Vascular Innovation Spotlight: PEDRA Technology | Real-Time Tissue Perfusion Monitoring

Written by Kymberlie McNicholas, Founder of The Way to My Heart

“Every doctor has to make a series of on-table, real-time decisions as to which lesion to open, and whether he should continue or end the procedure,” explains PEDRA Technology Co-founder & CEO Kareen Looi. “The ideal tool to help these doctors make this critical decision is a device that can show changes in foot tissue perfusion, in real-time, as the doctor carries out his ballooning.” 

As part of our ongoing Vascular Innovation Series in conjunction with The Way to My Heart, Emmy Award-winning Journalist Kym McNicholas interviews PEDRA Technology Co-founder & CEO Kareen Looi.  Written by Kym McNicholas. 

I was in a procedure recently in which an interventional specialist unblocked a long, calcified occlusion in the Common Femoral Artery (CFA) extending beyond the profunda (deep artery of the thigh). Following rotational atherectomy and angioplasty using a low-slow inflation technique, the bolus chase showed continuous flow into the foot even with a one-vessel run-off. What it didn’t show was whether or not the body was using that additional flow and oxygen to heal the patient’s foot ulcer. The patient was back on the table within days to open additional vessels to increase flow to the foot, ultimately leading to complete wound healing months later. 

Angiography can be a tricky tool because it provides a two-dimensional image of a three-dimensional leg. Blood flow to the main arteries is critical but delivering the oxygen through the capillary bed (perfusion) is also important for wound healing. Doctors can’t measure perfusion with angiography. So, simply reestablishing one-vessel runoff may not negate the risk of worsening symptoms or amputation in the future.  

What if a doctor had a tool that in real-time could help them determine whether a nice-looking angiogram of a re-opened vessel is translating into perfusion changes? A perfusion monitor could help guide a doctor to determining in real-time whether a conservative intervention with single-vessel run-off is enough or be guided to opening more vessels to increase flow to the foot. That’s what PEDRA Technology, based in Singapore, has developed. Co-founder & CEO Kareen Looi explains how the technology was developed and plans to bring it to market.  

What is the story behind the trial? Where did it originate?

I would say the origin story started with renowned Interventional Cardiologist Dr. Craig Walker, from the Cardiovascular Institute of the South in Louisiana, who has been an advocate for saving limbs and lives for many years.  More than 10 years ago, he had voiced the need for real-time tissue perfusion monitoring in the cath lab where angioplasty procedures are undertaken.  As an experienced operator, he had observed that there were many cases where angiographically-defined success failed to translate to good patient outcomes.  Fast forward several years and literally on the other side of the globe, we saw this “black box with cables sticking out of it” on a university benchtop at the Nanyang Technological University of Singapore.  Didn’t look like much, but it could do what no other device was capable of, which is to provide a signal output that tracked perfusion changes in real-time.  A known clinical need meets the right technology, a light bulb goes on, and the rest is history. 

What need does it address?

In balloon angioplasty, a balloon catheter is used to open blocked blood vessels in the leg.  Typically, there are several blockages/lesions present in different blood vessels.  This requires the physician to make important decisions during the operation.  On the one hand, it makes sense to aggressively open all lesions so as to maximize blood flow to the foot.  On the other hand, every lesion that he attempts to open carries additional risk of vessel perforation, dissection (splitting) of the vessel wall, contrast- induced renal injury, and other potential complications.     

So, every doctor has to make a series of on-table, real-time decisions as to which lesion to open, and whether he should continue or end the procedure.  The ideal tool to help these doctors make this critical decision is a device that can show changes in foot tissue perfusion, in real-time, as the doctor carries out his ballooning.  Lacking such a tool, doctors rely on X-ray angiograms, which often give rise to “false positive” guidance i.e. a nice-looking angiogram of a re-opened vessel can give the doctor false confidence to end the procedure prematurely, only to see the patient lose a limb within weeks.     

What is the potential for patient impact?

The impact can be huge in terms of reducing errors in subjective judgment, which can happen even to the best operators when they rely solely on angiographic images in the cath lab.  By measuring success against an objective, quantitative perfusion number, we should see more instances of good angioplasty outcomes, which is critical to achieving pain alleviation, wound healing and limb salvage.  When a wound has sufficient blood flow, it heals faster, and this reduces the number of follow-up visits to a wound care center.  Additionally, wounds that are adequately perfused are much more likely to benefit from hyperbaric oxygen therapy.

If you have a specific example of how your technology has helped a patient or testimonials and are able to share, we would love to include it. 

We are still in early clinical research and our device is largely used in blinded studies, so we are not yet in a position to obtain patient testimonials.  However, I remember a case from our UK study where the physician had opened up the main blockage in the anterior tibial artery, and the completion angiogram suggested strongly that this had restored perfusion significantly to the foot. But our perfusion feedback guided to the contrary i.e. that perfusion had fallen.  So, which guidance was correct?  Fortunately, that case took place in a sophisticated cath lab expensively equipped with a 2D perfusion imaging system, so we were able to confirm that PEDRA’s perfusion guidance was more on point.  When the physician opened up the ATA, that presented well on the angiographic image, but in reality, the microcirculatory blood flow had, as an inadvertent result, been shunted AWAY from the tissue around the foot wound to other parts of the foot.  This was what our device was able to pick up.  If the physician had not been blinded to our signal during the study, he could have been guided to open more vessels, and that patient might have had a much better outcome. 

We’ve also seen pre-clinical and clinical examples of how our perfusion monitor was able to help in detecting elastic recoil, as well as the under-sizing of an angioplasty balloon.  The latter may be important in the era of drug-coated balloons, where appropriate balloon sizing is critical. 

Where is the technology in development and what is next for the company? 

We’ve reached a pre-production prototype, which is one step away from scaled-up manufacturing design and will be entering more clinical studies in the US in 2021.  Having had several discussions with the FDA, we anticipate that regulatory approval could be achieved as early as November this year.  

How can patients or advocates get involved?

By sharing awareness for the need for real-time perfusion monitoring in the cath lab.  Ask your doctors about its potential benefits.    


This interview was produced by The Way To My Heart in partnership with Vascular Cures. Neither The Way To My Heart nor Vascular Cures endorse any specific products, entrepreneurs, companies, organizations, drug or device trials, and/or healthcare professionals, including diagnosis or treatment programs. The information, advice, and views shared in this interview are that of the individual speakers and are offered for educational and informational purposes only.

This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Don’t act on any information provided in this interview without the explicit consent of your own healthcare provider who knows your situation best.

The safety and efficacy of the investigational use of the product discussed by Emory University’s Dr. Arshed Quyyumi has not been determined. There is no guarantee that the investigational use discussed will be filed with and/or approved for marketing by a regulatory agency.

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