First Look: Flow Medical’s next-generation thrombolysis catheter for pulmonary embolism

The startup designed its minimally invasive system to diagnose blood clots, expand inside them and deliver thrombolytic drugs with a single device. 

Flow Medical is developing a thrombolysis catheter to improve the treatment of blood clots in pulmonary embolism patients.

The Chicago-based startup designed its minimally invasive system with a novel nitinol scaffold that perforates blood clots and infuses them with tissue plasminogen activator (TPA), a thrombolytic drug commonly referred to as a clot-buster.

Flow Medical recently offered Medical Design & Outsourcing our first good look at the prototype with some images that we’re sharing here.

“We wanted to build a device where you can perform pulmonary angiograms through the device with a scaffold that would expand into the clot and deliver thrombolytic drugs. That’s a lot of things to try and do in a relatively small-profile device,” Flow Medical co-founder and CEO Jennifer Fried said in an interview.

Free webinar: Nitinol knowledge with former Edwards Lifesciences Engineering SVP Ming Wu

Flow Medical is now starting verification and validation (V&V) testing, supported by a $5 million seed round the company closed in December 2024.

Here’s what we know about the system, including details from our previous interviews with Fried and other information the company has made public in recent months.

The Flow Medical system accesses a patient’s lungs via the femoral artery and through the heart. To help physicians navigate the multi-function catheter to where it’s needed, Flow Medical designed the outer sheath of its catheter for simultaneous high-pressure diagnostics angiography.

That outer sheath has holes in it to release dye for visualizing the patient’s vasculature, allowing the physician to locate the clot and place the device inside it with precision and accuracy — and avoiding the need for device swaps between diagnosing the clot and treating it.

After the catheter is all the way through the length of the clot, the sheath pulls back to reveal the scaffold. The adjustable catheter allows for different lengths of the scaffold to match the length of the clot.

The company engineered the delivery scaffold with hollow nitinol tubing and laser-cut holes specifically for thrombolytic delivery. Nitinol’s super-elasticity allows the scaffold to compress down for catheter delivery and expand inside the patient when the sheath is retracted to disrupt the clot.

Flow Medical designed the scaffold to maximize surface contact with the clot as it delivers TPA.

The catheter also has a fiber-optic pulmonary artery pressure sensor for real-time hemodynamic monitoring. That’s meant to help physicians determine how much of the clot-busting drug to administer and for how long.

When the job is done, the scaffold compresses back down into the catheter as it retracts.

Flow Medical previously aimed for a diameter of 8 Fr for its catheter. The latest prototype is 9 Fr, and that’s the size the company plans to introduce to the market, Fried said.

“We’re really proud of the progress that we’ve made so far. We’ve done 15 animal studies to date, which have been super informative and helped us get to design freeze and to the stage where we are right now,” Fried said.

“It’s a multifunction catheter,” she later continued. “The scaffold itself took a lot of engineering in order to get it to the point where it is today. Having all of these nitinol tubes that come together, in addition to the fiber-optic sensor, in addition to the ability to perform pulmonary angiograms — that’s what makes us a 9 Fr device.”

Fried and her Flow Medical co-founders, Dr. Jonathan Paul and Dr. Osman Ahmed, discussed the system and showed how it works in the video below, which they submitted as a finalist for the MedTech Innovator accelerator’s 2024 grand prize.