The primary objective in this randomized trial is to evaluate the safety and efficacy of a MitraClip treatment in symptomatic patients with severe mitral regurgitation in comparison to the previous default medical treatment - in a study population who is not amenable for the conventional surgical approach as current gold standard.

The presence of a significant mitral regurgitation (MR) seriously effects the patient's quality of life and is associated with an increased mortality rate. The operative treatment of MR - either mitral valve repair or replacement - is the current gold standard. However mere half of the patients with a severe and symptomatic MR actually undergo an operative treatment (EURO-HEART-SURVEY) due to restricted left ventricular ejection fraction, elderly patients with co-morbidities and high perioperative morbidity and mortality. In contrast, patients with severe and symptomatic MR not suitable for operation are treated with palliative medical therapy (heart insufficiency therapy). With the development of the MitraClip device - a minimal-invasive, percutaneous catheter-based technique - high-risk patients not suitable for surgery may receive a promising alternative treatment by approximating the mitral leaflets, thus creating a permanent leaflet coaptation and reducing or even abrogating the MR. The current data support the assumption of a safe and effective MR reduction with the MitraClip-System in inoperable high-risk patients with severe MR. But the feasibility still has to be proven in this special patient population.

Inclusion Criteria:

• age ≥ 18 years
• signed written consent
• symptomatic patients (NYHA-stadium ≥ III) for at least 3 months with an exploited medical heart insufficiency therapy
• increased perioperative risk with a logistic EuroScore ≥ 15 or STS-Score ≥ 15
• MR grade ≥ 2, amenable for MitraClip intervention assessed by an experienced interventional cardiologist
• Affirmation of in-operability by a "Heart-Team" consisting of either 1 cardiac surgeon and 1 cardiologist or 3 cardiologists

Exclusion Criteria:

• one essential cardiovascular event in the past 6 weeks; i. e. myocardial infarction, stroke, shock, cardiac decompensation, or the necessity of catecholamine therapy for haemodynamic stabilisation
• implantation of a biventricular pacemaker-device for cardiac resynchronisation therapy in the past 3 months
• solid tumor with a live expectancy < 1 year