Organic mitral regurgitation (MR): genetic analysis, morphological and tissue characterization.

Despite a systematic use of the classification of organic mitral regurgitation
(MR) into Barlow*s disease and fibroelastic deficiency (FED), little is known
about the etiology of these syndromes and the differences in histopathological,
molecular and genetic abnormalities and possible overlapping of the currently
used definitions. Furthermore, correlation between echocardiographic
characteristics of different forms of organic MR and a more specific
histological and genetic classification has so far not been performed. However,
an accurate characterization of organic MR would have crucial implications for
surgical referral process and counselling, for selection of the surgical
procedure and for early diagnosis of the disease with potential identification
of the valve lesions more prone to progression and more difficult to be
operated.

See pages 8-10 of the Protocol

Main objectives of the study can be summarized as follows:
1. To thoroughly characterize valve tissue of Barlow*s MR as compared to FED.
2. To investigate the familial distribution of different forms of organic MR
and the prevalence of genetic abnormalities
3. To better identify morphological (mainly echocardiographic) characteristics
between Barlow*s and FED MR and eventually between and within familial and
non-familial MR.

See page 10 of the Protocol

observational

Main management (including peri-operative and follow-up out-patient visits,
ECG, general blood test and imaging analysis) of patients enrolled in the study
will follow current guidelines or at the discretion of the treating physician
and will therefore not bring any additional risk or benefit for the patients.
Resection of mitral valve tissue (rest material) for the histological analysis
will not be influenced by the participation of the patient to the study and
material will only be removed when it is in accordance with the optimal
surgical approach. However, a specific informed consent will be asked to
perform the histological analysis, considering that outside this study MV
tissue would not be preserved but thrown away. For the genetic analysis, a
specific informed consent will be asked, since it is currently not considered
standard clinical practice. However, Barlow*s disease is considered a
congenital (and potentially hereditary) valve abnormality for which genetic
analysis is suggested in Centers where the specific expertise is available. If
the patient agrees, genetic analysis will be performed from a simple blood
sample after an evaluation by the Clinical Geneticist (20 minutes), which
would represent for the patients a relatively small burden with minimal risks.