HEART TRANSPLANTS & REDESIGNING THE NEW
AN INTERVIEW WITH PROFESSOR PETER MACDONALD Peter is a professor at The University of New South Wales and Senior Staff Cardiologist at St Vincent's Hospital, Sydney.
LJ: The concept of our first issue is “Redesigning the New”, looking in particular at the constant evolution that designers, researchers and innovators undergo every day. Do you think this factors into your life and work?
PM: Very much so. Medical knowledge is constantly evolving and with this evolution comes new approaches to disease diagnosis and management.
LJ: What inspired you to pursue a research career in medicine? What are the rewards?
PM: When I started out in Medicine, I did so with the expectation that I would complete my medical training (6 years undergraduate & 6 years specialist training) after which I would know everything I needed to practice as a clinician. It was only when I finished my specialist training that I realised that while the knowledge I had gained enabled me to practice as a specialist cardiologist, the knowledge was based more on expert opinion rather than scientific evidence. After completing my specialty training I undertook a laboratory-based PHD which made me realise how shallow my knowledge was and how medical research was a long way ahead of medical practice.
LJ: Speaking from your own experiences, what are the main issues of current heart transplant technologies and procedures?
PM: The main challenge in heart transplantation is the lack of suitable heart donors in relation to the need for heart transplantation. The number of people who could benefit from a heart transplant is far in excess of the number of donors. Someone else has to die before a person is able to receive a heart transplant. No one wishes for more people to die simply so that others can benefit from heart (or other organ) transplant but if a person does die in circumstances that allow the possibility of organ transplantation my hope is that that person or his/her family consent to organ donation. At present the consent rate for organ donation in Australia is just over 60%. The consent rate has been improving over the last 6 years since the establishment of a DonateLife network but as a nation we are still well short of the target of 75% consent rate.
In the meantime, we only retrieve and transplant hearts from about 30% of deceased donors. The hearts of the remaining 70% are considered either unsuitable due to known pre-existing heart disease in the donor or because of uncertainty about the state of the heart after death. I believe that with recent advances in the technology available to retrieve and preserve the heart (e.g like the ‘heart in the box’) we can overcome much of this uncertainty. So, I think this technology has the potential to double the current rate of heart transplantation.
LJ: How does Australia place in terms of research and medical innovation? How does being part of a leading transplant program influence your work?
PM: I think Australia performs very well in terms of research & medical innovation. The heart & lung transplant program at St Vincent’s where I work, as well as the other Australian centres, are highly regarded internationally. Indeed two of our members are past-presidents of the International Society for Heart & Lung Transplantation. I think being part of a leading transplant program does stimulate everybody who is a part of the program to strive to maintain world’s best practice in the service that we provide to the people of Australia.
LJ: How is your research team structured? How are ideas shared? How are programs and research goal defined? How do you believe this correlates with the quality and efficiency of your work?
PM: We have a multi-disciplinary team that is made up of a number of clinician scientists who have experience both in the clinic as well as in the research lab, two post-doctoral research scientists who have a background in biomedical science and anywhere between 2 and 4 higher degree students – mainly PhD but also Honours and MD students. Most of our students have a medical or surgical background. We have weekly lab meetings which mainly focus on the progress of our current research projects but also provide a forum for ‘brain-storming’ new ideas and concepts. Our research group has always had a strong translational (bench to bedside) focus and the clinician scientists are the ones best placed strategically to identify the clinical challenges that can be addressed through laboratory research. The ‘hard core’ scientists bring a unique perspective and the students who haven’t yet been indoctrinated into a scientific pattern of thinking are the ones who often come up with the crazy ideas that turn out to be the most interesting! I think the students are critical to the success of any research group.
LJ: What is the biggest change you have seen within cardiology and organ donation since you first started? How has your work contributed to the evolution of modern medicine and research practices?
PM: In clinical Cardiology, the biggest change has been the emergence of evidence-based medicine through large scale clinical trials which have established the life-saving benefits of many new drugs and procedures. There has also been a strong shift away from traditional complex cardiac surgical procedures towards catheter-based or minimally invasive procedures for many diseases. Many more people now are surviving heart attacks than when I first started training in Cardiology however there is a price to pay for this. We are now seeing an ageing population with damaged hearts who are presenting with heart failure as a clinical syndrome. There is a lot we can do to help these people but ultimately most of these patients will die from their heart condition.
As mentioned above, I think the major contribution of our laboratory-based research has been to increase the number of hearts that can be transplanted from deceased donors.
LJ: Education is a crucial component to clinical research. How do you think those unaffected by heart disease can best be educated/made aware in regards to heart related illnesses?
PM: I think the Australian public generally has a good understanding of those life-style factors that lead to heart disease. Both Government and NGOs like the National Heart Foundation have a role to play in educating the general public. I think this needs to start early – during school – but needs constant reinforcement. While we have been very successful as a society in controlling some risk factors like smoking others e.g being overweight and diabetes are on the increase. Cardiovascular disease, including heart disease and stroke remains the leading cause of death and disability in our society so we still have a lot of work to do.
LJ: You mention in your recent interview at the 2015 ESOT in Brussels the importance of using the correct terminology in discussing organ donation with the public. What current strategies do you see put in place to limit the language gap between medical professionals and the general public? Is there room for improvement?
PM: The example I gave in that interview is the use of the term ‘donation after cardiac death’ in place of the term ‘donation after circulatory death’. The term ‘donation after cardiac death’ is wrong both medically and legally. Unfortunately it is a term that has been used widely especially within the transplant community and has even appeared on official Government documents. When terms like this are used, it is easy to see how the general public becomes confused about the diagnosis of death when a heart is removed from a DCD donor and successfully transplanted into a recipient. How can a heart be successfully transplanted after ‘cardiac death’? Was the donor actually dead? These are the sort of questions I hear.
The heart is not the circulation. While the heart is critical to maintaining the circulation, it is only one of a number of vital organs needed to maintain an intact circulation. Failure of any or all of these organs e.g brain, lungs, kidneys or liver will lead to cessation of the circulation. In the most common clinical scenario, the potential DCD donor has suffered a catastrophic brain injury but has not progressed to brain death. When life support is withdrawn in the intensive care unit (because of the futility of maintaining life support) after family consent, the heart, lungs, liver and kidney all stop working. The circulation ceases and after an observation period that is determined by law, death is declared. At this time-point the patient has died. If the family of that person has consented to organ donation and the organs are suitable for transplantation then the deceased person will be transferred to the operating theatre where the organs are rapidly removed. The surgical wounds are closed and the deceased then transferred to the mortuary. If the family has not consented to organ donation or the donor is not medically suitable for donation then the deceased is transferred directly to the mortuary from the intensive care unit.
LJ: Are there other fields within medical research that you would like to pursue in the future or bring more awareness towards?
PM: As I have grown older along with my patients I have become interested in ‘frailty’. Frailty is well recognised among geriatricians as a syndrome of reduced physiological reserve usually in associated with weight loss, loss of muscle bulk (sarcopenia), reduced strength and mobility. We have begun to assess frailty in all patients referred for heart and lung transplantation and found it to be quite prevalent and not necessarily related to chronological age. We know from our own studies and from the work of other investigators that frail patients have a much higher mortality risk when undergoing complex surgical procedures like heart or lung transplantation and VAD implantation. We also know that frailty is reversible after heart or lung transplantation at least in some cases. As our population ages I think frailty is going to become an increasingly important factor in determining what is the best treatment for our patients.