Pioneering anastomotic device technologies to set new standard in CABG procedures

Washington 08 May 2002At the recently held 82nd Annual Meeting of the American Association for Thoracic Surgery (AATS), two anastomotic products used in coronary artery bypass grafting (CABG) procedures drew the attention of the audience. Coalescent Surgical's U-CLIP anastomotic device and Ventrica's anastomotic connector, the Magnetic Vascular Positioner (MVP), have successfully been tested in a series of clinical trials. Both new tools allow surgeons to perform complex high-quality distal coronary anastomoses on a beating heart.

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Coronary artery disease is a major health care problem worldwide, with approximately 850.000 bypass procedures performed each year. The current methods of coronary bypass surgery can be time-consuming and technically demanding, and have limited the ability for minimally invasive CABG surgery to be routinely performed due to the constraints of manually suturing the blood vessels together.

Since the inception of coronary artery bypass surgery more than thirty years ago, surgeons have used sutures to attach or connect blood vessels called grafts, to bypass blocked coronary arteries. The site of this attachment, or connection, is called an anastomosis. It is the most critical and challenging aspect of the entire procedure and the primary purpose for the presence of the surgeon in the operating room. Anastomotic patency, or "openness", has long been the standard for evaluating the quality of this connection.

Randall K. Wolf, M.D., Director of Minimally Invasive Cardiac Surgery and Robotics at the Ohio State University Medical Center, revealed the outcome of a study entitled "Clinical and Six-Month Angiographic Evaluation of Coronary Arterial Graft Interrupted Anastomoses Using a Self-Closing Clip Device - A Multi-Center Prospective Clinical Trial". The study utilised Coalescent Surgical's U-CLIP anastomotic device, which is the first and only anastomotic product in the United States with a specific indication for CABG procedures.

Independent core lab analysis demonstrated that left internal mammary artery to left anterior descending coronary artery (LIMA to LAD) anastomoses created with the U-CLIP anastomotic device, were 100 percent perfectly patent at six months. Quantitative Coronary Angiography (QCA) revealed unprecedented outcomes in terms of overall anastomotic geometry. The ratio of the diameters of the anastomosis to the coronary vessel was greater than one, indicating uninhibited graft flow to the diseased portion of the heart.

"Although I initially recognised the potential of this new technology, I desired both personal experience and evidence-based data to support the contention that the device would result in a higher quality anastomosis", stated Richard J. Shemin, Chief of Cardiothoracic Surgery at Boston Medical Center. "These impressive study results deliver the evidence I required to confirm my own clinical experience and validate the use of the U-CLIP anastomotic device for distal coronary anastomoses."

Dr. Wolf presented three major conclusions. First, the interrupted anastomosis demonstrates excellent and unequalled long-term graft patency. Second, the U-CLIP anastomotic device technology consistently facilitates the interrupted technique in both On-Pump, or surgery performed with a cardiopulmonary bypass machine, and Off-Pump, also know as beating heart, CABG procedures. Third, the compelling patency results give cause to reevaluate the standard continuous suturing technique.

"We knew that a study of this depth and scope had the potential to make or break us as a company", commented Charles Maroney, President and Chief Executive Officer of Coalescent Surgical. "We are the first and only anastomotic device company that has chosen to validate its technology in a multi-centre, multi-surgeon study with six-month angiographic follow-up and independent core lab evaluation of LIMA to LAD graft patency using QCA. We challenged our technology on arguably the toughest anastomoses on the body, the distal coronaries on the beating heart, and compared our data to the standard of care which has been established over the last twenty years."

The U-CLIP anastomotic device was launched in August of 2000 and has been used in more than 35.000 anastomoses to date. While the majority of its usage has occurred on distal coronary anastomoses, the U-CLIP anastomotic device is experiencing adoption across multiple market segments including peripheral vascular, AV access, transplant, and general surgery.

In turn, Ventrica has developed the Magnetic Vascular Positioner (MVP), a revolutionary and proprietary method for creating a suture-less vessel anastomosis, using magnetic attraction to form an instantaneous self-aligning, self-sealing connection between two blood vessels.

The MVP device connects the "bypass graft" to the coronary artery in seconds, and is designed to be used in the distal, or smallest, portion of the coronary arteries. The technology has potential benefits as a replacement for sutures due to shorter procedure times, uniform and repeatable connections, and the potential to allow for significantly smaller incisions. Ventrica received CE Mark approval in February 2002 and intends to apply for 510(k) clearance from the United States Food and Drug Administration within a year.

In the meanwhile, Medtronic and Ventrica have signed a distribution agreement effective immediately under which Medtronic is the sole distributor of Ventrica's magnetic anastomotic connectors for use in coronary artery bypass graft (CABG) surgery in Europe.

Last February, Ventrica announced early results of its European clinical trial. The trial is designed to evaluate the safety and performance of the MVP System. Volkmar Falk, M.D., Ph.D. presented the data on behalf of Uwe Klima, M.D., Ph.D. and Gerhard Wimmer-Greinecker, M.D., Ph.D. Interim results of the clinical trial, which included 32 patients, showed a pre-discharge angiographic patency rate of 94 percent. The trial also demonstrated a 100-percent pre-discharge angiographic patency in the LIMA to LAD subset.

The Ventrica MVP System may reduce many of the challenges that are currently limiting minimally invasive bypass surgery such as space constraints, lengthy procedure times and ease-of-use. In addition, this technology has the potential to expand the number of beating-heart, "closed chest" and robotic CABG procedures.

Since 1997, Medtronic has been a pioneer in minimally invasive, beating-heart surgery with the introduction of the Octopus tissue stabiliser system and its family of products, and most recently with the release of the Starfish2 Heart Positioner. Medtronic continues to invest in minimally invasive surgical techniques, and the partnership with Ventrica is another major step forward. More news on the Ventrica study are available in the VMW March 2002 article European heart surgeons present positive clinical trial results using Ventrica's Magnetic Vascular Positioner.


Leslie Versweyveld

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