Patent Ductus Arteriosus (PDA) in Cats

Overview of Patent Ductus Arteriosus in Cats

The ductus arteriosus is a blood vessel that connects the two main arteries of the body – the aorta and the pulmonary artery. This blood vessel is normal in the fetus, but shortly after birth, it should close. When the ductus arteriosus remains open or patent after birth, this abnormal communication between the aorta and pulmonary artery passes extra volumes of blood into the lungs.

Below is an overview of Patent Ductus Arteriosus in Cats followed by in-depth information on this heart defect.

Patent ductus arteriosis (PDA) is a birth defect representing the second most common congenital heart defect of cats. Approximately seven out of 1000 live birth kittens are affected.

Generally, there are no serious symptoms of PDA unless congestive heart failure has caused fluid buildup in the lungs. The condition is typically identified in kittens during a routine veterinary visit for vaccinations. Continual blood flow through the PDA into the lungs produces a continuous (machinery) heart murmur.

Even when the veterinarian identifies a PDA, most people believe their cat is normal. In some cases, the cat can be smaller than littermates or play less vigorously. However, the situation can be very misleading as symptoms usually occur within a year of diagnosis. If untreated, about 60 percent of affected cats die within a year of diagnosis.

When caught early, and following treatment with successful closure of the PDA, most cats live a normal life. Unless there are complications from other heart defects or heart failure has already developed, there is rarely any future need for medication. While special circumstances can influence the prognosis, most cases are straightforward.

Patent ductus arteriosus is genetically determined in almost every case, and this fact impacts the value of purebred cats used for breeding.

What to Watch For

These are common symptoms, but not specific for PDA.

Diagnosis of Patent Ductus Arteriosus in Cats

Veterinary care should include diagnostic tests and subsequent treatment recommendations. Diagnostic tests are needed to recognize PDA, and exclude other diseases. Tests may include:

Treatment of Patent Ductus Arteriosus in Cats

Home Care and Prevention

Before any surgery, provide only the exercise your pet can tolerate. Do not allow your pet to become short of breath with activity.

Follow-up with your veterinarian after surgery or surgical closure. In most cases, only a suture removal is needed and further follow-up is unnecessary.

Kittens should be vaccinated against infectious diseases and dewormed.

Never breed cats with PDA, even if the defect has been corrected.

In-depth Information on Patent Ductus Arteriosus in Cats

Patent ductus arteriosus (PDA) is a common birth defect. The pressure in the aorta is higher than the pressure in the pulmonary artery, therefore, blood crosses the ductus from left (aorta) to right (pulmonary artery). Very infrequently, the increased blood flowing into the lungs injures the pulmonary blood vessels. This can reverse the path of blood flow from right to left. In this case, unoxygenated blood flows into the aorta to the rear limbs, causing weakness and complications such as an elevated red blood cell count (polycythemia), which makes the blood thick. Symptoms are usually precipitated by exercise and include weakness and even seizures.

There are a number of reasons for heart murmurs in kittens. These conditions require different management and include:

Veterinary care should include diagnostic tests and subsequent treatment recommendations.

Diagnosis In-depth

Diagnostic tests are needed to recognize PDA and exclude other diseases. A definitive diagnosis may require additional tests including chest X-rays, electrocardiogram and ultrasound examination of the heart (echocardiography or cardiac echo). It is important to exclude other congenital heart defects. Tests may include:

Treatment In-depth

Treatments for PDA may include one or more of the following:

Follow-up Care for Cats with Patent Ductus Arteriosus

Optimal treatment for your pet requires a combination of home and professional veterinary care. Follow-up can be critical. Administer prescribed medications as directed and be certain to contact your veterinarian if you are experiencing problems treating your pet.

Following successful PDA closure, the initial follow-up is about 10 to 14 days later. In uncomplicated cases, no further follow up is required.

Referral to a veterinary cardiologist can be helpful in hard to diagnose cases or when there are questions about alternative treatment options.

If heart failure has occurred, follow-up care is critical.