Heilman-Wholey Injector

The history of fluoroscopy and injectors

April 13, 2018
by Sean Ruck, Contributing Editor
Dr. Mark Wholey is the director for vascular and neurovascular interventions at the Allegheny Health Network in Pittsburgh and an adjunct professor of engineering in medicine at Carnegie Mellon University.

He is also one of the two people behind the creation of the flow-controlled angiographic power injector and an original founder of Medrad, now part of Bayer, which provides a portfolio of products and services along the radiology workflow, including contrast injection, informatics and service.

“The idea came about when I returned from Sweden where I had my fellowship,” said Wholey. “That’s where angiographic studies really originated, in the Scandinavian countries, mainly Sweden. I had been use to the injectors that existed in Sweden, at the university. When I came back, I met up with Steve Heilman, who was always interested in operating a business, although he was a primary care physician. I told him there was a definite need for an angiographic injector because in Sweden, where most of it was done, they were primitive but the world didn’t really have a good angiographic injector.”

The pair met for lunch nearly every day over the course of six or seven months to discuss the potential design and to determine the necessities of the equipment. Then they started the build with the initial results falling short of what they had hoped for.

“The first injector we built was a hydraulic injector. We noticed it was very hard to build because it was always leaking as oil does,” recalled Wholey.

Heilman decided they needed to build an electric motor-driven injector.

“I said ‘no … we have to … no, starting all over…’ but he insisted,” said Wholey.

Fortunately, the second time was the charm. Once the concept was decided, they stayed with it with Heilman working day and night on it, even turning his own home into a laboratory according to Wholey.

It would be difficult to replicate their success story today, partly because at the time (mid-1960s) there wasn’t FDA regulation on devices.

“It was an era in medicine where a lot of freethinking and device development occurred and that’s why so much progress was made in that era. I don’t recall any major objections, but we were so wound up ourselves. We really didn’t look for problems,” said Wholey.

On further contemplation Wholey remembered some problems, some they had control over and others that required innovation to catch up with the work they were doing.

“Syringes weren’t disposable at the time, so there were leaks that periodically had to be corrected,” said Wholey. “Obviously, since it was a flow-controlled injector, we also spent a lot of time measuring to calculate flow for carotid artery versus aortic, versus coronary.”

The duo addressed the different flow characteristics and flow features of the various compartments.

“The aorta, for example, required a high-speed 25 ccs a second because it’s a big compartment, whereas the carotid artery to the brain required 5 ccs a second,” said Wholey. “This was an innovative idea because in the past, nobody calculated flow, coronary artery or carotid to the brain. Everyone got the same injection. So it was a major accomplishment that we established a concept that flow rate control was necessary and that could control injections to the vessels.”

Even after developing the technology there were hurdles. For years, they focused on the science behind their creation, exhibiting at meetings and hoping to be recognized with science awards rather than financing. But when the time came for the next step, they flew with their injector from Pittsburgh to New York and then headed to the Connecticut factory of Picker X-ray.

“We thought it would have a great reception, that they would be very interested because it was so innovative,” said Wholey. “They weren’t. Neither in financing or distributing. When we got back to Pittsburgh, Steve said, ‘let’s do our own financing,’ so we did that, the initial funding.” Eventually, the Heilman-Wholey Injector was commercialized in 1967 by Medrad.

The first testing was done at the VA hospital in Pittsburgh where Wholey was a consultant.

“We carried the injector in and set it up for my patient,” said Wholey. “At the time, angiography was done by handheld injectors, so now we were putting a flow rate-controlled injector in for the aorta and we had it at a high 20-25 ccs per second and contrast in those days was ionic, which was transiently painful. So the first patient we ever did with ionic contrast, he felt it immensely and sat right up on the table to the point where we said to the engineer working with us we must have killed the patient.
Dr. Mark Wholey
But obviously, normal blood flow corrects and the pain goes away right away. Still, that was something we never forgot. After that, we controlled the flow much earlier.”

Their commitment to the design is admirable, taking 24 years (from 1964 to 1988) before they saw a return on investment. But that commitment also resulted in very little need to change their design.

“We had changes in syringes when they became disposable, but the dramatic changes occurred with the introduction of CT in the 1980s and MR in the 1990s,” said Wholey. “Those developments kept us very busy working to match the fluid with the efficiency of those new technologies.”