The scope of percutaneous cardiac therapy has expanded from percutaneous coronary and peripheral intervention to percutaneous valve intervention, first used in the mid- eighties. Today mitral regurgitation represents the second most important native valve disease in Europe (30%) as shown by the Euro Heart Survey.
When patients present with symptoms, or when there are objective signs of poor tolerance in patients without symptoms, surgery should be performed using as often as possible surgical mitral valve repair, as this treatment has shown safety, efficacy and good long-term results.
However, real life observation, once again from the Euro Heart Survey, has shown that mitral valve repair is performed only 50% of the time. This shortfall is mostly due to a lack of expertise in performing the procedure. Finally, observations from the Euro Heart Survey also stress the fact that half of the patients, despite the presence of severe symptoms and severe mitral regurgitation, are not considered for surgery by their practising physicians. Thus, there is a need for treatment, other than surgery, for high-risk patients or those denied surgery.
Percutaneous mitral valve repair was introduced only a few years ago. There are two different approaches to percutaneous mitral valve repair.
The first approach is the edge-to-edge technique, which creates a double mitral valve orifice replicating the surgical intervention pioneered by Professor Alfieri. This technique is very demanding since it requires transseptal catheterisation and sophisticated collaboration between the echocardiographist and interventionist to catch the valve at the appropriate moment and location. Preliminary clinical results obtained in over 100 patients suggest that in expert hands the feasibility of the technique is high (80-90%) and the degree of mitral regurgitation can be reduced to mild in two-thirds of cases. In addition, the risk is low, once again, in experienced centres. In patients where the procedure was successful, two-thirds of the cases remained event free after three years. Thus these data, even if only preliminary, are encouraging.
The second possible approach is mitral annuloplasty, which is achieved by introducing a constraining device in the coronary sinus located in the vicinity of the mitral annulus. The rationale here is that ring annuloplasty is almost always combined with other procedures during surgical interventions on the mitral valve. More than ten devices have been designed and three are currently being studied. They share common technical features: distal fixation and proximal fixation in the coronary sinus and a bridge between these two fixating elements. Here the procedure is easier since it only requires a catheterisation of the coronary sinus. Preliminary results from the EVOLUTION study in 60 patients show here again high feasibility (90%) and good safety profiles since almost 80% of the patients experienced no complications within 90 days. Very preliminary efficacy data suggest a reduction in the degree of regurgitation.
Clearly at the present stage these two approaches do not yet reach the standard of the multiple surgical techniques that make the success of surgical mitral valve repair.