Diagnostic utility of D-dimer concentrations in dogs with pulmonary embolism

Pulmonary embolism (PE) is a complication of systemic disease in dogs. Antemortem diagnosis is challenging because of the lack of a confirmatory test.

To retrospectively determine the diagnostic utility of D-dimer concentrations in dogs with necropsy-confirmed PE.

Ten dogs with PE confirmed at necropsy that had D-dimer concentrations measured and 10 control dogs with D-dimer concentrations available that lacked PE on necropsy.

The computerized medical record database was searched for dogs with necropsy-confirmed PE that had D-dimer concentrations measured at that visit. An age-, sex-, and breed-matched control group was identified. Signalment, location of PE, and coagulation profiles were collected. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated using a D-dimer concentration of 250 ng/mL.

Coagulation profiles were not different between dogs with and without PE. Using 250 ng/mL as a cut-off D-dimer concentration, the sensitivity and specificity were 80 and 30%, respectively, for the diagnosis of PE. The NPV and PPV were 60 and 53.0%, respectively. D-dimer concentration <103 ng/mL had 100% sensitivity for ruling out PE and no value was 100% specific.

D-dimer concentrations <250 ng/mL have a high sensitivity for the absence of PE, but PE still can occur in dogs with a normal D-dimer concentration. Increased D-dimer concentrations are not specific for PE.