Recent advances in Feline ATE

This month Nathalie Dowgray is joined by Clare Rusbridge for part two of their conversation about neuropathic pain in cats. We then join Kelly St Denis and Julien Guillaumen as they discuss recent advances in feline aortic thromboembolism.

Our episode begins with Professor Clare Rushbridge sharing her expertise on managing neuropathic pain in cats. We discuss the burdens that caregivers face as well as the various tools and medications that she has found to be helpful with her patients.

Dr Kelly St Denis is then joined by Dr Julien Guillaumen to discuss his latest JFMS article ‘Feline Aortic Thromboembolism: Recent Advances and Future Prospects’. Guillaumen provides a historical overview of FATE research, dating back to 1953, and they discuss the delicate balance required in clinical management of these cases, especially concerning hydration and heart failure.

For further reading material please visit:

Neuropathic pain in cats: Mechanisms and multimodal management

AAFP and ISFM Feline Environmental Needs Guidelines

Clare's Youtube Channel

Feline Aortic Thromboembolism: Recent Advances and Future Prospects

For ISFM members, full recordings of each episode of the podcast is available for you to listen to at portal.icatcare.org. To become an ISFM member, or find out more about our Cat Friendly schemes, visit icatcare.org


Host:
Nathalie Dowgray, BVSc, MANZCVS, PgDip, MRCVS, PhD, Head of ISFM, International Society of Feline Medicine, International Cat Care, Tisbury, Wiltshire, UK

Speakers:
Clare Rusbridge, BVMS PhD DipECVN FRCVS, RCVS and European Specialist in Veterinary Neurology & JFMS Author

Kelly St Denis, MSc, DVM, DABVP (Feline), 2022 ISFM/AAFP Cat Friendly Veterinary Environment Guidelines Co-Chair, St Denis Veterinary Professional Corporation, Powassan, Ontario, Canada

Julien Guillaumen, Doct Vet, DACVECC, DECVECC, Associate Professor of Emergency and Critical Care at Colorado State University and JFMS Author.

Creators & Guests

Host

Nathalie Dowgray

What is Chattering With ISFM?

Welcome to Chattering With ISFM, the official monthly podcast of the International Society of Feline Medicine, hosted by Nathalie Dowgray (Head of ISFM). Each month, we chatter about cats and cat-friendly practices with industry experts and contributors to The Journal of Feline Medicine and Surgery. Each episode contains highlights from our longer discussions and interviews, which are accessible to ISFM members at portal.icatcare.org. If you would like access to our full episodes, would like to become an ISFM member, or find out more about our Cat-Friendly schemes, visit icatcare.org.

Nathalie Dowgray: Welcome to the
June episode of Chattering with ISFM.

I'm Nathalie Dowgray, Head of ISFM
and host of this month's podcast.

First up this month, we have part
two of my interview with Professor

Clare Rusbridge, and we're talking
further about neuropathic pain in cats.

And then Dr Kelly St Denis from
AAFP is going to be speaking

with Dr Julien Guillaumen

on his clinical spotlight article,
feline aortic thromboembolism,

recent advances and future prospects.

You gave some fantastic case studies
in the paper, but with a number of

those, I also noticed that actually,
while we achieved in the first outcome

successful management, there were often
then flare ups when maybe other disease

conditions occurred, and that may have
led to the medications being difficult.

So these aren't necessarily
straightforward for the owners.

How do you manage those initial
discussions with them, but then

also that longer term sort of role
in monitoring the quality of life?

Clare Rusbridge: Yes, I'd say that
the biggest burden that caregivers

have is giving medication.

Some of these medications that we
use for neuropathic pain are better

to be given sometimes three times a
day, and that may inform my choices.

For example, pregabalin, one of the
gabapentinoids, is about five times

more bioactive than gabapentin,
and I prefer it for cats because

it can be given twice daily, which
is much less effort for the owners.

And there are some cases where we'll
use quite unusual drugs for pain.

You wouldn't expect
phenobarbital, for example, to

be useful for a pain condition.

And I'm not sure that it necessarily
is for dogs, but it does seem to

be useful in some cats, especially
with feline oral facial pain.

And phenobarbital can in some
circumstances be given once daily.

So if I have a very challenging case,
then I will consider that perhaps a poor

choice you might think because of the side
effects, but sometimes a low dose of a

once daily drug of a small tablet, which
the owner finds easier to hide in food is

going to be better than them struggling
to give capsules three times a day.

There are some options for
giving topical medication.

For example, we can apply things like
tramadol to formulations to the ear

and topical amitriptyline also exists.

But the problem with that is that
they are very poorly absorbed.

And so they're definitely
not an option for many cats.

So I think the first caregiver
burden is really that they can

struggle to give medication.

And it can be difficult for
them to find solutions for that.

And sometimes it can be so difficult
that you have to have the euthanasia

discussion, that the quality of the life
of the owner and the cat are just so poor.

The quality of the life of the cat,
because they are miserable with the

condition and miserable having medication.

And the owner just can't cope.

So I think, although we focus on
treatment in the article, I think we

have to also acknowledge that euthanasia
plays a role in some of these cases

because it can be a difficult situation.

As far as quality of life tools, I
think they definitely will have a place.

It's challenging sometimes to find
one that is suitable for chronic

pain and chronic neuropathic pain.

And so if people are asking what I
would tend to use, it would be the AWAG.

That is a pretty useful tool for looking
at quality of life and the impact of

the disease and monitoring over time.

Nathalie Dowgray: It's useful to know
what works and we're still, I think,

at the stage of developing good health
related quality of life tools for cats.

It's a growing area of interest.

You also, within the article, created this
really lovely treatment algorithm as well.

And I have to say I do love an algorithm.

In terms of a reference guide as
well, I think it's really helpful.

And I wanted to just ask a few
questions about some of the drugs.

The first one was around the anti nerve
growth factor monoclonal antibodies.

We've only had them available for
the last sort of three or four years.

And some people listening to this
podcast, it only might just be

coming available in your country.

So I was just really interested in how
you've been using them in your work

with pain cases and which ones that
you've found them the most useful for.

Clare Rusbridge: Yes, I think
this is probably the most exciting

development in pain management
that has come out in recent years.

And obviously the big advantage
of these drugs is that they're

given by injection and they can
be given once monthly, much less

challenging than giving tablets daily.

I think it's important to state
that this is most indicated for

peripheral neuropathic pain.

So what it's having an effect on is
affecting the way that information about

pain is translated through the peripheral
nerve and the dorsal nerve root ganglia,

where the cell body of the nociceptor is.

And so it affects changes
in that cell nucleus.

So I wouldn't expect these drugs to work
on central neuropathic pain, only in

peripheral neuropathic pain, and people
say, Oh, isn't it for osteoarthritis.

Actually, the mechanism
is through the nerve.

And so theoretically, it could
work for any condition with

peripheral neuropathic pain.

So the conditions that I have used it
on successfully in cats, most notably

feline oral facial pain syndrome, which
is a challenging condition to treat.

Related to that is dental pain.

Now, I consider those two separate.

Yeah, feline oral facial pain is a
syndrome of mutilation that cats probably

have an inherited tendency to, having
abnormal processing of information

and it's triggered by teething and
other oral lesions, which you wouldn't

normally expect to cause pain.

I would normally expect severe
periodontal disease to cause pain, but

sometimes those cats can be left in a
lot of pain despite having dentistry.

So they were in a lot of pain beforehand.

They have dentistry.

A lot of cats are discharged from dentals
having had extensive dental work with

barely any or no oral medication Just
imagine if you had that work done.

I know I'd be a complete baby.

I have seen some cases that where
the cat has had some chronic pain

relating to tooth problems, and
I've used these anti NGF monoclonal

antibodies successfully in that.

One of the examples I'm thinking
about was a cat that had chronic

pain related to its upper canines.

And I was referring to a veterinary
dentist to deal with that because

that's quite a complex surgery
and there was a long waiting list.

So I had to manage that cat's
pain for quite a long time.

So that was one sort of example.

I've also used it successfully for
lumbosacral disc disease in the cat.

So I think going forward, I would
consider it for any neuropathic pain

syndrome in a cat where the pain is
peripheral as opposed to central and

lumbosacral disc disease I regard
that as peripheral because the

nerve roots are being compressed.

Nathalie Dowgray: No, that makes sense.

Yeah, and it is definitely exciting
and obviously with these drugs came

out they've been licensed in cats and
dogs for osteoarthritis, but it's that

bigger piece as well that we're now
starting to explore a little bit more.

Clare Rusbridge: It should be said
that all drugs used for neuropathic

pain in cats are not licensed.

So you need to make that, those
discussions with their caregivers that

you're not giving a licensed medication.

Nathalie Dowgray: Yeah, no,
that's important to consider.

And now over to Dr Kelly St Denis and
she's speaking with Julien Guillaumen

on feline aortic thromboembolism.

Kelly St Denis: When I was reading
through this, one of the things I

always forget about is this potential
side effect or sequela of FATE is

acute kidney injury, which you have a
lot of really good information in here

about, but I wondered if you would
talk a little bit about that aspect of

FATE as a sequela from the problem, how
that happens, what you do to monitor.

Julien Guillaumen: That's something
that I didn't know that came out of the

paper that we published a few years ago.

Again, funded from Morris Animal
Foundation, and I like medical

history, and so I'm gonna start, I'm
going to start all over in, in 1953,

but the first case report in cats is
actually from a French veterinarian,

I guess the first case report that
I can read, and I can only read

in two languages, and so it was
published in 1953 in, in, from France.

Dr Collet described the syndrome.

I think it was a necropsy,
but so talked about it.

And then, we didn't have a
lot of things that was in a

big scale until the eighties.

And so, In 1980, Paul Pion, who was
a cardio resident at QC Davis, is

now better known for founding VIN,
but before founding VIN, Paul was a,

a cardiology resident and he treated
a lot of those cats in the 80s.

I talked to him a few times, and
that's kind of what he told me.

And he did a lot of formalising.

At that time, when he published the
case theory, there was actually no,

no retrospective studies in the 80s on
ATE cats, which I think is fascinating.

The first kind of larger case
series was in the 80s when he used

TPA, and he said we didn't expect
those cats to get complications.

So when we gave TPA and they got
complications, we thought that it

was because of the TPA and because
we had nothing to compare with.

And so that's how TPA got its
bad reputation as a thrombolytic.

And then in the 90s, there have been a
couple of more retrospective studies,

usually from the East Coast, looking at
ATE cats, and they do basically say the

same thing in terms of 30 or 40 percent
survival rate, all those type of things.

And, but they don't really,
they didn't really go into the

details about why those cats died.

And to the point that when I designed
my study with the cardiology team at

Ohio State University, while I was
there at that time and then other

people, we also did not expect those
cats to die very quickly in a way.

And so I think our study was the first one
that reported why they died and, and the

complications associated with treatment.

Which again was acute kidney injury

and probably more acute kidney injury
than reperfusion injury to be very honest.

And so that's something that I was
not expecting and treating those

cats, having those grants, being
able to treat a lot of those cats.

That's something that we saw.

Kelly St Denis: Yeah, and so it seems like
based on what I read in your articles that

there's the, maybe there's a concern that
cats that have pre existing kidney disease

may be at increased risk of that acute
kidney injury if they have a FATE episode.

Is that what I'm reading correctly?

Julien Guillaumen: Yes, I know.

Again, that's for me a little bit
more of a clinical experience.

So most of the cats are old, right?

I think the average is
about 8 to 10 years old.

They have chronic kidney parts in necropsy
or ultrasound if you do those things.

And when I have a cat that has
an ATE, the first thing I'm going

to look at, it's going to be
its admission creatinine value.

Kelly St Denis: Right.

Julien Guillaumen: If it is 3, or if it
is 0.8, I think my suspicion is that the

ones that are coming with a creatinine
of 3 are going to be more likely to get

into a more rapid acute kidney injury
compared to the one that is coming

in with a creatinine of 0.8, right.

I looked at that spreadsheet for a
very, very long time and I've treated

a decent amount of those cats and
this is my clinical impression.

I'm going to be very
careful with those cats.

A lot of those cats
are dehydrated as well.

In our study, we had cats
that came in with a PCV of

55 and a total protein of 10.

And when they are in
congested heart failure.

So, you know, they are coming in with
a PCV of 55, a total protien of 10,

a creatinine of 3, and in congestive
heart failure, at some point I'm going

to have to switch from Lasix to IV fluid.

And we are all very scared by giving IV
fluids to a cat who is in severe HCM.

So, that's why I say it's tricky.

That's why I say it's not
an easy clinical management.

Kelly St Denis: Sounds like a
crazy balance to do when you do

start being what's going to roll
out for that individual patient.

Julien Guillaumen: One of the things
I wanted to mention, Dr St Denis as

well, is that even if they develop
acute kidney injury, it's not a death

sentence because in our study, we
found that around 40 percent of them

will survive their complications.

And so, you know, I have a cat that,
you know, did develop a KI, creatinine

goes up 5, 6, 7, but with time,
judicious fluids, then they kind

of go back to, to their baseline.

Kelly St Denis: Brilliant.

Okay.

That's good to know.

Again, like, like I said, that wasn't
something I was really aware of, and

I think it's partly because I've been
in general practice for so long, and

most of these patients don't make it
very far in general practice, as we

discussed, for a variety of reasons.

So hopefully we can
start seeing that change.

Nathalie Dowgray: Thank you for listening.

If you're an ISFM member, don't forget
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