Total Artificial Heart - In The Mountains?



Posted by Jeremy Windsor on Oct 03, 2018

How do you live without your heart?

In the UK there's only a handful of people who know how.

In a recent article in the Guardian, Rebecca Henderson* told her story,

"I came home from hospital in April. I'm the 19th person in the UK to get a total artificial heart (TAH) and only the second to leave hospital. Apparently I'm the only person in the world with a TAH as a treatment for heart cancer (they are usually fitted for heart failure). ... I'm attached to the pump by two tubes coming out of my stomach. I have to make sure it's charged at all times. At cafes, we have to sit near plug sockets. I have to plug myself in to stay alive. The batteries last for two and a half hours, but at about the two hour point, a loud alarm sounds. It's happened once, in a supermarket..."


Rebecca Henderson with her TAH (Image: The Guardian)


For the full article see:

https://www.google.co.uk/amp/s/amp.theguardian.com/lifeandstyle/2018/aug/31/experience-i-have-an-artificial-heart


We asked Dr Steve Pettit, consultant cardiologist and speaker at the recent British Mountain Medicine Society (BMMS) launch, some questions about the TAH.

Steve, can we start off by asking who's the TAH designed for?

The TAH is designed for patients with cardiogenic shock who are likely to die in the coming days or weeks unless they receive mechanical circulatory support. It is used to support the circulation for a limited period of time until the patient is able to undergo heart transplantation. The TAH is only used if the patient is unsuitable for more conventional forms of mechanical circulatory support, such as an implantable left ventricular assist device. 

How does it work?

A surgeon removes the majority of the patient's heart, leaving behind both atria and the great arteries. The TAH is a pump that is attached to (1) the right atrium and pulmonary arteries and (2) the left atrium and aorta. The TAH is powered by a pneumatic driveline which is tunnelled out through the abdominal wall. Patients must remain attached to a power source at all times.



The Syncardia TAH


What are the limitations of the device?

The practical day-to-day problems are that the TAH is noisy, requires a lot of heavy paraphernalia and a continuous power supply.  The major strategic limitations of the TAH relate to adverse events such as bleeding, stroke, infection and device thrombosis. These have limited the success of the TAH as a bridge to heart transplantation, particularly in countries like the UK where there is a shortage of suitable donor hearts and consequently long waiting times for heart transplantation. 

Given these limitations what will future TAH's look like?

The most widely used TAH in the current era (SynCardia TAH) is actually a relatively old device. It was developed from the Jarvik-7, a pump that was originally used in the 1970s. It is likely that future TAH will be smaller, have a more portable power supply and have biocompatible internal surfaces to reduce adverse events. A device called the Carmat heart is currently in clinical trials. It may be that advances in regenerative medicine in the coming millenia render the TAH obsolete.

From your answers this question will sound ridiculous, but given our mountain medicine bent, how do you think someone with a TAH would cope on a trip to the mountains?

It would be a brave TAH recipient who set off into the mountains. The risk of life-threatening or life-ending problems would be substantial. I don't expect that I will ever encounter this situation but I think I would advise patients to concentrate on getting through to heart transplantation, after which they can return to life as normal!

Thanks Steve for speaking to us!

*Sadly, Rebecca Henderson died from complications following heart transplant surgery in February 2019.


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