Supplier Selection Ensures Timely Development Delivery

The AtriClip Gillinov-Cosgrove Left Atrial Appendage (LAA) Exclusion System, developed by AtriCure and physicians from the Cleveland Clinic, Cleveland, OH, is implanted during an open-chest procedure in a minimally invasive manner from the outside of the heart.Sometimes called the body's most lethal attachment is the left atrial appendage (LAA). This is due to the LAA's link to the formation of blood clots, which can travel to the brain and cause strokes in atrial fibrillation (AF) patients. The LAA is a small, windsock-like structure attached to the left atrium (LA), an embryologic remnant that serves no identifiable purpose in adults.

According to the American Heart Association (AHA), approximately 2.2 million Americans have AF – a number that may swell to more than 5 million by 2050 with aging U.S. demographics. AF patients also have a five-fold higher risk of stroke than the general population, according to a longitudinal study that followed 5,070 patients during 34 years. The American College of Cardiology and other leading cardiac societies recommend removal of the LAA during cardiac procedures in cases where the patient is at risk of stroke.

The most common methods, sewing the appendage closed and surgical stapling, have been shown to be largely unreliable and often introduce significant risks. Sewing the appendage prolongs cardiac bypass time and is subject to surgeon technique. Surgical stapling is reproducible, but often results in tearing and/or bleeding due to the excessive firing forces on tissue that is often diseased and friable.

A landmark study performed at the Cleveland Clinic showed that only 40% of LAA exclusions fully closed the LAA to the point where no fluid could continue to travel between the two structures. Without successful exclusion of the LAA, 50% contained thrombus, leaving patients at an even higher risk of stroke. In addition, these closure methods address only the fluid communication between the structures and electrical communication can persist. These firings have been shown to maintain AF and should be a target for elimination for therapeutic benefit.

Understanding these challenges, Jason Glithero, director of engineering and product development for AtriCure, a leading medical device company specializing in innovative cardiac surgical ablation systems explains his company's vision for a device. "We wanted to create a device that could be applied epicardially, from the outside of the heart, to eliminate the LAA from the LA." As Glithero goes on to explain, "The device works similarly to a potato chip bag clip. The continuous pressure acutely inhibits fluid communication between the structures and chronically starves the LAA muscle causing atrophy and necrosis. On the epicardial surface, the fabric provides a means for epithelial in-growth so that the device does not migrate."


A Novel Solution
The AtriClip is creating a lot of buzz at surgeon conferences, as it is the only device specifically approved for LAA exclusion; a safe and reliable method of exclusion has been the Holy Grail for cardiac thoracic surgeons.The AtriClip Gillinov-Cosgrove Left Atrial Appendage (LAA) Exclusion System, developed by AtriCure and physicians from the Cleveland Clinic, Cleveland, OH, is implanted during an open-chest procedure in a minimally invasive manner from the outside of the heart. This avoids contact with circulating blood, while eliminating blood flow communication between the LAA and the heart. Once the LAA muscle has atrophied, the device also eliminates electrical communication.

The device has two parallel titanium beams with springs on each end that create a constant, controlled pressure along its length. Polyester fabric covers the beams to stimulate epithelial ingrowth and help secure the device to the left atrium over the long term. The key to the success of the AtriClip design is controlling the rate of atrophy and necrosis of the LAA tissue – the two biggest drivers being the consistent closing force of the beams and the optimization of the fabric covering to establish rapid tissue in-growth and stability.

"Finding the right biomedical fabric supplier was a challenge; they were either so big they did not want to deal with a startup company, or they lacked the quality systems we required for a cardiac product," says Sam Privitera, vice president of product development for AtriCure. "After a few months of working with the first supplier, we realized it was a mistake, and by then our timeline was incredibly tight. We needed a partner that was nimble and could move fast."

"We were not getting the right diameter fluffiness to stimulate the right biological response. The fabric had to be soft, yet controllable, for the best tissue reaction," Glithero adds.

Privitera goes on to explain that in their business, a relationship can sometimes work from a technical standpoint even with some deficiencies, but it is impossible to overcome a mindset where quality falls short. A turning point for the company was the introduction to Secant Medical, which AtriCure immediately realized had the expertise, quality systems, and a pragmatic and open process for problem solving. Secant Medical also took a different approach by using a standard piece of equipment with a few modifications to create a fabric with a hole in the center that wrapped around the AtriClip with the right strength, elongation, and diameter.

"The project really took off from there," says Jeffrey Koslosky, director of technology and product development for Secant Medical, Perkasie, PA. "The relationship with AtriCure was unique. They were open about sharing information and even invited us to observe some of the animal studies for a better understanding of insertion of the device, and how it would function in vivo. This triggered a number of refinements that probably would not have happened in such a timely manner otherwise. Our robust collaboration, I believe, helped shorten the development time lifecycle. We had live data and a free exchange of ideas about what worked and did not work, particularly about the in-growth, so nothing was lost in translation."

About half way through the development process, new challenges developed that prompted AtriCure and Secant Medical to switch from the existing tube-shaped fabric to a ribbon design, only to revert to the tube once again. Then, later in the process, an issue arose that required a more robust suture material. "Secant Medical always stepped up and supported our needs at each stage," Privitera notes.
 

ATRIclip Specifics:
The left atrial appendage is sometimes called the body’s most lethal attachment.Physical Features:

• Malleable shaft and articulating distal mechanism enable precise delivery

Enclosed Woven Dacon Fabric:

• Atraumatic fabric used extensively in cardiac procedures
• Available in various sizes compatible with specific anatomy

Performance Features:

• Repositioning: Can be easily repositioned prior to suture release
• Parallel Closure: Corresponds to anatomy
• Dynamic Closure: Closes as tissue is compressed; Orifice is permanently sealed and tissue is fully absorbed
• Atraumatic Tissue Compression: Consistent force is applied along entire access
• Low Parallel Compression Force: Force varies with tissue thickness between 2psi to 8psi
   

Strong Relationships
In the end, Secant Medical provided three components for the AtriClip: the fabric covering the beams, the sewing suture, and a new deployment suture.In the end, Secant Medical provided three components for the AtriClip: the fabric covering the beams, the sewing suture, and a new deployment suture. According to Koslosky, the deployment suture on the original device elongated during use. Once discovered, Secant Medical had only about 10 days to identify a solution and start ramping up to produce large quantities for a launch deadline just 45 days away. To make it all work, Secant Medical also invested in and qualified a new piece of equipment based solely on a verbal commitment from AtriCure.

"There is no doubt in my mind; we will work with Secant Medical again if we ever have a product in need of a medical fabric. They are as good a partner as you can get, with the right technical and customer service skills – who constantly asks questions to improve their product," Privitera says. "The results in the field have been consistent with our preclinical and clinical trials. Customers find the AtriClip intuitive, and it is already being used for occlusion of the LAA in about 60 cardiovascular centers in the U.S. and Europe."

The AtriClip also has the potential to create an entirely new mindset for Cardio-Thoracic (CT) Surgeons. "Many surgeons fear the LA in surgery and try to avoid it at all costs because sometimes just touching it can causing bleeding and prolong a case," says Michael Rogge, director of marketing at AtriCure. "The AtriClip is creating a lot of buzz at surgeon conferences, as it is the only device specifically approved for LAA exclusion; a safe and reliable method of exclusion has been the Holy Grail for cardiac thoracic surgeons. We expect a significant increase in the number of LAA exclusions being performed with the device as the clinical evidence builds."

Approved in Europe in October 2009, and by the FDA in June 2010, AtriCure is for use under direct visualization in conjunction with other open-heart cardiac procedures on patients with AF, or for those who are at a strong risk of getting AF, which account for 30% to 60% of all heart surgeries. This groundbreaking innovation promises vast improvements to the quality of life for this patient population.

Secant Medical LLC Perkasie, PA secantmedical.com

AtriCure Inc. West Chester, OH atricure.com