Platelet function in clinically healthy cats and cats with hypertrophic cardiomyopathy: Analysis using the Platelet Function Analyzer-100

Background: There is currently no simple analytical tool for the evaluation of hypercoagulability in cats. The Platelet Function Analyzer-100® (PFA-100; Dade Behring Inc., Deerfield, IL, USA) is a bench-top machine that evaluates platelet function by measuring closure time (CT) in citrated whole blood under high shear conditions. We hypothesized that cats with hypertrophic cardiomyopathy (HCM) have up-regulated platelet function, which shortens their CT and increases their risk for thromboembolic events. Objectives: The goals of this study were to: (1) establish a feline reference interval for CT using the PFA-100, (2) measure CT in blood from cats with HCM, and (3) determine if there is a measurable difference between the CT of healthy cats compared with cats with HCM. Methods: Citrated blood samples from 42 clinically healthy cats and 30 cats with HCM were analyzed according to manufacturer's specifications. CT was measured in triplicate and the mean value was used for analysis. Transformed data were compared between clinically healthy cats and cats with HCM using a Student's t-test, and among cats with mild, moderate, or severe HCM using ANOVA. Results: The median CT of clinically healthy cats was 64 seconds (range 43-176 seconds). The median CT of cats with HCM was 74 seconds (range 48-197 seconds). There was no significant difference in CT between cats with HCM and clinically healthy cats. There also were no significant differences in cats with mild, moderate, or severe HCM. Conclusions: A feline reference interval for PFA-100 CT will be useful in future studies of platelet function in cats. Cats with HCM do not have shorter CTs when compared with clinically healthy cats.