By using computational fluid dynamics software and other modeling techniques for complex congenital heart disease patients, Boston Children's Hospital's pediatric cardiology team said it now better understands flow balance and characteristics in preoperative planning and is improving surgical decision-making and patient outcomes.

Turning to CFD for decision support

As a parent, when finding out your child's heart does not work perfectly, you turn to the most gifted surgeons you can find to fix and patch the flow pathways. While there are many different types of pediatric heart surgeries, most children require multiple surgeries.

The sizes and shapes of these patches and sometimes the physiologic outcomes can leave children with extra workload on their hearts. Historically, it's been hard to predict exactly how to operate to get each growing patient long-term results.

"It's a matter of how do you get that patch perfect so the child doesn't have to come back for a revision of that patch, or has narrowing of that patch that creates extra work for the heart over time, and that historically has been left to the surgeon's judgment in the operating room," explained Dr. David Hoganson, director of the Computational 3D Visualization Program in the Boston Children's Hospital's Department of Cardiac Surgery.

Engineering efforts that have been standard outside of healthcare now are helping "to take a lot of the guesswork and intraoperative decision-making off the table to dramatically increase the consistency of the outcomes, both in the geometric standpoint and from a physiologic standpoint," he told Healthcare IT News.

"I think we had one patient for whom we did about 80 different flow simulations before we settled on exactly what the best approach was," said Hoganson. "Had we done what we would have guessed from the beginning, we would have been 100% wrong, and the patient would have been back for another operation."

When the program first sought to create a team of professional engineers seven years ago, Boston Children's hired a computational fluid dynamics expert from the U.S. Department of Defense who was very familiar with the ANSYS software the hospital chose to establish a presurgical cardiac computer modeling program.

Adding more engineers from various academics and industry backgrounds, the hospital now has a team of 12 – soon to be 14 – that perform the 3D modeling workflows for patients, Hoganson said.

Getting solutions before surgery

Patients and parents will seek multiple opinions and points of view when time is available. But of course, there are times when the engineers race against the clock. 

"It's built into the challenge of this disease," Hoganson said.

"Sometimes you have the luxury of time and sometimes you don't. I think that's where building a professional engineering team that can respond and do this as quickly as can possibly be done has been totally transformational."

He said it's been exciting as a clinician to watch the CFD engineering analysis delivered on time and when the patients need it most. The time constraint piece is an important part of the solution.

"It's not just the math. It's not just the science. It's the service and the delivery and the on-time delivery that is really important."

Hoganson said his team has been working with several pediatric heart centers adopting their model and hiring engineers. While the program does not have quality metrics to share at this time, they are working on getting data published.

"We now have 75 patients in a particular valve repair workflow, and, you know, the data is extraordinary," he said.

Pediatric patients, parents embrace CFD

Though the math, science and engineering behind CFD modeling is extraordinary, Hoganson said it's the three-dimensional pictures of a child's heart that resonate with clinical families.

Because there is a lot of reliance on doctors to make complicated decisions in pediatric cardiac surgery, Boston Children's families are shown the models and flow simulation data for those options to engage in the results and "see what we see," said Hoganson.

"My little line drawings and hand-waving and the things that are sort of the standard in the field are really short of ideal," he said.

"We're putting literally the best technology on Earth to apply to these patients and doing the most we can to eliminate variability questions that could come up in the operation because we've thought of all that. We've tested all that, and we know that this is the best option."

"We've had teenage patients say, 'Well, obviously you're gonna do that, right?"

"They know we're doing everything we can … but we want the families to feel like they truly understand what's on the table."

Evolving practice, proposing billing codes

CFD is also used in respiratory medicine, the development of medical devices like dialysis machines to improve their operation, pharmaceutical efficacy, patient education, treatment decisions, air quality systems and more. The technology can also be used with artificial intelligence to analyze complex datasets and develop diagnostics. 

Using CFD to model repairs of congenital heart defects used to take two months with upwards of 19 software packages, Hoganson said, but now it takes about three weeks.

"We wanted to get to about four days for submit. Or, what takes us now 12 hours, we should get to two hours, right?

"A lot of that is software and workflow development" that continues to be refined, he said.

While some of the program's modeling workflows are not created with CFD software, Hoganson said the team is working with other heart centers and the U.S. Food and Drug Administration to standardize the workflows and build on the use of CFD in other practices.

Case complexity can challenge modeling assumptions, or team members could experience differing opinions across the iterations produced by the modeling.

"We'd like to simulate a lot more things than we can right now," Hoganson said.

Confidence from an engineering standpoint requires simulating cardiac flows "in a way that the results are trustworthy" and at this time CFD cannot be used in all patient cases.

When there are complexities, particularly in arterial circulation, they require "a very careful assessment of 'Are the tools up to up to par to tackle this?' And still, in a lot of those areas, the answer is no," he said.

Hoganson and his team also are working on payer support for CFD modeling, and are working at the national level to do that.

"There are not yet billing codes approved for these efforts, but we are pursuing those right now," he said. 

"We've actually submitted billing codes to the CPT in conjunction with the Society of Thoracic Surgeons and several other cardiology, radiology and other groups to come together to try to get this approved, which has been really exciting."

Andrea Fox is senior editor of Healthcare IT News.
Email: afox@himss.org
Healthcare IT News is a HIMSS Media publication.