Visualization of blood flow sharpens artificial heart

Using magnetic cameras, researchers at Linköping University have examined blood flow in an artificial heart in real time. The results make it possible to design the heart in a way to reduce the risk of blood clots and red blood cells breakdown, a common problem in today’s artificial hearts. The study, published in Scientific Reports, was done in collaboration with the company Scandinavian Real Heart AB, which is developing an artificial heart.

“The heart is a muscle that never rests. It can never rest. The heart can beat for a hundred years without being serviced or stopping even once. But constructing a pump that can function in the same way – that’s a challenge,” says Tino Ebbers, professor of physiology at Linköping University.

Nearly 9,000 heart transplants are performed worldwide per year, and the number keeps increasing. So does the number of people queuing for a new heart, with some 2,800 on the waiting list in the EU alone, and around 3,400 in the US.

Most of the patients whose heart does not work at all are currently connected to a machine that takes care of their blood circulation for them. It is a large device, and the patient is confined to their hospital bed. For those patients, an artificial heart could be an option while waiting for a donor heart. 

“Finding a biologically compatible heart for a transplant can take a long time. In those cases, an artificial heart can enable the patient to wait at home. They may not be running around like Usain Bolt, but patients can be with their loved ones during the waiting period,” says Twan Bakker, PhD student at the Center for Medical Image Science and Visualization, CMIV, at LiU.

For this to happen, the technology needs refining. Blood clots and damaged red blood cells are common problems in artificial hearts with pulsating function. This is often due to areas of high and low blood speed being close to each other, or areas where the blood is stationary in the heart. High speed and turbulence can lead to the destruction of red blood cells, i.e. hemolysis, whereas low speed increases the risk of blood clots.

Minimising the risk of complications requires an in-depth understanding of how blood flows in the artificial heart. Researchers at LiU, in collaboration with the company Scandinavian Real Heart, have therefore used magnetic resonance imaging, often abbreviated as MRI, for real-time observation of the blood flow in a pulsating artificial heart. The results were then compared with the blood flow in a real heart.

“The cool thing about this technology is that it’s possible to look inside a patient, or in this case an artificial heart, without physically opening and checking – this is completely unique,” says Tino Ebbers.

What the researchers could see in the MRI images was that the blood flow in the artificial heart resembled that of a truly healthy heart. Proof that the heart is well-designed. 

Scandinavian Real Heart’s artificial heart was recently granted the designation Humanitarian Use Device (HUD) by the US Food and Drug Administration (FDA). The HUD designation makes it possible to apply for Humanitarian Device Exemption (HDE), an accelerated regulatory framework that may grant the product limited marketing rights. According to the researchers, clinical use is still a couple of years away, as pre-clinical and clinical studies first need to be completed.

“Our dream is to develop an artificial heart as a permanent solution. We’re not there yet, as we’re required to first show that it functions as a bridge to transplantation so as to prevent the patient from dying while waiting for a heart. But our ultimate goal is fantastic, and when we reach it, there will be no need for donor hearts,” says Twan Bakker.