In 2013, a research team led by Prof. Dr. Georg Lutter, senior physician at the Clinic for Cardiovascular Surgery and principal investigator at the DZHK partner site Hamburg/Kiel/Lübeck, succeeded in developing the world's first mitral valve stent that can be implanted in the beating heart. The implant is inserted directly into the heart in a minimally invasive procedure through a small incision of about three centimetres in the chest and with the help of a catheter between two ribs. Once there, the implant can immediately take over the function of the defective mitral valve. The procedure takes about an hour and a half.
The new heart valve technology developed in Kiel has been used worldwide since 2015, including in the USA, Australia, Norway and the UK as part of a pivotal study involving more than 300 patients. The study showed that 98 out of 100 patients achieved complete tightness of the valve, which is essential for heart function, even after twelve months. In addition to restoring heart function, the majority of patients also showed significant improvement in their kidney function. Overall, the patients' quality of life improved: Patients were able to breathe more easily, move around more and feel much better. These very positive results for patients have been published in the prestigious Journal of the American College of Cardiology.
The mitral valve is one of the heart's four valves. It lies between the left atrium and the left ventricle. If it does not close completely, blood flows back into the left atrium with each heartbeat. Moderate or severe mitral valve insufficiency is the second most common heart valve defect in Europe. In severe cases, the organs are not supplied with enough oxygen-rich blood and lung function is impaired. Shortness of breath, fluid in the lungs and severe fatigue may be signs of this heart failure.
Defective heart valves are usually replaced or reconstructed in well-established surgical procedures: Under general anaesthetic, all or part of the chest is opened and a heart-lung machine temporarily takes over the heart's work. Catheter-based valve replacement is mainly used when this procedure is not medically justified due to secondary diseases.
So far, catheter-based procedures have been developed to replace two heart valves, the pulmonary valve and the aortic valve. Since 2008, new aortic valves have been implanted under certain conditions using a minimally invasive catheter procedure (TAVI) at the UKSH, Campus Kiel. More than 1,800 patients have already undergone this procedure. As only a small incision and in some cases no anaesthesia is required to implant the aortic valve through a catheter, the operation time and physical stress for the patient can be significantly reduced. "The same applies to the new catheter-based mitral valve stent," says Prof. Lutter, who holds the Research Chair in Experimental Heart Surgery and Valve Replacement at the Department of Cardiovascular Surgery. Patients only need a short anaesthetic. The pivotal study showed that many were able to go home just five days after the procedure.
In contrast to the aortic valve, the mitral valve is much more complex to treat with a stent: "The biggest challenge in developing the new catheter procedure was the fact that the mitral valve is very mobile and is located between two left ventricles," says Prof. Lutter. "There is a lot of muscle movement and a lot of flow, so the new mitral valve, which is also inserted with the cardiac catheter through a small chest incision under the left breast, has to have a good hold for fixation in this area." However, the procedure has now become so sophisticated that even poorly closing and heavily calcified mitral valves can be treated well.
Contact: Prof. Dr. Georg Lutter, University Hospital Schleswig-Holstein, Campus Kiel
Clinic for Cardiovascular Surgery, georg.lutter(at)uksh.de
Source: Press release University Medical Centre Schleswig-Holstein