A patent ductus arteriosus (PDA) is the result of a fetal vessel that fails to close at birth.  This abnormal communication between the pulmonary artery and aorta permits re-circulation of blood creating extra work for the left side of the heart.  Varying degrees of blood are shunted for each individual patient, so severity can vary.  If this defect is left uncorrected, most dogs will progress to development of left-sided congestive heart failure at an early age. Some patients develop high pressures in the pulmonary blood vessels and reverse shunting (right to left) occurs.  Once right to left shunting develops, cure is no longer possible.

The diagnosis is made by a combination of auscultation, echocardiography with doppler interrogation, thoracic radiographs, and electrocardiography.  If an uncomplicated PDA is diagnosed, correction is recommended.  Usually a CBC and chemistry screen is run prior to the procedure.  There are several options for PDA correction at present.  Surgery involves ligation (or tying off) of the abnormal vessel.  In experienced hands, the surgical success rate is high.  Less invasive procedures can achieve correction with catheter delivered occluding devices or coils.  However, potential problems include tearing of the vessel during the procedure  with subsequent death, incomplete ligation or occlusion of the ductus necessitating a second procedure, or post-operative infection.  If the procedure goes well, a full recovery and normal life expectancy are the expected outcome.