Development of a Percutaneously Implantable Venous Valve Prosthesis
Chronic venous insufficiency (CVI) is an affection which occurs as an after-effect of long-time vein complaints and can be traced back to a dysfunction of vein valves. Through damage of the natural valvular cusps, which leads to a defect of the valves and consequently to an increase in pressure in the venous system, edemas appear even in mild severity codes. In the worst case, open ulcers arise, which may lead to amputation of the affected limbs.
This desease generates severe costs in the tune of 1,2 billion Euros per year for the health care system. Additionally, the community is burdend with 2,5 million days of disability per year and a high number of premature retirements. For the affected patients it personates a severe reduction in quality of life, which ranges from limitation of activity, over every degree of pain to total social isolation. The conventional method of treadment includes apart of conservative, medicamentous therapy mostly surgical strategies. Considerably gentler, percutaneous ("through the skin") procedures are currently in the transfer from animal experiments to first feasability studies in the patient. In doing so different processed animal tissues or autogenic valve-carrying vascular segments are applied to a carrying frame (stent) and implanted. However, until now available research shows the already from heart-surgery known limitations of biological valve prosthesis in terms of an unsufficient long-term function.
is therefore to develop a by catheter percutaneously implantable venous valve prosthesis, which
- is extremely miniaturized for the application in the periphery
- is inserted minimally invasive
- posesses a complex but functional geometry
- is subjected to large variations in environment
- despite slow blood flow speeds in the venous system doesn't cause thrombosis
- must be precisely produced from flexible plastics
- endures many million load cycles
- posesses a secure anchorage in the venous system and a sufficient stability
To achieve these goals, biomechanical aspects of natural vein valves are particulary considered, since these are vital for the design and the layout of a correctly functioning prosthesis. For the manufacturing of the valvular cusps a special 3D printing technology is particulary suitable. A handling system is used to precisely dose droplets of polymers of different hardness degrees to form complex free-form surfaces and edges along exactly followed paths. So a defined and locally variable distribution of deposit thickness is achievable. The process has to do this in a time- and cost-effective manner to allow for a future competitive process-technology. The to be develloped production-process offers many possible applications. The target audience for this innovative 3D printing technology are other than medical technology producers in the field of dosing technology, drive systems, valve technology, producers of mecanical plastic dampers and in general the field of rapid prototyping.
 © X. Snelgrove, under GNU Free Documentation License