Radiographic Findings in Dogs With Patent Ductus Arteriosus: Left-to-Right, Right-to-Left, and Bidirectional Shunt

Area of Science:

• Veterinary Cardiology
• Diagnostic Imaging in Animals

Background:

• Patent ductus arteriosus (PDA) is a prevalent congenital heart defect in canine patients.
• PDA commonly manifests as a left-to-right (L-R) shunt, but right-to-left (R-L) and bidirectional (BID) shunts also occur.

Purpose of the Study:

• To characterize thoracic radiographic alterations in dogs diagnosed with L-R, R-L, or BID PDA.
• To correlate radiographic findings with echocardiographic diagnoses of PDA shunt type.

Main Methods:

• A multicenter retrospective study analyzed thoracic radiographs from 22 dogs with confirmed PDA.
• Qualitative assessments included left heart enlargement (LHE), right heart enlargement (RHE), main pulmonary artery dilation (MPAD), aortic dilation (AD), and lung patterns.
• Quantitative assessments utilized vertebral heart score (VHS) and vertebral left atrial size (VLAS).

Main Results:

• L-R and BID shunts showed significantly higher LHE prevalence and lower MPAD compared to R-L shunts.
• All L-R PDA cases exhibited RHE on radiography, despite echocardiography revealing LHE.
• R-L shunts were associated with a higher incidence of normal lung appearance and only RHE on radiographic evaluation.
• L-R PDA cases had significantly higher VHS and VLAS compared to R-L PDA cases.

Conclusions:

• Thoracic radiography effectively differentiates radiographic changes associated with different PDA shunt types in dogs.
• Radiographic findings correlate with echocardiographic assessments, aiding in the diagnosis and characterization of PDA.