In order to stop this from happening, physicians can use a special metal clip ("MitraClip") to clip the leaflets of the mitral valve together, thus effectively using the enlarged valve leaflet to turn one valve into two smaller ones, significantly reducing regurgitation. During this procedure, the interventional cardiologist inserts a catheter via a vein in the groin and advances it to the right atrium. Once a small cut has been made in the thin atrial wall, the cardiologist pushes the catheter into the atrium and to the mitral valve. The entire procedure is monitored using ultrasound and x-ray imaging and, in contrast to many other catheter-based interventions, is performed under general anesthesia.



The catheter-based procedure to replace a narrowed aortic valve between the left ventricle and the aorta is of even greater significance than the MitraClip procedure. Aortic valve stenosis is the most common type of heart valve disease, particularly so in elderly patients. In this condition, the left ventricle has to overcome the resistance offered by the hardened valve in order to pump blood out of the heart and into the aorta. In order to be able to replace the faulty valve, the physician inserts a balloon catheter via an artery in the groin, advancing it to the heart. Once the catheter has reached the heart, the balloon is inflated in order to dilate the narrowed aortic valve. The native valve is then replaced with an expandable prosthetic valve. This procedure can be performed without the need for general anesthesia.



Catheter-based aortic valve replacement, which is also referred to as TAVI (transcatheter aortic valve implantation), can also be performed using a minimally-invasive surgical approach. This approach is a useful alternative for patients with narrow femoral arteries, and is performed under general anesthesia. In this procedure, the surgeon inserts the catheter via a small incision placed between the ribs and, through an additional small cut in the wall of the heart, advances it to the faulty valve. Once in place, the balloon is inflated to stretch the valve open. Afterwards, the prosthetic valve is fully expanded and anchored inside the tissue of the native valve. One of the drawbacks of catheter-based aortic valve implantation is that, so far, this procedure has only been able to use easily expandable tissue valves. Tissue valves have limited durability, which has resulted in this procedure being considered mainly suitable for use in elderly patients.



As yet, there are no suitable mechanical valves available for use in this procedure. These would have to be durable, as well as flexible enough to be suitable for use with a catheter. Nonetheless, this rather promising treatment method has already become firmly established in clinical practice. In Germany, almost a third of all patients undergoing isolated (without the need for any additional surgical procedures involving the heart) aortic valve replacement are now being treated using catheter-based technologies.