Mitral regurgitation and unmet therapeutic needs
Mitral valve regurgitation affects around two percent of the population and about nine percent of over 75s in industrialised countries.1 It is the most common valvular heart disease and it is continuing to grow as a result of an ageing global population.
The mitral valve ensures unidirectional blood flow from the left atrium to the left ventricle. Mitral regurgitation, is the dysfunction of this valve where a certain amount of blood, depending on the degree of insufficiency, is returned from the ventricle to the atrium during ventricular contraction. This blood regurgitation is leading to a decrease in heart function, dilation of the left ventricle and left atrium. It is responsible for patient dyspnea, deterioration of quality of life, progression to heart failure and even death.
Figure 1 : Anatomical illustration of the heart with a focus on the normal and pathological mitral valve with a coaptation defect of the valve leaflets causing mitral insufficiency.
Patients unsuitable for surgical replacement
Mitral regurgitation can be treated with open heart surgery but most patients with severe mitral regurgitation are unsuitable for it, so their failed valves cannot be replaced.
Mitral regurgitation is prevalent in high-risk patients because it is often the result of heart failure, myocardial infarction or other cardiomyopathies (secondary) and it is generally associated with poor clinical outcomes.2
Transcatheter Mitral Valve Replacement may enable their treatment and improve and extend their lives. Today there are no devices approved for TMVR.
There are two delivery approaches: the trans-apical approach and the trans-femoral trans-septal approach.
The trans-femoral/trans-septal (TF/TS) approach is the less invasive and less traumatic. It consists in introducing the delivery system by puncturing the femoral vein and delivery it through the atrial septum to reach the mitral valve.
In order to use this preferred approach, certain technological barriers must be overcome, including the possibility of introducing large valve devices into small catheter sheaths while maintaining a high degree of flexibility to facilitate anatomical navigation by following an acute-angle trajectory. This technological challenge requires a technological paradigm shift.
1 Nkomo VT, Gardin JM, Skelton TN, Gottdiener JS, Scott CG, Enriquez- Sarano M. Burden of valvular heart diseases: a population-based study. 2006;368:1005–1011. doi: 10.1016/S0140-6736(06)69208-8.
2 Mirabel M, Iung B, Baron G, et al. What are thecharacteristics of patients with severe, symptomatic,mitral regurgitation who are denied surgery? Eur Heart J 2007;28:1358–65.