Patent ductus arteriosus is one of the most common congenital defects in dog. The ductus arteriosus is a vessel that is normally present in the fetus to allow blood to bypass the fetal lungs (as they receive oxygen from the mother’s placenta). At birth when the lungs expand and fill with air, the ductus normally closes. If this vessel does not close, there is an abnormal communication between the two great vessels of the heart, the pulmonary artery and aorta. This results in a larger volume of blood reentering the left heart. This increased volume of blood causes the heart to dilate and ultimately can result in congestive heart failure. Signs of congestive heart failure include: coughing, shortness of breath, rapid breathing rate, breathing effort, weakness, collapse, fainting, decreased appetite, restlessness, and weight loss. A Procedure is recommended to close or occlude this vessel and prevent further overloading of the heart. This can be done minimally invasively through a vessel in the leg, the femoral artery. This is done using special catheters to place an ACDO device, canine ductal occluder. This is a device specially made for this specific defect in the dog and has a high success rate. It works by obstructing the ductus and preventing further blood flow across the abnormal communication. This can also be done surgically where the surgeon enters the chest and ties off the vessel. If the vessel is large and is not closed, dogs are at a high risk of congestive heart failure in their first years of life. Both procedures are relatively safe but not without risk. Once the vessel is occluded, your pet can have a good quality of life and a normal life span.