Comparison of laboratory test results before and after surgical removal of heartworms in dogs with vena caval syndrome.

OBJECTIVE

To compare results of laboratory tests in dogs with vena caval syndrome before and after surgical removal of heartworms.

DESIGN

Longitudinal uncontrolled clinical trial.

ANIMALS: 51 dogs with vena caval syndrome.

PROCEDURE: Heartworms were removed from the area of the tricuspid valve and pulmonary arteries via venotomy and by use of flexible alligator forceps. Blood samples were obtained before and 10 days after removal of heartworms. Red and white blood cell counts were determined, using an automated cell counter. Biochemical tests were performed, using a dry chemical method.

RESULTS

45 dogs survived the procedure, and 6 died or were euthanatized after surgical treatment. After surgery, RBC count and total protein, albumin, calcium, and sodium concentrations increased, and total bilirubin, ammonia, BUN, creatinine, uric acid, and potassium concentrations decreased in dogs that survived. Creatine kinase, L-lactate dehydrogenase, and amylase activities decreased, whereas alkaline phosphatase and gamma-glutamyltransferase activities and total cholesterol concentration increased. Alanine transaminase activity decreased in 27 dogs but increased in 3 dogs. Changes in test results in dogs that did not survive. Significant differences were found in RBC count, gamma-glutamyltransferase activity, and total protein, total cholesterol, BUN, and total bilirubin concentrations before and after removal of heartworms.

CLINICAL IMPLICATIONS: Hepatic and renal functions improve rapidly after surgical removal of heartworms, presumably because general and pulmonary circulation is normalized. However, cholestasis may develop, and dogs that survive may need additional treatment to preserve hepatic function.