Project: Novel technique for Coronary Artery Bypass Graft (CABG) surgery on the beating heart.

Coronary Artery Disease (CAD) occurs when atherosclerotic plaque builds up in the wall of the arteries that supply blood to the heart. When coronary arteries narrow the blood supply might become inadequate to meet the oxygen demand and the heart muscle starts getting depleted of oxygen. If a blood clot forms on top of this plaque, the artery becomes completely blocked which might cause a heart attack (see figure 1). Obstruction of the blood flow can result in damage or death of the heart tissue. In the US alone, more than 13 million people suffer from CAD and 1.25 million people have a heart attack each year. In 2006, more than 425,000 people died as a result [1,2]. _x000D__x000D_Medicines and surgery are the two CO treatment options. Drugs aim to reduce the heart muscle demand for oxygen, lower bad cholesterol levels in the blood to prevent plaque buildup and blood thinners are used to prevent undesired platelet activation and formation of blood clots. Percutaneous coronary intervention (PCI) might also be used. In this procedure a small balloon (called percutaneous transluminal coronary angioplasty (PTCA)), stent or atherectomy device is used to compress the plaque. However, in many patients drug therapy fails and they are no candidates for PCI. In those patients, Coronary Artery Bypass Graft (CABG) surgery is required (see figure 1). In CABG surgery a blood vessel is removed or redirected from one area of the body and placed around the area or areas of narrowing to "bypass" the blockages and restore blood flow, oxygen and nutrients supply (see figure 1). 800,000 CABG surgeries are performed annually worldwide making it one of the most common major operations. CABG surgery is no easy surgical procedure, requires complex microsurgical skills, is time-consuming, invasive and is associated with high risks. _x000D__x000D_Current methods include “on pump or open heart” surgery in which the chest needs to be opened and the heart is temporarily stopped to perform the bypass surgery, using a heart lung machine that takes over. Open heart surgery is highly invasive, takes 4-6 hours and is associated with high risks for the patient. “Off pump or beating heart” surgery is a relatively new procedure, in which the surgery is performed on the beating heart using special equipment to stabilize the heart. This method is less invasive than traditional on pump surgery, but limited to only a small number of patients because it requires microsurgical suturing (stitching) to connect the donor vessel to the recipient vessel on the beating heart, posing significant risks. The most recent and advanced method is “minimally invasive key-hole size” surgery. Key-hole size surgery allows the surgeon to create a bypass through a tiny, two-and-a-half inch opening between two ribs. Although most promising to date, this procedure is complex and technical challenging. Microsurgical suturing of the donor vessel to the recipient vessel is one of the most critical, technical challenging and time-consuming steps in applying a surgical bypass. It demands a high level of microsurgical skills, including microsutures that have to be performed on the tissue of the beating heart using surgical equipment involving numerous difficult movements close to the heart. Using key-hole size bypass is therefore extremely challenging to perform on arteries under difficult angles in a limited space and therefore arteries at difficult location (e.g. the back of the heart) cannot be reached. This limits the scalability of this approach to only a small number of patients with easy to access arteries. _x000D__x000D_Moreover, current key-hole size methods do not allow performing bypass surgery without temporary occlusion of the arteries. Procedures that allow for occlusive cardiac bypass surgery are highly invasive and risky for the patient. In conventional bypass surgery the surgeon selects 1 or 2 suitable sites on a recipient blood vessel to make an anastomosis. During this procedure the arteries need to be clamped to make the anastomosis possible. In this way, the bloodstream is temporarily closed (see picture 2). This could result in a so called ischemic event due to low oxygen supply and damage of local tissue. In addition, the use of clamps is associated with increased risk for embolic stroke because plaque in the arteries could get loose resulting in blocking of arteries. These aspects of current key-hole size methods make bypass surgery too risky for a majority of patients. _x000D__x000D_Surgeons at renowned medical centers world-wide strongly believe that if minimally invasive key-hole CABG surgical procedure could be made more simple and non-occlusive, CABG surgery could be safely applied to a much larger patient population. Therefore, the consortium aims to develop a novel surgical method for advanced, efficient and safe cardiac bypass. To achieve this goal, the consortium will combine innovative technology platforms. Elana bv, Peter Lazic GmbH and the University Medical Center Utrecht join forces._x000D_

Acronym NewHeart (Reference Number: 5732)
Duration 01/07/2010 - 30/06/2013
Project Topic This program aims to develop a new surgical technique that will facilitate to perform a safe, minimally-invasive and sutureless coronary bypass surgery on the beating heart.
Project Results
(after finalisation)
The NewHeart project aimed to develope a completely sutureless anastomosis to be applied during bypass surgery at the beating heart (CABG). The to be developed device will be based on the principle of the non-occlusive Elana Technique. Further we used the experience gained during the development of an earlier experimental anastomotic device (Elana Slide) for cerebral bypass surgery. _x000D__x000D_ The physiological requirements for CABG were researched and the indication range was determined. An analysis was made for existing, partly commercialized anastomotic devices for CABG and their success / failure. Important factors for success are: a minimal amount of body foreign material inside the vessel (BENIS Score), and to cause as little as possible damage to the endothelial lining of the blood vessel during application of the device._x000D__x000D_A side-to-side anastomose technique was developed for the Elana Slide. A bypass graft (LIMA/RIMA) is connected sidewards to the recipient artery and the anastomosis opening is burned open with a laser catheter. In-vivo experiments on a series of 12 rabbits was performed to test the safety of the side-to-side anastomose design. _x000D__x000D_The prototype of the new anastomotic device (Elana Clip 3.0) was a combination of the existing Elana Slide and a hinge mechanism used in aneurysm clips made by the company Peter Lazic. Through in-vitro experiments (Elana Praxis Model with rabbit arteries and on pig hearts obtained from a commercial slaughterhouse), and in-vivo experiments (pigs) the applicability and safety of the new clip was tested. _x000D_First design aspect of the clip concerned the configuration of the upper ring and the ring-shaped lower fork. We compared a ring to ring contact with a push button configuration. It appeared that the push button gives a better hemostasis and a more stable anastomosis. _x000D_Second design aspect was the fixation of the donor graft to the ring element of the clip. We compared a smooth ring with a tagged ring (crown ring). Both designs offered a comparable reliable performance, whereby the tagged ring the bypass graft better fixates, but a repositioning of bypass graft becomes more difficult as soon as the graft is connected to the tagged ring. Both designs can be applied in the final design, whereby the opinion of the surgeon becomes leading for the to be commercialized device. _x000D_Third design aspect concerned the combined use of the new Clip 3.0 and the laser catheter. In order to better position the tip of the catheter in the ring element of the clip a catheter design change was conceived whereby a cone is placed on the tip of the catheter. In-vitro experiments showed that the cone improves the positioning of the catheter. However, modification of the Elana Catheter would mean an enormous investment. Therefore it was verified in a pig survival model whether the standard Elana catheter would function reliably in a clinical setting. A small pilot series of 7 pigs on the Carotis model showed that the standard Elana catheter performs unreliable with the new clip 3.0. The pig survival study on the beating heart was cancelled until the design change of the catheter will be implemented. _x000D__x000D_ The test protocol for the Elana Clip 3.0 included the measurement of mechanical strength and stability, fatigue testing at a simulated physiological load of 1 year use, MRI compatibility, and biocompatibility (survival study on 14 pigs). All test results confirmed the safety and a reliable performance of the Clip 3.0. With the company Peter Lazic we started the setup of the serial production of the clip. The production process was determined and suppliers were selected. Production will happen based on the principle of the ISO 13485 quality system and preferably with certified supplier. Cleaning, packaging and gamma sterilization are still open, but that has no immediate priority._x000D__x000D_
Network Eurostars
Call Eurostars Cut-Off 4

Project partner

Number Name Role Country
3 Vascular Connect BV Coordinator Netherlands
3 Peter Lazic GmbH Microsurgical Instruments Partner Germany
3 University Medical Center Utrecht Partner Netherlands