Transcription:

Another episode of Radio Rounds, the podcast interview series presented by St. Louis Children's Hospital, covering pediatric topics of interest to doctors and healthcare professionals. Here's Melanie Cole.

Melanie: In 2020, St. Louis Children's Hospital began using aquapheresis therapy to care for babies with congenital or acquired renal disorders, one of the few centers in the country to offer this advanced treatment.

Welcome to Radio Rounds, the podcast series from Washington University Pediatric Specialists at St. Louis Children's Hospital. I'm Melanie Cole. And joining me today is Dr. Eileen Ciccia. She's the co-director of the St. Louis Children's Hospital Renal Replacement Program.

Dr. Ciccia, it's a pleasure to have you with us today. And as we get into this such an interesting topic, tell us a little bit about what we know about renal disease in newborns and how prevalent this is.

Dr Eileen Ciccia: Thank you so very much for having me. I'm excited to share this information. So we know in newborns, kidney disease is overall relatively rare. There's a couple of ways that we consider and describe kidney disease in children.

So the first group of patients that we would think about is patients that are diagnosed with chronic kidney disease. Usually, especially for neonates, this is associated with an abnormal development of the kidneys or the urinary tract. We see this occurring in about one in 10,000 live births. Now, in that grouping of patients that go on to develop what we call end-stage kidney disease, which means they would require renal replacement therapy or dialysis, that's even less common, so approximately seven in a million in this population.

There's another grouping of kids who may have a sudden decline in what we would expect to be an otherwise normal kidney function. This is known as acute kidney injury, and that can be more common in particularly the NICU population or neonatal intensive care units. Somewhere, you know, in estimates between 20% to 40% of infants can at some point in their care have this condition, but that may vary based on their gestational age and what some of their other comorbidities are.

Melanie: So tell us the options that had been available previously to treat newborns that had renal failure and how did this evolve.

Dr Eileen Ciccia: Our first line and our typical go-to option has traditionally been peritoneal dialysis. My colleagues, listening in may be familiar. This is a process by which we remove excess fluid and toxins from the blood using the natural lining of the abdomen that's called the peritoneal membrane. This is done through repeated cycles of filling that free space in the abdomen with a dialysate solution, swelling to allow for the exchange of fluids and toxins to occur, and then draining that solution into a waste bag.

The limitations for this procedure, unfortunately, this can be limited by skin integrity, for example, with premature infants. Or if this catheter is needing to be used right away after it's been placed surgically, we can have some leakage around the catheter, which would limit that treatment.

Additionally, for patients that have abdominal processes like inflammatory issues, necrotizing enterocolitis or scarring of the peritoneum or if they have really tenuous lung status to tolerate a fluid volume in the abdomen, peritoneal dialysis is unfortunately not always an option.

Our other chronic form of dialysis that we think of traditionally is hemodialysis. Unfortunately, the high blood flow rates and the large circuit volumes that are required for this therapy is particularly challenging relative to the blood volume of our neonatal population. And we see that this could have a significant impact on their blood pressure and temperature stability.

What my colleagues are probably more familiar with in the sicker ICU patients is continuous renal replacement therapy. For patients that require continuous fluid removal and clearance, that has traditionally been a very good option. Unfortunately, until very recently, the machines and circuits that are available to provide CRRT have been again relatively quite large to the infant blood volume. And so you run into many of those same hemodynamic issues as you do with hemodialysis. And that's where aquapheresis fortunately fills the gap.

Melanie: Well, let's talk about aquapheresis therapy then. Tell us a little bit about how it works, are there particular diagnoses specific to it? And I'd like you to tell us when St. Louis Children's Hospital started using it.

Dr Eileen Ciccia: So aquapheresis actually in its original iteration, it was developed as a fluid removal device originally for adult heart failure patients, for patients that were recalcitrant to diuretic medical management alone. The way that it works is generally set up similar to our other blood-based dialysis devices, where you have access to a patient's blood via a catheter. And then this will go through a circuit with a filter attached. The fluid removal occurs via a process using hydrostatic pressure generated by pumps on the machine to pull excess plasma water across that filter into a waste bag.

Fortunately, with many of the advanced technologies and applying some of the other ways that we're able to provide clearance, some of these other modalities, the pediatric nephrology world has been able to make some modifications to this original device in order to facilitate convective clearance, which means that waste products and toxins are also pulled across that filter membrane into the waste bag as well. This is driven by the addition of a replacement fluid solution to this circuit.

Renal replacement therapy, this will allow us to clean the blood in infants that would require blood-based dialysis. When we think about what population would benefit most from this particular target, in its original iteration, this therapy again was really for anyone that was requiring fluid removal, so using just the aquapheresis, the aqueduct circuit itself.

However, our population, as I've mentioned, because of the limitations of many of the other modalities and other technologies has been focused a lot at the infant, the neonatal population. Due to the smaller circuit volume of this circuit, we find that they actually benefit from not having many of the hemodynamic effects and the challenges that we were seeing with the larger circuits.

So again, thinking back to those original kidney diagnoses that may drive this, a majority of our patients who receive modified aquapheresis have chronic kidney disease or end-stage kidney disease, roughly 60% in the published literature and our experience has been on track for that as well. So traditionally, those diagnoses might again be the congenital anomalies of the kidney or urinary tract, such as your posterior urethral valves, children that had been diagnosed with multicystic dysplastic kidney disease, and other developmental abnormalities of that system.

The final 40% again consists of those children who have acute kidney injury. And that could be related to a number of different things with systemic illness or its treatment, including infections, kids who require cardiac surgery or extracorporeal membrane oxygenation, such as our congenital diaphragmatic hernia patients.

Here at St. Louis Children's, we were very excited after extensive preparation with policies, procedures, and training. We began using aquapheresis last year amidst the pandemic. I'm actually extremely proud of our team that we were able to get our training, that we were fairly agile with the training in the midst of all the COVID restrictions that came through. And we have been performing aquapheresis here at St. Louis Children's since July of last year 2020,

In the pediatric population, the neonatal use of modified aquapheresis has been used since about 2013. The device has been around since 2007. So as a field, we're accruing more and more, experience and literature with this.

Melanie: Isn't that amazing? All the new technologies. So how long can a newborn be on this type of therapy? How long do babies stay on it?

Dr Eileen Ciccia: It really depends on the situation. Most of the time in our ideal situation, in a patient that has chronic kidney disease where we were expecting them to then convert over to a chronic outpatient ideally, our target will be to provide modified aquapheresis for a couple of weeks. While that peritoneal catheter that I had spoken to earlier, you want to ideally give it some time to heal, so two weeks until that catheter heals and then can be used.

Now, in some patients, as I've mentioned, peritoneal dialysis either does not work or is not an option for some babies. And therefore, we may find that we're having to bridge them until they're large enough to tolerate another modality such as hemodialysis. So that could be a bit of a longer road. So really, for those patients, their course may look more on the order of weeks to months until they're ready to make that transition.

For our acute kidney injury population, this is a matter of providing that renal replacement support until their kidneys heal. That, again, looks over the course of days to weeks, depending on the severity of the injury and any ongoing challenges.

Melanie: Can it be used for older children in renal failure? And what other uses for this technology do you see coming down the pike?

Dr Eileen Ciccia: It's a great question. So in its original iteration, as I mentioned, just for the fluid removal as the original adults indications came about, this canon has been used successfully in older children. With these modifications, the same principles will translate. Typically, our older kids being of a larger size, many times when you're using a blood-based dialysis, the membrane, you want to fairly closely approximate their body surface area to provide an appropriate amount of clearance for them. So by that point, of course, they're also larger and more able to tolerate the other modalities, for example, hemodialysis. So, at that point, many times, they'll convert over.

Melanie: So as we wrap up, Dr. Ciccia, what would you like other providers, other pediatricians to know about this amazing technology, aquapheresis therapy that you're using at St. Louis Children's Hospital?

Dr Eileen Ciccia: I would like to just share I think this is an exciting time as always as with many other fields in medicine, as our technology is advancing. We are finding new ways and better ways in which to support our patients. Our patients with kidney disease, our goal is always for them to experience the goals of life that their families have for them and it's a very exciting time that we're able to offer and advance these technologies for them.

Melanie: Certainly, it is. And thank you so much for joining us and telling us about aquapheresis therapy at St. Louis Children's Hospital.

And to learn more about this therapy or to speak with a pediatric specialist at St. Louis Children's Hospital, you can call the Children's Direct Physician Access Line at 1-800-678-HELP or you can visit stlouischildrens.org.

That concludes this episode of Radio Rounds, the podcast series from Washington University Pediatric Specialists at St. Louis Children's Hospital. Please remember to subscribe, rate and review this podcast and all the other St. Louis Children's Hospital Podcasts. I'm Melanie Cole.