Vascular News talks to Juan Parodi – professor of surgery at the Washington University School of Medicine and creator of the Parodi Endograft, one of the biggest innovations in the history of vascular surgery.
Parodi was led to a career in surgery through natural interest and family influence – his uncle was a surgeon,
“At school I liked biology, chemistry, everything related to science was very attractive to me,” he told Vascular News.
“In addition there was the motivation of being close to my uncle who was a surgeon.”
Initially, however, the young Parodi was also interested in architecture.
“My mother was concerned because one day I wanted to be a physician, the next day an architect, and the third day a physician again!” he recalls.
The physician in Parodi, however, won out, and in 1960 he began his medical training at the Universidad del Salvador, Buenos Aires, Argentina.
A further influence on his career, which is significant given Parodi’s destiny for creating new vascular technologies, was that of engineering.
“I had three brothers who were engineers, through them I had some background in engineering,” he explained.
“That was very positive for my career because a lot of my inventions were related more to physics than biology.”
Beginning his surgical training in Buenos Aires, an early career mentor for Parodi was Professor Manrique, whom he remains in contact with. He lists Professor Alfred Humphries and Edwin Beven at the Cleveland Clinic, where he began his residency in 1976 as the other two significant mentors in his career.
Birth of a concept
Shortly after Parodi began his surgical career, in the early 1970s, vascular surgery began to blossom as a specialty.
“There was great attraction because there was a lot of room for innovation – it was not an established sub-speciality and that particularly attracted me,” he said.
“I could see new things, as well as the treatments that were not working.”
After witnessing more than one failure in open surgical procedures, Parodi began thinking about what alternatives there might be for more vulnerable patients.
“I started to think that we needed a less aggressive treatment for patients and that we could be taking advantage of the bigger sizes of the arteries of patients with aneurysms,” he said.
“I thought we could use the femoral artery to navigate in a retrograde fashion, a graft inside the aneurysm and then to fix it with a metal frame – I call that a cage initially, because the name stent was not in use.
“But I didn’t have much success in convincing people!”
Initially, nobody paid attention to Parodi’s invention, which he continued to research without funding.
“I made the investment from my own pocket, nobody paid for any of the research that I did,” he recalls.
“I went to the lab and produced some prototypes which I tried on dogs. At first these were not very successful because I was using a primitive graft type.”
By the mid 1980s, however, Parodi was having more success with animal experiments – word of which was to lead to his first human patient.
Two vascular innovators meet
But in 1988, just before Parodi was to make history with his endograft, a meeting took place between the fathers of the two major innovations in vascular technology – Parodi and Julio Palmaz, creator of the stent.
“I met him in 1988, when he was presenting his data on stents,” Parodi recalls.
“He gave me a couple of stents because the kinds that I was using were very primitive. I tried his stents in combination with the grafts I was using. Finally I redesigned his stent for humans with big arteries, and that is the system I used in the first patient.”
Parodi’s first endograft patient
The first human being to be treated with Parodi’s endograft was fairly high profile – a friend of Carlos Menem, the then President of Argentina
“He was not a surgical candidate – he was old, had COPD, was having pains. He was on permanent oxygen – you can imagine general anaethesia in that condition.
“The president learned that I was doing some animal studies using the endograft. He called and asked if I’d ever tried it in humans. At that time I had about 45 animals treated and the results were pretty good. I met with the patient and his family, showed him the results we were having and he agreed – said ‘go ahead and try it’. And it was very successful – a very simple case really.”
On the 7 September, 1990 an excited Parodi phoned his wife from the Hospital. She thought he’d remembered their wedding anniversary, but he was actually calling to say he’d successfully used the endograft on his first human patient.
Surprisingly, despite the high profile nature of the patient, the procedure received no media attention and made little initial impact on the vascular surgery community.
“I presented the data at a small meeting: Cirujanos vasculares de habla hispana (Spanish Speaking Vascular Society) in Buenos Aires and some people, some Americans, were very impressed. The doctor who invited me to go to St Louis, Greg Sicard, was there at my first presentation in 1990. He invited me to go to St Louis as an assistant professor, where I’m now a co-professor,” Parodi recalls.
“But when I tried to publish the initial results they were not accepted in journals. They thought it was worthless, perhaps even a crazy experiment? I don’t know the reason they rejected it.
“But finally a well known vascular surgeon in America, John Bergan, invited me to dinner after attending one of my presentations. He told me he thought I had a great invention. He suggested I send the paper to a different journal, the Annals of Vascular Surgery, and finally it was accepted and published there in 1991. And that was when it made a big impact – one that’s been felt for the last 15 years I would say.”
The impact of the endograft
Parodi’s endograft undoubtedly caused the whole speciality of vascular surgery to change.
“Surgeons started to do the procedure, to treat aneurysms. They learnt you could do anything in endovascular procedures. They started to treat renal artery stenosis, iliac artery stenosis, carotids. I think I opened the door to surgeons just to learn about these new techniques, and that is very fortunate. Otherwise this specialty would disappear,” Parodi says.
“Today I would say between 40-70% of the cases, depending on where in vascular medicine, are done internventionally. That was the main impact, just to show the surgeons there was another, less invasive way to treat patients that was more effective.”
Today Parodi believes we have “level one evidence” that interventional treatment using the endograft is equivalent to standard treatment in the short term.
“In June we’ll have the results of the EVAR 2 trial which Professor Roger Greenhalgh is in charge of. Most probably we’re going to see that even in long term, this is comparable to the open surgical procedure with the advantages of being less aggressive with less morbidity – that is what we expect.
“We don’t have the results yet but we can base upon the experiences in the New York state that the long term is comparable. We are not so sure of the results of the EVAR 2 but we can predict that we’re going to find equivalencies.”
On the whole Parodi believes this is a very exciting time for everybody in vascular surgery.
“We are opening a new approach – I think there’s a lot of room for improvement, new developments. Young people can be more excited about having the opportunity for improving what we have, even creating new things. It’s an open field.
“I remember that vascular surgery for many years had no new developments. I used to go to the meetings and the subjects were all the same, and all of a sudden there was this explosion. Industry is also obviously now included and they are investing a lot of money.”
Parodi’s other innovations
While Parodi is famous for the endograft, he ironically never thought it would have any impact.
“I thought that one of my inventions, the (gastro-epiploic coronary bypass), was a great invention but that didn’t have any impact,” he muses.
“In the last years I’ve developed a new protection device to be used in carotid stenting, in stroke therapy and I think that’s what’s going to be very useful.
“Stroke is one of the last frontiers for interventionists, mechanical revascularisation of the brain assisted by flow reversal will probably have an important role.
“Mechanical revascularisation of the brain has obvious advantages such as rapid removal of occlusions and extended window for treatment with less hemorrhagic complications than the use of lytic therapy. Probably mechanical revascularisation associated with a low doses of Tissue Plasminogen Activator or Urokinase will be the first choice. Embolisation of fragments generated by mechanical treatment can now be prevented by means of temporarily induction of flow reversal in the intracranial vessels.”
Fact File: Juan Carlos Parodi,
August 16, 1942, Buenos Aires – Argentina
1966: Universidad del Salvador, Buenos Aires, Argentina
Physician and surgeon Honor Certificate
1972: University of Buenos Aires
Board Certificate in General Surgery
1979: Argentinean College of Medicine Argentinean College of Cardiovascular Surgery, Buenos Aires Province
Board Certificate in Vascular Surgery
1993: Universidad del Salvador, Buenos Aires, Argentina, Assistant Professor of Surgery :
1993-1996: The Bowman Gray School of Medicine Wake Forest University, Winston-Salem, N.C, Adjunct Associate Professor of Surgery :
1995-2003: Vice Director of the Post-Graduate Training Program in Cardiovascular Surgery of the University of Buenos Aires
1998-2000: Professor of Surgery, Division of Vascular Surgery, Wayne State University, Detroit, Michigan
1999: Honorary Professor of Surgery, Facultad de Medicina, University of Buenos Aires
2000: Clinical Professor, Department of Surgery, Wayne State University, Detroit, Michigan:
2003-: Professor of Surgery and Radiology, Department of Surgery, Washington University School of Medicine, St. Louis, MO:
Distinction and Award highlights
1976: Cleveland Clinic Foundation (Research) Award
1979: Argentine Academy of Surgery Award
1989: Argentine Society for Cardiovascular Surgery Award
1995: Erasmus Universiteit Rotterdam, Andreas Gruentzig Award
1995: Argentine Surgical Society – Poster Presentation “Eduardo Schieppatti” Award
1998: Trayectoria Nacional e Internacional Security 1998″ Award
1999: International Society of Surgery (ISS), “The Rene Leriche Prize”
2000: ISES – International Society of Endovascular Specialists, “2000 Honor Award for Excellence in Endovascular Surgery”
2005: Fourth ISET Innovator Award