25 Jun 2021
“…PCV appeared to decrease with increasing severity of preclinical disease, producing a significant difference when stages B1 and B2 were compared” – Jenny Wilshaw, co-author for the paper.
Paul Imrie
Job Title
IMAGE: © BSAVA Manual of Canine Practice
A study has identified an inverse relationship between PCV and myxomatous mitral valve disease (MMVD) in dogs.
The BSAVA-PetSavers funded study, published in the Journal of Small Animal Practice, was a retrospective analysis of prospectively collected data, with clinical data selected from 289 dogs on more than one occasion – 1,465 visits – between 2004-17 at RVC-conducted clinics.
To be included, dogs must have received echocardiographic diagnosis of MMVD by a board-certified cardiologist and a measure of PCV available from the same examination.
Dogs were repeatedly examined every six months and a jugular blood sample taken. PCV, total solids (TS; g/L) and blood urea nitrogen (mmol/L) concentration were measured, and standard right parasternal echocardiographic views taken, and from these the left atrial to aortic root ratio and the normalised left ventricular internal diameter at end diastole were calculated.
Heart disease was staged according to the American College of Veterinary Internal Medicine (ACVIM) guidelines.
Jenny Wilshaw, corresponding author for the paper, said: “In this study, PCV appeared to decrease with increasing severity of preclinical disease, producing a significant difference when stages B1 and B2 were compared. Interestingly, this inverse relationship with ACVIM stage did not continue through to stage C. PCV in stage C was significantly greater than either preclinical stage, lying closer to that of the unaffected dogs.
“A second analysis indicated that the increased PCV in stage C disease may be due to diuresis reducing plasma volume, as dogs receiving furosemide had higher values of PCV. We therefore concluded that dogs with MMVD may develop small reductions in PCV as a result of haemodilution. This study adds to our understanding of the pathophysiology of MMVD by suggesting that plasma volume is expanded as early as stage B1.”
Dr Wilshaw added: “Similar associations between left ventricular internal diameter at end diastole, furosemide administration and TS were observed when TS was analysed as the dependant variable. Haemodilution would not be expected to affect PCV in isolation, so finding these results for another component of blood provides further support for our interpretation.
“In addition to ACVIM stage, several demographic factors also remained in the model. When grouped as cavalier King Charles spaniel (CKCS) or non-CKCS, PCV was significantly lower in CKCS.”
The full study is available online.
