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Heart surgery through a key hole


Heart valve regurgitation is one of the most common reasons for cardiac failure. The current gold standard therapy for the most complicated mitral valve is surgical repair. In collaboration with the Berne University of Applied Sciences (BFH), CoreMedic is developing medical devices for heart valve repair that are less invasive, easy to use and most importantly, result in an excellent outcome for the patient.

Fig. 1: Mitral valve regurgitation.
Photo: <a data-htmlarea-external="1" title="Opens external link in new window" class="external-link-new-window" target="_blank" href="http://www.heart-valve-surgery.com">www.heart-valve-surgery.com</a>

What is mitral valve regurgitation?
Mitral valve regurgitation (mitral insufficiency) describes the malfunctioning of the mitral valve, allowing a backflow of blood into the left atrium, which eventually results in heart failure (see Fig. 1). Mitral insufficiency is the most common form of valvular heart disease. According to the Cleveland clinic and the American Heart Association mitral valve regurgitation occurs in about 2% of the world’s population. Every year about 250 000 patients are diagnosed with it worldwide. Taking these figures into account, approximately 160 000 people suffer from this disease in Switzerland. Mitral valve regurgitation occurs with different levels of severity, with not all patients exhibiting symptoms. Patients can thus be divided into “symptomatic” and “asymptomatic” cohorts. Gold standard is surgical mitral valve repair. One of the most successful surgical interventions is the replacement of torn or elongated ligaments with sutures (see Fig. 2).

Fig. 2: Replacement of ligaments with surgical suture. Photo: A 20-year experience with mitral
valve repair with artificial chordae in 608 patients, Salvador L, et al., J Thorac Cardiovasc Surg.
2008 Jun;135(6):1280-7. doi: 10.1016/j.jtcvs.2007.12.026

While the surgical treatment of mitral valve malfunction results in excellent outcome, the procedure is delicate, requiring exquisite surgical skills and experience. The potential for applying this procedure “minimally invasive” is limited, as the surgeon needs direct access to the valve. Since this procedure is performed by opening the chest and working on the arrested heart it may be associated with potentially severe complications. This “extreme” invasiveness makes the treatment unattractive for asymptomatic patients even though their life expectancy is reduced, if the disease remains untreated. Another group of patients who are difficult to treat by open heart surgery are the so called “high risk” patients. These patients are too sick and often have various contraindications that do not allow an open chest/heart surgery. Trying to reduce the invasiveness adds to the complexity of the procedure even for experienced surgeons.

Fig. 3: Dynamic test bench to evaluate fatigue behavior (design and actual equipment). Source: CoreMedic AG

Addressing the “user’s need”
CoreMedic’s goal is to achieve the outstanding results of gold standard open heart surgery while dramatically reducing invasiveness and simultaneously keeping the complexity for the user at a minimum.
In this context CoreMedic is developing devices for both open heart surgery and minimally invasive approaches. These devices focus on allowing an easy and long lasting repair of the mitral valve with excellent outcome for the patient.
One of the devices aims at reducing the invasiveness of the surgical procedure by repairing the valve in a fast, precise and safe way while making it less user dependent. Another device is taking the treatment to a next level by reducing the invasiveness of the procedure even more. The goal is to allow for the valve repair to be carried out via the vascular route through a tiny incision in the groin, all the while performing the procedure on the beating heart. This results in dramatically reduced trauma for the patient, leading to fewer risks, a faster recovery as well as reduced costs. Such devices could therefore be a treatment option for “high risk”, “asymptomatic” and “symptomatic” patients.

Fig. 4: Proof of concept testing in an animal model under realistic conditions. In picture: Prof. Dr Thierry Carrel and PD. Dr Alberto Weber (animal laboratory at the Inselspital Berne). Source: CoreMedic AG

Design and development: beyond the product
Since the development of such a device explores “untouched” areas, an important part of the design and development requires the engineering of dedicated test equipment and set-ups.
For example, a specialized high-cycle fatigue test equipment has been designed, assembled and validated in order to simulate the load conditions a product will experience during its multiple years of use in a patient (see Fig. 3). Such a test bench allows the evaluation of a multitude of designs as well as different loading scenarios.

Joining the forces … Who we are
The area of mitral valve repair is complicated and challenging and requires a multidisciplinary approach combining different specialists to reach an optimal result.
The same applies for the development of such devices. The research and development started as a project under the Swiss Federal Commission for Technology and Innovation (CTI). This program combines teams and talents with different backgrounds and disciplines, such as academia and clinical science, as well as industry. Collaboration includes Berne University of applied Sciences, specifically the Institute of Human Centered Engineering HuCE, the Cardiovascular Engineering group of the ARTORG Center for Biomedical Engineering Research of the University of Berne, multiple clinical and medical advisors and specialists at the Inselspital, Berne University Hospital, as well as other hospitals and medical device industry specialists of CoreMedic. The current project is supervised by Prof. Dr. Josef Götte at BFH. The aim of the collaboration is to develop several minimally invasive instruments, each of which is currently in different product development phases. One of the strengths lies within the exceptional interactions and networking possibilities between the surgical, engineering and scientific disciplines. This allows for the products to be tested and evaluated by future users, with constant and direct feedback, thanks to short and uncomplicated two-way communication (see Fig. 4).
In summary, the culmination of all the efforts of the interdisciplinary teams will result in a range of unique medical devices that will revolutionize the field of cardiovascular surgery. Most importantly, these new, minimally invasive devices aim to vastly improve patient outcome, with shorter recovery times and significantly fewer perioperative complications.

Stijn Vandenberghe, Oliver Wüthrich, Thomas Bauer, Tobias Aeschlimann, Prof. Dr Josef Götte Photo: arteplus.ch