Patent Ductus Arteriosus
What Is Patent Ductus Arteriosus?
The ductus arteriosus is a foetal vessel that connects the main pulmonary artery and descending aorta. During development, it shunts blood away from the collapsed foetal lungs. This vessel normally closes shortly after birth. Remaining open beyond a few days after birth is abnormal, at which point this vessel is termed Patent Ductus Arteriosus (PDA).
PDA allows left-to-right shunting of blood from the aorta to the pulmonary artery. The result is severe volume overload of the left heart, leading to progressive changes to the heart and eventually resulting in left-sided congestive heart failure.
Untreated patients may die from progressive heart failure within the first year of life. Pulmonary over circulation, leading to pulmonary hypertension may cause reversal of blood flow, which then excludes the patient from surgical treatment.
How Is PDA Diagnosed?
Clinical signs include a continuous heart murmur at the heart base, that will be identified by your primary care clinician. As the disease progresses your pet may start to develop signs consistent with left-sided heart failure (cough, exercise intolerance).
A diagnosis of PDA is definitively obtained with echocardiogram (ultrasound of the heart and major vessels). Echocardiogram assessment also helps to exclude any concurrent heart defects.
Animals with right-to-left patent ductus arteriosus have very different clinical presentations and diagnostic findings.
How is PDA treated?
While intravascular occlusion techniques are available (injecting of filler material into the blood vessel so that it blocks), surgery can be performed in most patients with PDA. Surgical treatment can be curative and has a low mortality rate. Standard surgical correction is accomplished by ligation of the vessel. Correction is not used in patients with right-to-left shunting.
When is surgery performed?
What is the prognosis?
Dogs that have a surgically correct PDA have an excellent long-term prognosis. This surgery can be curative if performed at an early age.
If left untreated, the majority of cases will progress to develop left-sided congestive heart failure. These cases will often die before a year of age.
If you have concerns for your pet in connection to this condition we recommend discussing it with your primary care vet in the first instance, or get in touch with our team for more info.
If you need urgent medical help, contact our 24 hour Pet Emergency team at Stafford, North Lakes, or Sunshine Coast on 1300 QLD VET (1300 753 838)