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Platelet indices and their association with chronic valvular heart disease in Cavalier King Charles spaniels

Tong, Linda (2017) Platelet indices and their association with chronic valvular heart disease in Cavalier King Charles spaniels. Other thesis, Murdoch University.

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Chronic valvular heart disease (CVHD) is common in Cavalier King Charles spaniel (CKCS) and has the potential to affect platelet activation or function.

The present study objective was to determine platelet closure time, mean platelet component (MPC) concentration and platelet component distribution width (PCDW) in dogs with subclinical CVHD, and to assess the factors influencing these variables. A second objective was to assess platelet count, MPC concentration, PCDW, mean platelet volume (MPV), platelet volume distribution width (PDW), plateletcrit (PCT), mean platelet mass (MPM) and platelet mass distribution width (PMDW) in CKCS.

Haematological values, closure time, murmur grade and echocardiographic variables were recorded in 89 CKCS. Associations between explanatory variables (sex, age, murmur grade, echocardiographic variables, platelet count, and haematocrit (HCT)) and outcomes (closure time, MPC concentration, and PCDW) were examined using multivariate regression analysis. Platelet indices were compared between CKCS and a group of 39 control dogs (non-CKCS).

A model with 5 variables best explained variation in closure time (R2, 0.74), with greater than 60% of the variance of closure time explained by mitral valve regurgitant jet size. The model of best fit to explain variation in MPC concentration included only platelet count (R2, 0.24). The model of best fit to explain variation in PCDW included platelet count and sex (R2, 0.25). The MPC concentration, MPV, PDW, MPM and PMDW values were significantly higher, and the platelet count, PCT, PCDW and HCT values significantly lower, in the CKCS compared to control dogs.

In the present study, a significant effect of mitral valve regurgitant jet size on closure time was consistent with platelet dysfunction. However, platelet activation, as determined by MPC concentration and PCDW, was not a feature of subclinical CVHD in CKCS.

Item Type: Thesis (Other)
Murdoch Affiliation(s): School of Veterinary and Life Sciences
Notes: Research Masters with Training
Supervisor(s): Shiel, Robert
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