Partnership for Cardiac Device Development Pays Off

Cardiac arrhythmias can be treated by creating scar tissue to stop the electrical conduction of the heart. This scar tissue can be created mechanically or thermally (using heat or cold), though both methods have drawbacks. Creating scar tissue mechanically, which involves opening the chest and placing the patient onto a cardiopulmonary bypass circuit, is invasive, painful for patients, and carries risks including infection, kidney and lung failure, and memory loss. Creating scar tissue thermally, via a catheter with a heated tip placed in the patient’s vein and threaded into the heart, is difficult because the catheter tips are small (4.5–8 mm) and the beating heart makes creating a linear transmural lesion (from the endocardium to the epicardium) challenging. In addition, the electrophysiologist cannot directly see the catheter tip location or how much movement has occurred between the catheter tip and the heart wall. The more movement between the catheter tip and heart tissue, the less effective the coagulation of tissue procedure.

Cardiac device company nContact Inc. (Morrisville, NC) saw a need for a product that can be placed directly onto the outside of the heart to create a long, linear lesion without going through the chest wall. The challenge for nContact’s designers was to create a device that could maintain consistent contact on the outside of the heart to deliver constant energy to create visual, complete lesions. The company initially approached contract manufacturer Xeridiem (Tucson, AZ) to help design the product, which integrates radiofrequency (RF) energy transmission, perfusion, and vacuum suction to create lesions on the outside of a beating heart. However, as the clinical application evolved, so did a working partnership between the companies that furthered innovation for epicardial ablation.

Based on the initial design concept, the companies assembled a development team to build a marketable product. In less than 12 months, the product was validated, cleared by FDA, and brought to market—an incredible feat for a new technology. By working closely with the OEM, Xeridiem was able to finalize the design and production of the device for commercialization. The resulting product, the Numeris Guided Coagulation System with VisiTrax, is currently the only FDA-cleared device for the coagulation of cardiac tissue using RF energy via thoracoscopic, endoscopic, and laparoscopic surgical techniques. The Numeris System is also CE Mark-approved for the coagulation of cardiac tissue using RF energy during cardiac surgery for the treatment of arrhythmias including atrial fibrillation or atrial flutter.

The ability to respond to an evolving marketplace is crucial to success and innovation. Since FDA first cleared the device in 2006, nContact and Xeridiem have continued to rapidly develop four generations of design improvements in just five years. Here’s how they did it.

The Device

The initial product was designed for open-chest applications, but it was clear that truly minimally invasive procedures that didn’t require chest incisions (sternotomies or thorocotomies), lung deflation, or heart dissections were more likely to produce patient referrals. As such, nContact developed a new approach to access the heart through the diaphragm and a small incision through the abdomen. With the new access, an innovative device design was required. The joint nContact-Xeridiem development team had gained market experience and leveraged the technical expertise gained in the initial development. The next generation of the product was uniquely designed for endoscopic application. 

The resulting Numeris device was flexible enough to be positioned gently, under direct endoscopic visibility, throughout the atria and ventricles. To create complete, nonconductive lesions to interrupt erratic electrical signals, an ablation device must remain in constant contact with cardiac tissue, delivering consistent energy to form a complete lesion. The inability to maintain uniform tissue contact is the gating technology factor for most ablation devices, including endocardial catheters, and why reported positive patient outcomes are limited and decline over time.

Suction capabilities in the ablation system device ensure consistent and predictable contact with cardiac tissue during the creation of linear lesions by gently drawing the uneven surface of cardiac tissue into consistent contact with the RF energy source while maintaining both audible and visual confirmation of tissue contact. Perfusion through a dedicated lumen acts to cool the external surface of the device, preventing collateral tissue damage. The device directs energy epicardially deep into the tissue to prevent charring and create complete lesions.

The integration of three critical components—suction, perfusion, and energy—ensures consistent tissue contact and complete, visible lesions. The design and manufacturability of the device has allowed nContact to quickly respond to market demands and requirements as they evolve.

Manufacturing Challenges

A Xeridiem development manager championed the project to ensure the project maintained high visibility, priority, and resource allocation. The manager also discussed bigger picture items with nContact to make sure Xeridiem was properly supporting nContact’s needs.

Rather than opt for several different vendors, nContact sought a single partner to streamline the development process and manufacturing of the coagulation device line. By eliminating extra parties, which can add unnecessary complexity to a project, the company was able to maintain focus and keep critical items in priority, so problems didn’t escalate down the road. Through the various development stages, engineers from the nContact and Xeridiem teams worked closely to overcome various challenges, including manufacturing silicone tubing with the proper flexibility and stiffness that also protected areas of the body from heat generated by the ablation process. To overcome this and other hurdles, the companies met regularly to brainstorm and discuss product requirements for design and process solutions. Concepts were prototyped, and the design and process were refined through feedback from users of the medical device. At Xeridiem, the project had to be coordinated through tooling, development, production, quality, process, and engineering.

The knowledge gained in the process fostered camaraderie and trust that translated into engineering continuity, speed of development, and regulatory clearances of several generational improvements. For example, nContact had the idea for the design of the distal end of the device. Leveraging Xeridiem's experience in liquid injection molding, nContact was able to finalize a design that met its requirements and was still moldable. The third generation of the Numeris was a total redesign based on clinical feedback from physicians that took approximately 18 months from conceptualization through product delivery. The speed of this accomplishment was attributed to the proactive and symbiotic relationship between the two companies and the use of a proven development methodology.

The third-generation Numeris design gave the joint development team an opportunity to incorporate new design and manufacturing improvements based on clinical feedback. For example, physicians thought the device was too tall; the solution was to change the figure-eight extrusion to a rounded configuration using a multilumen extrusion. Another improvement increased the diameter of the vacuum lumen to increase the suction of the device. In addition, the ablation electrode was increased to create a larger lesion capability. Incorporating different silicones into the device reduced cure times and production labor. All the enhancements improved the product and decreased manufacturing costs.

Lessons Learned

As nContact discovered, selecting the right contract manufacturer is crucial to the success of any development project. Mutual respect, a commitment to excellence, attention to detail, and a focus on improving healthcare are the key ingredients in creating a great team and improving collective expertise and performance.

Medical device developers should strive to find a partner who demands excellence and has the expertise and willingness to commit the resources to the project. For an idea or project to come to fruition, there must be champions on both sides who have the respect and clout within their respective organizations to spur action and innovation. True innovation is only possible when there is open communication among an experienced team with diverse talents and an ability to test new devices, gain feedback, and redesign in a timely manner. But open communication doesn’t always come easily in an industry such as medical device development, which relies heavily on propriety information and design. For example, Xeridiem has acquired industry expertise over time. When the team at Xeridiem got the design from nContact, it could have made the device exactly as the print. However, the Xeridiem team elected to share its knowledge to make a better product. The trust is that nContact will not take the trade secrets and take them to another manufacturer.

The most successful product development occurs when technical expertise is continuously leveraged among respected partners over time. True complementary partnerships can overcome technical challenges that would be difficult to achieve individually.

New markets, new patients, and improved care are the future of healthcare. Proactively meeting these demands requires forethought and collaboration with like-minded partners who can bring specialty knowledge and experience to the development table. The symbiotic relationship between nContact and Xeridiem drove the development of the fourth generation of the Numeis EPi-Sense Guided Coagulation System with VisiTrax, which is already CE-marked and being sold in Europe. Fifth generation improvements are already being discussed. All of the different generations of coagulation devices use the same basic principle of RF energy with an integrated suction and perfusion, and the use of silicone as a thermal and electrical barrier. These products represent new applications for new markets that would not be possible without a dynamic relationship built on trust and mutual respect.

Karl Sprague joined Xeridiem in 2005 as a senior engineer to lead the development team. Since then, he has led projects to develop atrial fibrillation treatment, cardiothoracic drainage, and various enteral feeding projects. Sprague’s efforts helped the PleuraFlow Active Tube Clearance System earn a Medical Device Excellence Award and R&D 100 award in 2011. Sprague has more than 15 years of medical device design experience in cardiovascular, orthopedics, drug-delivery systems, enteral feeding, and urology. He holds a bachelor’s degree in mechanical engineering from Purdue University. Reach him at
[email protected].

Sidney Fleischman is a cofounder and the vice president of development and operations at nContact Inc. He previously cofounded the medical device companies Converge Medical Inc. (Sunnyvale, CA) and Cayenne Medical (Scottsdale, AZ). He has 21 years of experience in bringing medical devices from concept to commercialization. He holds a bachelor’s degree in mechanical engineering from the University of California, Santa Barbara. Contact him at
[email protected].