Here's what you might not know about the device capable of reviving dead heart

Image credit: SERGEY NIVENS/SHUTTERSTOCK

You've most likely heard of the device capable of reviving dead hearts — the device revolutionizing heart transplant, but here are some facts & figures you might not have known about it. Let's break it down to understand it better, shall we?

Designed by Transmedics, the "Organ care system", or simply "Heart in a box", was announced back in 2016. The device is capable of reviving a dead heart by supplying fresh, nutrient-rich, blood which aids in restoring the energy of the organ, alongside maintaining an optimum warm temperature to ensure maximum recovery. Nutrient-rich blood is fed through a tube clamped directly to the heart ensuring maximum flow or circulation of blood. The device contains a "mini circulation" system within — consisting of tubes both supplying the heart with blood as well as tubes to circulate the blood being pumped by the heart.

Currently, "heart in a box" costs $250,000 – too expensive to be distributed to every hospital at this stage of the design.

In the past only brain-dead patients were eligible as heart donors for a heart transplant, as the heart of a deceased patient was not recovered with technology in hand. However, with the introduction of "Heart in a box", the heart which has undergone "circulatory death" can now be recovered, meaning with "Heart in a box", doctors may now use deceased patients with non-functioning heart as a donors for heart transplant. This could therefore increase the number of heart transplants per year, a figure that has stayed fairly constant at 2,400 hearts annually for the last 20 years.

The system could increase the number of hearts that are transported, overcoming issues such as the time limit heart porters have when transporting a chilled heart. Typically, an organ is cooled to about 4°C (39°F) to slow down the tissue's metabolic rate and the rate of degenerative processes. Lungs, for example, only last three to six hours on ice – whereas the Transmedics device preserves lungs for 24 hours without needing to cool the organ down.

There is no blood flow around a cooled organ so it is susceptible to damage, and there is no way to test its function. This is especially critical for a patient about to undergo the invasive surgery to receive it, and the months of adapting to the new organ afterwards. Now, a team near Cambridge has taken radical steps to test how the heart functions. Using Transmedics' device, the team claims to have restarted hearts while still inside dead donors. The doctors can then observe the blood flow to vital organs, before clamping and removing the heart five minutes later. These results are unpublished.

This new technology clearly comes with challenging moral questions, in particular determining when a patient is classified as dead.

“How can you say it’s irreversible, when the circulatory function is restored in a different body? We tend to overlook that because we want to transplant these organs,” mused Robert Truog, a medical ethicist from Harvard University, to MIT Technology Review.

“My argument is that they are not dead, but also that it doesn’t matter” provided that the family has consented to the procedure. “The question is whether they are being harmed, and I would say they are not.”