Interview with David Hahn, MD, Interventional Radiologist

An Interventional Radiology Laboratory’s Experience with the REEF HP PTA Balloon Catheter

Tell us about your experience with the REEF HP PTA balloon catheter. I have had the opportunity to use the REEF HP PTA balloon catheter (Invatec, Inc., Bethlehem, Pennsylvania) since its U.S. release back in January 2010. I have been using the balloon in a busy interventional radiology lab providing the full spectrum of vascular and non-vascular interventional services in a tertiary care health system. Essentially, we needed a product that could serve as a “workhorse” angioplasty balloon for a variety of cases.

How many cases have you performed using the REEF HP PTA balloon catheter? Overall, I have used the REEF balloon in approximately 50 cases. In what types of lesions is the REEF HP PTA balloon catheter used? I have used the REEF HP PTA balloon catheter in a variety of cases including dialysis access management, declotting of arteriovenous grafts and fistulas, as well as during interventions in arterial peripheral vascular disease patients.

Describe the design features of the REEF balloon catheter and how it is deployed. The REEF HP balloon catheter has many of the design features that are necessary in a high-pressure balloon used for a variety of applications. First and foremost, the REEF has a rated burst pressure up to 22 atmospheres, which is extremely useful when faced with the particularly fibrotic and resistant lesions seen in dialysis outflow cases. The neointimal hyperplasia that constitutes the cellular biology of these lesions translates to a stenosis that is often difficult to efface at standard inflation pressures. In addition, these patients frequently have multiple angioplasties performed at the same site over the years due to restenosis and repetitive buildup of neointima. In the past, these lesions were typically dilated using a standard-pressure balloon, reserving the more costly high-pressure balloons in the event of primary balloon failure. A competitively priced workhorse high-pressure balloon such as the REEF could alleviate the cost of opening two balloons for the same lesion and decrease the overall procedure time. By “workhorse”, I am referring to the type of balloon that is most frequently stocked in the endovascular suite and is the most commonly used balloon in the laboratory. When such a balloon can address a stenosis requiring both standard and high pressures without compromising the working sheath diameter, it becomes an added design feature in a balloon. This leads us to the second useful feature, which is its low-profile diameter. The catheter can be used through the standard 6- to 8-French sheaths required for most dialysis access intervention. In addition, it has very good trackability over a guidewire, which becomes useful when navigating acute angles such as the retrograde access required for addressing a stenosis at the arterial anastomosis of an arteriovenous graft or fistula. With other high-pressure balloons on the market, I have frequently found kinking of the catheter to be an issue, especially when dealing with this type of lesion. In comparison, the REEF balloon has tended to be both kink-resistant and trackable. Lastly, the balloon appears to have a very good compliance profile. This is particularly important when treating a lesion that requires high pressure in order to efface the waist of the balloon. A compliant or semi-compliant balloon may assume an hourglass shape near burst pressures, and actually overdilate near the ends of the balloon. This can be potentially harmful to the non-diseased portion of the vessel, particularly in arteries where the risk of dissection is higher. The REEF balloon maintains its shape with minimal overdilation at the ends.

What is the learning curve with this device? Like any new device, no matter how straightforward, there is a small learning curve. Using an angioplasty balloon is a subjective experience, and different operators become comfortable with different balloons depending on personal techniques and the type of practice one has. For a high-pressure balloon, the operator must feel confident that the balloon will consistently perform without rupture at its rated burst pressure. In the event of balloon rupture, one must be able to successfully retrieve the torn balloon without worrying about distal embolization of a balloon fragment. Almost every operator who has used a balloon in this setting has experienced balloon rupture. With the current inventory of balloons on the market, rupture is usually not a large concern. When testing a new balloon, the operator has to feel that the new product will perform in a fashion consistent with or better than its competitors in terms of rupture, inflation/deflation times, trackability and compliance. From my experience, the REEF balloon requires a learning curve similar to that of the other balloons available.

Can you describe a case that illustrates the unique design features of the REEF balloon catheter? One of my first experiences using the REEF involved a dialysis patient with an upper-arm arteriovenous fistula and poor flows during hemodialysis. The fistula was approximately three years old and had required multiple interventions in the past for progressively worsening peripheral and central outflow vein stenoses. The initial diagnostic fistulagram confirmed restenosis of multiple outflow vein lesions and a new narrowing at the arterial anastomosis. In addition, there was more diffuse narrowing of the outflow vein immediately downstream from the arterial anastomosis. Of note, the outflow vein narrowing was an extremely acute angle, requiring a balloon that would track well across the narrowing. I used a 5 x 30 mm REEF balloon to first dilate the narrowing across the arterial anastomosis without difficulty. The balloon tracked well and maintained a curved shape during balloon inflation, much like a standard low-pressure balloon. Then, the same 5 x 30 mm balloon was used to treat the diffusely narrowed segment immediately downstream from the arterial anastomosis. This particular lesion required 20 atmospheres of pressure to fully efface the lesion. Conveniently, this was achieved without having to change balloons and, to me, illustrates a very basic but practical application of a versatile, modern-day high-pressure balloon. Obviously, there are clear practical advantages to consolidating a laboratory’s balloon inventory with a single product line. Changing economic factors constantly push us to streamline our inventory in order to trim unnecessary stock and costs. The challenge, however, is to achieve this without compromising the quality of the product or the outcomes of the services rendered. I think the development of a reliable, versatile, high-pressure balloon such as the REEF takes a step in the right direction.

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David Hahn, MD, is Co-Section Chief of Interventional Radiology at NorthShore University HealthSystem, and Clinical Assistant Professor of Radiology at the University of Chicago Pritzker School of Medicine in Evanston, Illinois.