Terumo Pinnacle® Destination®
Anatomy of a guiding sheath.
The past decade has seen extensive growth in the number and types of endovascular procedures. As interventional procedures become more complex and the device armamentarium becomes more extensive—not to mention the increased demands of the patient population—the physical, material, and technical demands heavily impact the performance characteristics of the tools of the trade.
Interventionists do not want or need to be concerned about devices that may not perform adequately throughout the procedure. Consistency, simplicity, and reliability have become requisites for interventional device performance.
For guiding sheaths, the increasing scope of the endovascular procedure milieu places increasing demands on design and function. In this article, we review the structure and function of Terumo's Pinnacle Destination, an increasingly widely used interventional guiding sheath. The article concludes with a case study in which an interventional cardiologist successfully uses a Pinnacle Destination guiding sheath in a difficult intervention.
STRUCTURE: A UNIQUE BLEND OF PROPRIETARY MATERIALS AND CONSTRUCTION
Terumo's Pinnacle Destination guiding sheath owes its performance to a unique design of materials and construction. Each structural component relates to a distinct intended use and function within the device (Figure 1).
Nylon Outer Layer
The outer layer is a thermoplastic elastomer, which has a unique combination of softness and flexibility. With a high degree of kink resistance and low coefficient of friction, the nylon outer layer facilitates passage through the vasculature.
PTFE Inner Layer
The inner layer is a fluoropolymer compound. While adding strength to Destination, the inner layer has an extremely low coefficient of friction, facilitating multiple-wire passages and exchanges of interventional devices.
The stainless steel coil structure lends itself to maintaining Destination's structural integrity, which is responsible for Destination's trackability and pushability, as well as reinforcing the structure of the lumen.
The distal hydrophilic coating facilitates entry and retrieval of the Destination sheath through the arteriotomy, as well as negotiation of difficult, tortuous anatomy.
The radiopaque marker is made of gold, which allows precise visualization of Destination's tip under fluoroscopy.
The distal tip of Destination is softer and more pliable than the sheath shaft, minimizing risk of vessel trauma, while also allowing a smooth transition and easy vessel penetration.
FORM AND FUNCTION: DESIGN WITH A PURPOSE
Ease of Vessel Insertion
Destination guiding sheaths are designed to minimize vessel trauma. Smooth wire-to-dilator and dilator-to-sheath transitions allow easy insertion with decreased resistance (Figure 2).
Destination guiding sheaths are designed to be seen. The radiopaque sheath, dilator, and gold marker all contribute to visualization for precise positioning (Figure 3).
Two Valve Options: Cross-Cut and Tuohy-Borst
Destination guiding sheaths are designed with a choice of valve in mind. Both Cross-Cut and Tuohy-Borst valves are available on all Destination configurations (Figure 4).
Variety of Tip Shapes
Destination guiding sheaths are designed considering anatomical variations in vessel access; five tip shapes are available (Figure 5).
EVERY SUCCESSFUL INTERVENTION BEGINS AND ENDS WITH A GUIDING SHEATH
Approximately 1,395,000 endovascular procedures will be performed in 2007—8.2% more than in 2006 (Source: MRG, 2005). Millions of Americans are affected by peripheral vascular disease (PVD), and the market is driven by obesity, diabetes, smoking, and other lifestyle factors. As the interventional procedure market to treat PVD has grown, the numbers and types of devices utilized in these interventional procedures have likewise grown in numbers and types, variations, and new technologies and designs—all coupled with advances in clinical techniques.
Interventionists rely on delivery devices, such as guiding sheaths, to take the interventional devices (stents, balloons, atherectomy and thrombectomy devices, embolic protection devices, inferior vena cava filters, and others) to their desired anatomical destinations; otherwise, the intervention cannot be effectively performed. Thus, in their function as a "gatekeeper," the design, integrity, and performance of the guiding sheath are integral to the successful completion of the intervention.
However, in terms of the guiding sheath itself, it is not only important to deliver the interventional device to its anatomical destination, but, in the cases of atherectomy devices and other devices, it is equally important to be able to retrieve the device once it has been deployed and utilized. If the physical construct of the guiding sheath deteriorates during the course of the intervention, the results can be consequential. For example, if the lumen of a guiding sheath loses its roundness, meaning it ovalizes during the course of a procedure, then the interventional device may not be able to be retrieved without extreme complication or possibly even surgical intervention.
The Destination guiding sheath lumen is manufactured exactly round, and the stainless steel ribbon is coiled evenly along the length of the sheath, providing structural support to reinforce this roundness over the course of the intervention (Figure 6). In combination with the stainless steel outer coil, the inner liner and outer coil layers together also provide the structural strength to facilitate excellent trackability while resisting kinking. Resistance to kinking can be an important factor to consider in completing an intervention and is often overlooked, but when an interventional device such as a balloon or atherectomy device is retrieved after the procedure, withdrawal can occasionally cause the sheath to "accordion," complicating the withdrawal process.
Additionally, the PTFE inner layer, due to its inherent lubricity, allows multiple wire passes and catheter exchanges (important factors during the long and complex interventional procedures), without creating friction or roughness at the inner surface of the Destination sheath. Further, the PTFE surface is both hard and smooth, resisting gouges and scrapes that may occur in inner sheath surfaces constructed of plastic or other softer, nonslippery materials.