was interventional cardiologists who told the device companies how easy it is for us to work from a radial approach to treat heart disease and that we also wanted to treat peripheral disease from a radial approach. With radial access, we can do away with the majority of access site complications for our patients. 

One of the newer tools that can be used from a radial access is CSI’s Diamondback orbital atherectomy device. How are you using orbital atherectomy in your peripheral disease patients?

Not so long ago, if we had a very calcified lesion in the SFA, the goal was to remove that calcium and use a rotational atherectomy device that was like a drill – a high-spinning drill with a burr on the end that dislodged the calcium. We used to try to debulk most of this calcium, hoping that those tiny fragments would be taken up by the reticuloendothelial system. These plaques in the arteries are so hard that they resist balloon dilatation. The balloon is unable to break or crack the calcium, meaning we could not obtain an adequate result with balloon angioplasty. Orbital atherectomy has been very helpful in that it partially shaves the plaque, modifying it in such a way that the plaque does not have the same strength or morphology any more. Once the plaque has been modified by orbital atherectomy, balloon angioplasty is able to crack the plaque, which allows for a better luminal gain. Orbital atherectomy is the premier atherectomy tool because of its ease of use and ability to modify plaque. Originally, these devices came with a fixed crown size, so, for example, if you wanted to treat an SFA lesion, you might use the 2 mm crown size. The problem was that if you want to go down and fix the infrapopliteal vessels, that  mm crown size is too big for the infrapopliteal vessels. In that situation, operators were in a conundrum as to what crown size to use. Obviously, these devices are expensive, so we want to use one device if possible. Mostly operators would choose something in the middle, like a 1.25 Solid or a 1.5 crown that could accommodate both the SFA and infrapopliteal vessel sizes. Now CSI has a new Diamondback Exchangeable Series orbital atherectomy system that allows operators to change to different crown sizes on one device. It has allowed us to treat and accommodate all vessel sizes in multivessel disease, working with one device and multiple crowns in the same patient, in the same setting. Some of these patients used to come back for a repeat procedure because they required a different crown size for a different vessel, but now patients can be treated in the same setting, regardless of the variety in vessel sizing.

How do you change out the crown?

The Diamondback Exchangeable Series orbital atherectomy device has a handle, which is the main body of the machine. It is connected to a wire that has a crown at the tip. To remove the crown, you press a button and it comes off. You then take the crown size you need, put it on the wire, it clicks in, and you are good to go. It is as easy as it gets. The Diamondback Exchangeable Series comes not only with different crown sizes, but different lengths. If I am treating from a radial access, I could have a larger crown with short length for the SFA, and then change again to a smaller crown with longer length in order to go down into the infrapopliteal vessels if necessary. The process of removing and changing the crown size is easy and user friendly. The Diamondback Exchangeable Series also has another feature called the GlideAssist, which enables the crown to spin at a slower speed. It facilitates device tracking and allows for easy removal.

In what scenarios do you find the ability to change out crown sizes and lengths most useful?

In critical limb ischemia (CLI), two-degree revascularization has been the standard of care, meaning if we find SFA disease, we don’t stop at just improving the inflow, but go into the outflow to open the other popliteal vessels as well. Atherectomy that is incomplete, meaning performed solely in an inflow vessel, along with only doing balloon angioplasty in the infrapopliteal vessels, results in poor vessel patency, increased dissections, and early vessel closures. The Diamondback Exchangeable Series is useful as we try to fix all vessels in the same setting, when it is particularly important, such as in a CLI patient. We can work with a 2.0 crown for an SFA or a 1.5 Solid crown for SFA, and then size down to a 1.25 Solid crown for an infrapopliteal vessel. We had one case where we not only treated the SFA, but also went on to treat all three infrapopliteal vessels with a different crown, and came up with an excellent result. We used one crown size for the suprapopliteal and another one for the infrapopliteal vessels. If you want a little extra length, it is possible to take a different length size.

Has the use of orbital atherectomy been affected by the debate over paclitaxel use in the lower extremities?

At this time, the jury is still out on the use of paclitaxel. One good thing that has happened is a lot of attention is again being focused on how to perform a good balloon angioplasty. Think about how we used to approach balloon angioplasty before the advent of stents and drug-coated balloons. We used to go very easy on the vessels, go up very slowly while inflating the balloon, have a prolonged inflation, and come down very slowly. This was done in order to minimize trauma to the vessel. By minimizing trauma, we worked to ensure that vessels have higher patency and lower target lesion revascularization rates. Somewhere down the line, once stents were available, we did not retain that art of a good angioplasty, because we knew we could always put a stent in and tack up any dissections. What is really needed now is how to improve the patency of these vessels without using a drug-coated balloon. Good atherectomy devices that debulk the calcified plaque and slow and prolonged balloon inflation at lower pressures are providing great results. We do not really have a trial evaluating this option after the advent of stents and drug-coated balloons, but atherectomy remains the key to providing a good balloon angioplasty result. The Diamondback Exchangeable Series now offers us the ability to treat different vessel sizes with different crowns in one device. It is important for us to optimally perform atherectomy and balloon angioplasty, and come up with a great result.

Any final thoughts?

We need to make every effort to try and go through the radial approach. Patient comfort, patient safety, and patient satisfaction are paramount, and all can be achieved easily with radial access. I cannot emphasize enough the fact that my patients are very happy when they come back to see me after a radial access procedure. They wonder why we had ever gone through the groin in their past interventions. This is a revolutionary phase for peripheral interventions. And now that we have a longer stent and all the tools, radial access for the treatment of peripheral vascular disease should take off. We must work together to not only improve patient safety but also patient comfort. 

What do you recommend for peripheral interventionalists who are interested in learning the radial approach?

The first step is to start by doing diagnostic angiograms via a radial approach. Use diagnostic catheters, and work on your ability to navigate the aortic arch and then come down and take the pictures. I would also recommend a training course. We run training courses here at Cardiovascular Institute of the South for people who are interested in learning radial access for peripheral procedures. They can sign up for the courses via their CSI representatives. I am one of the proctors, and we would be happy to show people how the lab is being prepared and what kind of equipment is needed. Since peripheral intervention via radial access is a newer field, there is a slight hesitation in adopting a new technology, but we have all the tools available at this time to do a safe intervention.   

Disclosure: Dr. Lodha reports a consulting agreement with CSI.

Address for correspondence: Dr. Ankur Lodha can be contacted at
ankur.lodha@cardio.com.