C2I 2017: Nuclear industry innovation inspires life-saving heart implant

Nuclear physics and cardiology may not seem like natural bedfellows but the winner in the Health & Wellbeing category has cleverly combined the two. The Spiral-Inducing Bypass Graft is an artificial implant for the heart that induces a helical flow of blood, which improves the success of cardiovascular surgery and ultimately saves lives. It’s the result of a multi-faceted, international collaboration that spans the globe, led by Dr Amir Keshmiri.

Almost 35,000 coronary artery bypass graft (CABG) procedures take place in the UK each year. However, according to the British Heart Foundation, more than half of CABGs fail within 10 years. Haemodynamic factors are widely acknowledged as playing a key role in the thickening of blood vessels that can cause graft failure. Finding a way to manipulate blood flow would have the potential to dramatically improve the procedure’s success rate.

“My PhD was in nuclear engineering but, towards the end of 2013, I started working on a number of biomedical projects,” said Keshmiri, assistant professor of fluid dynamics at Manchester University.

Fundamentally, the principles of fluid dynamics are the same across all mediums, with the laws governing the flow of blood also applying to the dynamics of coolant in nuclear reactors. Keshmiri had studied how helical ribs on the outer surface of nuclear fuel pins in the UK’s advanced gas-cooled reactors (AGRs) led to better mixing of coolant, resulting in the enhancement of heat transfer. After developing an interest in biomed, he began to look for applications of his expertise in CFD (computational fluid dynamics) simulation.

“I was intrigued by how we could potentially apply our simulation techniques to aneurysms and try to predict ruptures, for example,” he said.

In 2014, Keshmiri met Mark Slevin, a professor in cardiovascular biology at Manchester Metropolitan University. Their relationship would form the basis of this collaboration. Discussing bypass grafts, Keshmiri noted that all the implants he had encountered had been straight. He suggested that the helical shape used in reactors could have the potential to manipulate blood flow in heart implants. After discussing the idea with Slevin, Keshmiri took to the road, attending conferences and speaking to academics and surgeons.

“Some people were really interested; some people were a bit sceptical,” Keshmiri explained. “I got various feedback and I decided to include some of those people that I had met in the project, and that’s actually how it started.”

The EPSRC provided funding for the first stage of the project, which not only supported the UK-based research but enabled Keshmiri to visit international partners and collaborators that had joined the activity.

“When the project was funded, we brought in one or two more partners because we realised some more expertise was required to achieve the objectives,” he said.

These new partners included the University of Michigan, renowned for its strong biomedical engineering unit. Here, Keshmiri worked alongside Dr Foad Kabinejadian, an expert in cardiovascular biomechanics. Together they set about optimising the graft’s structure, conducting numerous simulations to achieve the best configuration.

In 2015, Keshmiri spent three months at the Cardiovascular Research Institute at Sant Pau Hospital, Barcelona. His experience in the clinical setting helped deepen his understanding of the surgical issues at play, and the institute became a prominent partner in the project.

“That placement was fantastic because I was immersed in that medical environment, dealing with biologists and surgeons every day,” said Keshmiri. “It was a real eye-opener.”

With collaborative partners in the US and Europe already on board, Keshmiri found himself looking to Asia for the final piece of the puzzle. His extensive research led him to a journal featuring the work of biomedical engineers from Singapore.

“One of the key publications when I was doing my research was written by a group at the National University of Singapore,” Keshmiri said. “I sent an email to the main author asking about some of their results. Then I asked for some data. They were very helpful, and that led to a very successful collaboration.”

The result of the multi-disciplinary, cross-border venture is a unique biomedical device that makes use of both non-planar helicity and an optimised internal ridge within the graft. The implant promotes improved blood flow within the anastomosis – the surgical connection between the prosthetic graft and the blood vessels of the human body.

Media reports have previously referred to the graft as ‘gun barrel’, because the helical shape has a similar effect to the rifling that imparts spin on bullets. However, the reality is not as straightforward.

“The gun-barrel analogy is so catchy – and it does make sense – but in reality it’s a lot more complicated than that,” said Keshmiri.  “[The graft] has a non-planar helicity, and a gun barrel doesn’t have that.”

With so many partners working across different time zones, project co-ordination was a major challenge. Communication between the teams generally took place over Skype, with Doodle Polls used to ascertain the most convenient times. For the workload itself, a Google Drive folder was used to share documents, and the team employed a software tool called Trello to assign tasks and give everyone visibility over the project and its progress.

“Whenever you have a number of people working on different aspects of a project, Trello is a nice platform that allows everyone to access and see what everyone else is up to,” Keshmiri said. “You can signpost messages, you can upload stuff, you can do so much with it and it’s fantastic for group projects.”

Patent applications for the design of the graft are currently in review, and the team is continuing to work on the device’s optimisation while seeking development partners.

“Before you go into clinical trials or even animal trials, you’re talking about huge amounts of money required for such projects. You’re talking about millions of pounds,” said Keshmiri. “We’re looking at potential industrial partners to see if any of them might be interested in helping or contributing, or developing the design. That’s the stage we’re at now.”