Objective—To compare platelet aggregation in
healthy dogs and dogs with mitral valve regurgitation
(MVR) to determine whether regurgitation had an
effect on platelet function.
Animals—32 dogs with MVR and 43 healthy dogs.
Procedure—Platelet aggregation was measured with
an aggregometer, using adenosine 5'-diphosphate as
the aggregating agent, and the maximum aggregation
and the enhancement of platelet sensitivity (EPS) values
Results—Platelet count and maximum aggregation
were not significantly different between healthy dogs
and dogs with MVR. However, EPS values in dogs
with MVR were significantly higher than values in
healthy dogs. Platelet count and maximum aggregation
were not significantly different between dogs
classified as New York Heart Association functional
class I or II and dogs classified as functional class III
or IV; however, EPS values were significantly higher in
dogs classified as functional class III or IV.
Conclusions and Clinical Relevance—Results suggest
that platelet aggregation is decreased in dogs
with MVR and that the EPS value may be more sensitive
to differences in disease severity than in measurement
of maximum aggregation. (Am J Vet Res