Carlson College of Veterinary Medicine

OBJECTIVES: The aims of this study were to determine if stable chronic kidney disease (CKD) cats and uremic crisis cats have altered platelet function, and to determine the prevalence of positive fecal occult blood in CKD cats.

METHODS: Platelet function in normal cats, clinically stable International Renal Interest Society (IRIS) stage 2-4 CKD cats and CKD cats experiencing a uremic crisis were evaluated using impedance aggregometry. Area under the curve (AUC) at 6 mins was calculated for saline, adenosine diphosphate (AUC) and arachidonic acid (AUC). The AUC in addition to hematocrit, platelet count and mean platelet volume (MPV) were compared between groups using the Kruskal-Wallis test followed by Dunn's post-hoc analysis. Guaiac fecal occult blood tests were performed on fecal samples and results were compared between groups using a χ for trend test.

RESULTS: AUC ( = 0.04) and AUC ( = 0.05) were significantly higher in uremic crisis cats compared with normal cats at 6 mins. Hematocrit was significantly higher in normal cats when compared with IRIS stage 3 and 4 ( = 0.002) and uremic crisis ( = 0.0008) cats, with no difference among groups for platelet count or MPV. The proportion of cats with positive fecal occult blood samples was significantly different between groups ( = 0.0017); 50% uremic crisis cats, 33% IRIS stage 3 and 4 cats, and 10% IRIS stage 2 cats were positive, while no normal cats were positive. The proportion of cats with platelet clumping was significantly different between groups ( = 0.03).

CONCLUSIONS AND RELEVANCE: Platelet hyper-reactivity may be occurring in CKD cats experiencing a uremic crisis. The etiology of positive fecal occult blood samples in CKD cats is unclear and did not appear to be related to decreased platelet function as measured in this study and requires further investigation.