Star Scientist of the Month- Dr Sam Emmanuel

As a cardiothoracic surgery registrar, Dr Sam Emmanuel knows only too well just how scarce donor hearts can be. Only 121 people received a heart transplant in 2021 Australia, with many more on the waiting list.

29 March 2022

This month’s Star Scientist, Dr Sam Emmanuel, was moved by this stark statistic to study mechanical hearts to provide a lifeline for those on the waiting list. As part of his PhD, he’s trying to improve existing technology for patients with end-stage heart failure. He’s also part of a team working on a modern generation total artificial heart.

A passion for technology

Dr Sam Emmanuel has always been fascinated by technology – both at work and at home where he’s designed a water-cooling system for his home computer that looks like it’s come straight out of a lab.

It’s this passion and curiosity that makes him the perfect fit for the Institute’s Cardiac Mechanics Laboratory where’s he completing his PhD under the guidance of Professor Chris Hayward and Dr Paul Jansz.

“It was when I was studying medicine in Sydney that I really opened my eyes to the array of interventions that could be performed surgically. I was incredibly lucky and spoiled that the University of Notre Dame was attached to St Vincent’s Hospital Sydney.”

Dr Emmanuel was able to see firsthand the positive impact of the Heart in a Box technology developed by the Institute’s Professor Peter Macdonald in conjunction with St Vincent’s Hospital.

Whilst heart disease is decreasing around the world thanks to improvements in treatment and public awareness campaigns, the number of people with end-stage heart failure is on the rise.

Heart failure on the rise

Dr Emmanuel explains why: “One of the main causes for heart failure is ischemic cardiomyopathy, which typically affects older people. Naturally, as life expectancy increases and we have an older population, we expect that proportion of individuals who are in heart failure will also increase.

“We are also seeing more and more older individuals who are still very active in their 60s and 70s, so the threshold for who’s eligible for a transplant has changed as society has changed. That’s contributing to organ scarcity and will only increase - so whilst innovations such as the heart in a box program is incredible, it became clear to me that we need to look at alternatives.”

Improving LVAD’s

Dr Emmanuel is working closely with Professor Hayward on mechanical heart pumps, known as left ventricular assist devices (LVAD). These are bridging devices to those on the heart-transplant wait list but whilst they can be a lifeline, they also have several side effects including raising the risk of stroke, pump thrombosis and gastro-intestinal bleeding.

“The current generation of devices that we use don't pulse like a heart would normally pulse. They have a motor which runs continuously. My PhD looks at the implications of having continuous blood flow in these devices. A lot of research has already shown that this mechanism raises the risk of complications, so I am focused on how to improve these devices.

“One innovation we are exploring is how to integrate the heart’s natural pacemaker signal (sino-atrial node) into these devices so that devices can learn to pulse like a normal heart would. This works by capturing the signal sent from the top of the heart (the natural pacemaker, or sino-atrial node) and relay it to the LVAD. This is work no-one else is doing and is incredibly exciting.”

Preliminary trials have shown that this is feasible, and further trials will be underway this year.

The world’s first permanent artificial heart

Dr Emmanuel is also part of the team working on the BiVACOR total artificial heart and is helping prepare for its surgical implant ahead of human trials.

He has placed a dummy replica version of the device in patients undergoing transplants to see how the device will fit in real life.

“It’s the same weight as the actual total artificial heart, and during the time between when the heart's taken out and when the new heart is put in, we have a little bit of time to put a prototype of this heart in the chest of these patients who are happy to help us out with our study.

“We were able to look at what this new device would look like in a human chest which provided us with a heap of useful data.”

Dr Emmanuel has recently published the findings as part of his PhD. “I think we are only in the infancy of what mechanics can achieve in the field of heart surgery” he adds.

A supportive mentoring environment

Dr Emmanuel also feels very lucky to be mentored by Professor Hayward who he says has been incredibly supportive.

“There is never a question which is too basic to ask him which is fantastic, and he is incredibly encouraging about my work. I've brought him some of my ideas that others might dismiss as ridiculous but he has helped me progress them.

“I also feel very fortunate to be working alongside St Vincent’s Hospital’s head of cardiac surgery - Dr Paul Jansz who is my co-supervisor. He really is the expert in this field and makes many of these complex surgical procedures look easy!”

Outside of his studies, Dr Emmanuel enjoys spending time in the great outdoors with his girlfriend.

“We have been to the Blue Mountains about six times this year already – it’s a favourite location of ours and I do try and get back to New Zealand where my parents live as much as I can but that has been hard over the last couple of years due to the pandemic.”

It’s no surprise that he also has a passion for technology outside of his work. “I really love tech and I spent a lot of time tinkering with my computer. I’ve even installed a somewhat elaborate cooling system which looks like the sort of mock circulatory loop we use in the lab which I'm somewhat embarrassed to admit to.”