UK: New Heart Valve Long-Life Heart Valve Could Relieve Millions of Patients
A new polymeric heart valve with a life span potentially longer than current artificial valves has been developed by scientists at the universities of Bristol and Cambridge. The valves would also prevent the need for the millions of patients with diseased heart valves to require life-long blood thinning tablets.
Bristol/UK — More than 1.3 million patients with diseased heart valves need valve replacement therapy globally each year. There are two artificial valves currently available for this; both have limitations either in durability or in biocompatibility. Biological valves are made from fixed pig or cow tissue and have good biocompatibility, meaning patients do not need life-long blood thinning tablets. However, they only last ten to 15 years before failing. While mechanical valves have very good durability, they have poor biocompatibility and patients must take daily blood thinning drugs to prevent life threatening complications due to blood clots.
Professor Geoff Moggridge, Head of the Structured Materials Group at Cambridge's Department of Chemical Engineering and Biotechnology and Professor Raimondo Ascione, NHS Adult Cardiac Surgeon and Head of the Translational Biomedical Research Centre (TBRC) at the University of Bristol have spent three years conducting developmental work and extra-vivo and in-vivo testing on the new Polivalve.
The Polivalve, created by Professor Moggridge, Dr Marta Serrani and Dr Joanna Stasiak at Cambridge and Professor Ascione in Bristol, and building on earlier work with Professor Costantino’s group, is made from a special co-polymer and is designed to resemble the flexibility, biocompatibility and durability of a natural heart valve.
The device combines high durability with biocompatibility, addressing the limitations of current biological and mechanical artificial valves. It is made through a simple moulding process; hence it also reduces markedly manufacture and quality control costs. Initial testing in animal has been undertaken at Bristol’s TBRC facility as a first mandatory in-vivo testing step to ensure safety. Long-term in-vivo testing is already planned and funded as a necessary additional step before bringing this new treatment to patients.
According to the ISO standards a new artificial heart valve must withstand a minimum of 200 million repetitions of opening and closing during bench testing (equivalent to five-year of life span) to be tested in humans. The new Cambridge-Bristol polymeric valve has comfortably surpassed this.
The Polivalve has also exceeded the requirements of ISO standards for hydrodynamic testing, showing a functional performance in-vitro comparable to the best-in-class biological valve currently available on the market. The small feasibility pilot study in-vivo in three sheep at one to 24 hours after surgery has demonstrated the valve is easy to stitch in, no mechanical failure, no trans-valvular regurgitation, low trans-valvular gradients, and good biocompatibility at histopathology.
References: 'Design, Development, Testing at ISO standards and in-vivo feasibility study of a novel Polymeric Heart Valve Prosthesis' by G Moggridge, R Ascione et al in Biomaterials Science, a journal from the Royal Society of Chemistry