A research track record helps physicians assess new technology

Scott Tretola
Scott Tretola

Scott Trerotola, Stanley Baum Professor and chief, Vascular and Interventional Radiology, University of Pennsylvania Medical Center, Philadelphia, USA, delivered the Dr Charles T Dotter Lecture at the 2016 Society of Interventional Radiology (SIR) annual meeting in Vancouver, Canada. An inventor of both devices and procedures, he speaks to Interventional News about his belief in evidence-based medicine and the triumphs and travails of being a physician inventor.


What was the spark that set you thinking about the first device you invented?

The first device I invented was the Arrow-Trerotola percutaneous thrombolytic device. I invented it when I was still a fellow. We were just getting into dialysis access declotting and at the time, we were doing thrombolysis with urokinase. This procedure was long, resulted in lots of bleeding and did not work that well. That is what prompted me to do something different. We were also doing a lot of biliary work and using stone baskets all the time, so I came up with the idea of spinning around a stone basket really fast. That was the genesis of the device…necessity being the mother of invention.

I developed the first prototype between 1990 and 1991 and then identified the company I was going to work with, which was Arrow (now Teleflex). Between 1992 and 1996, we carried out a large series of pre-clinical animal testing and then started the clinical trial in 1996. The trial enrolled quickly and was completed by the end of that year. We received US FDA approval in 1997 as the third mechanical thrombectomy device approved in the USA. The whole process took seven years, which is pretty quick by present-day standards.

I have also recently devised endobronchial forceps retrieval of inferior vena cava filters, also called the “jaws of life” technique that allows filter retrieval rates of close to 100%. This particular technique is something I am proud of as it has helped thousands of patients worldwide. In fact, it is the basis of all highly successful filter retrieval programmes, including the Stanford programme, where a recent paper stated that over 80% of patients started with the forceps retrieval technique. So it is something that has been disseminated and practiced by other physicians. In many cases in which people have failed to remove filters after a three- or four-hour procedure, we have succeeded using this technique in much less time.

Do you think physicians are best placed to become inventors of devices because they are the closest to perceiving clinical need?

I think it is difficult to sit down and just dream things up. I really do believe that necessity is the mother of invention. For instance, with the “jaws of life” technique, I was watching one of my partners struggling to take a filter out. I understood the problem was that the filter cap was embedded in tissue, so I walked up to operating supplies and asked if I could see everything they had that might help. I found one of these forceps and went downstairs and used one of them and it worked. Since then, we have refined it, but the bottom line is having a problem and addressing it. Doctors are the best placed to see that need as they are literally in the trenches, in this case, trying to get that filter out.

There is no question that other factors have played a part in the procedure becoming more widely disseminated. For instance, the US FDA advisories (that recommended that implanting physicians responsible for the ongoing care of patients with retrievable filters consider removing the filter as soon as protection from pulmonary embolism was no longer needed) have helped because they got the message out there. And yet, these filters were first approved in the USA in 2003 and the first FDA advisory came out in 2010. In that seven-year period we had tried desperately to get people back [to have their filters removed] and several papers were published on filter clinics, but it was only after that advisory that we could get people in for the procedure more easily. The other factor that has helped is that there is a huge legal milieu around this in the USA. There is adverting across billboards, television and radio by lawyers talking about filters and class action lawsuits. Patients are now more aware of the importance of taking filters out and quite often phone us after seeing or hearing one of these legal advertisements. For the first time in memory, doctors and lawyers are on the same page, both trying to get filters out, but for different reasons.

How do you go about persuading other physicians of the value of the devices and techniques that you have invented?

It is all about practising evidence-based medicine. One of the things I am most proud of with the percutaneous thrombolytic device is the research track record that we developed for it. Raise the most important clinical questions about the device, and they have been answered with research. There are published data on everything from valve injury, endothelial damage, particle size and pulmonary embolization—there is no other device on the market that comes close to that research track record. That is why the device has remained on the market for such a long period, because physicians do not have to just take a sales representative’s word for it. They can read the paper for themselves. The same thing applies to the “jaws of life” technique. Very early on after I invented the technique, we had not published any of the results yet, and the reputation was built around speaking at national meetings about the positive results seen with it. From 2006 onwards, we have published our experience and S William Stavropoulos recently published our first 100-patient series in Radiology in which we reported that the endobronchial forceps technique was used to successfully retrieve 109 of 114 (96%) tip-embedded inferior vena cava filters on an intention-to-treat basis. As reported in the paper, there were five failures that occurred in four patients in whom the technique was attempted but failed and one patient in whom retrieval was not attempted. Filters were in place for a mean of 465 days. Three minor complications and one major complication occurred, with no permanent sequelae.

Being peer reviewed means that it is not just your opinion; the success rate and safety record has been validated.

What is your key message to other interventionalists who have an idea for a device?

The most import message for physician inventors is that you have to document and protect your idea. If you are in an academic setting, your institution generally owns your ideas, and it is easy to protect them by writing a Report of Invention and sending it off to the Office of Technology Transfer.

If you are not in an academic setting, but in a private practice, you are on your own. This means that you will have to hire a lawyer at considerable cost to protect your idea. There are currently also a group of incubators who will protect your ideas, in exchange for a piece of the action. Although I have no personal experience of these companies, I think they range from really good to really predatory ones.

Therefore, inventors have to be very careful about protecting themselves and being very clear about what is being offered to them. It is also really important to understand the laws of disclosure in different geographies. In general, I have been careful about my ideas, but I know people who say they have gone to industry with their ideas and had them stolen from them.

What are your views on competition bettering patient care by spurring innovation, a topic of your Charles Dotter lecture?

Briefly, what competition does is that instead of a select few individuals “owning” a procedure, you have a larger group of individuals who are competing with each other. Because they are competing, they are fostering innovation and finding new ways of doing things better. This leads to better outcomes and potentially increases the volume of work being done.

Using peripheral arterial disease as an example, some 20 years ago, we were the only people doing these interventions and there was very little uptake. Now that there are multiple specialties performing these interventions, the volume of peripheral arterial interventions has dramatically increased and the market for them, which means there is interest from the industry and as a result we have access to better tools. The problem for interventional radiology was that we were not part of that increase, but that too has changed and interventional radiology is coming back as a huge competitor in peripheral interventions.

That said, inventing and innovating is a blue water strategy that has also been very successful for interventional radiology. This will continue to hold true. Although it is important for us to compete in areas that we want to remain in or get back into, I believe that the blue water strategy is still a good one to pursue for interventional radiology.