Possible kidneys/Update

Hey, I posted the other day about my dogs back legs. Our vet isn’t too concerned, given that he’s been like this for a year and the progression has been very slow. She manipulated his hind legs and he honestly just stood there and allowed her too, he’s not stiff in them, nothing moves that shouldn’t move. I do have another question though while I wait for a phone call from our general vet. My boy had his heart scan last Friday and the scan has shown no progression in his heart disease for the last 2 years, he’s still stable at B2 but his bloods came back yesterday and the part that concerns me is, his NT-proBNP has over doubled since 6 months ago, his markers are 2830 pmol/L and his cardiac troponin has mildly increased to 0.153 ng/mL. So his BNP markers are high enough that he’d be classed as CHF now but given there’s no change to his heart measurements we obviously know this isn’t the case, he isn’t coughing, he isn’t struggling to breathe. No signs of CHF and no measurements of CHF either so my question is, can kidney disease increase this markers? Or is there anything else that can increase them? Thank you

Hello - no diagnostic test is perfect and that there are frequently other factors - besides the thing being 'tested for' - that can cause changes in the numbers.  For example, when diagnosing heart-disease, a high Pro-BNP implies a change in the stretch experienced by heart-muscle cells.  However, there are other things that can cause a high Pro-BNP too, so clinicians are told that therapy for heart disease should not be started on the basis of a high Pro-BNP alone.  Rather, it is a 'screening tool,' which essentially helps clinicians to answer the question 'should we scan this dog's heart?'   It sounds as though, in your dogs' case, the resulting scan picked up no problems, so therapy was not changed.  I suspect that your vets may ask to repeat the scan at some stage.

As I understand it, Pro-BNP is cleared from the body by the kidney.  So, in situations where the kidney isn't filtering the blood very quickly, Pro-BNP can also be raised.  This could happen because of kidney failure, but also if the kidney is simply not clearing the blood very quickly, for example if the blood flow to the kidney isn't optimal e.g. due to dehydeation.  Your vet should have the means to assess kidneys, e.g. by looking at the specific gravity, azotaemia and potentially other markers, so will be able to tell you if they think that your dogs' kidneys are under threat.  Also, vets love it when owenrs are interested in blood tests, so it's absolutely fine to say, 'I see that the Pro-BNP is high;  what do you think caused that?  Have you evaluated the kidneys?' because obviously they should have a good handle on what's going on for your dog in this context.

I'm sorry;  lots of rambling.  To get back to your questions:  1) Yes, Pro-BNP is very inspecific and it can be made higher by other, none heart-related things 2) Yes, kidney-related factors CAN affect Pro-BNP.  3) As can hydration level.     I hope that that's more useful!

I'm also glad to hear that those joints are OK when assessed in context.  Would love to hear how you get on.

Hi, thank you for your advice. Our cardiologist has suggested going to our general vet for further blood tests to see if they show anything that could also relate to the kidneys (I’m trying to find the cheapest options first as I have four children as well at home). Our general vet isn’t suggesting further blood tests, she’s told me to hope for the best but prepare for the worst basically. So I thought I’d come on here for a second opinion on following up on the heart blood results before seeking a second opinion from another veterinary clinic. So now I know further bloods would be best to determine any other factor, I will ring our other vet’s office tomorrow morning and speak to a vet from there to see what they would suggest and hopefully they suggest helping him. I know I could demand the bloods as I’m the one paying but I want him seen and cared for by someone who actually believes he has a shot. He’s still active (not loads but he does have the back leg issues as well) he still plays with our other dogs, eats normally and drinks (slightly more than normal but I wouldn’t say excessively), hes still excited to greet us when we get home and everything else so his quality of life is still good at the moment so if I can help him further I will. Thank you again