New valve gets to heart of implant issue via design

Paul Mayne//Western NewsWestern Chemical Engineering professor Kibret Mequanint is part of a research project looking at creating the first-ever nanocomposite biomaterial heart-valve, which looks to reduce complications related to the surgery.

A Western researcher has teamed up with colleagues across the country to develop a next-generation heart valve that may provide patients with a safer, longer-lasting implant alternative thus greatly reducing complications after surgery, according to a new study released this week.

The newly developed synthetic valve provides a more durable implant that enables the heart to adapt faster and more seamlessly to life after surgery than current valves utilizing animal tissue. When combined with non-invasive surgical techniques, this new value offers hope for millions of heart patients around the world.

The study is highlighted in a paper, Proposed percutaneous aortic valve prosthesis made of cryogel, published this month in the Journal of Engineering in Medicine, with financial support from the Natural Sciences and Engineering Research Council of Canada.

Existing transcatheter heart valves are made of animal tissues – most often from the pericardium membrane from a cow’s heart. These valves have only moderate success to date, explained Chemical Engineering professor Kibret Mequanint. “Like anything else, it has its limitations,” he said.

On the project, Mequanint is working alongside Hadi Mohammadi, PhD’09, the project’s lead investigator who runs the Heart Valve Performance Laboratory through the University of British Columbia Okanagan’s School of Engineering. Researchers at Kelowna General Hospital are also part of the effort.

The new valve uses naturally derived nanocomposites – a material assembled with a variety of small components including gels, vinyl and cellulose. The construction lowers stress on the valve by as much as 40 per cent. Manufactured in one continuous form, it gains strength and flexibility to withstand the circulatory complications that can arise following transplantation, according to the study.

One in 10 people over the age of 75 experience problem with heart valves. Usually, those problems centre on the valve not closing properly, often cracking or thickening to restrict blood flow. That makes the heart work harder and can be life threatening for some.

Polymeric materials do not to calcify to the extent of the cow tissue.

“Calcium in the blood will stick to it (cow tissue) and will begin to accumulate, once again making it very rigid,” said Mequanint , adding the vast majority receiving such surgery are over 70 and can expect the valve to last another 10-15 years.

Many in this age range, however, won’t survive open-heart surgery. That is where catheter-based technologies come in to play as a less invasive alternative. The combination of their new material and using the non-invasive catheter-based surgery makes this new design promising for use with high-risk patients, added Mequanint.

Also, if researchers can produce a better technology for the younger population, say those in their 40s or 50s who need the surgery, Mequanint said the new valve’s longevity can potentially avoid the need for repetitive surgeries.

The valve will now undergo testing to perfect its material composition and design. The testing will include human heart simulators and large animal in-vivo studies. If successful, the valve will then proceed to clinical patient testing and could have the potential to become the new standard in heart valve replacement.