CHF treatment in first opinion practice

RE: CHF treatment in first opinion practice

Dave Dickson — Sat, 14 Nov 2020 18:42:57 GMT

You don’t! We just have to trust that the studies showing improved outcome are true. Hence the problems many of us have with using ACEi - we just don’t trust all the data.

RE: CHF treatment in first opinion practice

Michael Woodhouse — Sat, 14 Nov 2020 18:27:16 GMT

[quote userid="14690" url="~/001/veterinary-clinical/small-animal/cardiology/f/discussions/29472/chf-treatment-in-first-opinion-practice/226517#226517"]4. Add in Cardalis for optimisation but don't expect to see a clinical difference and don't exceed standard doses (0.25mg/kg benazepril, 2mg/kg spironolactone once daily). [/quote]

How do I know it's doing anything?!

RE: CHF treatment in first opinion practice

Roger Wilkinson — Fri, 13 Nov 2020 17:16:02 GMT

I'll try to do some more studies of my own...honest!!

I'm always good for a bit of online jousting Dave. You are just about the the most measured and polite person on the entire internet!! This is as nothing compared to the abuse I have to take from my colleagues.....

You're absolutely right that it's interesting that PCE dogs aren't often azotaemic

4/90 in https://sci-hub.se/10.2460/javma.235.12.1456

....resisted the temptation to quote a human paper ;)

maybe that's because we don't usually give them diuretics? so they don't have the RAAS activation causing preglomerular vasoconstriction.

although perhaps cardiorenal syndrome isn't very common in any dogs? (<5% of stage C MVD dogs too I guess)

In the ones we see I'd say my feeling is most of them are dogs with type 2 PAH secondary to L CHF.

RE: CHF treatment in first opinion practice

Dave Dickson — Fri, 13 Nov 2020 10:00:26 GMT

(apologise if the tone of that message seems confrontational - it isn't meant to be - I'm just poking the bear. And my coffee hasn't filtered in yet).

RE: CHF treatment in first opinion practice

Dave Dickson — Fri, 13 Nov 2020 09:38:07 GMT

[quote userid="16471" url="~/001/veterinary-clinical/small-animal/cardiology/f/discussions/29472/chf-treatment-in-first-opinion-practice/226639#226639"]'just enough to relieve (pulmonary or systemic) congestion regardless of azotaemia[/quote]

This is what I was taught by Adrian Boswood (sits on the right side of God, IMHO) and still makes total sense.

Regarding the point about evidence for outcomes, I think we need to be very careful when comparing to human medicine evidence and principles. For a start, in human medicine HF is a surgical disease most of the time - they want to fix the valve or place a stent. Diuretics are just a bridge to surgery. Next, we have the consideration that although there may be no trials to prove diuretics improve outcome, I think you'd be hard pressed to find any one in CHF who's willing to take part in a placebo controlled trial. The placebo wing would be dead in short order. That's a parachute trial.

The next thing to consider is that we are often guilty of trying to extrapolate human evidence to our patients. Often, we have no choice. But when it comes to drugs, consider that we have convincing evidence in dogs and weak but believable evidence in cats that betablockers are a really bad idea in CHF, yet in people they are one of the cornerstones of treatment. We all use and love pimobendan - doctors no so much.

Someone will have to explain the whole renal congestion thing to me. Why does a dog with left heart failure, so elevated pulmonary venous pressures, get right-sided heart failure (renal vein pressure elevation) sufficient to cause azotaemia from 'cardiorenal syndrome' without evidence of hepatic venous congestion, ascites or pulmonary hypertension? I don't buy it, it makes no pathophysiologic sense. I rarely see azotaemia in pericardial effusion cases yet they have massive, acute RCHF. The renal vein thing sounds like a poor excuse for something we don't understand.

So whilst it's useful to have the medics' experience of CHF in people, we need to stop looking to their trials to guide what we do and instead do our own, on our own patients.

Dave

RE: CHF treatment in first opinion practice

Kate Richardson — Thu, 12 Nov 2020 23:47:38 GMT

Definite tangent! Dogs always get priority in discussions about cardiac disease management balancing management of renal disease and cardiac disease is a common scenario for me. Cats seem so much more susceptible to the negative effects of frusemide than dogs so torasemide is interesting although I don’t know enough to know if the side effects are any different- I suspect not.

RE: CHF treatment in first opinion practice

Roger Wilkinson — Thu, 12 Nov 2020 20:33:22 GMT

I've been ploughing through a load of human literature on CHF management -especially diuretic use.

This is good:

Loop diuretics, renal function and clinical outcome in patients with heart failure and reduced ejection fraction
Kevin Damman John Kjekshus John Wikstrand John G.F. Cleland Michel Komajda Hans Wedel Finn Waagstein John J.V. McMurray

https://onlinelibrary.wiley.com/doi/full/10.1002/ejhf.462

Considering this is a relatively recent paper it's slightly sobering that they start with...

'Loop diuretics are often prescribed in patients with chronic heart failure (HF) to manage symptoms and signs of congestion, but their effect on (long term) clinical outcomes is uncertain. The acknowledged effectiveness of loop diuretics for the management of congestion, the potential for non‐adherence to precipitate admissions and a meta‐analysis of heterogeneous studies suggested that these agents do reduce admissions for worsening congestion. However, no large, prospective, randomized, placebo‐controlled trial has been conducted to assess the effectiveness of loop diuretics in improving clinical outcome in patients with chronic HF.'

They go on to acknowledge that...

'The relationship between loop diuretics and WRF is bidirectional; they can cause WRF by contracting plasma volume resulting in neurohormonal activation while, at the same time, improve renal function by reducing the extent of renal venous congestion'

..which is broadly compatible with ideas discussed in this thread.

But the crunch is:

'Importantly, our results do not support the notion that higher doses of loop diuretics are associated with a faster decline in estimated GFR, suggesting that, from a renal perspective, higher dosages of diuretics could possibly safely be prescribed. However, our results may suggest that the lowest possible diuretic dose to achieve effective decongestion or euvolaemia could be preferred over higher doses'

Essentially, based on this, I think it sounds a reasonable proposition that the optimal long-term dose of loop diuretic for our patients might be 'just enough to relieve (pulmonary or systemic) congestion regardless of azotaemia'.

Interested to hear if anyone disagrees tho!

RE: CHF treatment in first opinion practice

Roger Wilkinson — Thu, 12 Nov 2020 07:54:56 GMT

well, this is the relatively easier bit....

https://onlinelibrary.wiley.com/doi/full/10.1111/jvim.15572

the case for ACEI in cats with CHF now looking very weak

and this is the complicated bit

https://pubmed.ncbi.nlm.nih.gov/25148095/

https://pubmed.ncbi.nlm.nih.gov/30778391/

those two papers suggesting that pimobendan could offer survival benefits in CHF cats and may be OK despite LV outflow tract obstruction

RE: CHF treatment in first opinion practice

Bibs — Wed, 11 Nov 2020 21:54:41 GMT

Hmmmm.....I'm thinking really general. You see a cat with dyspnea and you get it out of the crisis it's in and diagnose CHF - what next? I have been working in an emergency setting for a while and feel a bit rusty about the next step You can use dinosaurs as much as you want.

RE: CHF treatment in first opinion practice

Dave Dickson — Wed, 11 Nov 2020 21:29:56 GMT

I don't know! Maybe? What would you like to know? The more specific, the better! especially if I can use dinosaur or rowing boat analogies.

RE: CHF treatment in first opinion practice

Bibs — Wed, 11 Nov 2020 21:28:08 GMT

[quote userid="14690" url="~/001/veterinary-clinical/small-animal/cardiology/f/discussions/29472/chf-treatment-in-first-opinion-practice/226517#226517"]Are we talking dogs or cats? [/quote]

I'd love a similar discussion about cats. Do I have to set up a tangent for that maybe?

RE: CHF treatment in first opinion practice

Julian Earl — Tue, 10 Nov 2020 12:08:34 GMT

[quote userid="16471" url="~/001/veterinary-clinical/small-animal/cardiology/f/discussions/29472/chf-treatment-in-first-opinion-practice/226576#226576"].searches for human paper that shows it depends what kind of dinosaur ;).....[/quote]

Thanks Roger for making me smile! I need that at the moment!!

RE: CHF treatment in first opinion practice

Roger Wilkinson — Tue, 10 Nov 2020 08:18:33 GMT

....searches for human paper that shows it depends what kind of dinosaur ;).....

RE: CHF treatment in first opinion practice

Dave Dickson — Tue, 10 Nov 2020 08:05:00 GMT

Think about it from an evolutionary point of view - if a dinosaur bit off your leg and you suffer massive blood loss, your body will protect cerebral blood flow first, coronary blood flow second and renal perfusion first.

From an evolutionary POV, chronic heart failure is akin to massive blood loss - mechanisms to increase circulating blood volumes and maintain BP are activated and evolution would rather you died in 3 days of renal failure than in 10 minutes from hypoxic brain injury - so the kidneys get the raw end of the deal. Hence, we have to face a bit of azotaemia but it’s usually tolerable and preferable to fainting or drowning.

Interesting discussion

Dave

RE: CHF treatment in first opinion practice

Roger Wilkinson — Tue, 10 Nov 2020 07:50:37 GMT

the renal function vs diuretics thing is a proper mind-mender I find. Thought I'd leave that one for Dave!

if I understand it correctly then (as Dave says) it's not simply a matter of reduced arterial blood pressure driving renal hyperperfusion. There's an argument that systemic venous congestion is also a potential problem if it affects renal interstitial pressure.

I feel slightly better that the human guidelines (2019)

https://heart.bmj.com/content/heartjnl/105/12/904.full.pdf

are about as clear as my brain:

'Clinicians receive varying advice from cardiologists, nephrologists and other physicians.'

...yes I can believe that!

'The variation reflects the lack of robust evidence: designing and delivering randomised studies with management strategies directed both by changes in renal function and clinical response would be very complex'

these are passages relevant to your Q Julian

'Anxiety about rises in creatinine (and the associated falls in estimated glomerular filtration rate [eGFR]) can lead to underprescription of ACEI and ARBs. The tendency to withdraw ACEI and ARB has been exacerbated by the international adoption of the term ‘acute kidney injury’ (AKI) to describe acute changes in kidney function and by the inclusion of these drugs, which can also protect against progressive proteinuric kidney damage, in lists of drugs termed ‘nephrotoxic’. .....The results from clinical trials suggest that fears about renal function may be misplaced'

'Venous congestion also causes an inflammatory response within the renal parenchyma. Decongestion by diuretics can thus result in an increase in GFR,15 and withdrawal of diuretics from patients with stable chronic heart failure can cause tubular injury'

'Diuretic treatment does not prevent or ameliorate AKI. Although higher diuretic dose in CHF is associated with worse outcome,19 the reason is that higher doses of diuretics are a marker of more severe heart failure. Intravenous diuretics cause increased activity of the sympathetic nervous system and the RAAS,21 resulting in a fall in GFR, but diuretic-induced decongestion can improve GFR by reducing renal venous pressure'

' in patients with heart failure, the initial rise in creatinine is usually not due to intrinsic kidney injury but to a change in haemodynamics. Because patients with heart failure commonly have reduced renal function, even a small decline in renal function may produce a rise in creatinine large enough to trigger an e-alert and the stopping of prognostically vital medication

obviously human situation is slightly different (for a start most people have CHF with reduced ejection fraction and, in those patients RAAS blockade helps) but I suspect general principles might apply.

it's a very useful article....I never realised that, in people, tense ascites can actually cause functional ureteral obstruction!

in summary, I think the take home message is exactly what Dave says: that if they have pulmonary oedema (and probably also applies to significant ascites too) then you've got to diurese really. Uncorrected CHF is likely to lead to patient's demise faster than raised renal parameters.

RE: CHF treatment in first opinion practice

Julian Earl — Mon, 09 Nov 2020 23:24:02 GMT

[quote userid="14690" url="~/001/veterinary-clinical/small-animal/cardiology/f/discussions/29472/chf-treatment-in-first-opinion-practice/226549#226549"]The other way of thinking of it is that with renal disease and heart failure, the kidneys aren't able to regulate circulating fluid volume normally so they can't control the fluid balance anyway - we don't want to give them too much diuretic, but too little (in the hope that the failing kidneys will cause diuresis anyway) will be just as bad. It's a very fine balance and I hate managing them. thankfully, it isn't common. [/quote]

Thanks Dave for that thoughtful and comprehensive answer. Yes I think that you have understood my question. My concern is/was whether giving diuretic s to a dog with renal disease of any degree could be highly counterproductive by triggering serious dehydration and complete renal failure? But I see your point, thank you.

Interesting about client responses and Vetmedin as well! I think we all probably suspected as much about client/owner responses? Interesting o have it confirmed formally!

Cheers...

RE: CHF treatment in first opinion practice

Dave Dickson — Mon, 09 Nov 2020 19:32:53 GMT

True about the advanced cases - Torasemide is now my go-to rescue drug - but what I haven't found out yet is what happens to end-stage dogs who started out on torasemide. Can you rescue them as well? Do they become torasemide resistant and need to go onto frusemide? I have no idea but I guess we will find out. I don't think that because it's a good rescue drug necessarily means it will give better results if used first line. I think we need a proper study in dogs who are actually in CHF comparing long-term outcomes on one vs. the other.

The once a day thing to me is a non-starter in dogs. They are all on BID pimo so I don't think it has much real benefit. I don't think the diuretic effects are different enough to mean you can avoid some nocturia by dosing the torasemide in the morning, but I haven't actually treated my own dog with it so I'd be interested to hear of direct owner experience of frus vs. toras.

But, I think the once-a-day thing in cats is a massive bonus - which is why I probably use more torasemide in cats than I do frusemide now - not for efficacy or safety as we have bugger all data, but for compliance.

For me, torasemide's real benefit is in compliance. Understandably, the companies have done studies focusing on efficacy and are trying to claim (I think they are overoptimistic with their conclusions, personally) that torasemide is better. I think its more accurate just to say it is easier to give and leave it at that, pending decent prospective studies.

Dave

RE: CHF treatment in first opinion practice

Roger Wilkinson — Mon, 09 Nov 2020 18:54:16 GMT

Very useful discussion.

Dave, I'm just thinking that if we have two comparable loop diuretics with evidence of non-inferiority for torsemide then why choose the one that needs administering twice as often?

Secondly, albeit that we don't have proof of superiority for torsemide in CHF dogs in general, it is pretty universally accepted I think that there are some dogs in advanced CHF who do better on torsemide. If you choose torsemide as first line then the patient and owner don't have to go through the experience of frusemide not working very well before swapping.

RE: CHF treatment in first opinion practice

Dave Dickson — Mon, 09 Nov 2020 14:42:36 GMT

Hi Julian

Maybe I'm not understanding your question so come back to me if I have got the wrong end of the stick, but I think there is a difference between using diuretics in an end-stage renal patient and a patient with mild, pre-renal azotaemia resulting from decompensating heart failure. Dehydration is definitely never a good thing, but many dogs I see with CHF have mild azotaemia that is not a problem for them, yet if we don't manage the CHF they will drown. So I think it gets a lot more nuanced than "incr renal enzymes = bad kidneys".

The other way of thinking of it is that with renal disease and heart failure, the kidneys aren't able to regulate circulating fluid volume normally so they can't control the fluid balance anyway - we don't want to give them too much diuretic, but too little (in the hope that the failing kidneys will cause diuresis anyway) will be just as bad. It's a very fine balance and I hate managing them. thankfully, it isn't common.

For sure, most dogs feel better on pimobendan. What is interesting is that in EPIC, 100% of owners reported their dogs were better on treatment. However 50% of dogs were on placebo! And the 100% of dogs were supposed to be pre-clinical, so how can they feel better when they aren't supposed to be showing signs?! Bottom line, I don't trust owner reports of "he's feeling better on the tablets, doc".

I totally agree about exercise tolerance - it is one of the most important (though probably unreliable) signs of heart failure. Respiratory rate, particularly sleeping respiratory rate, is probably the best - but again it can be unreliable.

Dave

RE: CHF treatment in first opinion practice

Dave Dickson — Mon, 09 Nov 2020 14:35:19 GMT

Whilst I largely agree with your position on ACE and spiro Roger - well, certainly the ACEi bit, I think the torasemide story needs more work yet.

Many cardiologists don't like the Bernay trial (the one on spironolactone in CHF) because it had some pretty questionable inclusion criteria. However, the two studies so far in VetMed on torasemide (TEST and CARPEDIEM) both suffer from exactly the same inclusion criteria - do we even believe that the dogs enrolled on these trials were in CHF? I don't.

Similarly, the TEST study wasn't designed to look at outcome, only prove non-inferiority, so it's really risky to believe the conclusions they drew, namely that torasemide inferred better survival.

So whilst it's tempting to just look at human papers on torasemide and draw conclusions from the data we have so far, I think we are a long way from saying that torasemide is superior to frusemide. Not inferior, sure, but I don't know that it is superior yet.

Don't get me wrong, I'm a big torasemide fan. But I'm also a big frusemide fan and I don't think we have enough evidence to say one is better or worse, not yet anyway.

Dave

RE: CHF treatment in first opinion practice

Julian Earl — Sun, 08 Nov 2020 23:25:13 GMT

Sorry a basic question here; Why would anyone choose to use frusemide or other diuretic if the dog is already showing any biochemical suggestion of reduced kidney function? Surely the polydipsia/polyuria caused by loss of renal function drains as much fluid as needed? excessive loss of fluid is not beneficial for any dog, ever??

Also I found that Pimendoban was dramatically effective i many cardiac dogs, even if already on other apparently validated treatment such as ACE- inhibitors, or digoxin andd diuretics. The dogs were almost invariably a lot more exercise tolerant and active after starting. I have the view that exercise tolerance is the most important external clinical sign of cardiac function. Other than death I suppose?!

TIA for replies...

RE: CHF treatment in first opinion practice

Roger Wilkinson — Sun, 08 Nov 2020 22:08:22 GMT

https://www.vetpracticesupport.com/furosemide-vs-torasemide-as-first-line-oral-diuretic-in-dogs-with-congestive-heart-failure/

Pimo... twice a day fine for routine. Tid seems to help some if really struggling

RE: CHF treatment in first opinion practice

Annie Gleed — Sun, 08 Nov 2020 21:34:32 GMT

can I ask why you use torasemide? i thought it was found to be equally as good as furosemide but not superior? surely furosemide is cheaper? also q8hr pinobendan? i do it bid is that wrong? Sorry for so many questions!

RE: CHF treatment in first opinion practice

Roger Wilkinson — Sun, 08 Nov 2020 21:32:04 GMT

Welcome, it's the best revision for me to try to put together an answer to your question.

No, I haven't used much acei or spironolactone for a while. Used to add them occasionally in last ditch scenarios but torsemide plus q8hr pimobendan have taken their place.

RE: CHF treatment in first opinion practice

Annie Gleed — Sun, 08 Nov 2020 20:57:03 GMT

Thank you Roger! Plenty of bedtime reading for me there! So does that mean you dont use cardalis in any mvd cases? After so many years of using aceinhibitors seperately and incombination with spironolactone It feels weird to not consider them! Thank you again for your time, it is very much appreciated!