Tal Golesworthy is the inventor of the ExoVasc, a bespoke implant that supports the aortic root when it has becomes weak and dilated. Tal's invention was born out of his personal need for the device to support his aorta that was expanding dangerously due to Marfan syndrome. In 2004, Tal was the first patient to be implanted with the device that he invented, and many more patients have benefited from the ExoVasc Aortic Root Support since.
Medgadget editor Tom Peach spoke with Tal Golesworthy to hear about the inspiring journey that gave birth to the ExoVasc and to learn more about Exstent, the company that was formed as a result of Tal's invention.
Tom Peach, Medgadget: So Tal, please could you introduce yourself.
Tal Golesworthy: My name is Tal Golesworthy and I am a chartered engineer—with a background in research and development in coal combustion of all things—and because I have Marfan syndrome, and I was not satisfied with an aortic root replacement, I started the PEARS (Personalized External Aortic Root Support) Project. I am now the Technical Director of Exstent, where we manufacture bespoke implants, known as the ExoVasc external aortic root support, which supports dilated aortas. The implants are currently in use in 17 surgical centers around the world; I was the first patient to be fitted with the ExoVasc device 14 years ago, and I am still going strong!
Medgadget: What is Marfan syndrome and how did your personal story of Marfan lead to you creating the ExoVasc system?
Tal: Marfan syndrome is a connective tissue disorder that is inherited; so my grandfather had it, my father had it, and I have it. As a kid my Marfan-induced fibrillin deficiency meant poor eyesight and long thin bones that were prone to fracture. When I was about 35 my father convinced me to join the Marfan Association, and I went along to a genetic study, where I discovered that my aortic root was significantly dilated. From 1992 onwards, I had my aorta measured annually, which revealed that it was expanding steadily, and I began to learn about the frankly quite horrifying Total (Aortic) Root Replacement procedure.
I was told that the operation had been around since 1968; that during the procedure I would be on cardiopulmonary bypass; that my body temperature would be dropped to 18 centigrade (64 Fahrenheit); that my heart would be stopped—and that if everything was successful I would spend the rest of my life taking Warfarin, owing to a replacement metallic heart valve. Taking anticoagulants and walking that tightrope between a bleed and a clot was something I really did not want to be doing. But by the time it got to the year 2000, I thought I really had to do something.
I spoke to Tom Treasure, a cardiothoracic surgeon then at St George's Hospital in London, and floated the idea of scanning the aorta, creating a rapid prototype model reproduction, and using that model to manufacture a perfectly fitting external support that would manage the tensile loads that my fibrillin-deficient aorta was not managing. The beauty of the idea was that the underlying vasculature was not changed—I kept my aorta, I kept my endothelium, I kept my valve—so I would not need any drugs at all!
The next four years were a crazy rollercoaster ride, and after raising money, building commercial and technical teams, and perfecting the process, in May 2004 John Pepper, a surgeon at the Royal Brompton Hospital, performed the operation and implanted the first ExoVasc device in my chest. I woke up in intensive care the next day and I can remember lying in the bed, listening and feeling very carefully to the vibrations in my chest and thinking: "yeah…I reckon it has worked." The whole thing was a hell of an experience, but I would not want to go through it again!
Medgadget: What are the alternative procedures and what are the particular advantages of PEARS?
Tal: Conventional aortic root replacement is the only other option, which, as we have said, is a major procedure that takes a long time, involves being placed on cardiopulmonary bypass, and requires body cooling and stopping the heart. If you have total root replacement (TRR) you need anticoagulation therapy for the rest of your life. If instead valve sparing root replacement (VSRR) is opted for, then the anticoagulation therapy is not needed, but the annual reoperation rate is around 1.3%, which does not sound good if you're having the procedure aged 40. In the 137 patients fitted with ExoVasc and 474 total post-operative patient years, we've had no re-operations due to device failure, so that reoperation rate for PEARS is effectively 0 right now.
Typically the PEARS procedure takes around 2 hours to complete compared to the 4-7 hours for TRR or VSRR, which is also a big advantage. And 75% of the time PEARS procedures are done without cardiopulmonary bypass. Finally, it's always good to have a fall-back option. Now for TRR that fall-back is just doing the same failed procedure again, the beauty of PEARS is that no vasculature is removed so VSRR or TRR are always there as a fall-back.
I think these advantages of PEARS are really starting to speak for themselves, and the procedure is becoming more popular, but it has taken a long time to convince people—it took 11 years to complete the first 50 PEARS procedures, but only two more years to reach 100 implantations.
Medgadget: So talk me through the journey from diagnosis to a patient having the ExoVasc device implanted.
Tal: A patient will meet with their cardiologist, and hopefully PEARS is offered as an alternative to root replacement. If PEARS treatment is elected, then the patient has a standard CT scan in ventricular diastole—so that the aorta is at its rest diameter. The hospital sends us that CT scan; we run the imaging through our bespoke reconstruction and CAD pipeline, which produces a virtual CAD model of the patient's aorta. We then overlay the model on the original CT scans, which are sent back to the cardiothoracic surgeon as a sort of prescription for the bespoke medical device that the surgeon will have to sign-off. Following clinical approval, the physical model is created using rapid-prototyping, we manufacture the bespoke implant, and after a lot of checking, cleaning, sterilising and packaging, the implant is sent to the surgeon for implantation. Typically the entire process takes about six weeks.
During the implantation the ExoVasc graft is cut to allow access for the coronary arteries and placed over the diseased aortic root before being sewn-up along all the cut lines. The device then acts as an external scaffold, halting the expansion of the aorta, and eventually becoming completely incorporated into the vessel wall.
Medgadget: What is the ExoVasc implant made of?
Tal: Now crucially the device is not woven—it does not have sharp edges that could threaten the coronary arteries—it is actually knitted and is light, porous and very flexible, easily allowing pericardial fluid to pass through the device. So despite being made of polyester (or Dacron if you prefer the brand name), because of the manufacturing process, the finished textile is completely different to the stiff, watertight composite aortic root grafts that most surgeons are used to.
Medgadget: How is the ExoVasc device regulated, and where is it available?
Tal: Given that, classically speaking, the ExoVasc is a Class 3 implantable device, understandably the MHRA in the UK and FDA in the US take it very seriously. But because the device is bespoke, the typical CE mark route into the European market does not apply. All a CE mark really does is indicate that a product is produced to an identical standard—be it a replacement hip or a Biro—but because all ExoVasc implants are non-identical custom devices, they are not eligible for CE marking. The manufacturing process that we use is identical each time, and is ISO13485 compliant, but the end result is always unique.
We are currently going through an FDA application process and hope to get approval for using the ExoVasc in the US by 2019. We have a small number of surgeons in the US who are very keen to start offering the PEARS treatment to their patients, but we have also got a route via Hospitals Corporation of America, which allows for pre- and post-operative care in the US with patients flying over to London Bridge Hospital to actually have the procedure performed in the UK. Our other treatment centers are spread across six countries and are as far-flung as New Zealand.
Medgadget: What does the future look like for Exstent and the PEARS procedure?
Tal: A lot of this is governed by the economics of the situation. If you can achieve a similar outcome with a shorter procedure time and lower reoperation rate, everyone tends to be happy. We always supply two implants, in case the first one gets damaged or adulterated or there's a problem with the initial placement. And because our implants are bespoke, they do cost more than a regular composite aortic root graft. But if you consider the lifetime cost, PEARS is considerably cheaper.
At current capacity we are able to produce grafts for around 150 procedures a year. In the UK there are currently around 250 aortic root replacements a year, and PEARS is a viable option for approximately 75% of those cases. This translates into about 1000 cases a year that are suitable for PEARS throughout Europe and another 1000 in the US and Canada. Whether that can actually come to fruition, though, is less clear. We have over 40 peer-reviewed publications detailing the successes of PEARS, but many surgeons still consider the procedure "new and experimental"—because, sadly for patients, the field is full of people who are obstructionist and very conservative.
Medgadget: Do you think that the bespoke nature of the PEARS procedure is a factor that is going to become far more common in healthcare?
Tal: I really believe that personalized medicine is the future. Now if we can get over the corporate and psychological resistance to innovation that you see in some of the large healthcare systems, then personalized medicine can offer a way forward that is both lower cost and higher quality. We are already seeing the impact in areas of imaging and rapid prototyping with innovations like bespoke knee replacements and personalized implantation jigs. We have just got to get around all the people saying, "No. This will not work." I have spent 18 years working on this project and trying to do that, which has made me pretty outspoken about it; I passionately believe that in the UK the NHS has been the greatest gift to society of the 20th century, but if healthcare does not adapt, it will not survive. Fortunately, I have worked with some incredibly smart and generous surgeons who share my vision to make things better, and together we have drawn a new line in the sand…
Tal's TEDxKraków talk from 2012:
Link: Exstent webpage…
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