Patent Ductus Arteriosus (PDA)

Patent ductus arteriosus (PDA) is the most common congenital heart defect seen in dogs. Breeds commonly affected include Poodles, Keeshonds, Cocker spaniels, German Shepherds, Pekinese, Collies, Shelties, Pomeranians and Welsh corgis. Females are at an increased risk and a genetic basis is proven in poodles and suspected in other breeds.

During fetal development the ductus arteriosus is a normal anatomical structure that allows fetal blood to bypass the lungs since they are not needed for oxygenation prior to birth. Normally this vessel, which connects the pulmonary artery and the aorta, closes nearly immediately after birth once air expands the lungs. When the vessel remains open or patent, blood is shunted from the high pressure aorta to the lower pressure of the pulmonary artery which results in overcirculation of the lungs. The shunting of blood causes an overload of the left side of the heart, which leads to dilation and enlargement of the left heart wall. Untreated a PDA will usually lead to progressive left sided congestive heart failure and pulmonary edema within the first year of life.

A PDA will produce a characteristic continuous heart murmur, which is often noted during physical exam for initial vaccinations. Bounding pulses are also characteristic of a PDA. Additional diagnostics used to confirm the presence of a PDA are thoracic radiographs and an echocardiogram or ultrasound of the heart.

Surgical correction of a PDA is accomplished by ligation of the ductus to close the shunt. A left side thoracotomy is performed at the 4th rib space to isolate the vessel and pass sutures around the PDA. Once the vessel is ligated the murmur is eliminated and the physiologic abnormalities associated with the shunt are reversed. A temporary chest tube is used to evacuate air from the thorax and re-establish negative pressure for the lungs to expand normally.

After surgery the animals are treated for pain and the chest tube is usually removed within 24 hours. Most dogs are discharged 1-2 days after surgery to recover at home. Prognosis is generally very good especially if corrected before major secondary changes in the heart have occurred




				Patent ductus arteriosus (PDA) is the most common congenital heart defect seen in dogs. Breeds commonly affected include Poodles, Keeshonds, Cocker spaniels, German Shepherds, Pekinese, Collies, Shelties, Pomeranians and Welsh corgis. Females are at an increased risk and a genetic basis is proven in poodles and suspected in other breeds. During fetal development the ductus arteriosus is a normal anatomical structure that allows fetal blood to bypass the lungs since they are not needed for oxygenation prior to birth. Normally this vessel, which connects the pulmonary artery and the aorta, closes nearly immediately after birth once air expands the lungs. When the vessel remains open or patent, blood is shunted from the high pressure aorta to the lower pressure of the pulmonary artery which results in overcirculation of the lungs. The shunting of blood causes an overload of the left side of the heart, which leads to dilation and enlargement of the left heart wall. Untreated a PDA will usually lead to progressive left sided congestive heart failure and pulmonary edema within the first year of life. A PDA will produce a characteristic continuous heart murmur, which is often noted during physical exam for initial vaccinations. Bounding pulses are also characteristic of a PDA. Additional diagnostics used to confirm the presence of a PDA are thoracic radiographs and an echocardiogram or ultrasound of the heart. Surgical correction of a PDA is accomplished by ligation of the ductus to close the shunt. A left side thoracotomy is performed at the 4th rib space to isolate the vessel and pass sutures around the PDA. Once the vessel is ligated the murmur is eliminated and the physiologic abnormalities associated with the shunt are reversed. A temporary chest tube is used to evacuate air from the thorax and re-establish negative pressure for the lungs to expand normally. After surgery the animals are treated for pain and the chest tube is usually removed within 24 hours. Most dogs are discharged 1-2 days after surgery to recover at home. Prognosis is generally very good especially if corrected before major secondary changes in the heart have occurred
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